import asyncio
import logging
import os

import yaml

logger = logging.getLogger(__name__)

CONFIG_PATH = os.environ.get("CONFIG_PATH", os.path.join(os.path.dirname(os.path.dirname(__file__)), "config", "config.yaml"))
ENV_PATH = os.path.join(os.path.dirname(os.path.dirname(__file__)), "config", ".env")

_config = {}
_mtime = 0.0
_callbacks = []


def _load_env():
    if not os.path.exists(ENV_PATH):
        return
    with open(ENV_PATH, "r") as f:
        for line in f:
            line = line.strip()
            if not line or line.startswith("#") or "=" not in line:
                continue
            key, _, value = line.partition("=")
            os.environ.setdefault(key.strip(), value.strip())
    logger.info("Environment loaded from %s", ENV_PATH)


def _load():
    global _config, _mtime
    with open(CONFIG_PATH, "r") as f:
        _config = yaml.safe_load(f)
    _mtime = os.path.getmtime(CONFIG_PATH)
    logger.info("Config loaded from %s", CONFIG_PATH)


def _reload_if_changed():
    global _mtime
    try:
        current_mtime = os.path.getmtime(CONFIG_PATH)
        if current_mtime != _mtime:
            old_config = _config.copy()
            _load()
            logger.info("Config reloaded (changed)")
            for cb in _callbacks:
                try:
                    cb(old_config, _config)
                except Exception:
                    logger.exception("Error in config reload callback")
    except Exception:
        logger.exception("Error checking config file")


def on_reload(callback):
    _callbacks.append(callback)


async def watch(interval: float = 2.0):
    while True:
        await asyncio.sleep(interval)
        _reload_if_changed()


def get(key: str, default=None):
    keys = key.split(".")
    val = _config
    for k in keys:
        if isinstance(val, dict):
            val = val.get(k)
        else:
            return default
        if val is None:
            return default
    return val


def env(key: str, default: str = "") -> str:
    return os.environ.get(key, default)


# Load on import
_load_env()
_load()