import json
import re
import urllib.parse
import urllib.request

VIDEO_ID_PATTERN = re.compile(r"^[\w-]{11}$")
YOUTUBE_HOSTS = {"youtube.com", "www.youtube.com", "m.youtube.com", "music.youtube.com", "youtu.be"}
PATH_PREFIXES = ("/shorts/", "/embed/", "/live/")
PLAYER_RESPONSE_MARKER = "ytInitialPlayerResponse = "
TOPIC_SUFFIX = " - Topic"
REQUEST_HEADERS = {
    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0",
    "Accept-Language": "en-US,en;q=0.9",
    "Cookie": "CONSENT=YES+1",
}


def video_id(text: str) -> str | None:
    text = text.strip()
    if VIDEO_ID_PATTERN.match(text):
        return text

    url = urllib.parse.urlparse(text if "://" in text else f"https://{text}")
    if url.hostname not in YOUTUBE_HOSTS:
        return None
    if url.hostname == "youtu.be":
        candidate = url.path.strip("/").split("/")[0]
    elif url.path == "/watch":
        candidate = urllib.parse.parse_qs(url.query).get("v", [""])[0]
    else:
        prefix = next((prefix for prefix in PATH_PREFIXES if url.path.startswith(prefix)), None)
        candidate = url.path[len(prefix):].split("/")[0] if prefix else ""
    return candidate if VIDEO_ID_PATTERN.match(candidate) else None


def watch_url(identifier: str) -> str:
    return f"https://music.youtube.com/watch?v={identifier}"


def cover_url(identifier: str) -> str:
    return f"https://i.ytimg.com/vi/{identifier}/hqdefault.jpg"


def oembed(identifier: str) -> dict:
    query = urllib.parse.urlencode({"url": f"https://www.youtube.com/watch?v={identifier}", "format": "json"})
    try:
        with urllib.request.urlopen(f"https://www.youtube.com/oembed?{query}", timeout=10) as response:
            return json.load(response)
    except (OSError, ValueError):
        return {}


def player_response(identifier: str) -> dict:
    request = urllib.request.Request(f"https://www.youtube.com/watch?v={identifier}", headers=REQUEST_HEADERS)
    try:
        with urllib.request.urlopen(request, timeout=15) as response:
            page = response.read().decode("utf-8", errors="replace")
    except OSError:
        return {}
    start = page.find(PLAYER_RESPONSE_MARKER)
    if start == -1:
        return {}
    try:
        data, _ = json.JSONDecoder().raw_decode(page, start + len(PLAYER_RESPONSE_MARKER))
    except ValueError:
        return {}
    return data if isinstance(data, dict) else {}


def clean_artist(name: str | None) -> str | None:
    if name and name.endswith(TOPIC_SUFFIX):
        return name[: -len(TOPIC_SUFFIX)]
    return name


def as_number(value) -> int | None:
    try:
        return int(value)
    except (TypeError, ValueError):
        return None


def video_details(identifier: str) -> dict:
    response = player_response(identifier)
    details = response.get("videoDetails") or {}
    microformat = (response.get("microformat") or {}).get("playerMicroformatRenderer") or {}
    fallback = oembed(identifier) if not details.get("title") else {}

    return {
        "id": identifier,
        "title": details.get("title") or fallback.get("title"),
        "artist": clean_artist(details.get("author") or fallback.get("author_name")),
        "durationSeconds": as_number(details.get("lengthSeconds")),
        "views": as_number(details.get("viewCount")),
        "published": (microformat.get("publishDate") or "")[:10] or None,
        "description": details.get("shortDescription") or None,
        "cover": cover_url(identifier),
        "url": watch_url(identifier),
    }


def format_duration(seconds: int | None) -> str:
    if seconds is None:
        return "-"
    hours, remainder = divmod(seconds, 3600)
    minutes, seconds = divmod(remainder, 60)
    return f"{hours}:{minutes:02}:{seconds:02}" if hours else f"{minutes}:{seconds:02}"