"""0018 tool_call_attempts attribution — record user/agent on the journal.

Adds ``tool_call_attempts.user_id`` / ``agent_id`` so tool analytics can
attribute attempts that never get a ``message_id`` — headless runs
(scheduled / webhook) execute tools before any conversation message
exists, and parse-failure rows never reach one at all.

DDL only — a whole-table UPDATE here would hold the ALTERs' ACCESS
EXCLUSIVE lock across the rewrite and stall live tool journaling. The
backfill lives in ``scripts/db/backfill_tool_attempts_attribution.py``;
until it runs, the analytics reader falls back to the parent message's
user for unstamped rows.

The index is built ``CONCURRENTLY`` in an autocommit block: the
``ADD COLUMN`` ALTERs commit first (a fast metadata-only change), so the
O(table-size) index build never runs while their ACCESS EXCLUSIVE lock
is held and never blocks live journaling.

Revision ID: 0018_tool_attempts_attribution
Revises: 0017_oidc_scim
"""

from typing import Sequence, Union

from alembic import op


revision: str = "0018_tool_attempts_attribution"
down_revision: Union[str, None] = "0017_oidc_scim"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.execute("ALTER TABLE tool_call_attempts ADD COLUMN user_id TEXT;")
    op.execute("ALTER TABLE tool_call_attempts ADD COLUMN agent_id UUID;")
    # CONCURRENTLY can't run inside a transaction; the autocommit block
    # commits the ALTERs above (releasing their lock) before building.
    # DROP IF EXISTS first so a failed concurrent build (which leaves an
    # INVALID index) is cleaned up on re-run.
    with op.get_context().autocommit_block():
        op.execute("DROP INDEX IF EXISTS tool_call_attempts_user_ts_idx;")
        op.execute(
            "CREATE INDEX CONCURRENTLY tool_call_attempts_user_ts_idx "
            "ON tool_call_attempts (user_id, attempted_at DESC) "
            "WHERE user_id IS NOT NULL;"
        )


def downgrade() -> None:
    with op.get_context().autocommit_block():
        op.execute(
            "DROP INDEX CONCURRENTLY IF EXISTS tool_call_attempts_user_ts_idx;"
        )
    op.execute("ALTER TABLE tool_call_attempts DROP COLUMN IF EXISTS agent_id;")
    op.execute("ALTER TABLE tool_call_attempts DROP COLUMN IF EXISTS user_id;")