from urllib.parse import quote, urljoin

import httpx
from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import Response
from sqlalchemy.ext.asyncio import AsyncSession

from app.db.session import get_db
from app.services.tv_streams import get_public_tv_payload, is_allowed_tv_proxy_url

router = APIRouter()


@router.get("/streams")
async def list_public_tv_streams(
    db: AsyncSession = Depends(get_db),
):
    return await get_public_tv_payload(db)


@router.get("/proxy")
async def proxy_tv_stream(
    url: str = Query(..., description="Upstream TV stream or manifest URL"),
    db: AsyncSession = Depends(get_db),
):
    payload = await get_public_tv_payload(db)
    if not is_allowed_tv_proxy_url(url, payload.get("sources", [])):
        raise HTTPException(status_code=403, detail="TV proxy target is not allowed")

    try:
        async with httpx.AsyncClient(follow_redirects=True, timeout=20.0) as client:
            upstream = await client.get(
                url,
                headers={
                    "User-Agent": "Mozilla/5.0",
                    "Referer": "https://tv.cctv.com/live/cctv4/",
                },
            )
            upstream.raise_for_status()
    except httpx.HTTPError as exc:
        raise HTTPException(status_code=502, detail=f"Failed to fetch TV stream: {exc}") from exc

    content_type = upstream.headers.get("content-type", "application/octet-stream")
    raw_content = upstream.content
    response_url = str(upstream.url)
    is_manifest = (
        response_url.endswith(".m3u8")
        or "mpegurl" in content_type.lower()
        or raw_content.lstrip().startswith(b"#EXTM3U")
    )

    headers = {"Cache-Control": "no-store"}

    if is_manifest:
        manifest_text = upstream.text
        rewritten_lines: list[str] = []
        for line in manifest_text.splitlines():
            stripped = line.strip()
            if not stripped or stripped.startswith("#"):
                rewritten_lines.append(line)
                continue
            absolute_url = urljoin(response_url, stripped)
            rewritten_lines.append(f"/api/v1/tv/proxy?url={quote(absolute_url, safe='')}")
        return Response(
            content="\n".join(rewritten_lines),
            media_type="application/vnd.apple.mpegurl",
            headers=headers,
        )

    return Response(content=raw_content, media_type=content_type, headers=headers)