"""Duplicate clusters, their members, and not-duplicate negative links.

A cluster is a reviewable grouping produced by a detection ``method`` (exact,
pixel, or perceptual) at a ``confidence`` band. Exact/pixel clusters can be
decided automatically; perceptual clusters stay open for human review. Every
member carries the evidence behind its inclusion. Negative links record
``not_duplicate`` decisions so rescans do not re-suggest a rejected pair.
"""

from __future__ import annotations

from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, Integer, String, func
from sqlalchemy.orm import Mapped, mapped_column

from photo_pipeline.db import Base


class DuplicateCluster(Base):
    __tablename__ = "duplicate_clusters"

    id: Mapped[str] = mapped_column(String, primary_key=True)
    method: Mapped[str] = mapped_column(String, nullable=False)  # exact|pixel|perceptual
    confidence: Mapped[str] = mapped_column(String, nullable=False)  # band name
    state: Mapped[str] = mapped_column(String, nullable=False)  # open|decided|dismissed|reopened
    decision: Mapped[str | None] = mapped_column(String)  # canonical|not_duplicate|deferred
    canonical_asset_id: Mapped[str | None] = mapped_column(ForeignKey("assets.id"))
    version: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
    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()
    )
    decided_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))


class DuplicateMember(Base):
    __tablename__ = "duplicate_members"

    cluster_id: Mapped[str] = mapped_column(
        ForeignKey("duplicate_clusters.id"), primary_key=True
    )
    asset_id: Mapped[str] = mapped_column(ForeignKey("assets.id"), primary_key=True)
    role: Mapped[str] = mapped_column(String, nullable=False, default="member")  # member|canonical|variant
    distance: Mapped[int | None] = mapped_column(Integer)  # phash distance to representative
    evidence: Mapped[str | None] = mapped_column(String)  # JSON blob explaining inclusion
    added_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )


class DuplicateNegativeLink(Base):
    __tablename__ = "duplicate_negative_links"

    asset_a: Mapped[str] = mapped_column(ForeignKey("assets.id"), primary_key=True)
    asset_b: Mapped[str] = mapped_column(ForeignKey("assets.id"), primary_key=True)
    reason: Mapped[str | None] = mapped_column(String)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )