Introduce core library model

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
+        )