"""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,
    )