import os
import re
import json
import shutil
import subprocess
import threading
from pathlib import Path
from urllib.parse import urlparse
from flask import Flask, request, jsonify, send_from_directory
import requests as http_requests

YOUTUBE_HOSTS = (
    "youtube.com", "www.youtube.com", "m.youtube.com",
    "music.youtube.com", "youtu.be",
)
AUDIO_CONTENT_TYPES = ("audio/", "application/ogg")


def is_youtube_url(url: str) -> bool:
    try:
        host = (urlparse(url).hostname or "").lower()
    except Exception:
        return False
    return host in YOUTUBE_HOSTS


def fetch_youtube_title(url: str) -> str | None:
    if not shutil.which("yt-dlp"):
        return None
    try:
        proc = subprocess.run(
            ["yt-dlp", "--get-title", "--no-playlist", "--skip-download",
             "--no-warnings", url],
            capture_output=True, text=True, timeout=30,
        )
    except Exception:
        return None
    if proc.returncode != 0:
        return None
    title = (proc.stdout or "").strip().splitlines()
    return title[0] if title else None

SITE_DIR = Path(__file__).parent / "site"

app = Flask(__name__)

MP3_DIR       = Path(os.environ.get("MP3_DIR", "/mp3"))
DOWNLOADS_DIR = MP3_DIR / "downloads"
AUDIO_EXT     = {".mp3", ".m4a", ".aac", ".wav", ".ogg"}

DOWNLOADS_DIR.mkdir(parents=True, exist_ok=True)

_downloads = {}  # track_id -> {"status": ..., "error": ...}
_TITLES_FILE  = DOWNLOADS_DIR / "titles.json"
_SKIP_FILE    = DOWNLOADS_DIR / "skip.json"
_SOURCES_FILE = DOWNLOADS_DIR / "sources.json"


def safe_name(title: str) -> str:
    name = re.sub(r"[^\w\s\-]", "", title).strip()
    name = re.sub(r"\s+", " ", name)
    return name[:100] or "track"


def _load_titles() -> dict:
    if _TITLES_FILE.exists():
        try:
            with open(_TITLES_FILE) as f:
                return json.load(f)
        except Exception:
            pass
    return {}


def _save_titles(titles: dict) -> None:
    with open(_TITLES_FILE, "w") as f:
        json.dump(titles, f, indent=2, ensure_ascii=False)


def _load_skip() -> dict:
    if _SKIP_FILE.exists():
        try:
            with open(_SKIP_FILE) as f:
                return json.load(f)
        except Exception:
            pass
    return {}


def _save_skip(skip: dict) -> None:
    with open(_SKIP_FILE, "w") as f:
        json.dump(skip, f, indent=2)


def _load_sources() -> dict:
    if _SOURCES_FILE.exists():
        try:
            with open(_SOURCES_FILE) as f:
                return json.load(f)
        except Exception:
            pass
    return {}


def _save_sources(sources: dict) -> None:
    with open(_SOURCES_FILE, "w") as f:
        json.dump(sources, f, indent=2, ensure_ascii=False)


def strip_mp3_prefix(src: str) -> str:
    return src.lstrip("/").removeprefix("mp3/").lstrip("/")


# ── Downloads ────────────────────────────────────────────────────────────────

@app.route("/api/downloads")
def list_downloads():
    titles  = _load_titles()
    skip    = _load_skip()
    sources = _load_sources()
    files   = []
    for f in sorted(DOWNLOADS_DIR.iterdir()):
        if f.is_file() and f.suffix.lower() in AUDIO_EXT:
            files.append({
                "title":    titles.get(f.name, f.stem),
                "filename": f.name,
                "src":      f"/mp3/downloads/{f.name}",
                "skip":     skip.get(f.name, 0),
                "source":   sources.get(f.name, ""),
            })
    return jsonify(files)


@app.route("/api/download", methods=["POST"])
def start_download():
    data  = request.get_json(silent=True) or {}
    url   = (data.get("url")   or "").strip()
    title = (data.get("title") or "").strip()

    if not url:
        return jsonify({"error": "URL is required"}), 400
    if not url.startswith(("http://", "https://")):
        return jsonify({"error": "Only http/https URLs are supported"}), 400

    if not title and is_youtube_url(url):
        fetched = fetch_youtube_title(url)
        if fetched:
            title = fetched
    if not title:
        title = "track"

    filename = safe_name(title) + ".mp3"
    dest     = DOWNLOADS_DIR / filename
    track_id = filename

    if _downloads.get(track_id, {}).get("status") == "downloading":
        return jsonify({"status": "downloading", "track_id": track_id})

    _downloads[track_id] = {"status": "downloading", "progress": 0, "phase": "starting"}

    titles = _load_titles()
    titles[filename] = title
    _save_titles(titles)

    sources = _load_sources()
    sources[filename] = url
    _save_sources(sources)

    def fail(msg: str):
        _downloads[track_id] = {"status": "error", "error": msg}
        dest.unlink(missing_ok=True)
        t = _load_titles()
        t.pop(filename, None)
        _save_titles(t)
        s = _load_sources()
        s.pop(filename, None)
        _save_sources(s)

    def download_youtube():
        try:
            from yt_dlp import YoutubeDL
        except Exception:
            fail("YouTube download not available: yt-dlp is not installed")
            return

        out_template = str(DOWNLOADS_DIR / (Path(filename).stem + ".%(ext)s"))

        def hook(d):
            st = d.get("status")
            if st == "downloading":
                total = d.get("total_bytes") or d.get("total_bytes_estimate")
                done  = d.get("downloaded_bytes") or 0
                if total:
                    pct = max(0, min(99, int(done * 100 / total)))
                    _downloads[track_id]["progress"] = pct
                    _downloads[track_id]["phase"] = "downloading"
            elif st == "finished":
                _downloads[track_id]["progress"] = 99
                _downloads[track_id]["phase"] = "converting"

        opts = {
            "format": "bestaudio/best",
            "outtmpl": out_template,
            "noplaylist": True,
            "quiet": True,
            "no_warnings": True,
            "progress_hooks": [hook],
            "postprocessors": [{
                "key": "FFmpegExtractAudio",
                "preferredcodec": "mp3",
                "preferredquality": "0",
            }],
        }
        try:
            with YoutubeDL(opts) as ydl:
                ydl.download([url])
        except Exception as exc:
            tail = str(exc).strip().splitlines()
            fail(f"YouTube download failed: {tail[-1] if tail else exc}")
            return
        if not dest.is_file():
            fail("YouTube download failed: output file missing")
            return
        _downloads[track_id]["progress"] = 100
        _downloads[track_id]["status"] = "done"

    def download_direct():
        try:
            resp = http_requests.get(
                url, stream=True, timeout=600,
                headers={"User-Agent": "Mozilla/5.0"},
            )
            resp.raise_for_status()
        except Exception as exc:
            fail(f"Download failed: {exc}")
            return

        ctype = (resp.headers.get("Content-Type") or "").split(";")[0].strip().lower()
        if ctype and not any(ctype.startswith(p) for p in AUDIO_CONTENT_TYPES):
            resp.close()
            fail(
                f"URL is not a supported audio file (Content-Type: {ctype}). "
                "For YouTube/streaming sites, paste the page URL directly — "
                "other sites are only supported if they link straight to an audio file."
            )
            return

        total = 0
        try:
            total = int(resp.headers.get("Content-Length") or 0)
        except ValueError:
            total = 0
        try:
            done = 0
            with open(dest, "wb") as f:
                for chunk in resp.iter_content(chunk_size=65536):
                    f.write(chunk)
                    done += len(chunk)
                    if total:
                        pct = max(0, min(99, int(done * 100 / total)))
                        _downloads[track_id]["progress"] = pct
                        _downloads[track_id]["phase"] = "downloading"
        except Exception as exc:
            fail(f"Download failed: {exc}")
            return
        _downloads[track_id]["progress"] = 100
        _downloads[track_id]["status"] = "done"

    def do_download():
        if is_youtube_url(url):
            download_youtube()
        else:
            download_direct()

    threading.Thread(target=do_download, daemon=True).start()
    return jsonify({"status": "downloading", "track_id": track_id})


@app.route("/api/download/status/<path:track_id>")
def download_status(track_id):
    return jsonify(_downloads.get(track_id, {"status": "unknown"}))


@app.route("/api/downloads/<filename>", methods=["DELETE"])
def delete_download(filename):
    if not re.match(r"^[\w\s\-\.]+$", filename) or ".." in filename:
        return jsonify({"error": "Invalid filename"}), 400
    dest = DOWNLOADS_DIR / filename
    if dest.is_file() and dest.suffix.lower() in AUDIO_EXT:
        dest.unlink()
        titles = _load_titles()
        titles.pop(filename, None)
        _save_titles(titles)
        skip = _load_skip()
        skip.pop(filename, None)
        _save_skip(skip)
        sources = _load_sources()
        sources.pop(filename, None)
        _save_sources(sources)
        return jsonify({"status": "deleted"})
    return jsonify({"error": "Not found"}), 404


@app.route("/api/downloads/<filename>/skip", methods=["POST"])
def set_skip(filename):
    if not re.match(r"^[\w\s\-\.]+$", filename) or ".." in filename:
        return jsonify({"error": "Invalid filename"}), 400
    if not (DOWNLOADS_DIR / filename).is_file():
        return jsonify({"error": "Not found"}), 404
    data    = request.get_json(silent=True) or {}
    seconds = data.get("seconds", 0)
    try:
        seconds = max(0, int(seconds))
    except (TypeError, ValueError):
        return jsonify({"error": "seconds must be a number"}), 400
    skip = _load_skip()
    if seconds == 0:
        skip.pop(filename, None)
    else:
        skip[filename] = seconds
    _save_skip(skip)
    return jsonify({"status": "saved", "skip": seconds})


@app.route("/api/downloads/<filename>/rename", methods=["POST"])
def rename_download(filename):
    if not re.match(r"^[\w\s\-\.]+$", filename) or ".." in filename:
        return jsonify({"error": "Invalid filename"}), 400
    data      = request.get_json(silent=True) or {}
    new_title = (data.get("title") or "").strip()
    if not new_title:
        return jsonify({"error": "Title is required"}), 400

    if not (DOWNLOADS_DIR / filename).is_file():
        return jsonify({"error": "Not found"}), 404

    titles = _load_titles()
    titles[filename] = new_title
    _save_titles(titles)
    return jsonify({"status": "renamed"})


# ── Playlist track rename ─────────────────────────────────────────────────────

def _load_playlist():
    path = MP3_DIR / "playlist.json"
    if path.exists():
        try:
            with open(path) as f:
                return json.load(f)
        except Exception:
            pass
    tracks = []
    for f in sorted(MP3_DIR.iterdir()):
        if f.is_file() and f.suffix.lower() in AUDIO_EXT:
            title = f.stem.replace("_", " ").replace("-", " ").strip()
            tracks.append({"src": f.name, "title": title})
    return tracks


def _save_playlist(tracks):
    with open(MP3_DIR / "playlist.json", "w") as f:
        json.dump(tracks, f, indent=2)


@app.route("/api/tracks/rename", methods=["POST"])
def rename_track():
    data      = request.get_json(silent=True) or {}
    src       = (data.get("src")   or "").strip()
    new_title = (data.get("title") or "").strip()

    if not src or not new_title:
        return jsonify({"error": "src and title are required"}), 400

    bare   = strip_mp3_prefix(src)
    tracks = _load_playlist()

    for track in tracks:
        if strip_mp3_prefix(track.get("src", "")) == bare:
            track["title"] = new_title
            _save_playlist(tracks)
            return jsonify({"status": "renamed"})

    tracks.append({"src": bare, "title": new_title})
    _save_playlist(tracks)
    return jsonify({"status": "renamed"})


# ── Playlist tracks (read) ────────────────────────────────────────────────────

@app.route("/api/tracks")
def list_tracks():
    tracks = _load_playlist()
    return jsonify([
        {"src": t.get("src", ""), "title": t.get("title", "")}
        for t in tracks
    ])


# ── UI ────────────────────────────────────────────────────────────────────────

@app.route("/")
def ui_index():
    return send_from_directory(SITE_DIR, "index.html")


@app.route("/<path:filename>")
def ui_static(filename):
    return send_from_directory(SITE_DIR, filename)


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8001, debug=False)