"""
VNEWS Shorts Runtime Cache - External Updater Module
GitHub Actions fetches YouTube shorts via yt-dlp -> POST to /api/shorts/update
Space saves to RAM cache + persistent file if /data available
"""
import os
import json
import time
import threading

# Runtime cache (RAM)
_shorts_runtime_cache = None
_shorts_cache_ts = 0
_shorts_cache_lock = threading.Lock()

# Secret for authenticating update requests
SHORTS_UPDATE_SECRET = os.environ.get("SHORTS_UPDATE_SECRET", "vnews-shorts-2026")

# Paths
SHORTS_CACHE_FILE = "/data/shorts_runtime_cache.json" if os.path.isdir("/data") else "/app/shorts_runtime_cache.json"


def get_runtime_cache():
    """Get cached shorts (from RAM or file fallback)"""
    global _shorts_runtime_cache, _shorts_cache_ts
    with _shorts_cache_lock:
        if _shorts_runtime_cache is not None:
            age = time.time() - _shorts_cache_ts
            if age < 7200:  # 2h fresh
                return _shorts_runtime_cache

    # Try file fallback
    try:
        if os.path.exists(SHORTS_CACHE_FILE):
            with open(SHORTS_CACHE_FILE, "r", encoding="utf-8") as f:
                data = json.load(f)
            age = time.time() - data.get("ts", 0)
            if age < 86400:  # 24h stale limit
                items = data.get("items", [])
                with _shorts_cache_lock:
                    _shorts_runtime_cache = items
                    _shorts_cache_ts = data.get("ts", time.time())
                return items
    except Exception as e:
        print(f"[cache] read error: {e}")

    return None


def set_runtime_cache(items):
    """Update runtime cache from external data"""
    global _shorts_runtime_cache, _shorts_cache_ts
    ts = time.time()
    with _shorts_cache_lock:
        _shorts_runtime_cache = items
        _shorts_cache_ts = ts

    # Also write to file (persistent if /data mounted)
    try:
        os.makedirs(os.path.dirname(SHORTS_CACHE_FILE), exist_ok=True)
        payload = {"items": items, "ts": ts, "count": len(items)}
        with open(SHORTS_CACHE_FILE, "w", encoding="utf-8") as f:
            json.dump(payload, f, ensure_ascii=False, indent=2)
        print(f"[cache] saved {len(items)} shorts to {SHORTS_CACHE_FILE}")
    except Exception as e:
        print(f"[cache] write skipped: {e}")

    return len(items)


def get_cache_status():
    """Return status dict for the cache"""
    cache = None
    with _shorts_cache_lock:
        if _shorts_runtime_cache is not None:
            cache = _shorts_runtime_cache
            age = int(time.time() - _shorts_cache_ts)
        else:
            age = -1
    return {
        "cached": cache is not None,
        "count": len(cache) if cache else 0,
        "age_seconds": age,
        "has_persistent": os.path.isdir("/data"),
        "cache_file_exists": os.path.exists(SHORTS_CACHE_FILE),
    }