from __future__ import annotations

import re
from typing import Any
from urllib.parse import parse_qs, urlparse

import httpx

VIDEO_ID_RE = re.compile(r"^[a-zA-Z0-9_-]{11}$")


def extract_video_id(url_or_id: str) -> str:
    raw = url_or_id.strip()
    if VIDEO_ID_RE.match(raw):
        return raw

    parsed = urlparse(raw)
    host = (parsed.netloc or "").lower().replace("www.", "")

    if host in ("youtu.be",):
        candidate = parsed.path.lstrip("/").split("/")[0]
        if VIDEO_ID_RE.match(candidate):
            return candidate

    if host in ("youtube.com", "m.youtube.com", "music.youtube.com"):
        if parsed.path == "/watch":
            qs = parse_qs(parsed.query)
            vid = qs.get("v", [""])[0]
            if VIDEO_ID_RE.match(vid):
                return vid
        match = re.match(r"^/(embed|shorts|live)/([a-zA-Z0-9_-]{11})", parsed.path)
        if match:
            return match.group(2)

    raise ValueError("Keine gültige YouTube-URL oder Video-ID.")


async def fetch_metadata(video_id: str) -> dict[str, Any]:
    async with httpx.AsyncClient(timeout=15.0) as client:
        resp = await client.get(
            "https://www.youtube.com/oembed",
            params={"url": f"https://www.youtube.com/watch?v={video_id}", "format": "json"},
        )
        if resp.status_code == 404:
            raise ValueError("Video nicht gefunden.")
        resp.raise_for_status()
        data = resp.json()

    return {
        "video_id": video_id,
        "title": data.get("title") or "Unbekanntes Video",
        "channel": data.get("author_name") or "",
        "thumbnail_url": data.get("thumbnail_url") or f"https://i.ytimg.com/vi/{video_id}/hqdefault.jpg",
    }


def youtube_watch_url(video_id: str, timestamp_seconds: int | None = None) -> str:
    base = f"https://www.youtube.com/watch?v={video_id}"
    if timestamp_seconds is not None and timestamp_seconds >= 0:
        return f"{base}&t={int(timestamp_seconds)}s"
    return base