import os
import asyncio
import urllib.parse
from fastapi import FastAPI, Request, HTTPException, Query, Form, Depends, status
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from fastapi.responses import FileResponse, RedirectResponse
from pydantic import BaseModel
from typing import List, Dict, Any, Optional

from app.config import settings
from app.db import init_db, get_recent_tracks, get_tracks_count, get_db
from app.queue import sync_manager
from app.core.search import search_all
from app.core.tagger import get_track_dest_path
from app.core.auth import (
    verify_credentials,
    create_session_token,
    get_authenticated_user,
    require_auth,
    COOKIE_NAME
)
from app.wave.rotator import wave_rotator
from app.wave.playlist import ensure_smart_playlist

app = FastAPI(title="Navidrome Music Sync", version="1.0.0")

# Mount static and templates
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
app.mount("/static", StaticFiles(directory=os.path.join(BASE_DIR, "static")), name="static")
templates = Jinja2Templates(directory=os.path.join(BASE_DIR, "templates"))

class DownloadRequest(BaseModel):
    url: str

class WaveGenerateRequest(BaseModel):
    mood: Optional[str] = "auto"

async def _wave_auto_rotation_loop():
    """Background loop to periodically rotate and refill Smart Wave buffer."""
    while True:
        try:
            # Sleep interval in hours
            await asyncio.sleep(settings.WAVE_AUTO_ROTATE_HOURS * 3600)
            print(f"[AutoRotate] Running scheduled Wave rotation & refill (every {settings.WAVE_AUTO_ROTATE_HOURS}h)...")
            await wave_rotator.fill_buffer(mood="auto")
        except asyncio.CancelledError:
            break
        except Exception as e:
            print(f"[AutoRotate] Error during scheduled rotation: {e}")
            await asyncio.sleep(300)

@app.on_event("startup")
def on_startup():
    init_db()
    try:
        ensure_smart_playlist()
    except Exception as e:
        print(f"Warning: Failed to ensure smart playlist: {e}")

    # Launch background auto-rotation task
    if settings.WAVE_AUTO_ROTATE_HOURS > 0:
        asyncio.create_task(_wave_auto_rotation_loop())

def get_prefix(request: Request) -> str:
    """Return URL prefix when hosted behind reverse proxy."""
    prefix = request.headers.get("x-forwarded-prefix", "")
    if prefix:
        return prefix.rstrip("/")
    if "music.qpid.pro" in request.headers.get("host", ""):
        return "/sync"
    return ""

# --- Authentication Routes ---
@app.get("/login")
def login_page(request: Request):
    if get_authenticated_user(request):
        return RedirectResponse(url=f"{get_prefix(request)}/", status_code=303)
    return templates.TemplateResponse(request=request, name="login.html")

@app.post("/login")
def handle_login(request: Request, username: str = Form(...), password: str = Form(...)):
    user = username.strip()
    pwd = password.strip()
    if verify_credentials(user, pwd):
        resp = RedirectResponse(url=f"{get_prefix(request)}/", status_code=303)
        token = create_session_token(user)
        resp.set_cookie(
            key=COOKIE_NAME,
            value=token,
            max_age=30 * 86400,
            httponly=True,
            samesite="lax",
            path="/"
        )
        return resp
    return templates.TemplateResponse(
        request=request,
        name="login.html",
        context={"error": "Неверное имя пользователя или пароль Navidrome"}
    )

@app.get("/logout")
@app.post("/logout")
def handle_logout(request: Request):
    resp = RedirectResponse(url=f"{get_prefix(request)}/login", status_code=303)
    resp.delete_cookie(COOKIE_NAME, path="/")
    return resp

# --- Protected Views & API Endpoints ---
@app.get("/")
def read_root(request: Request):
    user = get_authenticated_user(request)
    if not user:
        return RedirectResponse(url=f"{get_prefix(request)}/login", status_code=303)
    return templates.TemplateResponse(request=request, name="index.html", context={"user": user})

@app.get("/api/search")
async def search_music(q: str = Query(..., min_length=1), user: str = Depends(require_auth)):
    """Search tracks and albums across Yandex, Apple Music and YouTube."""
    results = await search_all(q.strip())
    return results

@app.post("/api/download")
async def start_download(req: DownloadRequest, user: str = Depends(require_auth)):
    url = req.url.strip()
    if not url:
        raise HTTPException(status_code=400, detail="URL is required")
    
    task = await sync_manager.start_sync_task(url)
    return {"task_id": task.id, "status": task.status}

@app.get("/api/direct-download")
async def direct_download(url: str = Query(...), user: str = Depends(require_auth)):
    """Download track directly to user's browser/device."""
    provider = sync_manager.get_provider(url)
    tracks = await provider.resolve(url)
    if not tracks:
        raise HTTPException(status_code=404, detail="Track not found")
    
    track = tracks[0]
    dest_path = get_track_dest_path(
        settings.MUSIC_DIR,
        artist=track.artist,
        album=track.album or "Singles",
        track_num=track.track_number,
        title=track.title,
        ext="mp3"
    )

    if not os.path.exists(dest_path):
        success = await provider.download_track(track, dest_path)
        if not success and track.service == "yandex":
            success = await sync_manager.universal_provider.download_track(track, dest_path)
        if not success:
            raise HTTPException(status_code=500, detail="Failed to fetch track audio")

    filename = f"{track.artist} - {track.title}.mp3"
    quoted_filename = urllib.parse.quote(filename)
    return FileResponse(
        dest_path,
        media_type="audio/mpeg",
        headers={
            "Content-Disposition": f"attachment; filename*=UTF-8''{quoted_filename}"
        }
    )

@app.get("/api/stream")
async def stream_audio(request: Request, url: str = Query(...)):
    """Stream audio track for in-browser playback and seeking with HTTP Range support."""
    # Ensure user has access
    user = get_authenticated_user(request)
    if not user:
        raise HTTPException(status_code=401, detail="Authentication required")

    # Local file preview (e.g. Wave buffer tracks)
    if url.startswith("/") and os.path.exists(url) and os.path.realpath(url).startswith(os.path.realpath(settings.MUSIC_DIR)):
        return FileResponse(
            url,
            media_type="audio/mpeg",
            headers={"Accept-Ranges": "bytes", "Content-Disposition": "inline"}
        )

    provider = sync_manager.get_provider(url)
    tracks = await provider.resolve(url)
    if not tracks:
        raise HTTPException(status_code=404, detail="Track not found")
    
    track = tracks[0]
    dest_path = get_track_dest_path(
        settings.MUSIC_DIR,
        artist=track.artist,
        album=track.album or "Singles",
        track_num=track.track_number,
        title=track.title,
        ext="mp3"
    )

    if not os.path.exists(dest_path):
        success = await provider.download_track(track, dest_path)
        if not success and track.service == "yandex":
            success = await sync_manager.universal_provider.download_track(track, dest_path)
        if not success:
            raise HTTPException(status_code=500, detail="Failed to fetch track audio")

    return FileResponse(
        dest_path,
        media_type="audio/mpeg",
        headers={
            "Accept-Ranges": "bytes",
            "Content-Disposition": "inline"
        }
    )

@app.post("/api/sync/yandex-likes")
async def sync_yandex_likes(user: str = Depends(require_auth)):
    if not settings.YANDEX_MUSIC_TOKEN:
        raise HTTPException(status_code=400, detail="Yandex Music Token is not configured.")
    
    task = await sync_manager.start_sync_task("yandex:likes")
    return {"task_id": task.id, "status": task.status}

@app.get("/api/tasks")
def list_tasks(user: str = Depends(require_auth)):
    return list(sync_manager.tasks.values())

@app.get("/api/tasks/{task_id}")
def get_task(task_id: str, user: str = Depends(require_auth)):
    if task_id not in sync_manager.tasks:
        raise HTTPException(status_code=404, detail="Task not found")
    return sync_manager.tasks[task_id]

@app.get("/api/history")
def get_history(limit: int = 50, user: str = Depends(require_auth)):
    tracks = get_recent_tracks(limit)
    total = get_tracks_count()
    return {"total": total, "tracks": tracks}

@app.get("/api/health")
def healthcheck():
    return {
        "status": "ok",
        "yandex_configured": bool(settings.YANDEX_MUSIC_TOKEN),
        "auth_enabled": settings.AUTH_ENABLED
    }

# --- Smart Wave Endpoints (Phase 2) ---
@app.get("/api/wave/status")
def get_wave_status(user: str = Depends(require_auth)):
    """Return status of Smart Wave buffer."""
    return wave_rotator.get_status()

@app.post("/api/wave/generate")
async def generate_wave(req: Optional[WaveGenerateRequest] = None, user: str = Depends(require_auth)):
    """Discover candidates and fill Smart Wave buffer up to capacity using LLM reranker."""
    mood = req.mood if req else "auto"
    result = await wave_rotator.fill_buffer(mood=mood)
    return result

@app.post("/api/wave/rotate")
def rotate_wave(user: str = Depends(require_auth)):
    """Promote starred tracks and purge expired tracks in Smart Wave buffer."""
    promoted = wave_rotator.promote_starred_tracks()
    purged = wave_rotator.purge_expired_tracks()
    ensure_smart_playlist()
    return {
        "promoted_count": len(promoted),
        "promoted_tracks": promoted,
        "purged_count": len(purged),
        "purged_tracks": purged,
        "current_status": wave_rotator.get_status()
    }