from yt_dlp import YoutubeDL
from file_util import _load_urls_from_file, _create_or_get_cache, _save_cache
import subprocess
import json
import threading
import random
import os
from dotenv import load_dotenv
import logging
import time
from queue import Queue
import uuid
import tempfile


load_dotenv()

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(message)s")
logger = logging.getLogger(__name__)


BITRATE_KBPS = int(os.environ.get("BITRATE_KBPS", "192"))
BURST_SECONDS = int(os.environ.get("BURST_SECONDS", "10")) # allow pre-buffering of 10 sec on /stream
BASE_URL = os.environ.get("BASE_URL", "http://localhost:8000")
PLAYLIST_URL = os.environ.get("PLAYLIST_URL")
CACHE_FILE = os.environ.get("CACHE_FILE", "cache.json")
RANDOMIZE_PLAYLIST = bool(os.environ.get("RANDOMIZE_PLAYLIST", "false"))
META_INTERVAL_SECONDS = int(os.environ.get("META_INTERVAL_SECONDS", "5"))

# optional / page
SITE_TITLE = os.environ.get("SITE_TITLE", "yt_radio.py")
SITE_IMAGE = os.environ.get("SITE_IMAGE", "")
if not PLAYLIST_URL:
    raise RuntimeError("Please set PLAYLIST_URL environment variable")

METADATA = {}
NOW_PLAYING = {"index": None, "title": "Nothing", "artist": "Unknown", "id": ""}

_CACHE_LOCK = threading.Lock()
_CACHE = _create_or_get_cache(CACHE_FILE)

SUBSCRIBERS = {}  # sid -> Queue[bytes]
SUBSCRIBERS_LOCK = threading.Lock()
RADIO_THREAD = None
RADIO_STOP = threading.Event()
SUBSCRIBER_EVENT = threading.Event()

CHUNK_SIZE = 8192
QUEUE_MAX_CHUNKS = 256

def convert_playlist_to_links(link: str):
    # Loading a .radio file
    if link.endswith(".radio"):
        logger.info(".radio file specified, loading from local file")
        return _load_urls_from_file(link)

    # Pull YouTube list of URLs from YouTube Playlist
    ydl_opts = {
        "quiet": True,
        "extract_flat": True,
    }
    urls = []
    logger.info("Starting conversion of playlist to links: %s", link)
    try:
        with YoutubeDL(ydl_opts) as ydl:
            info = ydl.extract_info(link, download=False)
    except Exception:
        logger.exception("yt-dlp failed to extract playlist info for %s", link)
        exit(1)

    entries = info.get("entries") if isinstance(info, dict) else None
    if isinstance(entries, list):
        logger.info("Playlist info returned %d entries", len(entries))
    else:
        logger.error("Could not find list of links. Are you providing a YouTube Playlist URL?")
        exit(1)

    for idx, entry in enumerate(entries, start=1):
        entry_id = None
        if isinstance(entry, dict):
            entry_id = entry.get("id") or entry.get("url")
        elif isinstance(entry, str):
            entry_id = entry
        if not entry_id:
            logger.debug("Skipping playlist entry #%d: no id/url present", idx)
            continue

        if isinstance(entry_id, str) and entry_id.startswith("http"):
            urls.append(entry_id)
            logger.debug("Playlist entry #%d: added direct URL %s", idx, entry_id)
        else:
            constructed = f"https://www.youtube.com/watch?v={entry_id}"
            urls.append(constructed)
            logger.debug("Playlist entry #%d: constructed URL %s from id %s", idx, constructed, entry_id)

    logger.info("Finished converting playlist: %d links generated", len(urls))
    return urls


def fetch_metadata(index, url):
    with _CACHE_LOCK:
        cached = _CACHE.get(url)
    if cached: # we can skip fetching from youtube if we've cached it before
        try:
            METADATA[index] = {
                "title": cached.get("title", f"Track {index+1}"),
                "artist": cached.get("uploader", "Unknown"),
                "duration": cached.get("duration", -1),
                "id": cached.get("id", ""),
            }
            return
        except Exception:
            logger.exception("Failed to use cached metadata for %s, will refetch", url)

    # Get metadata via yt-dlp
    try:
        result = subprocess.run(
            ["yt-dlp", "--dump-json", url],
            capture_output=True,
            text=True,
            encoding="utf-8",
            errors="replace",
            timeout=30,
        )
        if result.returncode != 0 or not result.stdout:
            logger.error("Failed to get metadata from yt-dlp, you may or may not be throttled!")
            raise RuntimeError(f"yt-dlp failed for {url}: {result.stderr.strip()}")
        data = json.loads(result.stdout)
        METADATA[index] = {
            "title": data.get("title", f"Track {index+1}"),
            "artist": data.get("uploader", "Unknown"),
            "duration": data.get("duration", -1),
            "id": data.get("id", ""),
        }
        with _CACHE_LOCK: # get lock
            _CACHE[url] = {
                "title": data.get("title"),
                "uploader": data.get("uploader"),
                "duration": data.get("duration"),
                "id": data.get("id")
            }
        _save_cache(_CACHE, CACHE_FILE)
    except Exception:
        # Even if we fail to get meta we may be able to stream music still? So don't exit
        METADATA[index] = {
            "title": f"Track {index+1}",
            "artist": "Unknown",
            "duration": -1,
            "id": ""
        }
        logger.debug("Failed to fetch metadata for index %s, using fallback", index)


# Bootstrap
PLAYLIST = convert_playlist_to_links(PLAYLIST_URL)
PRELOAD_COUNT = min(4, len(PLAYLIST))
_preload_indices = random.sample(range(len(PLAYLIST)), PRELOAD_COUNT) if PLAYLIST else []
for i in _preload_indices:
    threading.Thread(target=fetch_metadata, args=(i, PLAYLIST[i]), daemon=True).start()
logger.info("Playlist loaded: %d tracks (preloading %d)", len(PLAYLIST), PRELOAD_COUNT)
logger.info("Stream available at %s/stream", BASE_URL)
logger.info("M3U available at %s/playlist.m3u", BASE_URL)


def _ensure_metadata(index):
    if index not in METADATA:
        fetch_metadata(index, PLAYLIST[index])


def _stream_track(index):
    url = PLAYLIST[index]
    _ensure_metadata(index)
    meta = dict(METADATA.get(index, {"title": f"Track {index+1}", "artist": "Unknown", "duration": -1, "id": ""}))
    logger.info("Now playing [%d/%d]: %s - %s", index + 1, len(PLAYLIST), meta.get("artist", ""), meta.get("title", ""))
    ytdlp_err = tempfile.TemporaryFile()
    ffmpeg_err = tempfile.TemporaryFile()

    ytdlp = subprocess.Popen(
        ["yt-dlp", "-f", "bestaudio", "-o", "-", url],
        stdout=subprocess.PIPE,
        stderr=ytdlp_err,
    )

    ffmpeg = subprocess.Popen(
        [
            "ffmpeg",
            "-hide_banner",
            "-loglevel", "error",
            "-i", "pipe:0",
            "-f", "mp3",
            "-ab", f"{BITRATE_KBPS}k",
            "-ar", "44100",
            "-ac", "2",
            "pipe:1",
        ],
        stdin=ytdlp.stdout,
        stdout=subprocess.PIPE,
        stderr=ffmpeg_err,
    )
    if ytdlp.stdout:
        ytdlp.stdout.close()

    bytes_per_sec = (BITRATE_KBPS * 1000) // 8
    burst_bytes = bytes_per_sec * BURST_SECONDS
    bytes_sent = 0
    start_time = time.monotonic()

    try:
        while True:
            if ffmpeg.stdout is None:
                logger.warning("No stdout available from FFMPEG")
                break
            chunk = ffmpeg.stdout.read(8192)
            if not chunk:
                break
            bytes_sent += len(chunk)
            yield chunk

            elapsed = time.monotonic() - start_time
            expected_bytes = elapsed * bytes_per_sec + burst_bytes
            if bytes_sent > expected_bytes:
                sleep_for = (bytes_sent - expected_bytes) / bytes_per_sec
                time.sleep(sleep_for)
    finally:
        try:
            ffmpeg.kill()
        except Exception:
            pass
        try:
            ytdlp.kill()
        except Exception:
            pass
        ffmpeg.wait()
        ytdlp.wait()
        elapsed = time.monotonic() - start_time
        logger.info("Finished sending [%d/%d]: %r - %r (bytes_sent=%d, elapsed=%.2fs)", index + 1, len(PLAYLIST), meta.get("artist"), meta.get("title"), bytes_sent, elapsed)
        try:
            ffmpeg_err.seek(0)
            ferr = ffmpeg_err.read().decode("utf-8", errors="replace")
            if ferr:
                logger.warning("ffmpeg stderr for track %d: %s", index + 1, ferr.strip())
            ytdlp_err.seek(0)
            yerr = ytdlp_err.read().decode("utf-8", errors="replace")
            if yerr:
                logger.warning("yt-dlp stderr for track %d: %s", index + 1, yerr.strip())
        except Exception:
            logger.exception("Failed to read subprocess stderr")
        finally:
            try:
                ffmpeg_err.close()
            except Exception:
                pass
            try:
                ytdlp_err.close()
            except Exception:
                pass


def add_subscriber():
    q = Queue(maxsize=QUEUE_MAX_CHUNKS)
    sid = uuid.uuid4().hex
    with SUBSCRIBERS_LOCK:
        SUBSCRIBERS[sid] = q
        SUBSCRIBER_EVENT.set()
    logger.info("Subscriber added sid=%s (total=%d)", sid, len(SUBSCRIBERS))
    return sid, q


def remove_subscriber(sid):
    with SUBSCRIBERS_LOCK:
        if sid in SUBSCRIBERS:
            SUBSCRIBERS.pop(sid, None)
            logger.info("Subscriber removed sid=%s (total=%d)", sid, len(SUBSCRIBERS))
        if not SUBSCRIBERS:
            SUBSCRIBER_EVENT.clear()


def broadcast_chunk(track_index: int, chunk: bytes):
    with SUBSCRIBERS_LOCK:
        subs = list(SUBSCRIBERS.items())
    for _, q in subs: # push the same chunk to all subscribers, we do nothing with sid for now
        if q.full():
            try:
                q.get_nowait()
            except Exception:
                pass
        try:
            q.put_nowait((track_index, chunk))
        except Exception:
            pass


def _radio_loop():
    played = []
    while not RADIO_STOP.is_set():
        if not SUBSCRIBER_EVENT.wait(timeout=1):
            continue
        if not PLAYLIST:
            logger.error("Playlist is empty, cannot stream")
            time.sleep(1)
            continue
        available = [i for i in range(len(PLAYLIST)) if i not in played]
        if not available:
            played.clear()
            available = list(range(len(PLAYLIST)))

        index = random.choice(available)
        played.append(index)
        try:
            for chunk in _stream_track(index):
                if RADIO_STOP.is_set():
                    break
                with SUBSCRIBERS_LOCK:
                    if not SUBSCRIBERS:
                        logger.info("No subscribers remaining; stopping track early")
                        break
                broadcast_chunk(index, chunk)
        except Exception:
            logger.exception("Error in radio producer, skipping track")
            time.sleep(1)
            continue


def ensure_radio_running():
    global RADIO_THREAD
    if RADIO_THREAD and RADIO_THREAD.is_alive():
        return
    RADIO_STOP.clear()
    RADIO_THREAD = threading.Thread(target=_radio_loop, daemon=True)
    RADIO_THREAD.start()
    logger.info("Radio producer started; listeners will share the same track")

ensure_radio_running()

if __name__ == "__main__":
    from routes import app
    app.run(host="0.0.0.0", port=8000, threaded=True)