"""agent runtime closed loop contract

Revision ID: 202603050001
Revises: 435419f8121c
Create Date: 2026-03-05 12:00:00
"""

from __future__ import annotations

from typing import Sequence, Union

from alembic import op


revision: str = "202603050001"
down_revision: Union[str, Sequence[str], None] = "202603040001"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.execute("ALTER TABLE sessions ADD COLUMN IF NOT EXISTS state_snapshot JSONB")
    with op.get_context().autocommit_block():
        op.execute(
            "CREATE INDEX CONCURRENTLY IF NOT EXISTS ix_messages_session_seq ON messages (session_id, seq)"
        )

    op.execute(
        """
        ALTER TABLE messages
        ADD CONSTRAINT chk_messages_tool_result_metadata
        CHECK (
            role != 'tool'
            OR (metadata IS NOT NULL AND metadata->>'type' = 'tool_result')
        )
        NOT VALID
        """
    )
    op.execute(
        "ALTER TABLE messages VALIDATE CONSTRAINT chk_messages_tool_result_metadata"
    )
    op.execute(
        """
        ALTER TABLE messages
        ADD CONSTRAINT chk_messages_assistant_metadata
        CHECK (
            role != 'assistant'
            OR (metadata IS NOT NULL AND metadata->>'type' IN ('tool_call', 'assistant_output'))
        )
        NOT VALID
        """
    )
    op.execute(
        "ALTER TABLE messages VALIDATE CONSTRAINT chk_messages_assistant_metadata"
    )


def downgrade() -> None:
    op.execute(
        "ALTER TABLE messages DROP CONSTRAINT IF EXISTS chk_messages_assistant_metadata"
    )
    op.execute(
        "ALTER TABLE messages DROP CONSTRAINT IF EXISTS chk_messages_tool_result_metadata"
    )
    op.execute("DROP INDEX IF EXISTS ix_messages_session_seq")
    op.execute("ALTER TABLE sessions DROP COLUMN IF EXISTS state_snapshot")