Add backup-first duplicate repair

.gitignore

@@ -9,6 +9,7 @@ samples/small-library/generated/
 *.db
 *.csv
 *.html
+!serato_doctor/webui/*.html
 
 # Never commit personal Serato data
 database V2

README.md

@@ -0,0 +1,48 @@
+# Serato Doctor
+
+Serato Doctor is a read-only-first toolkit for inspecting and eventually repairing
+DJ libraries. Serato is the first supported engine.
+
+## Analyze a Library
+
+```shell
+serato-doctor analyze \
+  --serato ~/Music/_Serato_ \
+  --music ~/Music/Jukebox
+```
+
+Analysis prints a transparent reference-integrity score plus broken references,
+duplicate filenames, unused tracks, and suggested filename matches. It does not
+modify the library or create report files.
+
+If crates contain an older library root, supply it explicitly:
+
+```shell
+serato-doctor analyze --reference-root /Users/old-user/OneDrive/Jukebox
+```
+
+## Generate Detailed Reports
+
+Running without a command preserves the original scanner behavior and writes CSV
+and text reports:
+
+```shell
+serato-doctor --serato ~/Music/_Serato_ --music ~/Music/Jukebox
+```
+
+Use `--verbose` for progress on standard error or `--log-file PATH` for an
+aggregate diagnostic log.
+
+Serato Doctor never repairs files without an explicit future repair workflow,
+preview, backup, and rollback path.
+
+## Local Web Interface
+
+Launch the responsive, local-only dashboard with:
+
+```shell
+serato-doctor-web
+```
+
+Then open `http://127.0.0.1:8765`. The interface exposes the same read-only health
+analysis and never sends library paths or results to an external service.

ROADMAP.md

@@ -7,23 +7,24 @@
 - [x] Serato crate parser
 - [x] Missing reference CSV report
 - [x] Grouped missing reference report
-- [ ] HTML health dashboard
+- [x] HTML health dashboard
 - [x] Test suite
 - [x] Sample library fixtures
-- [ ] Database V2 read-only parser
+- [x] Database V2 read-only parser
 - [x] Configuration
 - [x] Logging
 - [x] Matching engine
 
 ## v0.2 — Diagnostics
 
-- [ ] Duplicate filename detection
+- [x] `serato-doctor analyze` command
+- [x] Duplicate filename detection
 - [ ] Duplicate audio hash detection
-- [ ] Broken symlink detection
+- [x] Broken symlink detection
 - [ ] Orphaned audio detection
 - [ ] OneDrive rename detection
-- [ ] Crate classification: static vs smart/dynamic
-- [ ] Library health score
+- [x] Crate classification: static vs smart/dynamic
+- [x] Library health score
 
 ## v0.3 — Safe Repair
 

docs/design/analyze-command.md

@@ -0,0 +1,27 @@
+# Analyze Command
+
+## Problem
+
+The health and matching engines are only Python APIs. Users need one safe command
+that summarizes library integrity without first interpreting CSV files.
+
+## Architecture
+
+`serato-doctor analyze` reuses the existing configured crate parser and filesystem
+scanner, then prints the immutable health report. The original no-command mode is
+retained as the report-producing scan workflow.
+
+Analyze mode does not create CSV or text reports. Both modes remain read-only with
+respect to Serato crates, databases, and music files.
+
+## Edge Cases
+
+- A library with no references displays `Not assessed` rather than a false score.
+- Historical roots continue to work through repeatable `--reference-root` flags.
+- Normal output remains separate from optional diagnostic logging.
+- Existing scripts that invoke the CLI without a subcommand remain compatible.
+
+## Verification
+
+Tests prove the legacy five-line output and reports remain unchanged, while analyze
+prints health metrics and does not create output files.

docs/design/broken-symlinks.md

@@ -0,0 +1,27 @@
+# Broken Symlink Detection
+
+## Problem
+
+Library migrations may leave symbolic links pointing to files or folders that no
+longer exist. The filesystem scanner previously skipped those links silently.
+
+## Architecture
+
+One read-only filesystem traversal now returns audio tracks and broken symbolic
+links. Each finding preserves the link path and its raw target when the operating
+system can read it. The library and health report retain only immutable findings.
+
+Broken links are reported separately and do not affect the reference-integrity
+score. The detector does not follow, recreate, remove, or rewrite any link.
+
+## Edge Cases
+
+- Relative and absolute link targets.
+- Links to missing files and missing directories.
+- Link targets that cannot be read due to an operating-system error.
+- Valid symlinks, which remain eligible for ordinary audio scanning.
+
+## Verification
+
+Tests create synthetic valid and broken links in temporary directories, verify the
+raw target, and confirm health integration. Existing scanner behavior is preserved.

docs/design/crate-classification.md

@@ -0,0 +1,38 @@
+# Crate Classification
+
+## Problem
+
+Static crates are manually maintained track lists. Smart crates are dynamic views
+generated from rules, so stale-looking entries in them should not be presented as
+broken manual references or given the same health-score weight.
+
+## Architecture
+
+Crates carry a `static`, `smart`, or `unknown` kind. Folder provenance is the
+primary signal: Serato stores regular `.crate` files in `Subcrates` and smart
+`.scrate` definitions in `SmartCrates`. `Compatible by key.crate` is also treated as smart
+when encountered in `Subcrates`, based on the original migration case study.
+
+Smart crate names use `≫≫` to encode hierarchy. The model preserves those segments,
+so `Compatible by key≫≫10A.scrate` has a parent of `Compatible by key` and a display
+name of `10A`. Smart definitions and dynamic `.crate` containers are counted
+separately.
+
+The library loader reads both folders. Health analysis reports all references but
+scores only non-smart references. Unknown crates remain scoreable so incomplete
+classification cannot silently hide potential problems.
+
+Serato documents the folder distinction in [What is in the _Serato_ folder?](https://support.serato.com/hc/en-us/articles/204022904-What-is-in-the-Serato-folder)
+and explains that smart crates are populated from rules in [Crates in Serato DJ](https://support.serato.com/hc/en-us/articles/227561407-Crates-in-Serato-DJ-Pro-Serato-DJ-Lite).
+
+## Edge Cases
+
+- The known `Compatible by key` dynamic crate in the `Subcrates` folder.
+- Crate fixtures outside a recognized Serato folder.
+- Libraries containing both static and smart references to the same track.
+- Dynamic references whose current materialized paths appear missing.
+
+## Verification
+
+Tests cover all three kinds, both Serato folders, the known dynamic fallback, the
+synthetic five-static/two-smart library, and exclusion from health scoring.

docs/design/database-v2-parser.md

@@ -0,0 +1,28 @@
+# Database V2 Read-only Parser
+
+## Problem
+
+Crates and files do not explain every orange track in Serato. The legacy
+`database V2` contains Serato's library-level track paths and metadata, so it must
+be inspected independently from crate references.
+
+## Architecture
+
+The parser reads the file as a big-endian tag-length-value stream. Top-level
+`otrk` records contain nested fields including `pfil` (path), `tsng` (title),
+`tart` (artist), `talb` (album), and `tgen` (genre). Text is UTF-16 big-endian.
+
+Analysis reports total database entries, entries whose filenames occur in the
+selected music scan, entries outside that scan, scanned tracks absent from the
+database, and duplicate database paths. “Outside scan” is deliberately not called
+missing because Serato databases can include samples and tracks from other roots.
+
+## Safety
+
+The parser calls only `read_bytes`; it never opens the database for writing. No
+metadata values or personal paths are sent to logs or the dashboard.
+
+## Verification
+
+Synthetic TLV fixtures cover version, paths, metadata, incomplete records, and
+health integration. The sample library includes a generated ten-entry database.

docs/design/diagnostic-drilldowns.md

@@ -0,0 +1,35 @@
+# Diagnostic Drill-Downs
+
+## Problem
+
+Aggregate health numbers are useful, but DJs need to understand what is behind
+each number before they can trust it. A count like "60 missing tracks" should be
+clickable enough to answer: which tracks, which saved paths, and why did Serato
+Doctor count them?
+
+## Architecture
+
+The health engine remains responsible for aggregate scoring. The web layer adds
+a separate `details` payload beside the existing health report so the UI can show
+examples without changing the core score model.
+
+The drill-down payload is intentionally capped. Serato Doctor should explain the
+finding quickly in the local browser, not dump an entire user library into the
+page.
+
+## Edge Cases
+
+- Smart/dynamic crate references stay excluded from old-reference scoring.
+- The same missing filename can appear more than once in Serato's database.
+- Duplicate filename and cloud-conflict groups are informational only.
+- Suggested matches remain read-only evidence and must never trigger repair.
+- Empty drill-downs should feel reassuring, not broken.
+
+## Testing
+
+- Web analysis should include detail sections for old crate references,
+  suggested matches, unused tracks, duplicates, cloud conflicts, broken
+  symlinks, and missing Serato database tracks.
+- Static assets should expose clickable diagnostic hooks.
+- Browser behavior should be verified manually when the local browser policy
+  allows access to the development server.

docs/design/duplicate-filenames.md

@@ -0,0 +1,32 @@
+# Duplicate Filename Detection
+
+## Problem
+
+Two files with the same filename may be ordinary copies, while names such as
+`Track.mp3` and `Track 2.mp3` may indicate a OneDrive conflict. These cases need
+review, but neither is sufficient evidence for deletion.
+
+## Architecture
+
+The duplicate detector emits immutable groups of two kinds:
+
+- `exact_name` groups filenames after case and Unicode normalization.
+- `cloud_conflict` groups names after additionally removing a trailing numeric
+  suffix from the stem.
+
+Groups contain every path, a stable comparison key, a display name, and the number
+of files beyond the first. Health analysis reports exact and suspected-conflict
+counts separately. Neither category changes the health score.
+
+## Edge Cases
+
+- Same filename in different folders.
+- Case-only and Unicode representation differences.
+- Multiple conflict suffixes such as `Track 2.mp3` and `Track 3.mp3`.
+- Legitimate numbered titles, which remain explicitly labeled as suspected.
+- A single file, which is never reported as a duplicate.
+
+## Verification
+
+Tests cover exact, normalized, conflict-family, unrelated, and deterministic-order
+behavior, plus integration with health analysis. Detection is read-only.

docs/design/duplicate-repair.md

@@ -0,0 +1,39 @@
+# Duplicate repair
+
+## Problem
+
+Duplicate and cloud-conflict files waste space, but deleting either path can
+unmap tracks in crates or Serato's database. DJs need to choose the authoritative
+copy and understand every change before it happens.
+
+## Design
+
+The web interface requires an analysis, an explicit keeper selection, and a
+dry-run preview. Applying the plan first creates a timestamped backup beneath
+`_Serato_/.serato-doctor-backups/`. The snapshot contains every replaced audio
+file, loaded crate/smart-crate metadata, database V2, and a JSON restore manifest.
+
+The non-kept audio path is then replaced with a symbolic link to the keeper.
+This removes the extra audio payload while preserving every existing saved path.
+Crate files and database V2 are never rewritten. The UI exposes immediate
+restore using the manifest.
+
+Users may retain all backups or set a positive rotation limit. Rotation occurs
+only after a repair succeeds.
+
+## Edge cases
+
+- The duplicate group is rescanned and validated immediately before preview and
+  apply.
+- Existing symlinks cannot be selected as disposable duplicate files.
+- A partial failure restores already-changed files before reporting the error.
+- Restore refuses to overwrite a real file.
+- Healthy symlink aliases are excluded from future duplicate counts.
+
+## Tests
+
+- Backup creation includes audio and Serato metadata.
+- The old path resolves to the selected keeper after repair.
+- Restore returns the original file contents.
+- Invalid keeper choices are rejected.
+- Limited and unlimited retention behave deterministically.

docs/design/health-engine.md

@@ -0,0 +1,32 @@
+# Library Health Engine
+
+## Problem
+
+Raw missing-reference counts do not provide a compact view of library integrity,
+but an opaque blended score would imply confidence the current data cannot support.
+
+## Architecture
+
+The health engine produces an immutable report from the core `Library`. Its score
+is only the percentage of non-dynamic crate references resolved by exact filename.
+Smart-crate references are counted but excluded because their contents are derived
+from rules. The report also exposes missing references, unique missing filenames,
+duplicate filename groups, extra duplicate files, unused tracks, and missing
+references with matching candidates.
+
+Duplicate, unused, and candidate counts are informational. They do not affect the
+score until the project has a documented and validated weighting policy. An empty
+library has no score rather than a misleading 0% or 100%.
+
+## Edge Cases
+
+- The same missing filename referenced by several crates.
+- Several disk files sharing a filename.
+- Conflict-suffixed files that are unused but may be match candidates.
+- Libraries with no crate references.
+- Tracks referenced by filename from more than one crate.
+
+## Verification
+
+Tests assert every metric, the disclosed score basis, candidate integration, and
+empty-library behavior. Analysis remains entirely read-only.

docs/design/plain-language-diagnostics.md

@@ -0,0 +1,25 @@
+# Plain-language Diagnostics
+
+## Problem
+
+“Broken references” combined crate occurrences with Serato's own missing-track
+concept. DJs naturally compared that number with orange/unmapped tracks in Serato,
+even though the two counts describe different layers.
+
+## Language
+
+- **Missing tracks in Serato** means database entries whose saved file location no
+  longer exists. This corresponds most closely to orange or unmapped tracks.
+- **Old crate references** means saved appearances in regular crates whose exact
+  filename was not found in the selected music folder. One track can appear in
+  several crates, so both appearances and unique filenames are shown.
+
+Every health card and diagnostic row has an accessible information button. Hover
+shows its explanation on desktop; click or tap keeps it open; Escape or clicking
+elsewhere closes it. Explanations describe uncertainty and avoid implying repair.
+
+## Verification
+
+Health tests verify database missing-path and unique-filename counts. Browser tests
+cover the two separate metrics, hover/click explanations, keyboard dismissal, and
+mobile layout.

docs/design/smart-crate-discovery.md

@@ -0,0 +1,19 @@
+# Smart Crate Discovery Correction
+
+## Problem
+
+The first classifier searched `SmartCrates` for `*.crate`. Real Serato smart-crate
+definitions use `.scrate`, so a library with 26 definitions displayed only the
+single name-based `Compatible by key.crate` fallback.
+
+## Correction
+
+Library discovery now reads `.scrate` definitions case-insensitively from the
+`SmartCrates` folder. Dynamic `.crate` containers remain excluded from manual
+reference scoring but are reported separately. The `≫≫` filename separator is
+preserved as smart-crate hierarchy metadata.
+
+## Verification
+
+Synthetic tests cover `.scrate` discovery, case-correct folder names, hierarchy,
+definition/container counts, and the existing five-static/two-smart sample.

docs/design/web-interface.md

@@ -0,0 +1,37 @@
+# Local Web Interface
+
+![Approved Serato Doctor dashboard concept](web-dashboard-concept.png)
+
+The generated concept above is the approved visual direction. The implemented UI
+keeps its hierarchy, palette, safety emphasis, health ring, diagnostic cards, and
+responsive behavior. Product truth takes precedence over mockup copy: a 77.8%
+library is labeled for review rather than described as healthy.
+
+## Problem
+
+The command line is useful for automation but makes the growing diagnostic set
+harder to explore. A visual dashboard lets users test analysis safely and understand
+which findings affect health.
+
+## Architecture
+
+`serato-doctor-web` binds to `127.0.0.1:8765` by default and serves package-owned
+HTML, CSS, and JavaScript with Python's standard library. A same-origin JSON endpoint
+runs the existing read-only parser, scanner, matcher, duplicate detector, crate
+classifier, and health engine. No web framework or external service is required.
+
+The UI clearly labels read-only mode, separates scored health from informational
+diagnostics, and adapts from a full sidebar layout to compact mobile navigation.
+
+## Edge Cases
+
+- Missing or invalid Serato and music directories.
+- Empty libraries with no assessable health score.
+- Large or malformed requests, capped at 64 KiB.
+- HTML injection, avoided by rendering all results through `textContent`.
+- Network exposure, avoided by a loopback-only default binding.
+
+## Verification
+
+Tests exercise the web analysis adapter and static package assets. Browser checks
+cover real form submission, result rendering, error display, and responsive layout.

pyproject.toml

@@ -14,9 +14,13 @@ dev = ["pytest>=8,<9"]
 
 [project.scripts]
 serato-doctor = "serato_doctor.cli:main"
+serato-doctor-web = "serato_doctor.web:main"
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
 
 [tool.setuptools.packages.find]
 include = ["serato_doctor*"]
+
+[tool.setuptools.package-data]
+"serato_doctor.webui" = ["*.html", "*.css", "*.js"]

samples/small-library/generate.py

@@ -10,6 +10,10 @@ SAMPLE_ROOT = Path(__file__).parent
 SERATO_PATH_PREFIX = "Users/sample-user/OneDrive/Jukebox/"
 
 
+def database_record(tag: bytes, payload: bytes) -> bytes:
+    return tag + len(payload).to_bytes(4, "big") + payload
+
+
 def load_manifest() -> dict:
     return json.loads((SAMPLE_ROOT / "manifest.json").read_text(encoding="utf-8"))
 
@@ -18,8 +22,7 @@ def build_sample(output: Optional[Path] = None) -> Path:
     root = output or SAMPLE_ROOT / "generated"
     manifest = load_manifest()
     music_root = root / "Music"
-    crate_root = root / "Serato" / "_Serato_" / "Subcrates"
-    crate_root.mkdir(parents=True, exist_ok=True)
+    serato_root = root / "Serato" / "_Serato_"
 
     for relative_path in manifest["tracks"]:
         track_path = music_root / relative_path
@@ -29,11 +32,38 @@ def build_sample(output: Optional[Path] = None) -> Path:
         )
 
     for crate in manifest["crates"]:
+        is_smart = crate["type"] == "smart"
+        folder_name = "SmartCrates" if is_smart else "Subcrates"
+        crate_root = serato_root / folder_name
+        crate_root.mkdir(parents=True, exist_ok=True)
+        output_name = (
+            Path(crate["name"]).with_suffix(".scrate").name
+            if is_smart
+            else crate["name"]
+        )
+        for other_folder in ("Subcrates", "Smartcrates", "SmartCrates"):
+            for stale_name in (
+                crate["name"],
+                Path(crate["name"]).with_suffix(".scrate").name,
+            ):
+                stale_path = serato_root / other_folder / stale_name
+                if stale_path.exists() and stale_path != crate_root / output_name:
+                    stale_path.unlink()
         records = "".join(
             f"{SERATO_PATH_PREFIX}{relative_path}otrk"
             for relative_path in crate["references"]
         )
-        (crate_root / crate["name"]).write_bytes(records.encode("utf-16-le"))
+        (crate_root / output_name).write_bytes(records.encode("utf-16-le"))
+
+    database_records = [
+        database_record(b"vrsn", "2.0/Serato Doctor Fixture".encode("utf-16-be"))
+    ]
+    for relative_path in manifest["tracks"]:
+        fields = database_record(
+            b"pfil", str(music_root / relative_path).encode("utf-16-be")
+        )
+        database_records.append(database_record(b"otrk", fields))
+    (serato_root / "database V2").write_bytes(b"".join(database_records))
 
     return root
 

serato_doctor/cli.py

@@ -2,19 +2,34 @@ from pathlib import Path
 import argparse
 
 from serato_doctor.config import ScanConfig
-from serato_doctor.crate_parser import parse_crates
+from serato_doctor.crate_parser import load_library_crates
+from serato_doctor.database_parser import parse_database
+from serato_doctor.health import analyze_health
 from serato_doctor.logging import configure_logging
 from serato_doctor.models.library import Library
-from serato_doctor.scanner import scan_audio
+from serato_doctor.scanner import scan_filesystem
 from serato_doctor.report import write_csv, write_missing_report
 
 
 def main():
     parser = argparse.ArgumentParser(prog="serato-doctor")
+    parser.add_argument(
+        "command", nargs="?", choices=("scan", "analyze"), default="scan"
+    )
     parser.add_argument("--serato", default=str(Path.home() / "Music/_Serato_"))
-    parser.add_argument("--music", default=str(Path.home() / "Library/CloudStorage/OneDrive-Personal/Jukebox"))
-    parser.add_argument("--out", default=str(Path.home() / "Desktop/serato_doctor_scan.csv"))
-    parser.add_argument("--report", default=str(Path.home() / "Desktop/serato_doctor_missing_report.txt"))
+    parser.add_argument(
+        "--music",
+        default=str(
+            Path.home() / "Library/CloudStorage/OneDrive-Personal/Jukebox"
+        ),
+    )
+    parser.add_argument(
+        "--out", default=str(Path.home() / "Desktop/serato_doctor_scan.csv")
+    )
+    parser.add_argument(
+        "--report",
+        default=str(Path.home() / "Desktop/serato_doctor_missing_report.txt"),
+    )
     parser.add_argument(
         "--reference-root",
         action="append",
@@ -37,15 +52,19 @@ def main():
         log_file=Path(args.log_file) if args.log_file else None,
     )
     logger = configure_logging(config.verbose, config.log_file)
-    logger.info("Starting read-only library scan")
+    logger.info("Starting read-only library inspection")
     logger.debug("Serato directory: %s", config.serato)
     logger.debug("Music directory: %s", config.music)
 
-    library = Library.build(
-        references=parse_crates(
-            config.serato / "Subcrates", config.reference_roots
-        ),
-        tracks=scan_audio(config.music),
+    crates = load_library_crates(config.serato, config.reference_roots)
+    filesystem = scan_filesystem(config.music)
+    database_path = config.serato / "database V2"
+    database = parse_database(database_path) if database_path.is_file() else None
+    library = Library.from_crates(
+        crates=crates,
+        tracks=filesystem.tracks,
+        broken_symlinks=filesystem.broken_symlinks,
+        database=database,
     )
     results = library.reconcile_by_filename()
     missing_count = sum(1 for result in results if not result.exists_by_filename)
@@ -53,10 +72,51 @@ def main():
     logger.info("Scanned %d disk tracks", len(library.tracks))
     logger.info("Found %d references missing by filename", missing_count)
 
+    if args.command == "analyze":
+        health = analyze_health(library)
+        score = f"{health.score:.1f}%" if health.score is not None else "Not assessed"
+        logger.info("Calculated library health: %s", score)
+        print(f"Overall Health: {score}")
+        print(f"Score Basis: {health.score_basis}")
+        print(f"Tracks: {health.disk_tracks}")
+        print(f"Crate References: {health.total_references}")
+        print(f"References Scored: {health.scored_references}")
+        print(f"Healthy References: {health.healthy_references}")
+        print(f"Broken References: {health.missing_references}")
+        print(f"Unique Missing Filenames: {health.unique_missing_filenames}")
+        print(f"Duplicate Filename Groups: {health.duplicate_filename_groups}")
+        print(f"Duplicate Files: {health.duplicate_files}")
+        print(
+            "Suspected Cloud Conflict Groups: "
+            f"{health.suspected_cloud_conflict_groups}"
+        )
+        print(
+            "Suspected Cloud Conflict Files: "
+            f"{health.suspected_cloud_conflict_files}"
+        )
+        print(f"Unused Tracks: {health.unused_tracks}")
+        print(f"Suggested Matches: {health.suggested_matches}")
+        print(f"Broken Symlinks: {health.broken_symlinks}")
+        print(f"Static Crates: {health.static_crates}")
+        print(f"Smart Crates: {health.smart_crates}")
+        print(f"Smart Crate Containers: {health.smart_crate_containers}")
+        print(
+            f"Dynamic References Excluded: {health.dynamic_references_excluded}"
+        )
+        print(f"Database Entries: {health.database_entries}")
+        print(f"Database / Library Matches: {health.database_library_matches}")
+        print(f"Database Entries Outside Scan: {health.database_unmatched_entries}")
+        print(f"Missing Tracks in Serato: {health.database_missing_paths}")
+        print(
+            "Unique Missing Tracks in Serato: "
+            f"{health.database_missing_unique_filenames}"
+        )
+        print(f"Tracks Missing From Database: {health.tracks_missing_from_database}")
+        print(f"Duplicate Database Paths: {health.duplicate_database_paths}")
+    else:
         write_csv(results, config.out)
         write_missing_report(results, config.report)
         logger.info("Wrote CSV and missing-reference reports")
-
         print(f"Crate references: {len(library.references)}")
         print(f"Disk tracks: {len(library.tracks)}")
         print(f"Missing by filename: {missing_count}")

serato_doctor/crate_parser.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 from typing import Iterable, Tuple
 
-from serato_doctor.models.crate import Crate
+from serato_doctor.models.crate import Crate, CrateKind
 from serato_doctor.models.reference import TrackReference
 
 
@@ -32,6 +32,17 @@ def path_markers(reference_roots: Iterable[Path]) -> Tuple[str, ...]:
     return configured or DEFAULT_PATH_MARKERS
 
 
+def classify_crate(crate_path: Path) -> CrateKind:
+    parent_names = {parent.name.casefold() for parent in crate_path.parents}
+    if "smartcrates" in parent_names:
+        return CrateKind.SMART
+    if crate_path.name.casefold() == "compatible by key.crate":
+        return CrateKind.SMART
+    if "subcrates" in parent_names:
+        return CrateKind.STATIC
+    return CrateKind.UNKNOWN
+
+
 def load_crate(crate_path: Path, reference_roots: Iterable[Path] = ()) -> Crate:
     text = read_crate_text(crate_path)
     refs = []
@@ -63,7 +74,11 @@ def load_crate(crate_path: Path, reference_roots: Iterable[Path] = ()) -> Crate:
                 )
             )
 
-    return Crate(path=crate_path, references=tuple(refs))
+    return Crate(
+        path=crate_path,
+        references=tuple(refs),
+        kind=classify_crate(crate_path),
+    )
 
 
 def parse_crate(
@@ -82,3 +97,25 @@ def parse_crates(
     for crate in root.rglob("*.crate"):
         refs.extend(parse_crate(crate, reference_roots))
     return refs
+
+
+def load_library_crates(
+    serato_root: Path, reference_roots: Iterable[Path] = ()
+) -> Tuple[Crate, ...]:
+    reference_roots = tuple(reference_roots)
+    if not serato_root.is_dir():
+        return ()
+
+    crates = []
+    folder_patterns = {
+        "subcrates": ("*.crate",),
+        "smartcrates": ("*.scrate", "*.crate"),
+    }
+    for folder in serato_root.iterdir():
+        patterns = folder_patterns.get(folder.name.casefold())
+        if patterns is None or not folder.is_dir():
+            continue
+        for pattern in patterns:
+            for crate_path in folder.rglob(pattern):
+                crates.append(load_crate(crate_path, reference_roots))
+    return tuple(sorted(crates, key=lambda crate: str(crate.path)))

serato_doctor/database_parser.py

@@ -0,0 +1,67 @@
+from pathlib import Path
+from typing import Dict, Iterator, Optional, Tuple
+
+from serato_doctor.models.database import DatabaseTrack, SeratoDatabase
+
+
+TEXT_FIELDS = {
+    b"tsng": "title",
+    b"tart": "artist",
+    b"talb": "album",
+    b"tgen": "genre",
+}
+
+
+def iter_records(data: bytes) -> Iterator[Tuple[bytes, bytes]]:
+    """Yield complete big-endian tag-length-value records."""
+
+    offset = 0
+    while offset + 8 <= len(data):
+        tag = data[offset : offset + 4]
+        length = int.from_bytes(data[offset + 4 : offset + 8], "big")
+        payload_start = offset + 8
+        payload_end = payload_start + length
+        if payload_end > len(data):
+            break
+        yield tag, data[payload_start:payload_end]
+        offset = payload_end
+
+
+def decode_text(payload: bytes) -> Optional[str]:
+    value = payload.decode("utf-16-be", errors="ignore").strip("\x00").strip()
+    return value or None
+
+
+def normalize_database_path(value: str) -> Path:
+    if value.startswith(("Users/", "Volumes/")):
+        value = "/" + value
+    return Path(value)
+
+
+def parse_track(payload: bytes) -> Optional[DatabaseTrack]:
+    fields: Dict[str, Optional[str]] = {}
+    path = None
+    for tag, value in iter_records(payload):
+        if tag == b"pfil":
+            decoded_path = decode_text(value)
+            if decoded_path:
+                path = normalize_database_path(decoded_path)
+        elif tag in TEXT_FIELDS:
+            fields[TEXT_FIELDS[tag]] = decode_text(value)
+    if path is None:
+        return None
+    return DatabaseTrack(path=path, filename=path.name, **fields)
+
+
+def parse_database(database_path: Path) -> SeratoDatabase:
+    data = database_path.read_bytes()
+    version = None
+    tracks = []
+    for tag, payload in iter_records(data):
+        if tag == b"vrsn":
+            version = decode_text(payload)
+        elif tag == b"otrk":
+            track = parse_track(payload)
+            if track is not None:
+                tracks.append(track)
+    return SeratoDatabase(database_path, version, tuple(tracks))

serato_doctor/duplicates.py

@@ -0,0 +1,43 @@
+from collections import defaultdict
+from typing import DefaultDict, Iterable, List, Tuple
+
+from serato_doctor.matching import cloud_conflict_name, normalize
+from serato_doctor.models.duplicate import DuplicateGroup, DuplicateKind
+from serato_doctor.models.track import DiskTrack
+
+
+def find_duplicate_groups(
+    tracks: Iterable[DiskTrack],
+) -> Tuple[DuplicateGroup, ...]:
+    """Find exact-name duplicates and suspected numeric conflict copies."""
+
+    # Healthy symlinks preserve legacy Serato paths without consuming another
+    # copy of the audio, so they are aliases rather than duplicate files.
+    track_tuple = tuple(track for track in tracks if not track.path.is_symlink())
+    by_name: DefaultDict[str, List[DiskTrack]] = defaultdict(list)
+    by_conflict_name: DefaultDict[str, List[DiskTrack]] = defaultdict(list)
+
+    for track in track_tuple:
+        by_name[normalize(track.filename)].append(track)
+        by_conflict_name[cloud_conflict_name(track.filename)].append(track)
+
+    groups = []
+    for key, matches in by_name.items():
+        if len(matches) > 1:
+            groups.append(_group(DuplicateKind.EXACT_NAME, key, matches))
+
+    for key, matches in by_conflict_name.items():
+        distinct_names = {normalize(track.filename) for track in matches}
+        if len(distinct_names) > 1:
+            groups.append(_group(DuplicateKind.CLOUD_CONFLICT, key, matches))
+
+    return tuple(
+        sorted(groups, key=lambda group: (group.kind.value, group.comparison_key))
+    )
+
+
+def _group(
+    kind: DuplicateKind, key: str, tracks: Iterable[DiskTrack]
+) -> DuplicateGroup:
+    ordered = tuple(sorted(tracks, key=lambda track: str(track.path)))
+    return DuplicateGroup(kind, key, ordered)

serato_doctor/health.py

@@ -0,0 +1,115 @@
+from collections import Counter
+
+from serato_doctor.duplicates import find_duplicate_groups
+from serato_doctor.matching import MatchingEngine, normalize
+from serato_doctor.models.crate import CrateKind
+from serato_doctor.models.duplicate import DuplicateKind
+from serato_doctor.models.health import HealthReport
+from serato_doctor.models.library import Library
+
+
+def analyze_health(library: Library) -> HealthReport:
+    """Calculate defensible health metrics without changing the library."""
+
+    dynamic_sources = {
+        crate.path for crate in library.crates if crate.kind is CrateKind.SMART
+    }
+    results = tuple(
+        result
+        for result in library.reconcile_by_filename()
+        if result.reference.source not in dynamic_sources
+    )
+    missing = [result for result in results if not result.exists_by_filename]
+    healthy_count = len(results) - len(missing)
+    score = (
+        round(healthy_count / len(results) * 100, 1) if results else None
+    )
+
+    duplicate_groups = find_duplicate_groups(library.tracks)
+    exact_duplicates = [
+        group
+        for group in duplicate_groups
+        if group.kind is DuplicateKind.EXACT_NAME
+    ]
+    cloud_conflicts = [
+        group
+        for group in duplicate_groups
+        if group.kind is DuplicateKind.CLOUD_CONFLICT
+    ]
+    referenced_names = {reference.filename for reference in library.references}
+    unused_count = sum(
+        1 for track in library.tracks if track.filename not in referenced_names
+    )
+
+    matcher = MatchingEngine(library.tracks)
+    suggested_count = sum(
+        bool(matcher.candidates_for(result.reference)) for result in missing
+    )
+
+    database_tracks = library.database.tracks if library.database else ()
+    database_names = {normalize(track.filename) for track in database_tracks}
+    library_names = {normalize(track.filename) for track in library.tracks}
+    database_path_counts = Counter(
+        normalize(str(track.path)) for track in database_tracks
+    )
+    missing_database_tracks = [
+        track for track in database_tracks if not track.path.exists()
+    ]
+
+    return HealthReport(
+        score=score,
+        total_references=len(library.references),
+        scored_references=len(results),
+        healthy_references=healthy_count,
+        missing_references=len(missing),
+        unique_missing_filenames=len(
+            {result.reference.filename for result in missing}
+        ),
+        disk_tracks=len(library.tracks),
+        duplicate_filename_groups=len(exact_duplicates),
+        duplicate_files=sum(group.extra_files for group in exact_duplicates),
+        suspected_cloud_conflict_groups=len(cloud_conflicts),
+        suspected_cloud_conflict_files=sum(
+            group.extra_files for group in cloud_conflicts
+        ),
+        unused_tracks=unused_count,
+        suggested_matches=suggested_count,
+        broken_symlinks=len(library.broken_symlinks),
+        static_crates=sum(
+            crate.kind is CrateKind.STATIC for crate in library.crates
+        ),
+        smart_crates=sum(
+            crate.kind is CrateKind.SMART and crate.is_smart_definition
+            for crate in library.crates
+        ),
+        smart_crate_containers=sum(
+            crate.kind is CrateKind.SMART and not crate.is_smart_definition
+            for crate in library.crates
+        ),
+        unknown_crates=sum(
+            crate.kind is CrateKind.UNKNOWN for crate in library.crates
+        ),
+        dynamic_references_excluded=sum(
+            len(crate.references)
+            for crate in library.crates
+            if crate.kind is CrateKind.SMART
+        ),
+        database_present=library.database is not None,
+        database_entries=len(database_tracks),
+        database_library_matches=sum(
+            normalize(track.filename) in library_names for track in database_tracks
+        ),
+        database_unmatched_entries=sum(
+            normalize(track.filename) not in library_names for track in database_tracks
+        ),
+        database_missing_paths=len(missing_database_tracks),
+        database_missing_unique_filenames=len(
+            {normalize(track.filename) for track in missing_database_tracks}
+        ),
+        tracks_missing_from_database=sum(
+            normalize(track.filename) not in database_names for track in library.tracks
+        ) if library.database else 0,
+        duplicate_database_paths=sum(
+            count - 1 for count in database_path_counts.values() if count > 1
+        ),
+    )

serato_doctor/models/__init__.py

@@ -1,4 +1,8 @@
-from serato_doctor.models.crate import Crate
+from serato_doctor.models.crate import Crate, CrateKind
+from serato_doctor.models.database import DatabaseTrack, SeratoDatabase
+from serato_doctor.models.duplicate import DuplicateGroup, DuplicateKind
+from serato_doctor.models.filesystem import BrokenSymlink, FilesystemScan
+from serato_doctor.models.health import HealthReport
 from serato_doctor.models.library import Library
 from serato_doctor.models.match import MatchEvidence, TrackMatch
 from serato_doctor.models.reference import ReferenceResult, TrackReference
@@ -6,10 +10,18 @@ from serato_doctor.models.track import DiskTrack
 
 __all__ = [
     "Crate",
+    "CrateKind",
+    "DatabaseTrack",
     "DiskTrack",
+    "DuplicateGroup",
+    "DuplicateKind",
+    "BrokenSymlink",
+    "FilesystemScan",
+    "HealthReport",
     "Library",
     "MatchEvidence",
     "ReferenceResult",
+    "SeratoDatabase",
     "TrackMatch",
     "TrackReference",
 ]

serato_doctor/models/crate.py

@@ -1,13 +1,33 @@
 from dataclasses import dataclass
+from enum import Enum
 from pathlib import Path
 from typing import Tuple
 
 from serato_doctor.models.reference import TrackReference
 
 
+class CrateKind(str, Enum):
+    STATIC = "static"
+    SMART = "smart"
+    UNKNOWN = "unknown"
+
+
 @dataclass(frozen=True)
 class Crate:
     """A Serato crate and the track references parsed from it."""
 
     path: Path
     references: Tuple[TrackReference, ...]
+    kind: CrateKind = CrateKind.UNKNOWN
+
+    @property
+    def hierarchy(self) -> Tuple[str, ...]:
+        return tuple(self.path.stem.split("≫≫"))
+
+    @property
+    def display_name(self) -> str:
+        return self.hierarchy[-1]
+
+    @property
+    def is_smart_definition(self) -> bool:
+        return self.path.suffix.casefold() == ".scrate"

serato_doctor/models/database.py

@@ -0,0 +1,22 @@
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Optional, Tuple
+
+
+@dataclass(frozen=True)
+class DatabaseTrack:
+    """Read-only metadata extracted from one database V2 track record."""
+
+    path: Path
+    filename: str
+    title: Optional[str] = None
+    artist: Optional[str] = None
+    album: Optional[str] = None
+    genre: Optional[str] = None
+
+
+@dataclass(frozen=True)
+class SeratoDatabase:
+    path: Path
+    version: Optional[str]
+    tracks: Tuple[DatabaseTrack, ...]

serato_doctor/models/duplicate.py

@@ -0,0 +1,30 @@
+from dataclasses import dataclass
+from enum import Enum
+from typing import Tuple
+
+from serato_doctor.models.track import DiskTrack
+
+
+class DuplicateKind(str, Enum):
+    EXACT_NAME = "exact_name"
+    CLOUD_CONFLICT = "cloud_conflict"
+
+
+@dataclass(frozen=True)
+class DuplicateGroup:
+    """A deterministic group of files that warrants duplicate review."""
+
+    kind: DuplicateKind
+    comparison_key: str
+    tracks: Tuple[DiskTrack, ...]
+
+    @property
+    def extra_files(self) -> int:
+        return max(0, len(self.tracks) - 1)
+
+    @property
+    def display_name(self) -> str:
+        return min(
+            (track.filename for track in self.tracks),
+            key=lambda name: (len(name), name.casefold()),
+        )

serato_doctor/models/filesystem.py

@@ -0,0 +1,21 @@
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Optional, Tuple
+
+from serato_doctor.models.track import DiskTrack
+
+
+@dataclass(frozen=True)
+class BrokenSymlink:
+    """A symbolic link whose target cannot be resolved."""
+
+    path: Path
+    target: Optional[Path]
+
+
+@dataclass(frozen=True)
+class FilesystemScan:
+    """Read-only findings from one traversal of a music folder."""
+
+    tracks: Tuple[DiskTrack, ...]
+    broken_symlinks: Tuple[BrokenSymlink, ...]

serato_doctor/models/health.py

@@ -0,0 +1,39 @@
+from dataclasses import dataclass
+from typing import Optional
+
+
+@dataclass(frozen=True)
+class HealthReport:
+    """Transparent aggregate findings from a read-only library analysis."""
+
+    score: Optional[float]
+    total_references: int
+    scored_references: int
+    healthy_references: int
+    missing_references: int
+    unique_missing_filenames: int
+    disk_tracks: int
+    duplicate_filename_groups: int
+    duplicate_files: int
+    suspected_cloud_conflict_groups: int
+    suspected_cloud_conflict_files: int
+    unused_tracks: int
+    suggested_matches: int
+    broken_symlinks: int
+    static_crates: int
+    smart_crates: int
+    smart_crate_containers: int
+    unknown_crates: int
+    dynamic_references_excluded: int
+    database_present: bool
+    database_entries: int
+    database_library_matches: int
+    database_unmatched_entries: int
+    database_missing_paths: int
+    database_missing_unique_filenames: int
+    tracks_missing_from_database: int
+    duplicate_database_paths: int
+
+    @property
+    def score_basis(self) -> str:
+        return "Resolved non-dynamic references / non-dynamic references scored"

serato_doctor/models/library.py

@@ -1,6 +1,9 @@
 from dataclasses import dataclass
-from typing import Iterable, Tuple
+from typing import Iterable, Optional, Tuple
 
+from serato_doctor.models.crate import Crate
+from serato_doctor.models.database import SeratoDatabase
+from serato_doctor.models.filesystem import BrokenSymlink
 from serato_doctor.models.reference import ReferenceResult, TrackReference
 from serato_doctor.models.track import DiskTrack
 
@@ -11,14 +14,46 @@ class Library:
 
     references: Tuple[TrackReference, ...]
     tracks: Tuple[DiskTrack, ...]
+    crates: Tuple[Crate, ...] = ()
+    broken_symlinks: Tuple[BrokenSymlink, ...] = ()
+    database: Optional[SeratoDatabase] = None
 
     @classmethod
     def build(
         cls,
         references: Iterable[TrackReference],
         tracks: Iterable[DiskTrack],
+        broken_symlinks: Iterable[BrokenSymlink] = (),
+        database: Optional[SeratoDatabase] = None,
     ) -> "Library":
-        return cls(tuple(references), tuple(tracks))
+        return cls(
+            tuple(references),
+            tuple(tracks),
+            broken_symlinks=tuple(broken_symlinks),
+            database=database,
+        )
+
+    @classmethod
+    def from_crates(
+        cls,
+        crates: Iterable[Crate],
+        tracks: Iterable[DiskTrack],
+        broken_symlinks: Iterable[BrokenSymlink] = (),
+        database: Optional[SeratoDatabase] = None,
+    ) -> "Library":
+        crate_tuple = tuple(crates)
+        references = tuple(
+            reference
+            for crate in crate_tuple
+            for reference in crate.references
+        )
+        return cls(
+            references,
+            tuple(tracks),
+            crate_tuple,
+            tuple(broken_symlinks),
+            database,
+        )
 
     def reconcile_by_filename(self) -> Tuple[ReferenceResult, ...]:
         disk_names = {track.filename for track in self.tracks}

serato_doctor/repair.py

@@ -0,0 +1,160 @@
+"""Backup-first duplicate consolidation.
+
+Serato's binary metadata is deliberately not rewritten.  Removed duplicate files
+are replaced with symbolic links, so every existing path continues to resolve.
+"""
+
+import json
+import shutil
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Iterable, Optional, Tuple
+from uuid import uuid4
+
+
+BACKUP_FOLDER = ".serato-doctor-backups"
+
+
+@dataclass(frozen=True)
+class DuplicateRepairPlan:
+    keeper: Path
+    replaced: Tuple[Path, ...]
+    metadata_files: Tuple[Path, ...]
+
+    @property
+    def changes(self) -> int:
+        return len(self.replaced)
+
+
+@dataclass(frozen=True)
+class RepairReceipt:
+    backup: Path
+    keeper: Path
+    replaced: Tuple[Path, ...]
+
+
+def plan_duplicate_repair(
+    keeper: Path, duplicates: Iterable[Path], serato_root: Path
+) -> DuplicateRepairPlan:
+    keeper = keeper.expanduser().resolve()
+    candidates = tuple(path.expanduser().resolve() for path in duplicates)
+    if keeper not in candidates:
+        raise ValueError("The file to keep must belong to this duplicate group")
+    if not keeper.is_file():
+        raise ValueError(f"The file to keep no longer exists: {keeper}")
+    replaced = tuple(path for path in candidates if path != keeper)
+    if not replaced:
+        raise ValueError("Choose a duplicate group containing at least two files")
+    if any(not path.is_file() or path.is_symlink() for path in replaced):
+        raise ValueError("A duplicate changed since the analysis; analyze again")
+    metadata = tuple(
+        sorted(
+            path
+            for path in serato_root.expanduser().resolve().rglob("*")
+            if path.is_file()
+            and BACKUP_FOLDER not in path.parts
+            and (
+                path.name == "database V2"
+                or path.suffix.casefold() in {".crate", ".scrate"}
+            )
+        )
+    )
+    return DuplicateRepairPlan(keeper, replaced, metadata)
+
+
+def apply_duplicate_repair(
+    plan: DuplicateRepairPlan,
+    serato_root: Path,
+    backup_limit: Optional[int] = 10,
+) -> RepairReceipt:
+    """Create a complete rollback snapshot, then replace extras with symlinks."""
+    if backup_limit is not None and backup_limit < 1:
+        raise ValueError("Backup limit must be at least 1, or unlimited")
+    backup_root = serato_root.expanduser().resolve() / BACKUP_FOLDER
+    backup = backup_root / _backup_name()
+    files_root = backup / "files"
+    metadata_root = backup / "serato-metadata"
+    backup.mkdir(parents=True)
+
+    entries = []
+    try:
+        for path in plan.replaced:
+            destination = files_root / _safe_backup_path(path)
+            destination.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(path, destination)
+            entries.append({"original": str(path), "backup": str(destination)})
+        for path in plan.metadata_files:
+            relative = path.relative_to(serato_root.expanduser().resolve())
+            destination = metadata_root / relative
+            destination.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(path, destination)
+        manifest = {
+            "created_at": datetime.now(timezone.utc).isoformat(),
+            "keeper": str(plan.keeper),
+            "replaced": entries,
+            "strategy": "symlink",
+        }
+        (backup / "manifest.json").write_text(
+            json.dumps(manifest, indent=2), encoding="utf-8"
+        )
+        for path in plan.replaced:
+            path.unlink()
+            path.symlink_to(plan.keeper)
+    except Exception:
+        _rollback_entries(entries)
+        shutil.rmtree(backup, ignore_errors=True)
+        raise
+
+    rotate_backups(backup_root, backup_limit)
+    return RepairReceipt(backup, plan.keeper, plan.replaced)
+
+
+def restore_backup(backup: Path) -> Tuple[Path, ...]:
+    manifest_path = backup.expanduser().resolve() / "manifest.json"
+    manifest = json.loads(manifest_path.read_text(encoding="utf-8"))
+    restored = []
+    for entry in manifest["replaced"]:
+        original = Path(entry["original"])
+        saved = Path(entry["backup"])
+        if original.exists() and not original.is_symlink():
+            raise ValueError(f"Restore would overwrite a real file: {original}")
+        if original.is_symlink():
+            original.unlink()
+        original.parent.mkdir(parents=True, exist_ok=True)
+        shutil.copy2(saved, original)
+        restored.append(original)
+    return tuple(restored)
+
+
+def rotate_backups(backup_root: Path, limit: Optional[int]) -> None:
+    if limit is None or not backup_root.is_dir():
+        return
+    backups = sorted(
+        (path for path in backup_root.iterdir() if (path / "manifest.json").is_file()),
+        key=lambda path: path.name,
+        reverse=True,
+    )
+    for expired in backups[limit:]:
+        shutil.rmtree(expired)
+
+
+def _backup_name() -> str:
+    stamp = datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+    return f"{stamp}-{uuid4().hex[:8]}"
+
+
+def _safe_backup_path(path: Path) -> Path:
+    anchorless = path.as_posix().lstrip("/").replace(":", "_")
+    return Path(anchorless)
+
+
+def _rollback_entries(entries: Iterable[dict]) -> None:
+    for entry in entries:
+        original = Path(entry["original"])
+        saved = Path(entry["backup"])
+        if original.is_symlink():
+            original.unlink()
+        if not original.exists() and saved.is_file():
+            original.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(saved, original)

serato_doctor/scanner.py

@@ -1,14 +1,23 @@
 from pathlib import Path
 
+from serato_doctor.models.filesystem import BrokenSymlink, FilesystemScan
 from serato_doctor.models.track import DiskTrack
 
 AUDIO_SUFFIXES = {".mp3", ".m4a", ".wav", ".aif", ".aiff", ".flac"}
 
 
-def scan_audio(folder: Path) -> list[DiskTrack]:
+def scan_filesystem(folder: Path) -> FilesystemScan:
     tracks = []
+    broken_symlinks = []
 
     for path in folder.rglob("*"):
+        if path.is_symlink() and not path.exists():
+            try:
+                target = path.readlink()
+            except OSError:
+                target = None
+            broken_symlinks.append(BrokenSymlink(path=path, target=target))
+            continue
         if not path.is_file():
             continue
         if path.suffix.lower() not in AUDIO_SUFFIXES:
@@ -28,4 +37,13 @@ def scan_audio(folder: Path) -> list[DiskTrack]:
             )
         )
 
-    return tracks
+    return FilesystemScan(
+        tracks=tuple(tracks),
+        broken_symlinks=tuple(broken_symlinks),
+    )
+
+
+def scan_audio(folder: Path) -> list[DiskTrack]:
+    """Scan audio files while preserving the prototype API."""
+
+    return list(scan_filesystem(folder).tracks)

serato_doctor/web.py

@@ -0,0 +1,367 @@
+import argparse
+import json
+from collections import Counter
+from dataclasses import asdict
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from importlib import resources
+from pathlib import Path
+from typing import Iterable, Optional
+
+from serato_doctor.crate_parser import load_library_crates
+from serato_doctor.database_parser import parse_database
+from serato_doctor.duplicates import find_duplicate_groups
+from serato_doctor.health import analyze_health
+from serato_doctor.matching import MatchingEngine, normalize
+from serato_doctor.models.crate import CrateKind
+from serato_doctor.models.duplicate import DuplicateKind
+from serato_doctor.models.library import Library
+from serato_doctor.scanner import scan_filesystem
+from serato_doctor.repair import (
+    BACKUP_FOLDER,
+    apply_duplicate_repair,
+    plan_duplicate_repair,
+    restore_backup,
+)
+
+
+MAX_REQUEST_BYTES = 64 * 1024
+DETAIL_LIMIT = 50
+STATIC_FILES = {
+    "/": ("index.html", "text/html; charset=utf-8"),
+    "/app.css": ("app.css", "text/css; charset=utf-8"),
+    "/app.js": ("app.js", "text/javascript; charset=utf-8"),
+}
+
+
+def _display_path(path: Path) -> str:
+    return str(path)
+
+
+def _first_reason(match) -> str:
+    for item in match.evidence:
+        if item.matched:
+            return item.explanation
+    return "Filename-related candidate"
+
+
+def diagnostic_details(library: Library, limit: int = DETAIL_LIMIT) -> dict:
+    dynamic_sources = {
+        crate.path for crate in library.crates if crate.kind is CrateKind.SMART
+    }
+    results = tuple(
+        result
+        for result in library.reconcile_by_filename()
+        if result.reference.source not in dynamic_sources
+    )
+    missing = [result for result in results if not result.exists_by_filename]
+
+    matcher = MatchingEngine(library.tracks)
+    suggested_matches = []
+    for result in missing:
+        candidates = matcher.candidates_for(result.reference)
+        if not candidates:
+            continue
+        best = candidates[0]
+        suggested_matches.append(
+            {
+                "filename": result.reference.filename,
+                "crate": _display_path(result.reference.source),
+                "saved_path": _display_path(result.reference.path),
+                "candidate": _display_path(best.track.path),
+                "score": f"{best.score_percent}%",
+                "reason": _first_reason(best),
+            }
+        )
+
+    duplicate_groups = find_duplicate_groups(library.tracks)
+    exact_duplicates = [
+        group
+        for group in duplicate_groups
+        if group.kind is DuplicateKind.EXACT_NAME
+    ]
+    cloud_conflicts = [
+        group
+        for group in duplicate_groups
+        if group.kind is DuplicateKind.CLOUD_CONFLICT
+    ]
+
+    database_tracks = library.database.tracks if library.database else ()
+    missing_database_tracks = [
+        track for track in database_tracks if not track.path.exists()
+    ]
+    database_filename_counts = Counter(
+        normalize(track.filename) for track in missing_database_tracks
+    )
+    referenced_names = {reference.filename for reference in library.references}
+    unused_tracks = [
+        track for track in library.tracks if track.filename not in referenced_names
+    ]
+
+    return {
+        "database_missing_tracks": {
+            "title": "Missing tracks in Serato",
+            "summary": (
+                "These are Serato database entries whose saved file location "
+                "does not currently exist on disk."
+            ),
+            "total": len(missing_database_tracks),
+            "items": [
+                {
+                    "filename": track.filename,
+                    "saved_path": _display_path(track.path),
+                    "artist": track.artist or "Unknown artist",
+                    "title": track.title or track.filename,
+                    "repeated_filename": database_filename_counts[
+                        normalize(track.filename)
+                    ]
+                    > 1,
+                }
+                for track in missing_database_tracks[:limit]
+            ],
+        },
+        "old_crate_references": {
+            "title": "Old crate references",
+            "summary": (
+                "These are regular crate appearances whose exact filename was "
+                "not found in the selected music folder."
+            ),
+            "total": len(missing),
+            "items": [
+                {
+                    "filename": result.reference.filename,
+                    "crate": _display_path(result.reference.source),
+                    "saved_path": _display_path(result.reference.path),
+                }
+                for result in missing[:limit]
+            ],
+        },
+        "suggested_matches": {
+            "title": "Suggested matches",
+            "summary": (
+                "These are read-only guesses where Serato Doctor found a "
+                "filename-related candidate on disk."
+            ),
+            "total": len(suggested_matches),
+            "items": suggested_matches[:limit],
+        },
+        "duplicate_filenames": {
+            "title": "Duplicate filenames",
+            "summary": (
+                "These groups contain different files with the same cleaned-up "
+                "filename. Review before making any decisions."
+            ),
+            "total": len(exact_duplicates),
+            "items": [
+                {
+                    "filename": group.display_name,
+                    "files": [_display_path(track.path) for track in group.tracks],
+                }
+                for group in exact_duplicates[:limit]
+            ],
+        },
+        "cloud_conflicts": {
+            "title": "Possible cloud conflicts",
+            "summary": (
+                "These filename families look like cloud sync conflict copies, "
+                "such as a duplicate ending in a number."
+            ),
+            "total": len(cloud_conflicts),
+            "items": [
+                {
+                    "filename": group.display_name,
+                    "files": [_display_path(track.path) for track in group.tracks],
+                }
+                for group in cloud_conflicts[:limit]
+            ],
+        },
+        "broken_symlinks": {
+            "title": "Broken shortcuts",
+            "summary": (
+                "These symbolic links point somewhere that no longer resolves."
+            ),
+            "total": len(library.broken_symlinks),
+            "items": [
+                {
+                    "path": _display_path(link.path),
+                    "target": _display_path(link.target) if link.target else "Unknown",
+                }
+                for link in library.broken_symlinks[:limit]
+            ],
+        },
+        "unused_tracks": {
+            "title": "Unused tracks",
+            "summary": (
+                "These scanned files were not referenced by any loaded crate. "
+                "That does not mean they should be deleted."
+            ),
+            "total": len(unused_tracks),
+            "items": [
+                {"filename": track.filename, "path": _display_path(track.path)}
+                for track in unused_tracks[:limit]
+            ],
+        },
+    }
+
+
+def analyze_paths(
+    serato: Path, music: Path, reference_roots: Iterable[Path] = ()
+) -> dict:
+    serato = serato.expanduser()
+    music = music.expanduser()
+    reference_roots = tuple(root.expanduser() for root in reference_roots)
+    if not serato.is_dir():
+        raise ValueError(f"Serato folder does not exist: {serato}")
+    if not music.is_dir():
+        raise ValueError(f"Music folder does not exist: {music}")
+
+    crates = load_library_crates(serato, reference_roots)
+    filesystem = scan_filesystem(music)
+    database_path = serato / "database V2"
+    database = parse_database(database_path) if database_path.is_file() else None
+    library = Library.from_crates(
+        crates,
+        filesystem.tracks,
+        filesystem.broken_symlinks,
+        database,
+    )
+    report = analyze_health(library)
+    result = asdict(report)
+    result["score_basis"] = report.score_basis
+    result["details"] = diagnostic_details(library)
+    return result
+
+
+def duplicate_repair(
+    serato: Path,
+    music: Path,
+    keeper: Path,
+    group_files: Iterable[Path],
+    backup_limit: Optional[int],
+    apply: bool = False,
+) -> dict:
+    """Validate a current duplicate group and preview or apply consolidation."""
+    serato = serato.expanduser().resolve()
+    music = music.expanduser().resolve()
+    keeper = keeper.expanduser().resolve()
+    requested = tuple(path.expanduser().resolve() for path in group_files)
+    if not serato.is_dir() or not music.is_dir():
+        raise ValueError("Analyze the library again before repairing duplicates")
+    tracks = scan_filesystem(music).tracks
+    groups = find_duplicate_groups(tracks)
+    valid_groups = [
+        {track.path.resolve() for track in group.tracks} for group in groups
+    ]
+    if set(requested) not in valid_groups:
+        raise ValueError("This duplicate group changed; analyze the library again")
+    plan = plan_duplicate_repair(keeper, requested, serato)
+    result = {
+        "keeper": str(plan.keeper),
+        "replaced": [str(path) for path in plan.replaced],
+        "metadata_backups": len(plan.metadata_files),
+        "strategy": "shortcut",
+        "database_v2_modified": False,
+    }
+    if apply:
+        receipt = apply_duplicate_repair(plan, serato, backup_limit)
+        result.update({"applied": True, "backup": str(receipt.backup)})
+    else:
+        result["applied"] = False
+    return result
+
+
+class SeratoDoctorHandler(BaseHTTPRequestHandler):
+    def do_GET(self) -> None:
+        asset = STATIC_FILES.get(self.path)
+        if asset is None:
+            self._json_response(404, {"error": "Not found"})
+            return
+        filename, content_type = asset
+        content = (
+            resources.files("serato_doctor.webui")
+            .joinpath(filename)
+            .read_bytes()
+        )
+        self.send_response(200)
+        self.send_header("Content-Type", content_type)
+        self.send_header("Content-Length", str(len(content)))
+        self.end_headers()
+        self.wfile.write(content)
+
+    def do_POST(self) -> None:
+        allowed = {
+            "/api/analyze",
+            "/api/duplicates/preview",
+            "/api/duplicates/apply",
+            "/api/backups/restore",
+        }
+        if self.path not in allowed:
+            self._json_response(404, {"error": "Not found"})
+            return
+        try:
+            length = int(self.headers.get("Content-Length", "0"))
+            if length <= 0 or length > MAX_REQUEST_BYTES:
+                raise ValueError("Invalid request size")
+            payload = json.loads(self.rfile.read(length))
+            if not isinstance(payload, dict):
+                raise ValueError("Request body must be a JSON object")
+            if self.path == "/api/analyze":
+                roots = [Path(value) for value in payload.get("reference_roots", [])]
+                result = analyze_paths(
+                    Path(payload["serato"]), Path(payload["music"]), roots
+                )
+            elif self.path == "/api/backups/restore":
+                serato = Path(payload["serato"]).expanduser().resolve()
+                backup = Path(payload["backup"]).expanduser().resolve()
+                backup_root = (serato / BACKUP_FOLDER).resolve()
+                if backup.parent != backup_root:
+                    raise ValueError("That backup does not belong to this library")
+                restored = restore_backup(backup)
+                result = {"restored": [str(path) for path in restored]}
+            else:
+                raw_limit = payload.get("backup_limit", 10)
+                backup_limit = None if raw_limit is None else int(raw_limit)
+                result = duplicate_repair(
+                    Path(payload["serato"]),
+                    Path(payload["music"]),
+                    Path(payload["keeper"]),
+                    (Path(value) for value in payload["group_files"]),
+                    backup_limit,
+                    apply=self.path.endswith("/apply"),
+                )
+        except (
+            KeyError,
+            TypeError,
+            OSError,
+            json.JSONDecodeError,
+            ValueError,
+        ) as error:
+            self._json_response(400, {"error": str(error)})
+            return
+        self._json_response(200, result)
+
+    def _json_response(self, status: int, payload: dict) -> None:
+        content = json.dumps(payload).encode("utf-8")
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json; charset=utf-8")
+        self.send_header("Content-Length", str(len(content)))
+        self.end_headers()
+        self.wfile.write(content)
+
+    def log_message(self, format: str, *args: object) -> None:
+        return
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(prog="serato-doctor-web")
+    parser.add_argument("--host", default="127.0.0.1")
+    parser.add_argument("--port", type=int, default=8765)
+    args = parser.parse_args()
+    server = ThreadingHTTPServer((args.host, args.port), SeratoDoctorHandler)
+    print(f"Serato Doctor web interface: http://{args.host}:{args.port}")
+    print("Press Ctrl+C to stop.")
+    try:
+        server.serve_forever()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        server.server_close()

serato_doctor/webui/__init__.py

@@ -0,0 +1 @@
+"""Static assets for the local Serato Doctor web interface."""

serato_doctor/webui/app.js

@@ -0,0 +1,229 @@
+const form = document.querySelector('#analysis-form');
+const button = document.querySelector('#analyze-button');
+const errorBox = document.querySelector('#error-message');
+const results = document.querySelector('#dashboard');
+const infoButtons = document.querySelectorAll('.info-button');
+const drillTriggers = document.querySelectorAll('[data-detail]');
+const drilldownTitle = document.querySelector('#drilldown-title');
+const drilldownCount = document.querySelector('#drilldown-count');
+const drilldownSummary = document.querySelector('#drilldown-summary');
+const drilldownList = document.querySelector('#drilldown-list');
+const repairPanel = document.querySelector('#duplicate-repair');
+const repairChoice = document.querySelector('#repair-choice');
+const repairPreview = document.querySelector('#repair-preview');
+const repairMessage = document.querySelector('#repair-message');
+const previewRepairButton = document.querySelector('#preview-repair');
+const applyRepairButton = document.querySelector('#apply-repair');
+const restoreRepairButton = document.querySelector('#restore-repair');
+let latestAnalysis = null;
+let selectedDuplicateGroup = null;
+let previewedRepair = null;
+let latestBackup = null;
+
+function expandHome(path) {
+  return path.trim();
+}
+
+function escapeHtml(value) {
+  return String(value ?? '').replace(/[&<>"']/g, (character) => ({
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+    '"': '&quot;',
+    "'": '&#039;',
+  }[character]));
+}
+
+function detailLines(item) {
+  if (item.files) {
+    return item.files.map((file) => `<li>${escapeHtml(file)}</li>`).join('');
+  }
+  const lines = [];
+  if (item.artist || item.title) lines.push(`${item.artist || 'Unknown artist'} — ${item.title || item.filename}`);
+  if (item.crate) lines.push(`Crate: ${item.crate}`);
+  if (item.saved_path) lines.push(`Saved path: ${item.saved_path}`);
+  if (item.candidate) lines.push(`Candidate: ${item.candidate}`);
+  if (item.path) lines.push(`File: ${item.path}`);
+  if (item.target) lines.push(`Target: ${item.target}`);
+  if (item.score || item.reason) lines.push(`${item.score || 'Match'} · ${item.reason || 'Candidate found'}`);
+  if (item.repeated_filename) lines.push('Same filename appears more than once in Serato’s missing list.');
+  return lines.map((line) => `<li>${escapeHtml(line)}</li>`).join('');
+}
+
+function renderDetail(key) {
+  const detail = latestAnalysis?.details?.[key];
+  if (!detail) return;
+
+  drillTriggers.forEach((trigger) => {
+    trigger.classList.toggle('selected', trigger.dataset.detail === key);
+  });
+  drilldownTitle.textContent = detail.title;
+  drilldownCount.textContent = `${detail.total ?? 0} found`;
+  drilldownSummary.textContent = detail.summary;
+
+  repairPanel.hidden = true;
+  selectedDuplicateGroup = null;
+  previewedRepair = null;
+  latestBackup = null;
+  restoreRepairButton.hidden = true;
+  if (!detail.items?.length) {
+    drilldownList.innerHTML = '<div class="empty-detail">Nothing to review here. Tiny victory parade, very tasteful.</div>';
+    return;
+  }
+
+  drilldownList.innerHTML = detail.items.map((item, index) => `
+    <article class="detail-item${item.files ? ' selectable-duplicate' : ''}" ${item.files ? `data-duplicate-index="${index}" role="button" tabindex="0"` : ''}>
+      <strong>${escapeHtml(item.filename || item.path || 'Untitled item')}</strong>
+      <ul>${detailLines(item)}</ul>
+      ${item.files ? '<small>Choose this group to review a safe cleanup →</small>' : ''}
+    </article>
+  `).join('');
+}
+
+function chooseDuplicate(detailKey, index) {
+  const group = latestAnalysis?.details?.[detailKey]?.items?.[index];
+  if (!group?.files) return;
+  selectedDuplicateGroup = group;
+  previewedRepair = null;
+  applyRepairButton.disabled = true;
+  repairPreview.hidden = true;
+  repairMessage.textContent = '';
+  repairChoice.innerHTML = group.files.map((file, fileIndex) => `
+    <label class="keeper-option"><input type="radio" name="keeper" value="${escapeHtml(file)}" ${fileIndex === 0 ? 'checked' : ''}><span><strong>${fileIndex === 0 ? 'Keep this file' : 'Keep instead'}</strong><small>${escapeHtml(file)}</small></span></label>
+  `).join('');
+  repairPanel.hidden = false;
+  repairPanel.scrollIntoView({behavior: 'smooth', block: 'start'});
+}
+
+function repairPayload() {
+  const keeper = document.querySelector('input[name="keeper"]:checked')?.value;
+  if (!selectedDuplicateGroup || !keeper) throw new Error('Choose a file to keep');
+  return {serato: expandHome(document.querySelector('#serato-path').value), music: expandHome(document.querySelector('#music-path').value), keeper, group_files: selectedDuplicateGroup.files, backup_limit: document.querySelector('#keep-all-backups').checked ? null : Number(document.querySelector('#backup-limit').value)};
+}
+
+async function requestRepair(endpoint) {
+  const response = await fetch(endpoint, {method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(repairPayload())});
+  const data = await response.json();
+  if (!response.ok) throw new Error(data.error || 'Duplicate cleanup failed');
+  return data;
+}
+
+previewRepairButton.addEventListener('click', async () => {
+  repairMessage.textContent = 'Checking the plan…'; applyRepairButton.disabled = true;
+  try {
+    previewedRepair = await requestRepair('/api/duplicates/preview');
+    repairPreview.innerHTML = `<strong>Ready to protect and consolidate</strong><p>${previewedRepair.replaced.length} duplicate file(s) will be backed up, then replaced with shortcuts to the keeper. ${previewedRepair.metadata_backups} Serato metadata file(s) will also be copied into the rollback snapshot. Database V2 will not be changed.</p>`;
+    repairPreview.hidden = false; applyRepairButton.disabled = false;
+    repairMessage.textContent = 'Preview complete. Nothing has changed yet.';
+  } catch (error) { repairMessage.textContent = error.message; }
+});
+
+applyRepairButton.addEventListener('click', async () => {
+  if (!previewedRepair) return;
+  applyRepairButton.disabled = true; repairMessage.textContent = 'Creating the backup before making changes…';
+  try {
+    const result = await requestRepair('/api/duplicates/apply');
+    latestBackup = result.backup;
+    repairMessage.textContent = `Cleanup complete. Restore backup: ${result.backup}`;
+    previewRepairButton.disabled = true;
+    restoreRepairButton.hidden = false;
+  } catch (error) { repairMessage.textContent = error.message; applyRepairButton.disabled = false; }
+});
+
+restoreRepairButton.addEventListener('click', async () => {
+  if (!latestBackup) return;
+  restoreRepairButton.disabled = true; repairMessage.textContent = 'Restoring the duplicate files…';
+  try {
+    const response = await fetch('/api/backups/restore', {method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({serato: expandHome(document.querySelector('#serato-path').value), backup: latestBackup})});
+    const result = await response.json();
+    if (!response.ok) throw new Error(result.error || 'Restore failed');
+    repairMessage.textContent = `Restore complete. ${result.restored.length} original file(s) returned.`;
+    restoreRepairButton.hidden = true;
+  } catch (error) { repairMessage.textContent = error.message; restoreRepairButton.disabled = false; }
+});
+
+repairChoice.addEventListener('change', () => { previewedRepair = null; applyRepairButton.disabled = true; repairPreview.hidden = true; repairMessage.textContent = 'Keeper changed. Preview the plan again.'; });
+drilldownList.addEventListener('click', (event) => { const item = event.target.closest('[data-duplicate-index]'); if (item) chooseDuplicate(document.querySelector('.drill-trigger.selected')?.dataset.detail, Number(item.dataset.duplicateIndex)); });
+drilldownList.addEventListener('keydown', (event) => { if (event.key !== 'Enter' && event.key !== ' ') return; const item = event.target.closest('[data-duplicate-index]'); if (item) { event.preventDefault(); chooseDuplicate(document.querySelector('.drill-trigger.selected')?.dataset.detail, Number(item.dataset.duplicateIndex)); } });
+
+function render(data) {
+  latestAnalysis = data;
+  document.querySelectorAll('[data-field]').forEach((element) => {
+    const value = data[element.dataset.field];
+    element.textContent = value ?? '—';
+  });
+  const score = data.score;
+  document.querySelector('#health-score').textContent = score == null ? '—' : `${score}%`;
+  document.querySelector('#score-ring').style.setProperty('--score', score ?? 0);
+  document.querySelector('#health-message').textContent = score == null
+    ? 'Not enough data yet'
+    : score >= 95 ? 'Looking excellent' : score >= 80 ? 'A few things need attention' : 'Review recommended';
+  document.querySelector('#score-basis').textContent = data.score_basis;
+  document.querySelector('#analysis-time').textContent = `Completed ${new Date().toLocaleTimeString([], {hour: '2-digit', minute: '2-digit'})}`;
+  renderDetail(data.database_missing_paths > 0 ? 'database_missing_tracks' : 'old_crate_references');
+  results.hidden = false;
+  results.scrollIntoView({behavior: 'smooth', block: 'start'});
+}
+
+function closeInfoButtons(except = null) {
+  infoButtons.forEach((infoButton) => {
+    if (infoButton !== except) {
+      infoButton.classList.remove('open');
+      infoButton.setAttribute('aria-expanded', 'false');
+    }
+  });
+}
+
+infoButtons.forEach((infoButton) => {
+  infoButton.addEventListener('click', (event) => {
+    event.stopPropagation();
+    const willOpen = !infoButton.classList.contains('open');
+    closeInfoButtons(infoButton);
+    infoButton.classList.toggle('open', willOpen);
+    infoButton.setAttribute('aria-expanded', String(willOpen));
+  });
+});
+
+drillTriggers.forEach((trigger) => {
+  trigger.addEventListener('click', () => renderDetail(trigger.dataset.detail));
+  trigger.addEventListener('keydown', (event) => {
+    if (event.key === 'Enter' || event.key === ' ') {
+      event.preventDefault();
+      renderDetail(trigger.dataset.detail);
+    }
+  });
+});
+
+document.addEventListener('click', () => closeInfoButtons());
+document.addEventListener('keydown', (event) => {
+  if (event.key === 'Escape') closeInfoButtons();
+});
+
+form.addEventListener('submit', async (event) => {
+  event.preventDefault();
+  errorBox.hidden = true;
+  button.disabled = true;
+  button.querySelector('span').textContent = 'Analyzing safely…';
+  const roots = document.querySelector('#reference-roots').value
+    .split('\n').map((value) => value.trim()).filter(Boolean);
+  try {
+    const response = await fetch('/api/analyze', {
+      method: 'POST',
+      headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({
+        serato: expandHome(document.querySelector('#serato-path').value),
+        music: expandHome(document.querySelector('#music-path').value),
+        reference_roots: roots,
+      }),
+    });
+    const data = await response.json();
+    if (!response.ok) throw new Error(data.error || 'Analysis failed');
+    render(data);
+  } catch (error) {
+    errorBox.textContent = error.message;
+    errorBox.hidden = false;
+  } finally {
+    button.disabled = false;
+    button.querySelector('span').textContent = 'Analyze library';
+  }
+});

serato_doctor/webui/index.html

@@ -0,0 +1,113 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <meta name="color-scheme" content="dark">
+  <title>Serato Doctor</title>
+  <link rel="stylesheet" href="/app.css">
+</head>
+<body>
+  <div class="ambient ambient-one"></div>
+  <div class="ambient ambient-two"></div>
+  <div class="shell">
+    <aside class="sidebar">
+      <a class="brand" href="/" aria-label="Serato Doctor home">
+        <span class="brand-mark">SD</span>
+        <span><strong>Serato</strong><small>Doctor</small></span>
+      </a>
+      <nav aria-label="Primary navigation">
+        <a class="nav-item active" href="#dashboard"><span>⌁</span> Dashboard</a>
+        <a class="nav-item" href="#scan"><span>◎</span> New analysis</a>
+        <a class="nav-item" href="#diagnostics"><span>◇</span> Diagnostics</a>
+      </nav>
+      <div class="safety-card">
+        <span class="safety-icon">✓</span>
+        <div><strong>Protected mode</strong><p>Analysis is read-only. Repairs require a preview and backup.</p></div>
+      </div>
+      <div class="sidebar-foot">Local interface · v0.1</div>
+    </aside>
+
+    <main>
+      <header class="topbar">
+        <div><p class="eyebrow">Library intelligence</p><h1>Good evening.</h1></div>
+        <div class="status-pill"><span></span> Local &amp; private</div>
+      </header>
+
+      <section id="scan" class="scan-panel panel">
+        <div class="panel-copy">
+          <p class="eyebrow">Start here</p>
+          <h2>Analyze your library</h2>
+          <p>Point Serato Doctor at your Serato and music folders. We inspect references, duplicates, smart crates, and symlinks without changing a thing.</p>
+        </div>
+        <form id="analysis-form">
+          <label>Serato folder
+            <input id="serato-path" name="serato" value="~/Music/_Serato_" required>
+          </label>
+          <label>Music folder
+            <input id="music-path" name="music" value="~/Music/Jukebox" required>
+          </label>
+          <label class="wide">Historical reference roots <span>optional · one per line</span>
+            <textarea id="reference-roots" rows="2" placeholder="/Users/old-user/OneDrive/Jukebox"></textarea>
+          </label>
+          <button id="analyze-button" type="submit"><span>Analyze library</span><b>→</b></button>
+        </form>
+        <div id="error-message" class="error" role="alert" hidden></div>
+      </section>
+
+      <section id="dashboard" class="results" aria-live="polite" hidden>
+        <div class="section-heading"><div><p class="eyebrow">Latest analysis</p><h2>Library health</h2></div><span id="analysis-time"></span></div>
+        <div class="hero-grid">
+          <article class="score-card panel">
+            <button class="info-button" type="button" aria-label="About library health" aria-expanded="false" data-info="Your health score is the percentage of saved, non-smart crate entries whose filenames were found in the selected music folder. Smart crates are left out because Serato rebuilds them from rules.">i</button>
+            <div class="score-ring" id="score-ring"><div><strong id="health-score">—</strong><span>health</span></div></div>
+            <div><p class="score-label">Reference integrity</p><h3 id="health-message">Ready to analyze</h3><p id="score-basis">We only score evidence we can defend.</p></div>
+          </article>
+          <div class="metrics-grid">
+            <article class="metric panel"><button class="info-button" type="button" aria-label="About tracks" aria-expanded="false" data-info="Audio files found inside the music folder you selected. This is the collection Serato Doctor compared with your crates and database.">i</button><span>Tracks scanned</span><strong data-field="disk_tracks">—</strong><small>audio files found</small></article>
+            <article class="metric panel warning drill-trigger" role="button" tabindex="0" data-detail="database_missing_tracks"><button class="info-button" type="button" aria-label="About missing tracks in Serato" aria-expanded="false" data-info="Tracks in Serato's database whose saved file location no longer exists. This should be close to the orange or unmapped track count you see in Serato.">i</button><span>Missing tracks in Serato</span><strong data-field="database_missing_paths">—</strong><small><b data-field="database_missing_unique_filenames">—</b> unique filenames · click for list</small></article>
+            <article class="metric panel drill-trigger" role="button" tabindex="0" data-detail="unused_tracks"><button class="info-button" type="button" aria-label="About unused tracks" aria-expanded="false" data-info="Files in the selected music folder whose filename is not used by any loaded crate. They may still be valid library tracks; this is informational, not a deletion recommendation.">i</button><span>Unused tracks</span><strong data-field="unused_tracks">—</strong><small>not referenced by crates · click for list</small></article>
+            <article class="metric panel drill-trigger" role="button" tabindex="0" data-detail="suggested_matches"><button class="info-button" type="button" aria-label="About suggested matches" aria-expanded="false" data-info="Missing crate entries with a filename-related candidate, such as an added OneDrive conflict number. Suggestions are evidence for review, never automatic repairs.">i</button><span>Suggested matches</span><strong data-field="suggested_matches">—</strong><small>explainable candidates · click for list</small></article>
+          </div>
+        </div>
+
+        <div id="diagnostics" class="diagnostics panel">
+          <div class="section-heading"><div><p class="eyebrow">Full picture</p><h2>Diagnostics</h2></div><span class="read-only-tag">No changes made</span></div>
+          <div class="diagnostic-list">
+            <div><span class="diag-icon violet">◇</span><p><strong>Crates</strong><small><b data-field="static_crates">—</b> regular · <b data-field="smart_crates">—</b> smart · <b data-field="smart_crate_containers">—</b> dynamic containers</small></p><button class="info-button" type="button" aria-label="About crates" aria-expanded="false" data-info="Regular crates are lists you maintain by hand. Smart crates are rebuilt by Serato from rules, so their generated references are not scored as broken.">i</button></div>
+            <div class="drill-trigger" role="button" tabindex="0" data-detail="duplicate_filenames"><span class="diag-icon amber">≋</span><p><strong>Duplicate filenames</strong><small><b data-field="duplicate_filename_groups">—</b> exact groups · <b data-field="duplicate_files">—</b> extra files · click for list</small></p><button class="info-button" type="button" aria-label="About duplicate filenames" aria-expanded="false" data-info="Different files with the same filename after case and Unicode cleanup. They need review, but matching names alone do not mean either file should be deleted.">i</button></div>
+            <div class="drill-trigger" role="button" tabindex="0" data-detail="cloud_conflicts"><span class="diag-icon blue">⌁</span><p><strong>Possible cloud conflicts</strong><small><b data-field="suspected_cloud_conflict_groups">—</b> groups · <b data-field="suspected_cloud_conflict_files">—</b> extra files · click for list</small></p><button class="info-button" type="button" aria-label="About cloud conflicts" aria-expanded="false" data-info="Filename families such as Track.mp3 and Track 2.mp3. OneDrive often creates these during sync conflicts, but numbered song titles can also be legitimate.">i</button></div>
+            <div class="drill-trigger" role="button" tabindex="0" data-detail="broken_symlinks"><span class="diag-icon red">↗</span><p><strong>Broken shortcuts</strong><small><b data-field="broken_symlinks">—</b> unresolved symbolic links · click for list</small></p><button class="info-button" type="button" aria-label="About broken shortcuts" aria-expanded="false" data-info="Shortcut-style symbolic links whose destination no longer exists. Serato Doctor reports them but never removes or recreates them automatically.">i</button></div>
+            <div class="drill-trigger" role="button" tabindex="0" data-detail="old_crate_references"><span class="diag-icon violet">▦</span><p><strong>Old crate references</strong><small><b data-field="missing_references">—</b> appearances · <b data-field="unique_missing_filenames">—</b> unique filenames · click for list</small></p><button class="info-button" type="button" aria-label="About old crate references" aria-expanded="false" data-info="Saved spots in regular crates whose exact filename was not found in the selected music folder. The same track can appear in several crates, so appearances are higher than unique filenames. These are separate from Serato's unmapped-track count.">i</button></div>
+            <div><span class="diag-icon amber">⌕</span><p><strong>Database coverage</strong><small><b data-field="database_entries">—</b> Serato entries · <b data-field="tracks_missing_from_database">—</b> scanned tracks absent</small></p><button class="info-button" type="button" aria-label="About database coverage" aria-expanded="false" data-info="Compares filenames in Serato's database with the selected music folder. A scanned track absent from the database may not have been imported, or may be represented under another filename.">i</button></div>
+          </div>
+        </div>
+
+        <div id="drilldowns" class="drilldowns panel">
+          <div class="section-heading"><div><p class="eyebrow">Look closer</p><h2 id="drilldown-title">Choose a diagnostic</h2></div><span id="drilldown-count">Read-only examples</span></div>
+          <p id="drilldown-summary">Click a metric above to see example files and saved paths behind that number.</p>
+          <div id="drilldown-list" class="detail-list"></div>
+        </div>
+
+        <div id="duplicate-repair" class="repair-panel panel" hidden>
+          <div class="section-heading"><div><p class="eyebrow">Backup-first cleanup</p><h2>Safely consolidate duplicates</h2></div><span class="repair-tag">Preview required</span></div>
+          <p>Choose the real file to keep. Every other path will be backed up and replaced with a shortcut to it, so existing Serato crates remain mapped. Serato’s database V2 is never edited.</p>
+          <div id="repair-choice" class="repair-choice"></div>
+          <div class="backup-options">
+            <label>Backups to keep <input id="backup-limit" type="number" min="1" value="10"></label>
+            <label class="check-label"><input id="keep-all-backups" type="checkbox"> Keep every backup</label>
+          </div>
+          <div id="repair-preview" class="repair-preview" hidden></div>
+          <div class="repair-actions">
+            <button id="preview-repair" type="button">Preview changes</button>
+            <button id="apply-repair" class="danger-action" type="button" disabled>Apply backed-up cleanup</button>
+            <button id="restore-repair" type="button" hidden>Restore this backup</button>
+          </div>
+          <div id="repair-message" class="repair-message" role="status"></div>
+        </div>
+      </section>
+    </main>
+  </div>
+  <script src="/app.js" defer></script>
+</body>
+</html>

tests/test_cli.py

@@ -84,3 +84,48 @@ def test_cli_accepts_old_reference_root(tmp_path, monkeypatch, capsys):
     output = capsys.readouterr().out
     assert "Crate references: 1" in output
     assert "Missing by filename: 0" in output
+
+
+def test_analyze_prints_health_without_writing_reports(tmp_path, monkeypatch, capsys):
+    serato = tmp_path / "serato"
+    subcrates = serato / "Subcrates"
+    music = tmp_path / "music"
+    subcrates.mkdir(parents=True)
+    music.mkdir()
+    crate_text = (
+        "Users/sample-user/Jukebox/Found.mp3otrk"
+        "Users/sample-user/Jukebox/Missing.mp3otrk"
+    )
+    (subcrates / "Test.crate").write_bytes(crate_text.encode("utf-16-le"))
+    (music / "Found.mp3").write_bytes(b"synthetic audio")
+    csv_path = tmp_path / "scan.csv"
+    report_path = tmp_path / "report.txt"
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        [
+            "serato-doctor",
+            "analyze",
+            "--serato",
+            str(serato),
+            "--music",
+            str(music),
+            "--out",
+            str(csv_path),
+            "--report",
+            str(report_path),
+        ],
+    )
+
+    main()
+
+    output = capsys.readouterr().out
+    assert "Overall Health: 50.0%" in output
+    assert "Tracks: 1" in output
+    assert "Crate References: 2" in output
+    assert "References Scored: 2" in output
+    assert "Healthy References: 1" in output
+    assert "Broken References: 1" in output
+    assert "Unused Tracks: 0" in output
+    assert not csv_path.exists()
+    assert not report_path.exists()

tests/test_crates.py

@@ -3,12 +3,15 @@ from pathlib import Path
 import pytest
 
 from serato_doctor.crate_parser import (
+    classify_crate,
     clean_path,
     load_crate,
+    load_library_crates,
     parse_crate,
     parse_crates,
     path_markers,
 )
+from serato_doctor.models.crate import CrateKind
 
 
 @pytest.mark.parametrize(
@@ -84,3 +87,50 @@ def test_parse_crates_reuses_configured_roots_for_every_crate(tmp_path):
         "First.mp3",
         "Second.mp3",
     }
+
+
+@pytest.mark.parametrize(
+    ("relative_path", "expected"),
+    [
+        ("_Serato_/Subcrates/House.crate", CrateKind.STATIC),
+        ("_Serato_/SmartCrates/Warmup.scrate", CrateKind.SMART),
+        ("_Serato_/Subcrates/Compatible by key.crate", CrateKind.SMART),
+        ("fixtures/Unknown.crate", CrateKind.UNKNOWN),
+    ],
+)
+def test_classify_crate_uses_provenance_and_known_dynamic_name(
+    tmp_path, relative_path, expected
+):
+    assert classify_crate(tmp_path / relative_path) is expected
+
+
+def test_smart_crate_preserves_encoded_hierarchy(tmp_path):
+    crate_path = (
+        tmp_path / "_Serato_" / "SmartCrates" / "Compatible by key≫≫10A.scrate"
+    )
+    crate_path.parent.mkdir(parents=True)
+    crate_path.write_bytes(b"")
+    crate = load_crate(crate_path)
+
+    assert crate.kind is CrateKind.SMART
+    assert crate.hierarchy == ("Compatible by key", "10A")
+    assert crate.display_name == "10A"
+    assert crate.is_smart_definition
+
+
+def test_load_library_crates_discovers_scrate_definitions(tmp_path):
+    smart_folder = tmp_path / "SmartCrates"
+    static_folder = tmp_path / "Subcrates"
+    smart_folder.mkdir()
+    static_folder.mkdir()
+    (smart_folder / "New EDM.scrate").write_bytes(b"")
+    (smart_folder / "Re-Drums.scrate").write_bytes(b"")
+    (static_folder / "House.crate").write_bytes(b"")
+
+    crates = load_library_crates(tmp_path)
+
+    assert [(crate.path.name, crate.kind) for crate in crates] == [
+        ("New EDM.scrate", CrateKind.SMART),
+        ("Re-Drums.scrate", CrateKind.SMART),
+        ("House.crate", CrateKind.STATIC),
+    ]

tests/test_database_parser.py

@@ -0,0 +1,48 @@
+from pathlib import Path
+
+from serato_doctor.database_parser import iter_records, parse_database
+
+
+def record(tag, payload):
+    return tag + len(payload).to_bytes(4, "big") + payload
+
+
+def text_record(tag, value):
+    return record(tag, value.encode("utf-16-be"))
+
+
+def test_parse_database_reads_track_paths_and_metadata(tmp_path):
+    track = b"".join(
+        [
+            text_record(b"pfil", "Users/sample/Music/Track.mp3"),
+            text_record(b"tsng", "Track title"),
+            text_record(b"tart", "Test artist"),
+            text_record(b"talb", "Test album"),
+            text_record(b"tgen", "House"),
+        ]
+    )
+    database_path = tmp_path / "database V2"
+    database_path.write_bytes(
+        text_record(b"vrsn", "2.0/Test Database") + record(b"otrk", track)
+    )
+
+    database = parse_database(database_path)
+
+    assert database.version == "2.0/Test Database"
+    assert len(database.tracks) == 1
+    parsed = database.tracks[0]
+    assert parsed.path == Path("/Users/sample/Music/Track.mp3")
+    assert parsed.filename == "Track.mp3"
+    assert parsed.title == "Track title"
+    assert parsed.artist == "Test artist"
+    assert parsed.album == "Test album"
+    assert parsed.genre == "House"
+
+
+def test_iter_records_ignores_incomplete_trailing_record():
+    complete = record(b"vrsn", "2.0".encode("utf-16-be"))
+    incomplete = b"otrk\x00\x00\x00\x10short"
+
+    records = list(iter_records(complete + incomplete))
+
+    assert records == [(b"vrsn", "2.0".encode("utf-16-be"))]

tests/test_duplicates.py

@@ -0,0 +1,57 @@
+from pathlib import Path
+
+from serato_doctor.duplicates import find_duplicate_groups
+from serato_doctor.models.duplicate import DuplicateKind
+from serato_doctor.models.track import DiskTrack
+
+
+def track(path):
+    path = Path(path)
+    return DiskTrack(path, path.name, 100, path.suffix.lower())
+
+
+def test_exact_names_in_different_folders_form_a_group():
+    groups = find_duplicate_groups(
+        [track("/A/Song.mp3"), track("/B/Song.mp3")]
+    )
+
+    assert len(groups) == 1
+    assert groups[0].kind is DuplicateKind.EXACT_NAME
+    assert groups[0].display_name == "Song.mp3"
+    assert groups[0].extra_files == 1
+
+
+def test_case_only_difference_is_an_exact_name_duplicate():
+    groups = find_duplicate_groups(
+        [track("/A/SONG.MP3"), track("/B/song.mp3")]
+    )
+
+    assert groups[0].kind is DuplicateKind.EXACT_NAME
+
+
+def test_numeric_suffixes_form_a_suspected_cloud_conflict_group():
+    groups = find_duplicate_groups(
+        [
+            track("/A/Track.mp3"),
+            track("/B/Track 2.mp3"),
+            track("/C/Track 3.mp3"),
+        ]
+    )
+
+    assert len(groups) == 1
+    assert groups[0].kind is DuplicateKind.CLOUD_CONFLICT
+    assert groups[0].display_name == "Track.mp3"
+    assert groups[0].extra_files == 2
+    assert [item.path for item in groups[0].tracks] == [
+        Path("/A/Track.mp3"),
+        Path("/B/Track 2.mp3"),
+        Path("/C/Track 3.mp3"),
+    ]
+
+
+def test_unrelated_and_single_files_are_not_reported():
+    groups = find_duplicate_groups(
+        [track("/A/First.mp3"), track("/B/Second.mp3")]
+    )
+
+    assert groups == ()

tests/test_health.py

@@ -0,0 +1,123 @@
+from pathlib import Path
+
+from serato_doctor.health import analyze_health
+from serato_doctor.models.crate import Crate, CrateKind
+from serato_doctor.models.filesystem import BrokenSymlink
+from serato_doctor.models.library import Library
+from serato_doctor.models.reference import TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+def reference(filename):
+    return TrackReference(
+        Path("Test.crate"), Path("/old/House") / filename, filename
+    )
+
+
+def track(filename, folder="House"):
+    path = Path("/new") / folder / filename
+    return DiskTrack(path, filename, 100, path.suffix.lower())
+
+
+def test_health_report_exposes_each_metric():
+    library = Library.build(
+        [
+            reference("Found.mp3"),
+            reference("Conflict.mp3"),
+            reference("Absent.mp3"),
+        ],
+        [
+            track("Found.mp3"),
+            track("Conflict 2.mp3"),
+            track("Conflict 2.mp3", "Backup"),
+            track("Unused.mp3"),
+        ],
+    )
+
+    report = analyze_health(library)
+
+    assert report.score == 33.3
+    assert report.score_basis == (
+        "Resolved non-dynamic references / non-dynamic references scored"
+    )
+    assert report.total_references == 3
+    assert report.scored_references == 3
+    assert report.healthy_references == 1
+    assert report.missing_references == 2
+    assert report.unique_missing_filenames == 2
+    assert report.disk_tracks == 4
+    assert report.duplicate_filename_groups == 1
+    assert report.duplicate_files == 1
+    assert report.unused_tracks == 3
+    assert report.suggested_matches == 1
+
+
+def test_empty_library_has_no_health_score():
+    report = analyze_health(Library.build([], []))
+
+    assert report.score is None
+    assert report.total_references == 0
+    assert report.scored_references == 0
+    assert not report.database_present
+    assert report.tracks_missing_from_database == 0
+
+
+def test_smart_crate_references_are_reported_but_not_scored():
+    static_reference = reference("Found.mp3")
+    smart_reference = TrackReference(
+        Path("SmartCrates/Dynamic.scrate"),
+        Path("/old/House/Dynamic.mp3"),
+        "Dynamic.mp3",
+    )
+    crates = [
+        Crate(Path("Subcrates/Static.crate"), (static_reference,), CrateKind.STATIC),
+        Crate(
+            Path("SmartCrates/Dynamic.scrate"),
+            (smart_reference,),
+            CrateKind.SMART,
+        ),
+    ]
+    library = Library.from_crates(crates, [track("Found.mp3")])
+
+    report = analyze_health(library)
+
+    assert report.score == 100.0
+    assert report.total_references == 2
+    assert report.scored_references == 1
+    assert report.missing_references == 0
+    assert report.static_crates == 1
+    assert report.smart_crates == 1
+    assert report.smart_crate_containers == 0
+    assert report.dynamic_references_excluded == 1
+
+
+def test_health_reports_cloud_conflicts_separately_from_exact_duplicates():
+    library = Library.build(
+        [],
+        [
+            track("Track.mp3", "Original"),
+            track("Track 2.mp3", "Conflict"),
+            track("Copy.mp3", "First"),
+            track("Copy.mp3", "Second"),
+        ],
+    )
+
+    report = analyze_health(library)
+
+    assert report.duplicate_filename_groups == 1
+    assert report.duplicate_files == 1
+    assert report.suspected_cloud_conflict_groups == 1
+    assert report.suspected_cloud_conflict_files == 1
+
+
+def test_health_reports_broken_symlinks_without_changing_score():
+    library = Library.build(
+        [reference("Found.mp3")],
+        [track("Found.mp3")],
+        [BrokenSymlink(Path("/music/Broken.mp3"), Path("missing.mp3"))],
+    )
+
+    report = analyze_health(library)
+
+    assert report.score == 100.0
+    assert report.broken_symlinks == 1

tests/test_repair.py

@@ -0,0 +1,67 @@
+from pathlib import Path
+
+import pytest
+
+from serato_doctor.repair import (
+    BACKUP_FOLDER,
+    apply_duplicate_repair,
+    plan_duplicate_repair,
+    restore_backup,
+    rotate_backups,
+)
+
+
+def library(tmp_path):
+    serato = tmp_path / "_Serato_"
+    crate = serato / "Subcrates" / "House.crate"
+    crate.parent.mkdir(parents=True)
+    crate.write_bytes(b"crate-data")
+    (serato / "database V2").write_bytes(b"database-data")
+    music = tmp_path / "Music"
+    keeper = music / "Main" / "Track.mp3"
+    duplicate = music / "Old" / "Track.mp3"
+    keeper.parent.mkdir(parents=True)
+    duplicate.parent.mkdir(parents=True)
+    keeper.write_bytes(b"keeper")
+    duplicate.write_bytes(b"duplicate")
+    return serato, keeper, duplicate
+
+
+def test_duplicate_repair_backs_up_then_preserves_old_path_as_link(tmp_path):
+    serato, keeper, duplicate = library(tmp_path)
+    plan = plan_duplicate_repair(keeper, (keeper, duplicate), serato)
+
+    receipt = apply_duplicate_repair(plan, serato, backup_limit=3)
+
+    assert duplicate.is_symlink()
+    assert duplicate.resolve() == keeper.resolve()
+    assert (receipt.backup / "manifest.json").is_file()
+    assert any((receipt.backup / "serato-metadata").rglob("House.crate"))
+    assert any((receipt.backup / "serato-metadata").rglob("database V2"))
+
+    restored = restore_backup(receipt.backup)
+    assert restored == (duplicate.resolve(),)
+    assert not duplicate.is_symlink()
+    assert duplicate.read_bytes() == b"duplicate"
+
+
+def test_plan_rejects_keeper_outside_duplicate_group(tmp_path):
+    serato, keeper, duplicate = library(tmp_path)
+    outsider = tmp_path / "outsider.mp3"
+    outsider.write_bytes(b"other")
+
+    with pytest.raises(ValueError, match="must belong"):
+        plan_duplicate_repair(outsider, (keeper, duplicate), serato)
+
+
+def test_backup_rotation_can_be_limited_or_unlimited(tmp_path):
+    root = tmp_path / BACKUP_FOLDER
+    for name in ("001", "002", "003"):
+        backup = root / name
+        backup.mkdir(parents=True)
+        (backup / "manifest.json").write_text("{}", encoding="utf-8")
+
+    rotate_backups(root, None)
+    assert len(list(root.iterdir())) == 3
+    rotate_backups(root, 2)
+    assert {path.name for path in root.iterdir()} == {"002", "003"}

tests/test_sample_library.py

@@ -1,7 +1,8 @@
 import runpy
 from pathlib import Path
 
-from serato_doctor.crate_parser import parse_crates
+from serato_doctor.crate_parser import load_library_crates
+from serato_doctor.models.crate import CrateKind
 from serato_doctor.models.library import Library
 from serato_doctor.scanner import scan_audio
 
@@ -13,16 +14,21 @@ def test_generated_sample_library_has_expected_scenario(tmp_path):
     build_sample = runpy.run_path(str(generator_path))["build_sample"]
     sample_root = build_sample(tmp_path / "sample")
 
-    references = parse_crates(sample_root / "Serato" / "_Serato_" / "Subcrates")
+    crates = load_library_crates(sample_root / "Serato" / "_Serato_")
     tracks = scan_audio(sample_root / "Music")
-    results = Library.build(references, tracks).reconcile_by_filename()
+    library = Library.from_crates(crates, tracks)
+    results = library.reconcile_by_filename()
     missing = {
         result.reference.filename
         for result in results
         if not result.exists_by_filename
     }
 
-    assert len(list((sample_root / "Serato").rglob("*.crate"))) == 7
-    assert len(references) == 13
+    crate_files = list((sample_root / "Serato").rglob("*.crate"))
+    smart_files = list((sample_root / "Serato").rglob("*.scrate"))
+    assert len(crate_files) + len(smart_files) == 7
+    assert len(library.references) == 13
     assert len(tracks) == 10
     assert missing == {"Missing.mp3", "Old Name.mp3"}
+    assert sum(crate.kind is CrateKind.STATIC for crate in crates) == 5
+    assert sum(crate.kind is CrateKind.SMART for crate in crates) == 2

tests/test_scanner.py

@@ -1,4 +1,6 @@
-from serato_doctor.scanner import scan_audio
+from pathlib import Path
+
+from serato_doctor.scanner import scan_audio, scan_filesystem
 
 
 def test_scan_audio_finds_supported_files(tmp_path):
@@ -15,3 +17,34 @@ def test_scan_audio_finds_supported_files(tmp_path):
     first = next(track for track in tracks if track.filename == "First.MP3")
     assert first.suffix == ".mp3"
     assert first.size == len(b"synthetic audio")
+
+
+def test_scan_filesystem_reports_broken_symlink(tmp_path):
+    music = tmp_path / "music"
+    music.mkdir()
+    link = music / "Missing.mp3"
+    link.symlink_to("not-there.mp3")
+
+    result = scan_filesystem(music)
+
+    assert result.tracks == ()
+    assert len(result.broken_symlinks) == 1
+    assert result.broken_symlinks[0].path == link
+    assert result.broken_symlinks[0].target == Path("not-there.mp3")
+
+
+def test_valid_audio_symlink_is_scanned_normally(tmp_path):
+    music = tmp_path / "music"
+    music.mkdir()
+    target = music / "Target.mp3"
+    target.write_bytes(b"synthetic audio")
+    link = music / "Linked.mp3"
+    link.symlink_to(target)
+
+    result = scan_filesystem(music)
+
+    assert {track.filename for track in result.tracks} == {
+        "Linked.mp3",
+        "Target.mp3",
+    }
+    assert result.broken_symlinks == ()

tests/test_web.py

@@ -0,0 +1,72 @@
+import runpy
+from pathlib import Path
+
+import pytest
+
+from serato_doctor.web import STATIC_FILES, analyze_paths, duplicate_repair
+
+
+def test_web_analysis_uses_production_health_pipeline(tmp_path):
+    generator = runpy.run_path(
+        str(Path(__file__).parents[1] / "samples/small-library/generate.py")
+    )
+    sample = generator["build_sample"](tmp_path / "sample")
+
+    result = analyze_paths(
+        sample / "Serato" / "_Serato_", sample / "Music"
+    )
+
+    assert result["score"] == 77.8
+    assert result["disk_tracks"] == 10
+    assert result["missing_references"] == 2
+    assert result["static_crates"] == 5
+    assert result["smart_crates"] == 2
+    assert result["database_entries"] == 10
+    assert result["database_library_matches"] == 10
+    assert result["database_missing_paths"] == 0
+    assert result["database_missing_unique_filenames"] == 0
+    assert result["tracks_missing_from_database"] == 0
+    assert result["details"]["old_crate_references"]["total"] == 2
+    assert result["details"]["old_crate_references"]["items"][0]["crate"]
+    assert result["details"]["suggested_matches"]["total"] == 0
+    assert result["details"]["unused_tracks"]["total"] == 1
+
+
+def test_web_analysis_rejects_missing_folders(tmp_path):
+    with pytest.raises(ValueError, match="Serato folder does not exist"):
+        analyze_paths(tmp_path / "missing", tmp_path)
+
+
+def test_web_static_assets_are_declared_and_packaged():
+    asset_root = Path(__file__).parents[1] / "serato_doctor" / "webui"
+
+    assert set(STATIC_FILES) == {"/", "/app.css", "/app.js"}
+    assert all((asset_root / filename).is_file() for filename, _ in STATIC_FILES.values())
+    html = (asset_root / "index.html").read_text(encoding="utf-8")
+    assert "Missing tracks in Serato" in html
+    assert "Old crate references" in html
+    assert "Choose a diagnostic" in html
+    assert 'data-detail="database_missing_tracks"' in html
+    assert 'data-detail="old_crate_references"' in html
+    assert html.count('class="info-button"') >= 10
+
+
+def test_duplicate_repair_preview_does_not_change_files(tmp_path):
+    serato = tmp_path / "_Serato_"
+    serato.mkdir()
+    music = tmp_path / "Music"
+    first = music / "A" / "Track.mp3"
+    second = music / "B" / "Track.mp3"
+    first.parent.mkdir(parents=True)
+    second.parent.mkdir(parents=True)
+    first.write_bytes(b"first")
+    second.write_bytes(b"second")
+
+    result = duplicate_repair(
+        serato, music, first, (first, second), backup_limit=10
+    )
+
+    assert result["applied"] is False
+    assert result["database_v2_modified"] is False
+    assert second.read_bytes() == b"second"
+    assert not second.is_symlink()