"""Add account_id to audit_logs and backfill via user_id.

Revision ID: 2a9056eddd90
Revises: 70a5dd746e83
Create Date: 2026-04-11 00:00:00.000000
"""
from typing import Sequence, Union
from alembic import op
import sqlalchemy as sa

revision: str = '2a9056eddd90'
down_revision: Union[str, None] = '70a5dd746e83'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.add_column('audit_logs', sa.Column('account_id', sa.UUID(), nullable=True))
    op.create_foreign_key(
        'fk_audit_logs_account_id', 'audit_logs', 'accounts',
        ['account_id'], ['id'], ondelete='CASCADE',
    )

    # Backfill: derive from the acting user's account
    op.execute("""
        UPDATE audit_logs al
        SET account_id = u.account_id
        FROM users u
        WHERE al.user_id = u.id
          AND u.account_id IS NOT NULL
          AND al.account_id IS NULL
    """)

    result = op.get_bind().execute(
        sa.text("SELECT COUNT(*) FROM audit_logs WHERE account_id IS NULL")
    )
    count = result.scalar()
    if count > 0:
        raise RuntimeError(
            f"ROLLBACK: {count} audit_logs rows have NULL account_id after backfill. "
            "All audit log entries must have an associated user with an account."
        )

    op.alter_column('audit_logs', 'account_id', nullable=False)
    op.create_index('ix_audit_logs_account_id', 'audit_logs', ['account_id'])


def downgrade() -> None:
    op.drop_index('ix_audit_logs_account_id', table_name='audit_logs')
    op.drop_constraint('fk_audit_logs_account_id', 'audit_logs', type_='foreignkey')
    op.drop_column('audit_logs', 'account_id')
