"""app.py — ani-web: FastAPI over upstream.py + HLS proxy + static UI.

Browser playback: hls.anidb.app sends no CORS headers, so the player is
pointed at /stream/{token}; the proxy fetches upstream (with the same
Cloudflare workaround) and rewrites playlist URIs to go through itself.
"""
import base64
import json
import time
from pathlib import Path
from urllib.parse import quote, urljoin

from fastapi import Body, FastAPI, HTTPException, Query
from fastapi.responses import FileResponse, JSONResponse, RedirectResponse, Response
from fastapi.staticfiles import StaticFiles
from itsdangerous import BadSignature, TimestampSigner

from . import credentials, upstream

ROOT = Path(__file__).parent.parent
app = FastAPI(title="ani-web")

# ---------- auth: single user, signed cookie ----------
_SIGNER = TimestampSigner(credentials.load()["secret"])  # exits with instructions if unset
_SESSION = "aniweb_session"
_SESSION_AGE = 30 * 86400
_PUBLIC = {("/login", "GET"), ("/login", "POST")}

# ponytail: in-memory lockout, single process — 5 fails lock for 15 min
_lockout = {"fails": 0, "until": 0.0}


def _auth_ok(request) -> bool:
    try:
        return _SIGNER.unsign(request.cookies.get(_SESSION, ""),
                              max_age=_SESSION_AGE) == b"ok"
    except BadSignature:
        return False


@app.middleware("http")
async def require_auth(request, call_next):
    if (request.url.path, request.method) in _PUBLIC or _auth_ok(request):
        return await call_next(request)
    if request.url.path.startswith("/api/"):
        return JSONResponse({"detail": "not authenticated"}, status_code=401)
    next_ = request.url.path + (f"?{request.url.query}" if request.url.query else "")
    return RedirectResponse(f"/login?next={quote(next_, safe='')}", status_code=302)


@app.get("/login", include_in_schema=False)
def login_page():
    return FileResponse(ROOT / "static" / "login.html")


@app.post("/login")
async def login(payload: dict = Body(...)):
    if time.time() < _lockout["until"]:
        return JSONResponse({"detail": "too many attempts, try later"}, status_code=429)
    if credentials.check(payload.get("password", "")):
        _lockout.update(fails=0, until=0.0)
        resp = JSONResponse({"ok": True})
        resp.set_cookie(_SESSION, _SIGNER.sign(b"ok").decode(),
                        max_age=_SESSION_AGE, httponly=True, samesite="lax")
        return resp
    _lockout["fails"] += 1
    if _lockout["fails"] >= 5:
        _lockout.update(fails=0, until=time.time() + 900)
    time.sleep(0.5)  # slow down brute force
    return JSONResponse({"detail": "wrong password"}, status_code=401)


@app.post("/logout")
def logout():
    resp = JSONResponse({"ok": True})
    resp.delete_cookie(_SESSION)
    return resp


HIST_FILE = Path(__file__).parent / "data" / "history.json"


def _load_hist():
    try:
        return json.loads(HIST_FILE.read_text())
    except (FileNotFoundError, json.JSONDecodeError):
        return []


def _save_hist(entries):
    HIST_FILE.parent.mkdir(exist_ok=True)
    # ponytail: unguarded read-modify-write, fine for a single-user tool
    HIST_FILE.write_text(json.dumps(entries, indent=1))


@app.get("/api/history")
def api_history():
    return sorted(_load_hist(), key=lambda e: e.get("t", 0), reverse=True)[:5]


@app.post("/api/history")
def api_history_post(entry: dict = Body(...)):
    if "ep_id" not in entry:
        raise HTTPException(422, "ep_id required")
    entry["t"] = time.time()
    entries = _load_hist()
    for i, e in enumerate(entries):
        if e.get("slug_id") == entry.get("slug_id") and e.get("ep_id") == entry.get("ep_id"):
            entries[i] = {**e, **entry}
            break
    else:
        entries.append(entry)
    _save_hist(sorted(entries, key=lambda e: e.get("t", 0), reverse=True)[:50])
    return entry


def _b64(url: str) -> str:
    return base64.urlsafe_b64encode(url.encode()).decode()


def _url(token: str) -> str:
    return base64.urlsafe_b64decode(token.encode()).decode()


def _upstream(fn, *a, **kw):
    try:
        return fn(*a, **kw)
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(502, f"upstream error: {e}")


@app.middleware("http")
async def no_cache(request, call_next):
    # ponytail: no-store on everything except /stream (segments should cache)
    r = await call_next(request)
    if not request.url.path.startswith("/stream"):
        r.headers["Cache-Control"] = "no-store"
    return r


@app.get("/api/search")
def api_search(q: str = Query(min_length=1)):
    return _upstream(upstream.search, q)


@app.get("/api/anime/{slug_id}")
def api_anime(slug_id: str):
    return _upstream(upstream.details, slug_id)


@app.get("/api/anime/{anime_id}/episodes")
def api_episodes(anime_id: int):
    return _upstream(upstream.episodes, anime_id)


@app.get("/api/episode/{ep_id}/stream")
def api_stream(ep_id: int, lang: str = "eng"):
    master = _upstream(upstream.master_m3u8, ep_id, lang)
    if not master:
        raise HTTPException(404, f"no {lang} stream for episode {ep_id}")
    return {"token": _b64(master),
            "qualities": _upstream(upstream.master_variants, master)}


def _rewrite_m3u8(text: str, base: str) -> str:
    # ponytail: rewrites plain URIs only; URI-list attributes in
    # #EXT-X-* tags (e.g. SUBTITLES) are ignored — fine for video-only playlists
    return "\n".join(
        line if line.startswith("#") or not line
        else "/stream/" + _b64(urljoin(base, line))
        for line in text.splitlines()) + "\n"


@app.get("/stream/{token}")
def stream(token: str):
    # ponytail: buffers whole response in memory; .ts segments are small
    url = _url(token)
    r = _upstream(upstream._get, url)
    body = r.content
    if url.endswith(".m3u8") or "mpegurl" in r.headers.get("content-type", ""):
        body = _rewrite_m3u8(body.decode(), url).encode()
    return Response(body, media_type=r.headers.get("content-type", "application/octet-stream"))


app.mount("/", StaticFiles(directory=ROOT / "static", html=True), name="static")