from __future__ import annotations

import json
import os
import time
from pathlib import Path
from typing import Any

_CACHE_TTL_SECONDS = max(3600, int(os.environ.get("YOUTUBE_ENCODER_CACHE_TTL", str(24 * 3600))))


def _cache_path(base_dir: str | Path | None = None) -> Path:
    root = Path(base_dir or os.environ.get("LIVE_PROJECT_ROOT") or Path(__file__).resolve().parent)
    path = root / "runtime"
    path.mkdir(parents=True, exist_ok=True)
    return path / "encoder_cache.json"


def load_encoder_cache(base_dir: str | Path | None = None) -> dict[str, Any]:
    path = _cache_path(base_dir)
    if not path.is_file():
        return {}
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
    except (OSError, json.JSONDecodeError):
        return {}
    return data if isinstance(data, dict) else {}


def get_cached_encoder(
    machine: str,
    ffmpeg_bin: str,
    *,
    base_dir: str | Path | None = None,
) -> str | None:
    blob = load_encoder_cache(base_dir)
    key = f"{machine}|{ffmpeg_bin}"
    row = blob.get(key)
    if not isinstance(row, dict):
        return None
    if time.time() - float(row.get("ts") or 0) > _CACHE_TTL_SECONDS:
        return None
    name = str(row.get("encoder") or "").strip()
    return name or None


def store_cached_encoder(
    machine: str,
    ffmpeg_bin: str,
    encoder: str,
    *,
    base_dir: str | Path | None = None,
) -> None:
    if not encoder:
        return
    path = _cache_path(base_dir)
    blob = load_encoder_cache(base_dir)
    key = f"{machine}|{ffmpeg_bin}"
    blob[key] = {"encoder": encoder, "ts": time.time()}
    try:
        path.write_text(json.dumps(blob, ensure_ascii=False, separators=(",", ":")), encoding="utf-8")
    except OSError:
        pass