from pathlib import Path

import chromadb
from typing import Callable, Optional

from app.core.config import get_settings


class _EmbeddingFunctionWrapper:
    def __init__(self, settings):
        self.settings = settings

    def __call__(self, input):
        from app.services.embedding_client import EmbeddingClient
        import asyncio
        from concurrent.futures import ThreadPoolExecutor

        def _run_in_thread(texts):
            client = EmbeddingClient(self.settings)
            loop = asyncio.new_event_loop()
            asyncio.set_event_loop(loop)
            try:
                return loop.run_until_complete(client.embed(texts))
            finally:
                loop.close()

        with ThreadPoolExecutor(max_workers=1) as executor:
            return executor.submit(_run_in_thread, input).result()


def get_embedding_function_settings(settings):
    """Return a synchronous wrapper suitable for embedding functions in ChromaDB."""
    # Lazy import to avoid import-time side effects in tests
    try:
        return _EmbeddingFunctionWrapper(settings)
    except Exception:
        return None


def get_chroma_client() -> chromadb.Client:
    settings = get_settings()
    persist_dir = Path(settings.chroma_db_path)
    persist_dir.mkdir(parents=True, exist_ok=True)
    return chromadb.PersistentClient(path=str(persist_dir))


def get_or_create_collection(client: chromadb.Client, name: str, embedding_function: Optional[Callable] = None):
    if embedding_function is not None:
        return client.get_or_create_collection(name=name, embedding_function=embedding_function)
    return client.get_or_create_collection(name=name)