from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import BigInteger, Boolean, DateTime, ForeignKey, Text, UniqueConstraint, func
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column

from . import Base


class Label(Base):
    __tablename__ = "labels"
    __table_args__ = (UniqueConstraint("owner_id", "name", name="uq_labels_owner_name"),)

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    owner_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    name: Mapped[str] = mapped_column(Text(), nullable=False)
    color: Mapped[str] = mapped_column(Text(), nullable=False, default="default", server_default="default")
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())
    # Last-edit time — the LWW comparison field for sync (a rename/recolor bumps it).
    # Sync-push overrides it with the winning client edit-time; web edits set server-now.
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
    )
    # Sync (M8): monotonic per-row revision (from sync_revision_seq via DB trigger) so a
    # label rename/recolor/merge/delete propagates to native clients independently of notes.
    sync_revision: Mapped[int | None] = mapped_column(BigInteger(), nullable=True)
    # Hard-delete tombstone (content-less) so a deleted label is removed on clients.
    purged_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)


class NoteLabel(Base):
    """Join between a note and a label (both owned by the same user)."""

    __tablename__ = "note_labels"

    note_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("notes.id", ondelete="CASCADE"), primary_key=True
    )
    label_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("labels.id", ondelete="CASCADE"), primary_key=True
    )
    # True when this attachment came from a #tag in the note body (kept in sync with
    # the body); False = added manually via the label picker (independent of #tags).
    via_tag: Mapped[bool] = mapped_column(Boolean(), nullable=False, server_default=func.false())