from datetime import timezone

from motor.motor_asyncio import AsyncIOMotorClient, AsyncIOMotorDatabase
from pymongo.errors import OperationFailure

from app.core.config import settings

_client: AsyncIOMotorClient | None = None


def get_db() -> AsyncIOMotorDatabase:
    global _client
    if _client is None:
        _client = AsyncIOMotorClient(
            settings.mongo_uri,
            tz_aware=True,
            tzinfo=timezone.utc,
        )
    return _client[settings.mongo_db]


async def ensure_indexes() -> None:
    db = get_db()

    async def safe_create_index(collection, keys, **options) -> None:
        """Create index and ignore already-existing/conflicting definitions."""
        try:
            await collection.create_index(keys, **options)
        except OperationFailure as exc:
            # Atlas/PyMongo can raise conflicts when an index with same name/key
            # already exists but with different options (e.g., unique vs non-unique).
            if exc.code in {85, 86}:
                return
            raise

    await safe_create_index(db.devices, "device_id", unique=True)
    await safe_create_index(db.policies, "device_id", unique=True)
    await safe_create_index(db.key_states, "device_id", unique=True)
    await safe_create_index(db.key_states, "expires_at")
    await safe_create_index(db.key_states, "lock_until")
    await safe_create_index(db.violations, "device_id")
    await safe_create_index(db.violations, "timestamp")
    await safe_create_index(db.violations, "expires_at")
    await safe_create_index(db.screenshot_audit, "created_at")
    await safe_create_index(db.alert_audit, "created_at")
    await safe_create_index(db.alert_audit, "type")
    await safe_create_index(db.url_verdicts, "url", unique=True)
    await safe_create_index(db.url_verdicts, "verdict")
    await safe_create_index(db.game_lock_reviews, "review_id", unique=True)
    await safe_create_index(db.game_lock_reviews, "status")
    await safe_create_index(db.game_lock_reviews, "created_at")