"""Add memory_relations table (Phase 3 — relational tier).

Revision ID: 006
Revises: 1f5975a4f3f4
Create Date: 2026-04-16
"""

from __future__ import annotations

from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op
from sqlalchemy.dialects import postgresql

revision: str = "006"
down_revision: Union[str, None] = "1f5975a4f3f4"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "memory_relations",
        sa.Column("id", postgresql.UUID(as_uuid=False), primary_key=True),
        sa.Column(
            "user_id",
            postgresql.UUID(as_uuid=False),
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column("subject_label", sa.String(128), nullable=False),
        sa.Column("subject_type", sa.String(32), nullable=False),
        sa.Column("predicate", sa.String(64), nullable=False),
        sa.Column("object_label", sa.String(128), nullable=False),
        sa.Column("object_type", sa.String(32), nullable=False),
        sa.Column("confidence", sa.Float, nullable=False, server_default="0.7"),
        sa.Column(
            "source_episode_id",
            postgresql.UUID(as_uuid=False),
            sa.ForeignKey("memory_episodic.id", ondelete="SET NULL"),
            nullable=True,
        ),
        sa.Column("notes_encrypted", sa.LargeBinary, nullable=True),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.func.now(),
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.func.now(),
        ),
        sa.Column("last_confirmed_at", sa.DateTime(timezone=True), nullable=True),
    )
    op.create_index(
        "memory_relations_user_subject_idx",
        "memory_relations",
        ["user_id", "subject_label"],
    )
    op.create_index(
        "memory_relations_user_predicate_idx",
        "memory_relations",
        ["user_id", "predicate"],
    )


def downgrade() -> None:
    op.drop_index("memory_relations_user_predicate_idx", "memory_relations")
    op.drop_index("memory_relations_user_subject_idx", "memory_relations")
    op.drop_table("memory_relations")