"""Duplicate engine: canonical link, phash version, clusters, members, negative links.

Revision ID: 0002_duplicate_engine
Revises: 0001_initial_identity
Create Date: 2026-07-15
"""

import sqlalchemy as sa
from alembic import op

revision = "0002_duplicate_engine"
down_revision = "0001_initial_identity"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # Plain ADD COLUMN: SQLite cannot ALTER-ADD a foreign key, and the ORM model
    # keeps the ForeignKey for relationship metadata. canonical_asset_id is a soft
    # self-link validated in the service (no cycles), not DB-enforced.
    op.add_column("assets", sa.Column("phash_version", sa.Integer(), nullable=True))
    op.add_column("assets", sa.Column("canonical_asset_id", sa.String(), nullable=True))
    op.create_index("ix_assets_canonical_asset_id", "assets", ["canonical_asset_id"])

    op.create_table(
        "duplicate_clusters",
        sa.Column("id", sa.String(), primary_key=True),
        sa.Column("method", sa.String(), nullable=False),
        sa.Column("confidence", sa.String(), nullable=False),
        sa.Column("state", sa.String(), nullable=False),
        sa.Column("decision", sa.String(), nullable=True),
        sa.Column(
            "canonical_asset_id", sa.String(), sa.ForeignKey("assets.id"), nullable=True
        ),
        sa.Column("version", sa.Integer(), nullable=False, server_default="1"),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.text("CURRENT_TIMESTAMP"),
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.text("CURRENT_TIMESTAMP"),
        ),
        sa.Column("decided_at", sa.DateTime(timezone=True), nullable=True),
    )
    op.create_index("ix_duplicate_clusters_state", "duplicate_clusters", ["state"])

    op.create_table(
        "duplicate_members",
        sa.Column(
            "cluster_id",
            sa.String(),
            sa.ForeignKey("duplicate_clusters.id"),
            primary_key=True,
        ),
        sa.Column(
            "asset_id", sa.String(), sa.ForeignKey("assets.id"), primary_key=True
        ),
        sa.Column("role", sa.String(), nullable=False, server_default="member"),
        sa.Column("distance", sa.Integer(), nullable=True),
        sa.Column("evidence", sa.String(), nullable=True),
        sa.Column(
            "added_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.text("CURRENT_TIMESTAMP"),
        ),
    )
    op.create_index("ix_duplicate_members_asset_id", "duplicate_members", ["asset_id"])

    op.create_table(
        "duplicate_negative_links",
        sa.Column(
            "asset_a", sa.String(), sa.ForeignKey("assets.id"), primary_key=True
        ),
        sa.Column(
            "asset_b", sa.String(), sa.ForeignKey("assets.id"), primary_key=True
        ),
        sa.Column("reason", sa.String(), nullable=True),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.text("CURRENT_TIMESTAMP"),
        ),
    )


def downgrade() -> None:
    op.drop_table("duplicate_negative_links")
    op.drop_table("duplicate_members")
    op.drop_table("duplicate_clusters")
    op.drop_index("ix_assets_canonical_asset_id", "assets")
    op.drop_column("assets", "canonical_asset_id")
    op.drop_column("assets", "phash_version")