"""API credentials for the optional cover sources (IGDB, ScreenScraper, TheMovieDB).

Credentials live in a small JSON file next to the database so both the GUI and
the HTTP API (running on the NAS) can share them. Environment variables take
precedence over the file.
"""
import json
import os
from pathlib import Path

from . import config

CREDENTIALS_PATH = Path(
    os.environ.get("PSP_CREDENTIALS", str(config.USER_DATA_DIR / "credentials.json"))
)

FIELDS = [
    "igdb_client_id",
    "igdb_client_secret",
    "tmdb_api_key",
    "google_api_key",
    "google_cx",
    "screenscraper_devid",
    "screenscraper_devpassword",
    "screenscraper_ssid",
    "screenscraper_sspassword",
    "screenscraper_softname",
]

_ENV_MAP = {
    "igdb_client_id": "IGDB_CLIENT_ID",
    "igdb_client_secret": "IGDB_CLIENT_SECRET",
    "tmdb_api_key": "TMDB_API_KEY",
    "google_api_key": "GOOGLE_API_KEY",
    "google_cx": "GOOGLE_CX",
    "screenscraper_devid": "SCREENSCRAPER_DEVID",
    "screenscraper_devpassword": "SCREENSCRAPER_DEVPASSWORD",
    "screenscraper_ssid": "SCREENSCRAPER_SSID",
    "screenscraper_sspassword": "SCREENSCRAPER_SSPASSWORD",
    "screenscraper_softname": "SCREENSCRAPER_SOFTNAME",
}

_cache = None


def load():
    """Return the credentials dict (cached; env vars win over the file)."""
    global _cache
    if _cache is None:
        creds = {}
        if CREDENTIALS_PATH.exists():
            try:
                creds = json.loads(CREDENTIALS_PATH.read_text(encoding="utf-8"))
            except (OSError, ValueError):
                creds = {}
        if not isinstance(creds, dict):
            creds = {}
        for key, env in _ENV_MAP.items():
            value = os.environ.get(env)
            if value:
                creds[key] = value
        _cache = creds
    return _cache


def save(values):
    """Merge `values` into the credential file and refresh the cache."""
    global _cache
    creds = dict(load())
    for key in FIELDS:
        if key in values:
            value = (values[key] or "").strip()
            if value:
                creds[key] = value
            else:
                creds.pop(key, None)
    try:
        CREDENTIALS_PATH.parent.mkdir(parents=True, exist_ok=True)
        tmp = CREDENTIALS_PATH.with_name(CREDENTIALS_PATH.name + ".tmp")
        tmp.write_text(json.dumps(creds, indent=2), encoding="utf-8")
        os.replace(tmp, CREDENTIALS_PATH)
    except OSError:
        pass
    _cache = creds
    return creds