feat: models

app/infrastructure/db/models/playlist.py

@@ -0,0 +1,55 @@
+"""ORM models for playlists and their ordered tracks."""
+
+import datetime as dt
+import uuid
+
+from sqlalchemy import DateTime, Float, ForeignKey, Integer, String, UniqueConstraint, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.infrastructure.db.base import Base
+from app.infrastructure.db.models.mixins import TimestampMixin, UUIDPrimaryKeyMixin
+
+
+class PlaylistModel(UUIDPrimaryKeyMixin, TimestampMixin, Base):
+    __tablename__ = "playlists"
+
+    name: Mapped[str] = mapped_column(String(512), nullable=False)
+    description: Mapped[str | None] = mapped_column(String(2048), nullable=True)
+    owner_id: Mapped[uuid.UUID] = mapped_column(
+        ForeignKey("users.id", ondelete="CASCADE"),
+        index=True,
+        nullable=False,
+    )
+    cover_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)
+    # Optimistic-locking / future sync counter — bumped on every mutation.
+    version: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
+
+
+class PlaylistTrackModel(UUIDPrimaryKeyMixin, Base):
+    """A track's membership in a playlist.
+
+    ``position`` is a float so a track can be inserted between two others
+    without reindexing the whole list (plan §4).
+    """
+
+    __tablename__ = "playlist_tracks"
+    __table_args__ = (
+        UniqueConstraint("playlist_id", "track_id", name="uq_playlist_tracks_playlist_id_track_id"),
+    )
+
+    playlist_id: Mapped[uuid.UUID] = mapped_column(
+        ForeignKey("playlists.id", ondelete="CASCADE"),
+        index=True,
+        nullable=False,
+    )
+    track_id: Mapped[uuid.UUID] = mapped_column(
+        ForeignKey("tracks.id", ondelete="CASCADE"),
+        index=True,
+        nullable=False,
+    )
+    position: Mapped[float] = mapped_column(Float, nullable=False)
+    added_at: Mapped[dt.datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
+    )