import os
from pathlib import Path
from typing import Any

import yaml
from qdrant_client import QdrantClient


DEFAULT_CONFIG_PATH = Path(__file__).resolve().parent / "config.yaml"

_DEFAULTS: dict[str, Any] = {
    "host": "localhost",
    "port": 6333,
    "path": None,
    "client_timeout": 10,
    "use_memory": False,
    "collection_name": "doc_ai_production",
}

_CLIENT_CACHE: dict[tuple, QdrantClient] = {}


def _env_bool(name: str, default: bool | None = None) -> bool | None:
    raw = os.environ.get(name)
    if raw is None:
        return default
    v = raw.strip().lower()
    if v in ("1", "true", "yes", "y", "on"):
        return True
    if v in ("0", "false", "no", "n", "off"):
        return False
    return default


def load_qdrant_settings(config_path: str | Path | None = None) -> dict[str, Any]:
    path = Path(config_path or DEFAULT_CONFIG_PATH)
    merged = dict(_DEFAULTS)

    if path.is_file():
        with open(path, "r", encoding="utf-8") as f:
            full = yaml.safe_load(f) or {}
        q = dict(full.get("qdrant") or {})
        if not q.get("host") and full.get("qdrant_host") is not None:
            q["host"] = full["qdrant_host"]
        if q.get("port") is None and full.get("qdrant_port") is not None:
            q["port"] = full["qdrant_port"]
        merged.update({k: v for k, v in q.items() if v is not None})

    # Env overrides used across app/pipeline.
    if os.environ.get("QDRANT_HOST"):
        merged["host"] = os.environ["QDRANT_HOST"]
    if os.environ.get("QDRANT_PORT"):
        try:
            merged["port"] = int(os.environ["QDRANT_PORT"])
        except ValueError:
            pass
    if os.environ.get("QDRANT_PATH", "").strip():
        merged["path"] = os.environ["QDRANT_PATH"].strip()
    if os.environ.get("QDRANT_COLLECTION"):
        merged["collection_name"] = os.environ["QDRANT_COLLECTION"]

    use_memory_env = _env_bool("QDRANT_USE_MEMORY")
    if use_memory_env is not None:
        merged["use_memory"] = use_memory_env

    return merged


def get_shared_qdrant_client(
    *,
    use_memory: bool,
    host: str,
    port: int,
    timeout: float,
    qdrant_path: str | None,
) -> QdrantClient:
    if use_memory:
        key = ("memory",)
        if key not in _CLIENT_CACHE:
            _CLIENT_CACHE[key] = QdrantClient(":memory:")
        return _CLIENT_CACHE[key]

    if qdrant_path:
        p = str(Path(str(qdrant_path)).expanduser().resolve())
        key = ("path", p)
        if key not in _CLIENT_CACHE:
            Path(p).mkdir(parents=True, exist_ok=True)
            _CLIENT_CACHE[key] = QdrantClient(path=p)
        return _CLIENT_CACHE[key]

    key = ("http", host, int(port), float(timeout))
    if key not in _CLIENT_CACHE:
        _CLIENT_CACHE[key] = QdrantClient(host=host, port=int(port), timeout=float(timeout))
    return _CLIENT_CACHE[key]