"""Add approval workflow columns to ab_directive_log

The approval router (/approval/pending, /approval/respond) and the MCP
get_pending_approvals tool both reference columns that were never added
in the initial schema migration.  This migration adds them so the
/approval/pending endpoint stops returning 500 UndefinedColumnError.

New columns on ab_directive_log:
  agent_name    — which specialist agent created the pending-approval entry
  action_type   — short label for the action type (e.g. 'create_expense')
  description   — human-readable summary shown in the approval UI
  context_data  — JSONB bag for any extra context the UI needs to display
  approver_id   — set when a human approves/rejects (VARCHAR to allow
                  Odoo user IDs or system strings like '__auto__')
  approval_note — free-text note from the approver
  updated_at    — timestamp of last status change; indexed for polling

Revision ID: 002
Revises: 001
Create Date: 2026-05-21
"""
from alembic import op
import sqlalchemy as sa

revision = '002'
down_revision = '001'
branch_labels = None
depends_on = None


def upgrade() -> None:
    # Add approval-workflow columns to ab_directive_log.
    # All columns are nullable so existing rows are not affected.
    op.execute("""
        ALTER TABLE ab_directive_log
            ADD COLUMN IF NOT EXISTS agent_name    VARCHAR(64),
            ADD COLUMN IF NOT EXISTS action_type   VARCHAR(64),
            ADD COLUMN IF NOT EXISTS description   TEXT,
            ADD COLUMN IF NOT EXISTS context_data  JSONB,
            ADD COLUMN IF NOT EXISTS approver_id   VARCHAR(64),
            ADD COLUMN IF NOT EXISTS approval_note TEXT,
            ADD COLUMN IF NOT EXISTS updated_at    TIMESTAMP
    """)

    # Index for quick polling of pending-approval rows by updated_at
    op.execute("""
        CREATE INDEX IF NOT EXISTS idx_dir_updated
        ON ab_directive_log(updated_at DESC)
        WHERE updated_at IS NOT NULL
    """)


def downgrade() -> None:
    op.execute("DROP INDEX IF EXISTS idx_dir_updated")
    op.execute("""
        ALTER TABLE ab_directive_log
            DROP COLUMN IF EXISTS updated_at,
            DROP COLUMN IF EXISTS approval_note,
            DROP COLUMN IF EXISTS approver_id,
            DROP COLUMN IF EXISTS context_data,
            DROP COLUMN IF EXISTS description,
            DROP COLUMN IF EXISTS action_type,
            DROP COLUMN IF EXISTS agent_name
    """)