import os
import uuid
import logging
import mimetypes

import requests

import config

logger = logging.getLogger(__name__)

IMAGE_MIME_TYPES = {
    "image/jpeg",
    "image/png",
    "image/bmp",
    "image/gif",
    "image/webp",
    "image/tiff",
}

EXT_MAP = {
    "image/jpeg": ".jpg",
    "image/png": ".png",
    "image/bmp": ".bmp",
    "image/gif": ".gif",
    "image/webp": ".webp",
    "image/tiff": ".tiff",
}


def _detect_ext(response) -> str:
    content_type = response.headers.get("Content-Type", "").split(";")[0].strip().lower()
    if content_type in EXT_MAP:
        return EXT_MAP[content_type]

    url_path = response.url.split("?")[0]
    guessed, _ = mimetypes.guess_type(url_path)
    if guessed and guessed in EXT_MAP:
        return EXT_MAP[guessed]

    return ".jpg"


def fetch_wallpaper() -> str:
    cfg = config.load()
    api = cfg["api"]
    wallpaper_cfg = cfg["wallpaper"]

    url = api["url"]
    mode = api.get("mode", "direct")
    timeout = api.get("timeout", 30)

    cache_dir = wallpaper_cfg.get("cache_dir", "./cache")
    cache_dir = _resolve_cache(cache_dir)
    os.makedirs(cache_dir, exist_ok=True)

    if mode == "json":
        image_url = _fetch_json(url, api.get("json_image_field", "url"), timeout)
        response = _download(image_url, timeout)
    else:
        response = _download(url, timeout)

    ext = _detect_ext(response)
    filename = f"{uuid.uuid4().hex}{ext}"
    filepath = os.path.join(cache_dir, filename)

    with open(filepath, "wb") as f:
        f.write(response.content)

    logger.info("Wallpaper saved to: %s", filepath)
    max_cache = cfg["wallpaper"].get("max_cache_files", 10)
    _cleanup_cache(cache_dir, keep=max_cache)
    return filepath


def _fetch_json(url: str, field: str, timeout: int) -> str:
    r = requests.get(url, timeout=timeout)
    r.raise_for_status()
    data = r.json()
    image_url = data.get(field)
    if not image_url:
        raise ValueError(f"Field '{field}' not found in JSON response")
    return image_url


def _download(url: str, timeout: int) -> requests.Response:
    r = requests.get(url, timeout=timeout, stream=True)
    r.raise_for_status()
    return r


def _resolve_cache(cache_dir: str) -> str:
    if os.path.isabs(cache_dir):
        return cache_dir
    base = os.path.dirname(os.path.abspath(__file__))
    return os.path.normpath(os.path.join(base, cache_dir))


def _cleanup_cache(cache_dir: str, keep: int) -> None:
    try:
        files = [os.path.join(cache_dir, f) for f in os.listdir(cache_dir)]
        files = [f for f in files if os.path.isfile(f)]
        files.sort(key=os.path.getmtime, reverse=True)
        for old in files[keep:]:
            os.remove(old)
    except Exception:
        pass