Add explainable matching engine

.gitignore

@@ -2,7 +2,9 @@ __pycache__/
 *.pyc
 .env
 .venv/
+*.egg-info/
 reports/
+samples/small-library/generated/
 *.sqlite
 *.db
 *.csv
@@ -11,3 +13,6 @@ reports/
 # Never commit personal Serato data
 database V2
 *.crate
+
+# macOS
+.DS_Store

CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing
+
+## Branching
+
+- `main` is stable.
+- `develop` is the integration branch.
+- Feature branches use: `feature/<name>`.
+
+## Safety Rules
+
+Never commit personal music library files, Serato databases, or crates.
+
+Never write repair code without dry-run mode, backup plan, and rollback log.
+
+## Testing
+
+Install development dependencies with `python3 -m pip install -e '.[dev]'`.
+
+Run `pytest` before committing. Tests and fixtures must use synthetic library data.

ROADMAP.md

@@ -0,0 +1,51 @@
+# Serato Doctor Roadmap
+
+## v0.1 — Library Inspector
+
+- [x] Project repository
+- [x] Filesystem scanner
+- [x] Serato crate parser
+- [x] Missing reference CSV report
+- [x] Grouped missing reference report
+- [ ] HTML health dashboard
+- [x] Test suite
+- [x] Sample library fixtures
+- [ ] Database V2 read-only parser
+- [x] Configuration
+- [x] Logging
+- [x] Matching engine
+
+## v0.2 — Diagnostics
+
+- [ ] Duplicate filename detection
+- [ ] Duplicate audio hash detection
+- [ ] Broken symlink detection
+- [ ] Orphaned audio detection
+- [ ] OneDrive rename detection
+- [ ] Crate classification: static vs smart/dynamic
+- [ ] Library health score
+
+## v0.3 — Safe Repair
+
+- [ ] Dry-run repair plan
+- [ ] Backup before repair
+- [ ] Compatibility symlink creation
+- [ ] Compatibility copy creation
+- [ ] Rename repair
+- [ ] Rollback log
+
+## v0.4 — Migration Wizard
+
+- [ ] Move library root
+- [ ] Cloud provider migration
+- [ ] External drive migration
+- [ ] Verify moved library
+- [ ] Update application references
+
+## v1.0 — DJ Library Doctor
+
+- [ ] Desktop UI
+- [ ] Serato support
+- [ ] Rekordbox support
+- [ ] VirtualDJ support
+- [ ] Engine DJ support

docs/ARCHITECTURE.md

@@ -0,0 +1,11 @@
+# Architecture
+
+Serato Doctor is designed as a DJ library inspection, repair, and migration platform.
+
+## Design Principles
+
+1. Read-only by default.
+2. Every repair must support preview/dry-run.
+3. Every repair must create a backup or rollback path.
+4. Application-specific logic lives in engines.
+5. Core matching and scanning logic should be application-agnostic.

docs/case-studies/onedrive-mac-migration.md

@@ -0,0 +1,26 @@
+# Case Study: OneDrive Mac Migration
+
+## Scenario
+
+A large Serato DJ library was migrated from an older Mac to a newer Mac using OneDrive.
+
+## Symptoms
+
+- OneDrive client stuck syncing
+- Duplicate OneDrive folders
+- Thousands of files renamed with trailing ` 2`
+- Serato reported many tracks as missing
+- Some files existed on disk but still appeared orange in Serato
+
+## Findings
+
+- OneDrive sync state was rebuilt successfully
+- Thousands of orphaned filename conflicts were repaired
+- Some Serato references were stale database objects, not missing files
+- Smart/dynamic crates should be classified separately from static user crates
+
+## Lessons
+
+- Filesystem health and Serato database health are separate problems
+- Smart crates should not be treated the same as static crates
+- Repair tools must be read-only by default and generate a plan before changing anything

docs/design/configuration.md

@@ -0,0 +1,25 @@
+# Scan Configuration
+
+## Problem
+
+The prototype recognized crate paths by matching one developer's historical
+OneDrive path. That made otherwise valid libraries invisible to the parser.
+
+## Architecture
+
+`ScanConfig` owns the paths for a read-only scan. The CLI accepts repeatable
+`--reference-root` options for roots embedded in crates before a migration. The
+parser uses those roots as record boundaries. Without explicit roots, it recognizes
+generic macOS home and mounted-volume paths without embedding a username.
+
+## Edge Cases
+
+- A library may have references from more than one historical root.
+- Root paths may contain spaces or have leading/trailing separators.
+- Existing `/Users/...` and `/Volumes/...` crates must work without new flags.
+- A record without a recognized terminator remains ignored.
+
+## Verification
+
+Tests cover default root discovery, a custom migrated root, the CLI option, and
+the existing synthetic sample library. The scanner remains read-only.

docs/design/logging.md

@@ -0,0 +1,25 @@
+# Application Logging
+
+## Problem
+
+The CLI reports final counts but provides no diagnostic trail when a scan behaves
+unexpectedly. Troubleshooting should not require adding print statements or expose
+library contents by default.
+
+## Architecture
+
+The project uses an isolated standard-library logger. It has no visible output by
+default. `--verbose` writes progress to standard error, while `--log-file PATH`
+writes an informational audit trail. Normal result lines remain on standard output.
+
+## Edge Cases
+
+- Reconfiguring logging in the same process must not duplicate handlers.
+- Console and file logging may be enabled together.
+- Log messages contain aggregate counts, not track names or crate contents.
+- A default scan must remain quiet except for its established result output.
+
+## Verification
+
+Tests verify quiet defaults, file output, handler replacement, and unchanged CLI
+result lines. The full sample-library scan remains read-only.

docs/design/matching-engine.md

@@ -0,0 +1,29 @@
+# Explainable Matching Engine
+
+## Problem
+
+Missing references need ranked candidate files, but a filename-only yes/no check
+cannot explain ambiguity or cloud-provider conflict names.
+
+## Architecture
+
+The read-only matching engine indexes normalized filenames and scores only related
+candidates. Every score contains evidence for filename, extension, and parent
+folder. Exact filenames earn 60 points, normalized names 55, numeric conflict-name
+matches 50, extensions 10, and parent folders 20.
+
+The displayed percentage is an evidence score, not a statistical probability.
+Metadata, duration, hashes, and fingerprints can add stronger evidence later.
+
+## Edge Cases
+
+- Unicode and case differences.
+- OneDrive-style names such as `Track 2.mp3`.
+- Duplicate candidates in different folders.
+- Legitimate numbered song titles, which remain candidates but are never repaired.
+- Unrelated names, which are not emitted as candidates.
+
+## Verification
+
+Tests cover exact, normalized, conflict-suffix, ambiguous, and unrelated filenames.
+Candidate ordering is deterministic. The engine never changes a track or reference.

docs/design/sample-library.md

@@ -0,0 +1,26 @@
+# Synthetic Sample Library
+
+## Problem
+
+Real Serato libraries contain private paths, listening history, and copyrighted
+music. Contributors still need a repeatable library for tests and demonstrations.
+
+## Architecture
+
+`samples/small-library/manifest.json` describes a compact migration scenario.
+`generate.py` turns that manifest into fake audio files and UTF-16-LE crate files
+inside an ignored `generated` directory. The generated files are disposable and
+contain no real audio or user library data.
+
+## Edge Cases
+
+- Five manually maintained crates and two smart/dynamic crates.
+- Mixed supported audio extensions.
+- One reference whose file is absent.
+- One stale reference whose file has been renamed.
+- References shared by static and smart crates.
+
+## Verification
+
+`pytest` generates the sample in a temporary directory and verifies its crate,
+track, and missing-reference counts through the production parser and scanner.

docs/design/test-foundation.md

@@ -0,0 +1,24 @@
+# Test Foundation
+
+## Problem
+
+The crate parser handles unusual binary text and known extension artifacts. Without
+automated tests, a small refactor could silently change library counts or reports.
+
+## Architecture
+
+Tests cover the read-only pipeline from crate and filesystem inputs through the
+core library model to CSV, text, and CLI output. All test data is synthetic and is
+created in temporary directories.
+
+## Edge Cases
+
+- Known MP3, M4A, WAV, and AIF decode artifacts.
+- Crate records without a recognized stop marker.
+- Supported extensions with mixed case and unsupported files.
+- References that exist by filename and references that remain missing.
+
+## Verification
+
+Run `pytest`. No test reads a real Serato library or writes outside pytest's
+temporary directory.

pyproject.toml

@@ -0,0 +1,22 @@
+[build-system]
+requires = ["setuptools>=61"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "serato-doctor"
+version = "0.1.0"
+description = "Inspect, diagnose, repair, and migrate DJ libraries."
+requires-python = ">=3.9"
+dependencies = []
+
+[project.optional-dependencies]
+dev = ["pytest>=8,<9"]
+
+[project.scripts]
+serato-doctor = "serato_doctor.cli:main"
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
+[tool.setuptools.packages.find]
+include = ["serato_doctor*"]

samples/small-library/README.md

@@ -0,0 +1,25 @@
+# Small Synthetic Library
+
+This fixture models a small Serato migration without containing music or personal
+library data. It has 10 fake audio files, five static crates, two smart crates,
+one absent song, and one renamed song.
+
+Generate it with:
+
+```shell
+python3 samples/small-library/generate.py
+```
+
+Analyze it with:
+
+```shell
+python3 -m serato_doctor.cli \
+  --serato samples/small-library/generated/Serato/_Serato_ \
+  --music samples/small-library/generated/Music \
+  --out samples/small-library/generated/scan.csv \
+  --report samples/small-library/generated/report.txt
+```
+
+Expected CLI counts are 13 crate references, 10 disk tracks, and 2 references
+missing by filename. Everything under `generated/` is disposable and ignored by
+Git.

samples/small-library/generate.py

@@ -0,0 +1,50 @@
+"""Generate a disposable, synthetic Serato library from the sample manifest."""
+
+import argparse
+import json
+from pathlib import Path
+from typing import Optional
+
+
+SAMPLE_ROOT = Path(__file__).parent
+SERATO_PATH_PREFIX = "Users/sample-user/OneDrive/Jukebox/"
+
+
+def load_manifest() -> dict:
+    return json.loads((SAMPLE_ROOT / "manifest.json").read_text(encoding="utf-8"))
+
+
+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)
+
+    for relative_path in manifest["tracks"]:
+        track_path = music_root / relative_path
+        track_path.parent.mkdir(parents=True, exist_ok=True)
+        track_path.write_bytes(
+            f"Synthetic Serato Doctor fixture: {relative_path}\n".encode("utf-8")
+        )
+
+    for crate in manifest["crates"]:
+        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"))
+
+    return root
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--output", type=Path)
+    args = parser.parse_args()
+    root = build_sample(args.output)
+    print(f"Generated synthetic library: {root}")
+
+
+if __name__ == "__main__":
+    main()

samples/small-library/manifest.json

@@ -0,0 +1,56 @@
+{
+  "tracks": [
+    "House/First.mp3",
+    "House/Second.m4a",
+    "Open Format/Third.wav",
+    "Open Format/Fourth.aif",
+    "Classics/Fifth.mp3",
+    "Classics/Sixth.flac",
+    "Warmup/Seventh.mp3",
+    "Warmup/Eighth.mp3",
+    "Renamed/New Name.mp3",
+    "Bonus/Ninth.MP3"
+  ],
+  "crates": [
+    {
+      "name": "House.crate",
+      "type": "static",
+      "references": ["House/First.mp3", "House/Second.m4a", "House/Missing.mp3"]
+    },
+    {
+      "name": "Open Format.crate",
+      "type": "static",
+      "references": ["Open Format/Third.wav", "Open Format/Fourth.aif"]
+    },
+    {
+      "name": "Classics.crate",
+      "type": "static",
+      "references": ["Classics/Fifth.mp3", "Classics/Sixth.flac"]
+    },
+    {
+      "name": "Renamed Tracks.crate",
+      "type": "static",
+      "references": ["Renamed/Old Name.mp3"]
+    },
+    {
+      "name": "Bonus.crate",
+      "type": "static",
+      "references": ["Bonus/Ninth.MP3"]
+    },
+    {
+      "name": "Compatible by key.crate",
+      "type": "smart",
+      "references": ["House/First.mp3", "House/Second.m4a"]
+    },
+    {
+      "name": "Smart Warmup.crate",
+      "type": "smart",
+      "references": ["Warmup/Seventh.mp3", "Warmup/Eighth.mp3"]
+    }
+  ],
+  "expected": {
+    "disk_tracks": 10,
+    "crate_references": 13,
+    "missing_by_filename": ["Missing.mp3", "Old Name.mp3"]
+  }
+}

serato_doctor/cli.py

@@ -1,9 +1,12 @@
 from pathlib import Path
 import argparse
-import csv
 
+from serato_doctor.config import ScanConfig
 from serato_doctor.crate_parser import parse_crates
+from serato_doctor.logging import configure_logging
+from serato_doctor.models.library import Library
 from serato_doctor.scanner import scan_audio
+from serato_doctor.report import write_csv, write_missing_report
 
 
 def main():
@@ -11,35 +14,54 @@ def main():
     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(
+        "--reference-root",
+        action="append",
+        default=[],
+        help="Old library root stored in crates; may be supplied more than once",
+    )
+    parser.add_argument(
+        "--verbose", action="store_true", help="Write diagnostic progress to stderr"
+    )
+    parser.add_argument("--log-file", help="Write scan progress to a log file")
     args = parser.parse_args()
 
-    serato = Path(args.serato)
-    music = Path(args.music)
-    out = Path(args.out)
+    config = ScanConfig.build(
+        serato=Path(args.serato),
+        music=Path(args.music),
+        out=Path(args.out),
+        report=Path(args.report),
+        reference_roots=(Path(root) for root in args.reference_root),
+        verbose=args.verbose,
+        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.debug("Serato directory: %s", config.serato)
+    logger.debug("Music directory: %s", config.music)
 
-    refs = parse_crates(serato / "Subcrates")
-    disk = scan_audio(music)
+    library = Library.build(
+        references=parse_crates(
+            config.serato / "Subcrates", config.reference_roots
+        ),
+        tracks=scan_audio(config.music),
+    )
+    results = library.reconcile_by_filename()
+    missing_count = sum(1 for result in results if not result.exists_by_filename)
+    logger.info("Parsed %d crate references", len(library.references))
+    logger.info("Scanned %d disk tracks", len(library.tracks))
+    logger.info("Found %d references missing by filename", missing_count)
 
-    disk_names = {t.filename for t in disk}
+    write_csv(results, config.out)
+    write_missing_report(results, config.report)
+    logger.info("Wrote CSV and missing-reference reports")
 
-    rows = []
-    for ref in refs:
-        rows.append({
-            "crate": str(ref.source),
-            "serato_path": str(ref.path),
-            "filename": ref.filename,
-            "exists_by_filename": ref.filename in disk_names,
-        })
-
-    with out.open("w", newline="", encoding="utf-8") as f:
-        writer = csv.DictWriter(f, fieldnames=["crate", "serato_path", "filename", "exists_by_filename"])
-        writer.writeheader()
-        writer.writerows(rows)
-
-    print(f"Crate references: {len(refs)}")
-    print(f"Disk tracks: {len(disk)}")
-    print(f"Missing by filename: {sum(1 for r in rows if not r['exists_by_filename'])}")
-    print(f"Wrote: {out}")
+    print(f"Crate references: {len(library.references)}")
+    print(f"Disk tracks: {len(library.tracks)}")
+    print(f"Missing by filename: {missing_count}")
+    print(f"CSV: {config.out}")
+    print(f"Report: {config.report}")
 
 
 if __name__ == "__main__":

serato_doctor/config.py

@@ -0,0 +1,37 @@
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Iterable, Optional, Tuple
+
+
+@dataclass(frozen=True)
+class ScanConfig:
+    """Read-only paths used for one library scan."""
+
+    serato: Path
+    music: Path
+    out: Path
+    report: Path
+    reference_roots: Tuple[Path, ...] = ()
+    verbose: bool = False
+    log_file: Optional[Path] = None
+
+    @classmethod
+    def build(
+        cls,
+        serato: Path,
+        music: Path,
+        out: Path,
+        report: Path,
+        reference_roots: Iterable[Path] = (),
+        verbose: bool = False,
+        log_file: Optional[Path] = None,
+    ) -> "ScanConfig":
+        return cls(
+            serato,
+            music,
+            out,
+            report,
+            tuple(reference_roots),
+            verbose,
+            log_file,
+        )

serato_doctor/crate_parser.py

@@ -1,47 +1,84 @@
 from pathlib import Path
-import re
+from typing import Iterable, Tuple
 
-from serato_doctor.models import TrackReference
-
-AUDIO_EXTS = "mp3|m4a|wav|aif|aiff|flac|MP3|M4A|WAV|AIF|AIFF|FLAC"
+from serato_doctor.models.crate import Crate
+from serato_doctor.models.reference import TrackReference
 
 
 def read_crate_text(crate_path: Path) -> str:
-    raw = crate_path.read_bytes()
-    for enc in ("utf-16-be", "utf-16-le", "utf-8", "latin1"):
-        text = raw.decode(enc, errors="ignore")
-        if "Users" in text or "Jukebox" in text:
-            return text
-    return raw.decode("latin1", errors="ignore")
+    return crate_path.read_bytes().decode("utf-16-le", errors="ignore").replace("\x00", "")
 
 
-def parse_crate(crate_path: Path) -> list[TrackReference]:
+def clean_path(raw: str) -> str:
+    # Common Serato decode artifacts where final extension char gets merged.
+    raw = raw.replace(".mp漳", ".mp3")
+    raw = raw.replace(".MP漳", ".MP3")
+    raw = raw.replace(".m4愠", ".m4a")
+    raw = raw.replace(".M4愠", ".M4A")
+    raw = raw.replace(".wa瘠", ".wav")
+    raw = raw.replace(".WA瘠", ".WAV")
+    raw = raw.replace(".ai映", ".aif")
+    raw = raw.replace(".AI映", ".AIF")
+    return raw.strip()
+
+
+DEFAULT_PATH_MARKERS = ("Users/", "Volumes/")
+
+
+def path_markers(reference_roots: Iterable[Path]) -> Tuple[str, ...]:
+    configured = tuple(
+        root.expanduser().as_posix().strip("/") + "/" for root in reference_roots
+    )
+    return configured or DEFAULT_PATH_MARKERS
+
+
+def load_crate(crate_path: Path, reference_roots: Iterable[Path] = ()) -> Crate:
     text = read_crate_text(crate_path)
-
-    # Serato crate files often decode with weird spacing/null-ish characters.
-    # This finds paths from /Users/... through the audio extension without
-    # greedily scanning the entire file.
-    pattern = rf"/?Users/[^\r\n]+?\.(?:{AUDIO_EXTS})"
-
     refs = []
-    for match in re.finditer(pattern, text):
-        raw_path = "/" + match.group(0).lstrip("/")
-        raw_path = raw_path.replace("\x00", "")
-        path = Path(raw_path)
 
-        refs.append(
-            TrackReference(
-                source=crate_path,
-                path=path,
-                filename=path.name,
+    # Serato record markers seen after paths in UTF-16-LE decoded crate data.
+    stop_markers = ["牴k", "otrk", "ptrk", "tvcn", "ovct"]
+
+    for marker in path_markers(reference_roots):
+        for part in text.split(marker)[1:]:
+            candidate = marker + part
+
+            stops = [
+                candidate.find(stop)
+                for stop in stop_markers
+                if candidate.find(stop) != -1
+            ]
+            if not stops:
+                continue
+
+            raw_path = "/" + candidate[: min(stops)]
+            raw_path = clean_path(raw_path)
+
+            path = Path(raw_path)
+            refs.append(
+                TrackReference(
+                    source=crate_path,
+                    path=path,
+                    filename=path.name,
+                )
             )
-        )
 
-    return refs
+    return Crate(path=crate_path, references=tuple(refs))
 
 
-def parse_crates(root: Path) -> list[TrackReference]:
+def parse_crate(
+    crate_path: Path, reference_roots: Iterable[Path] = ()
+) -> list[TrackReference]:
+    """Parse references from one crate, preserving the prototype API."""
+
+    return list(load_crate(crate_path, reference_roots).references)
+
+
+def parse_crates(
+    root: Path, reference_roots: Iterable[Path] = ()
+) -> list[TrackReference]:
     refs = []
+    reference_roots = tuple(reference_roots)
     for crate in root.rglob("*.crate"):
-        refs.extend(parse_crate(crate))
+        refs.extend(parse_crate(crate, reference_roots))
     return refs

serato_doctor/logging.py

@@ -0,0 +1,40 @@
+import logging
+from pathlib import Path
+from typing import Optional
+
+
+LOGGER_NAME = "serato_doctor"
+LOG_FORMAT = "%(asctime)s %(levelname)s %(message)s"
+
+
+def configure_logging(
+    verbose: bool = False, log_file: Optional[Path] = None
+) -> logging.Logger:
+    """Configure isolated application logging and return the project logger."""
+
+    logger = logging.getLogger(LOGGER_NAME)
+    logger.setLevel(logging.DEBUG)
+    logger.propagate = False
+
+    for handler in logger.handlers[:]:
+        handler.close()
+        logger.removeHandler(handler)
+
+    formatter = logging.Formatter(LOG_FORMAT)
+
+    if verbose:
+        console = logging.StreamHandler()
+        console.setLevel(logging.DEBUG)
+        console.setFormatter(formatter)
+        logger.addHandler(console)
+
+    if log_file is not None:
+        file_handler = logging.FileHandler(log_file, encoding="utf-8")
+        file_handler.setLevel(logging.INFO)
+        file_handler.setFormatter(formatter)
+        logger.addHandler(file_handler)
+
+    if not logger.handlers:
+        logger.addHandler(logging.NullHandler())
+
+    return logger

serato_doctor/matching.py

@@ -0,0 +1,86 @@
+import re
+import unicodedata
+from collections import defaultdict
+from pathlib import Path
+from typing import DefaultDict, Iterable, List, Tuple
+
+from serato_doctor.models.match import MatchEvidence, TrackMatch
+from serato_doctor.models.reference import TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+def normalize(value: str) -> str:
+    return unicodedata.normalize("NFKC", value).casefold()
+
+
+def cloud_conflict_name(filename: str) -> str:
+    """Remove a trailing numeric cloud-conflict suffix from a filename stem."""
+
+    path = Path(filename)
+    stem = re.sub(r" \d+$", "", path.stem)
+    return normalize(stem + path.suffix)
+
+
+def score_candidate(reference: TrackReference, track: DiskTrack) -> TrackMatch:
+    reference_name = reference.filename
+    track_name = track.filename
+
+    if reference_name == track_name:
+        filename_points = 60
+        filename_reason = "Filename is identical"
+    elif normalize(reference_name) == normalize(track_name):
+        filename_points = 55
+        filename_reason = "Filename matches after case and Unicode normalization"
+    elif cloud_conflict_name(reference_name) == cloud_conflict_name(track_name):
+        filename_points = 50
+        filename_reason = "Filename matches after removing a numeric conflict suffix"
+    else:
+        filename_points = 0
+        filename_reason = "Filename does not match"
+
+    same_extension = normalize(reference.path.suffix) == normalize(track.suffix)
+    same_parent = normalize(reference.path.parent.name) == normalize(
+        track.path.parent.name
+    )
+    evidence = (
+        MatchEvidence(
+            "filename",
+            filename_points > 0,
+            filename_points,
+            60,
+            filename_reason,
+        ),
+        MatchEvidence(
+            "extension",
+            same_extension,
+            10 if same_extension else 0,
+            10,
+            "File extension matches" if same_extension else "File extension differs",
+        ),
+        MatchEvidence(
+            "parent_folder",
+            same_parent,
+            20 if same_parent else 0,
+            20,
+            "Parent folder matches" if same_parent else "Parent folder differs",
+        ),
+    )
+    return TrackMatch(reference, track, evidence)
+
+
+class MatchingEngine:
+    """Find and rank filename-related disk candidates without modifying files."""
+
+    def __init__(self, tracks: Iterable[DiskTrack]):
+        self._by_conflict_name: DefaultDict[str, List[DiskTrack]] = defaultdict(list)
+        for track in tracks:
+            self._by_conflict_name[cloud_conflict_name(track.filename)].append(track)
+
+    def candidates_for(self, reference: TrackReference) -> Tuple[TrackMatch, ...]:
+        candidates = self._by_conflict_name.get(
+            cloud_conflict_name(reference.filename), []
+        )
+        matches = [score_candidate(reference, track) for track in candidates]
+        return tuple(
+            sorted(matches, key=lambda match: (-match.score, str(match.track.path)))
+        )

serato_doctor/models/__init__.py

@@ -0,0 +1,15 @@
+from serato_doctor.models.crate import Crate
+from serato_doctor.models.library import Library
+from serato_doctor.models.match import MatchEvidence, TrackMatch
+from serato_doctor.models.reference import ReferenceResult, TrackReference
+from serato_doctor.models.track import DiskTrack
+
+__all__ = [
+    "Crate",
+    "DiskTrack",
+    "Library",
+    "MatchEvidence",
+    "ReferenceResult",
+    "TrackMatch",
+    "TrackReference",
+]

serato_doctor/models/crate.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Tuple
+
+from serato_doctor.models.reference import TrackReference
+
+
+@dataclass(frozen=True)
+class Crate:
+    """A Serato crate and the track references parsed from it."""
+
+    path: Path
+    references: Tuple[TrackReference, ...]

serato_doctor/models/library.py

@@ -0,0 +1,31 @@
+from dataclasses import dataclass
+from typing import Iterable, Tuple
+
+from serato_doctor.models.reference import ReferenceResult, TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+@dataclass(frozen=True)
+class Library:
+    """The read-only view of crate references and audio found on disk."""
+
+    references: Tuple[TrackReference, ...]
+    tracks: Tuple[DiskTrack, ...]
+
+    @classmethod
+    def build(
+        cls,
+        references: Iterable[TrackReference],
+        tracks: Iterable[DiskTrack],
+    ) -> "Library":
+        return cls(tuple(references), tuple(tracks))
+
+    def reconcile_by_filename(self) -> Tuple[ReferenceResult, ...]:
+        disk_names = {track.filename for track in self.tracks}
+        return tuple(
+            ReferenceResult(
+                reference=reference,
+                exists_by_filename=reference.filename in disk_names,
+            )
+            for reference in self.references
+        )

serato_doctor/models/match.py

@@ -0,0 +1,39 @@
+from dataclasses import dataclass
+from typing import Tuple
+
+from serato_doctor.models.reference import TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+@dataclass(frozen=True)
+class MatchEvidence:
+    """One explainable scoring decision for a candidate track."""
+
+    field: str
+    matched: bool
+    points: int
+    max_points: int
+    explanation: str
+
+
+@dataclass(frozen=True)
+class TrackMatch:
+    """A ranked candidate backed by explicit, inspectable evidence."""
+
+    reference: TrackReference
+    track: DiskTrack
+    evidence: Tuple[MatchEvidence, ...]
+
+    @property
+    def score(self) -> int:
+        return sum(item.points for item in self.evidence)
+
+    @property
+    def max_score(self) -> int:
+        return sum(item.max_points for item in self.evidence)
+
+    @property
+    def score_percent(self) -> float:
+        if not self.max_score:
+            return 0.0
+        return round(self.score / self.max_score * 100, 1)

serato_doctor/models/reference.py

@@ -0,0 +1,27 @@
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass(frozen=True)
+class TrackReference:
+    """A track path referenced by a Serato crate."""
+
+    source: Path
+    path: Path
+    filename: str
+
+
+@dataclass(frozen=True)
+class ReferenceResult:
+    """The filename-level reconciliation result for a crate reference."""
+
+    reference: TrackReference
+    exists_by_filename: bool
+
+    def as_row(self) -> dict:
+        return {
+            "crate": str(self.reference.source),
+            "serato_path": str(self.reference.path),
+            "filename": self.reference.filename,
+            "exists_by_filename": self.exists_by_filename,
+        }

serato_doctor/models/track.py

@@ -2,15 +2,10 @@ from dataclasses import dataclass
 from pathlib import Path
 
 
-@dataclass(frozen=True)
-class TrackReference:
-    source: Path
-    path: Path
-    filename: str
-
-
 @dataclass(frozen=True)
 class DiskTrack:
+    """An audio file discovered on disk."""
+
     path: Path
     filename: str
     size: int

serato_doctor/report.py

@@ -0,0 +1,47 @@
+from collections import Counter, defaultdict
+from pathlib import Path
+from typing import Iterable
+import csv
+
+from serato_doctor.models.reference import ReferenceResult
+
+
+def write_missing_report(results: Iterable[ReferenceResult], out: Path) -> None:
+    rows = [result.as_row() for result in results]
+    missing = [r for r in rows if not r["exists_by_filename"]]
+
+    crate_counts = Counter(r["crate"] for r in missing)
+    filename_counts = Counter(r["filename"] for r in missing)
+
+    with out.open("w", encoding="utf-8") as f:
+        f.write("# Serato Doctor Missing Report\n\n")
+        f.write(f"Total missing references: {len(missing)}\n\n")
+
+        f.write("## Missing by crate\n\n")
+        for crate, count in crate_counts.most_common():
+            f.write(f"{count:5}  {crate}\n")
+
+        f.write("\n## Most common missing filenames\n\n")
+        for filename, count in filename_counts.most_common(100):
+            f.write(f"{count:5}  {filename}\n")
+
+        f.write("\n## Detail\n\n")
+        by_crate = defaultdict(list)
+        for r in missing:
+            by_crate[r["crate"]].append(r["filename"])
+
+        for crate, names in sorted(by_crate.items()):
+            f.write(f"\n### {crate}\n")
+            for name in sorted(set(names)):
+                f.write(f"- {name}\n")
+
+
+def write_csv(results: Iterable[ReferenceResult], out: Path) -> None:
+    rows = [result.as_row() for result in results]
+    with out.open("w", newline="", encoding="utf-8") as f:
+        writer = csv.DictWriter(
+            f,
+            fieldnames=["crate", "serato_path", "filename", "exists_by_filename"],
+        )
+        writer.writeheader()
+        writer.writerows(rows)

serato_doctor/scanner.py

@@ -1,6 +1,6 @@
 from pathlib import Path
 
-from serato_doctor.models import DiskTrack
+from serato_doctor.models.track import DiskTrack
 
 AUDIO_SUFFIXES = {".mp3", ".m4a", ".wav", ".aif", ".aiff", ".flac"}
 

tests/test_cli.py

@@ -0,0 +1,86 @@
+import csv
+import sys
+
+from serato_doctor.cli import main
+
+
+def test_cli_writes_reports_and_prints_counts(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/OneDrive/Jukebox/Found.mp漳牴k"
+        "Users/sample-user/OneDrive/Jukebox/Missing.mp漳牴k"
+    )
+    (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",
+            "--serato",
+            str(serato),
+            "--music",
+            str(music),
+            "--out",
+            str(csv_path),
+            "--report",
+            str(report_path),
+        ],
+    )
+
+    main()
+
+    captured = capsys.readouterr()
+    output = captured.out
+    assert captured.err == ""
+    assert "Crate references: 2" in output
+    assert "Disk tracks: 1" in output
+    assert "Missing by filename: 1" in output
+    assert f"CSV: {csv_path}" in output
+    assert f"Report: {report_path}" in output
+    with csv_path.open(newline="", encoding="utf-8") as csv_file:
+        rows = list(csv.DictReader(csv_file))
+    assert [row["exists_by_filename"] for row in rows] == ["True", "False"]
+    assert "Total missing references: 1" in report_path.read_text(encoding="utf-8")
+
+
+def test_cli_accepts_old_reference_root(tmp_path, monkeypatch, capsys):
+    serato = tmp_path / "serato"
+    subcrates = serato / "Subcrates"
+    music = tmp_path / "music"
+    subcrates.mkdir(parents=True)
+    music.mkdir()
+    (subcrates / "Test.crate").write_bytes(
+        "Archive/Jukebox/Found.mp3otrk".encode("utf-16-le")
+    )
+    (music / "Found.mp3").write_bytes(b"synthetic audio")
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        [
+            "serato-doctor",
+            "--serato",
+            str(serato),
+            "--music",
+            str(music),
+            "--out",
+            str(tmp_path / "scan.csv"),
+            "--report",
+            str(tmp_path / "report.txt"),
+            "--reference-root",
+            "/Archive/Jukebox",
+        ],
+    )
+
+    main()
+
+    output = capsys.readouterr().out
+    assert "Crate references: 1" in output
+    assert "Missing by filename: 0" in output

tests/test_config.py

@@ -0,0 +1,17 @@
+from pathlib import Path
+
+from serato_doctor.config import ScanConfig
+
+
+def test_scan_config_freezes_reference_roots():
+    roots = (Path(root) for root in ["/old/one", "/old/two"])
+
+    config = ScanConfig.build(
+        serato=Path("serato"),
+        music=Path("music"),
+        out=Path("scan.csv"),
+        report=Path("report.txt"),
+        reference_roots=roots,
+    )
+
+    assert config.reference_roots == (Path("/old/one"), Path("/old/two"))

tests/test_crates.py

@@ -0,0 +1,86 @@
+from pathlib import Path
+
+import pytest
+
+from serato_doctor.crate_parser import (
+    clean_path,
+    load_crate,
+    parse_crate,
+    parse_crates,
+    path_markers,
+)
+
+
+@pytest.mark.parametrize(
+    ("artifact", "expected"),
+    [
+        ("song.mp漳", "song.mp3"),
+        ("song.m4愠", "song.m4a"),
+        ("song.wa瘠", "song.wav"),
+        ("song.ai映", "song.aif"),
+    ],
+)
+def test_clean_path_repairs_known_extension_artifacts(artifact, expected):
+    assert clean_path(artifact) == expected
+
+
+def test_parse_crate_extracts_references(tmp_path):
+    crate_path = tmp_path / "House.crate"
+    crate_text = (
+        "header"
+        "Users/sample-user/OneDrive/Jukebox/House/First.mp漳牴k"
+        "metadata"
+        "Users/sample-user/OneDrive/Jukebox/House/Second.m4愠otrk"
+    )
+    crate_path.write_bytes(crate_text.encode("utf-16-le"))
+
+    crate = load_crate(crate_path)
+
+    assert crate.path == crate_path
+    assert [reference.filename for reference in crate.references] == [
+        "First.mp3",
+        "Second.m4a",
+    ]
+    assert parse_crate(crate_path) == list(crate.references)
+
+
+def test_parse_crate_ignores_record_without_stop_marker(tmp_path):
+    crate_path = Path(tmp_path) / "Incomplete.crate"
+    crate_path.write_bytes(
+        "Users/sample-user/OneDrive/Jukebox/House/Incomplete.mp3".encode(
+            "utf-16-le"
+        )
+    )
+
+    assert parse_crate(crate_path) == []
+
+
+def test_parse_crate_uses_configured_reference_root(tmp_path):
+    crate_path = tmp_path / "Migrated.crate"
+    crate_path.write_bytes(
+        "Archive/Old Library/House/Track.mp3otrk".encode("utf-16-le")
+    )
+
+    references = parse_crate(crate_path, [Path("/Archive/Old Library")])
+
+    assert references[0].path == Path("/Archive/Old Library/House/Track.mp3")
+
+
+def test_default_path_markers_do_not_contain_a_username():
+    assert path_markers([]) == ("Users/", "Volumes/")
+
+
+def test_parse_crates_reuses_configured_roots_for_every_crate(tmp_path):
+    for name in ("First", "Second"):
+        (tmp_path / f"{name}.crate").write_bytes(
+            f"Archive/Jukebox/{name}.mp3otrk".encode("utf-16-le")
+        )
+
+    references = parse_crates(
+        tmp_path, (root for root in [Path("/Archive/Jukebox")])
+    )
+
+    assert {reference.filename for reference in references} == {
+        "First.mp3",
+        "Second.mp3",
+    }

tests/test_library.py

@@ -0,0 +1,24 @@
+from pathlib import Path
+
+from serato_doctor.models.library import Library
+from serato_doctor.models.reference import TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+def test_library_reconciles_references_by_filename():
+    crate = Path("House.crate")
+    references = [
+        TrackReference(crate, Path("/old/Found.mp3"), "Found.mp3"),
+        TrackReference(crate, Path("/old/Missing.mp3"), "Missing.mp3"),
+    ]
+    tracks = [DiskTrack(Path("/new/Found.mp3"), "Found.mp3", 10, ".mp3")]
+
+    results = Library.build(references, tracks).reconcile_by_filename()
+
+    assert [result.exists_by_filename for result in results] == [True, False]
+    assert results[1].as_row() == {
+        "crate": "House.crate",
+        "serato_path": "/old/Missing.mp3",
+        "filename": "Missing.mp3",
+        "exists_by_filename": False,
+    }

tests/test_logging.py

@@ -0,0 +1,34 @@
+import logging
+
+from serato_doctor.logging import LOGGER_NAME, configure_logging
+
+
+def test_logging_is_quiet_by_default(capsys):
+    logger = configure_logging()
+
+    logger.info("not visible")
+
+    assert capsys.readouterr().err == ""
+
+
+def test_logging_writes_aggregate_progress_to_file(tmp_path):
+    log_path = tmp_path / "scan.log"
+    logger = configure_logging(log_file=log_path)
+
+    logger.info("Scanned %d disk tracks", 10)
+
+    contents = log_path.read_text(encoding="utf-8")
+    assert "INFO Scanned 10 disk tracks" in contents
+
+
+def test_reconfiguring_logging_replaces_handlers():
+    configure_logging(verbose=True)
+    logger = configure_logging(verbose=True)
+
+    active_handlers = [
+        handler
+        for handler in logger.handlers
+        if not isinstance(handler, logging.NullHandler)
+    ]
+    assert logger.name == LOGGER_NAME
+    assert len(active_handlers) == 1

tests/test_matcher.py

@@ -0,0 +1,62 @@
+from pathlib import Path
+
+from serato_doctor.matching import MatchingEngine, score_candidate
+from serato_doctor.models.reference import TrackReference
+from serato_doctor.models.track import DiskTrack
+
+
+def reference(filename, folder="House"):
+    return TrackReference(
+        Path("Test.crate"), Path("/old") / folder / filename, filename
+    )
+
+
+def track(filename, folder="House"):
+    path = Path("/new") / folder / filename
+    return DiskTrack(path, filename, 100, path.suffix.lower())
+
+
+def test_exact_candidate_has_full_evidence_score():
+    match = score_candidate(reference("Track.mp3"), track("Track.mp3"))
+
+    assert match.score == 90
+    assert match.max_score == 90
+    assert match.score_percent == 100.0
+    assert all(item.matched for item in match.evidence)
+
+
+def test_cloud_conflict_suffix_is_explained():
+    match = score_candidate(reference("Track.mp3"), track("Track 2.mp3"))
+
+    assert match.score == 80
+    assert match.score_percent == 88.9
+    assert match.evidence[0].explanation == (
+        "Filename matches after removing a numeric conflict suffix"
+    )
+
+
+def test_case_normalized_match_scores_below_exact():
+    match = score_candidate(reference("TRACK.MP3"), track("track.mp3"))
+
+    assert match.score == 85
+    assert match.evidence[0].points == 55
+
+
+def test_engine_omits_unrelated_filenames():
+    engine = MatchingEngine([track("Different.mp3")])
+
+    assert engine.candidates_for(reference("Missing.mp3")) == ()
+
+
+def test_ambiguous_candidates_are_ranked_deterministically():
+    engine = MatchingEngine(
+        [track("Track 2.mp3", "Other"), track("Track 3.mp3", "House")]
+    )
+
+    matches = engine.candidates_for(reference("Track.mp3"))
+
+    assert [match.track.filename for match in matches] == [
+        "Track 3.mp3",
+        "Track 2.mp3",
+    ]
+    assert [match.score for match in matches] == [80, 60]

tests/test_sample_library.py

@@ -0,0 +1,28 @@
+import runpy
+from pathlib import Path
+
+from serato_doctor.crate_parser import parse_crates
+from serato_doctor.models.library import Library
+from serato_doctor.scanner import scan_audio
+
+
+def test_generated_sample_library_has_expected_scenario(tmp_path):
+    generator_path = (
+        Path(__file__).parents[1] / "samples" / "small-library" / "generate.py"
+    )
+    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")
+    tracks = scan_audio(sample_root / "Music")
+    results = Library.build(references, tracks).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
+    assert len(tracks) == 10
+    assert missing == {"Missing.mp3", "Old Name.mp3"}

tests/test_scanner.py

@@ -0,0 +1,17 @@
+from serato_doctor.scanner import scan_audio
+
+
+def test_scan_audio_finds_supported_files(tmp_path):
+    music = tmp_path / "music"
+    nested = music / "House"
+    nested.mkdir(parents=True)
+    (nested / "First.MP3").write_bytes(b"synthetic audio")
+    (nested / "Second.flac").write_bytes(b"fixture")
+    (nested / "notes.txt").write_text("not audio", encoding="utf-8")
+
+    tracks = scan_audio(music)
+
+    assert {track.filename for track in tracks} == {"First.MP3", "Second.flac"}
+    first = next(track for track in tracks if track.filename == "First.MP3")
+    assert first.suffix == ".mp3"
+    assert first.size == len(b"synthetic audio")