import logging
import uuid
from typing import Optional

from qdrant_client import QdrantClient
from qdrant_client.models import Distance, PointStruct, VectorParams

from src.config import QDRANT_API_KEY, QDRANT_URL

logger = logging.getLogger(__name__)

_COLLECTION   = "user_prompts"
_DUMMY_VECTOR = [0.0]
_client: Optional[QdrantClient] = None


def _get_client() -> QdrantClient:
    global _client
    if _client is None:
        _client = QdrantClient(url=QDRANT_URL, api_key=QDRANT_API_KEY)
        _ensure_collection(_client)
    return _client


def _ensure_collection(client: QdrantClient) -> None:
    existing = {c.name for c in client.get_collections().collections}
    if _COLLECTION not in existing:
        client.create_collection(
            collection_name=_COLLECTION,
            vectors_config=VectorParams(size=1, distance=Distance.DOT),
        )
        logger.info("Qdrant: collection '%s' created.", _COLLECTION)


def _point_id(user_id: str) -> str:
    return str(uuid.uuid5(uuid.NAMESPACE_DNS, user_id))


def save_custom_prompt(user_id: str, prompt: str) -> bool:
    if not QDRANT_URL:
        logger.warning("QDRANT_URL chưa được cấu hình.")
        return False
    try:
        _get_client().upsert(
            collection_name=_COLLECTION,
            points=[PointStruct(
                id=_point_id(user_id),
                vector=_DUMMY_VECTOR,
                payload={"user_id": user_id, "prompt": prompt},
            )],
        )
        logger.info("Đã lưu custom prompt cho user '%s'.", user_id)
        return True
    except Exception as e:
        logger.error("Lỗi lưu custom prompt cho '%s': %s", user_id, e)
        return False


def get_custom_prompt(user_id: str) -> Optional[str]:
    if not QDRANT_URL:
        return None
    try:
        results = _get_client().retrieve(
            collection_name=_COLLECTION,
            ids=[_point_id(user_id)],
            with_payload=True,
        )
        if results:
            return results[0].payload.get("prompt")
        return None
    except Exception as e:
        logger.error("Lỗi lấy custom prompt cho '%s': %s", user_id, e)
        return None