from __future__ import annotations

import uuid
from datetime import datetime

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

from . import Base

# The Keep-style palette. Stored as a key string, so the actual tints live in the
# frontend and can change without a schema migration.
NOTE_COLORS = {
    "default",
    "red",
    "orange",
    "yellow",
    "green",
    "teal",
    "blue",
    "purple",
    "pink",
    "gray",
}


class Note(Base):
    __tablename__ = "notes"
    __table_args__ = (
        # Covers the board queries: a user's notes filtered by trash/archive state,
        # pinned first.
        Index("ix_notes_owner_board", "owner_id", "deleted_at", "archived", "pinned"),
    )

    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
    )
    title: Mapped[str | None] = mapped_column(Text(), nullable=True)
    # The note's display NAME: explicit title if set, else the first non-empty body
    # line (see notes.derive_display_title). Persisted + normalized-matched so every
    # note — even a body-only one — is nameable, searchable, graphable, and
    # [[wiki-link]]-able without forcing the user to type a title.
    display_title: Mapped[str] = mapped_column(Text(), nullable=False, server_default="")
    body: Mapped[str] = mapped_column(Text(), nullable=False, server_default="")
    color: Mapped[str] = mapped_column(Text(), nullable=False, server_default="default")
    # 'text' (freeform body) or 'list' (a checklist of note_items).
    kind: Mapped[str] = mapped_column(Text(), nullable=False, server_default="text")
    # Manual drag order (higher = earlier); 0 until the user reorders.
    position: Mapped[int] = mapped_column(Integer(), nullable=False, server_default="0")
    pinned: Mapped[bool] = mapped_column(Boolean(), nullable=False, server_default=func.false())
    archived: Mapped[bool] = mapped_column(Boolean(), nullable=False, server_default=func.false())
    # Soft delete: non-null => in Trash. Restore sets it back to null.
    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    # Optional reminder time (surfaced in the Reminders view; no push in M3).
    remind_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
    )
    # Sync (M8): a monotonic per-row revision drawn from sync_revision_seq and assigned
    # by a DB trigger on every insert/update — the delta cursor native clients pull
    # against. Nullable in the ORM because the trigger populates it server-side.
    sync_revision: Mapped[int | None] = mapped_column(BigInteger(), nullable=True)
    # Hard-delete tombstone: non-null => permanently deleted (content cleared), kept so
    # offline clients learn the row is gone. Distinct from deleted_at (= recoverable trash).
    purged_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    def serialize(self) -> dict:
        return {
            "id": str(self.id),
            "title": self.title,
            "display_title": self.display_title,
            "body": self.body,
            "color": self.color,
            "kind": self.kind,
            "position": self.position,
            "pinned": self.pinned,
            "archived": self.archived,
            "trashed": self.deleted_at is not None,
            "remind_at": self.remind_at.isoformat() if self.remind_at else None,
            "created_at": self.created_at.isoformat() if self.created_at else None,
            "updated_at": self.updated_at.isoformat() if self.updated_at else None,
        }