"""asyncpg pool management for Document Crawler."""

import asyncpg
from config import settings

_pool: asyncpg.Pool | None = None


async def get_pool() -> asyncpg.Pool:
    global _pool
    if _pool is None:
        _pool = await asyncpg.create_pool(
            settings.DATABASE_URL,
            min_size=2,
            max_size=10,
        )
    return _pool


async def close_pool():
    global _pool
    if _pool is not None:
        await _pool.close()
        _pool = None


async def run_migration():
    """Run the crawler migration on startup."""
    import os
    migration_path = os.path.join(
        os.path.dirname(__file__), "migrations", "014_crawler_tables.sql"
    )
    if not os.path.exists(migration_path):
        return

    pool = await get_pool()
    async with pool.acquire() as conn:
        # Check if migration already applied
        exists = await conn.fetchval(
            "SELECT EXISTS(SELECT 1 FROM information_schema.tables WHERE table_name = 'crawler_sources')"
        )
        if exists:
            return

        with open(migration_path) as f:
            sql = f.read()
        await conn.execute(sql)