import os
import uuid
from datetime import datetime
from fastapi import APIRouter, Depends, HTTPException, Query, Header
from fastapi.responses import FileResponse
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from ..dependencies import get_db, get_current_user
from ..models.user import User
from ..models.media_item import LibraryItem, BookFile, Chapter
from ..models.session import PlaybackSession
from ..models.progress import MediaProgress
from ..services.auth import decode_token

router = APIRouter(tags=["stream"])


@router.post("/api/items/{item_id}/play")
async def start_playback(
    item_id: str,
    body: dict | None = None,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    body = body or {}
    result = await db.execute(select(LibraryItem).where(LibraryItem.id == item_id))
    item = result.scalar_one_or_none()
    if not item:
        raise HTTPException(status_code=404, detail="Item not found")

    files_result = await db.execute(
        select(BookFile).where(BookFile.library_item_id == item_id).order_by(BookFile.track_index)
    )
    files = files_result.scalars().all()
    if not files:
        raise HTTPException(status_code=400, detail="Keine Audio-Dateien vorhanden")

    chapters_result = await db.execute(
        select(Chapter).where(Chapter.library_item_id == item_id).order_by(Chapter.chapter_index)
    )
    chapters = chapters_result.scalars().all()

    progress_result = await db.execute(
        select(MediaProgress).where(
            MediaProgress.user_id == current_user.id,
            MediaProgress.library_item_id == item_id,
        )
    )
    progress = progress_result.scalar_one_or_none()
    current_time = progress.current_time if progress else 0.0
    if body.get("startTime") is not None:
        current_time = float(body["startTime"])

    session_id = str(uuid.uuid4())

    session = PlaybackSession(
        id=session_id,
        user_id=current_user.id,
        library_item_id=item_id,
        media_type=item.media_type,
        current_time=current_time,
        duration=item.duration_seconds or 0.0,
        device_id=body.get("deviceId", ""),
        device_info=body.get("deviceInfo", {}),
        media_player=body.get("mediaPlayer", ""),
        hls_session_path=None,
        is_active=True,
    )
    db.add(session)
    await db.commit()

    chapters_out = [
        {"id": c.chapter_index, "start": c.start_seconds, "end": c.end_seconds, "title": c.title}
        for c in chapters
    ]

    _MIME = {
        ".mp3": "audio/mpeg", ".m4a": "audio/mp4", ".m4b": "audio/mp4",
        ".aac": "audio/aac", ".ogg": "audio/ogg", ".flac": "audio/flac", ".wav": "audio/wav",
    }
    audio_tracks = []
    offset = 0.0
    for i, f in enumerate(files):
        dur = f.duration_seconds or 0.0
        ext = os.path.splitext(f.filename or "")[1].lower()
        audio_tracks.append({
            "index": i,
            "startOffset": offset,
            "duration": dur,
            "title": f.filename or f"Part {i + 1}",
            "contentUrl": f"/api/stream/{session_id}?track={i}",
            "mimeType": _MIME.get(ext, "audio/mpeg"),
        })
        offset += dur

    total_duration = item.duration_seconds or offset

    return {
        "id": session_id,
        "userId": current_user.id,
        "libraryId": item.library_id,
        "libraryItemId": item_id,
        "episodeId": None,
        "mediaType": item.media_type,
        "chapters": chapters_out,
        "displayTitle": item.title,
        "displayAuthor": item.author,
        "coverPath": f"/api/items/{item_id}/cover" if item.cover_path else None,
        "duration": total_duration,
        "playMethod": 2,
        "mediaPlayer": body.get("mediaPlayer", ""),
        "deviceInfo": body.get("deviceInfo", {}),
        "serverVersion": "2.4.0",
        "date": datetime.utcnow().strftime("%Y-%m-%d"),
        "dayOfWeek": datetime.utcnow().strftime("%A"),
        "timeListening": 0,
        "startTime": current_time,
        "currentTime": current_time,
        "startedAt": int(datetime.utcnow().timestamp() * 1000),
        "updatedAt": int(datetime.utcnow().timestamp() * 1000),
        "audioTracks": audio_tracks,
        "videoTrack": None,
    }


@router.get("/api/stream/{session_id}")
async def stream_file(
    session_id: str,
    track: int = Query(0),
    token: str | None = Query(None),
    authorization: str | None = Header(None),
    db: AsyncSession = Depends(get_db),
):
    """Direktes Audio-Streaming mit Range-Request-Unterstützung."""
    raw = token
    if not raw and authorization:
        parts = authorization.split(" ", 1)
        if len(parts) == 2 and parts[0].lower() == "bearer":
            raw = parts[1]
    if not raw or not decode_token(raw):
        raise HTTPException(status_code=401, detail="Nicht autorisiert")

    result = await db.execute(
        select(PlaybackSession).where(PlaybackSession.id == session_id)
    )
    session = result.scalar_one_or_none()
    if not session:
        raise HTTPException(status_code=404, detail="Session nicht gefunden")

    files_result = await db.execute(
        select(BookFile)
        .where(BookFile.library_item_id == session.library_item_id)
        .order_by(BookFile.track_index)
    )
    files = files_result.scalars().all()

    if track >= len(files):
        raise HTTPException(status_code=404, detail="Track nicht gefunden")

    path = files[track].path
    if not os.path.exists(path):
        raise HTTPException(status_code=404, detail="Audio-Datei nicht gefunden")

    _MIME = {
        ".mp3": "audio/mpeg", ".m4a": "audio/mp4", ".m4b": "audio/mp4",
        ".aac": "audio/aac", ".ogg": "audio/ogg", ".flac": "audio/flac", ".wav": "audio/wav",
    }
    ext = os.path.splitext(path)[1].lower()
    return FileResponse(path, media_type=_MIME.get(ext, "audio/mpeg"))


@router.post("/api/playback-session/{session_id}/sync")
async def sync_session(
    session_id: str,
    body: dict | None = None,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    body = body or {}
    result = await db.execute(
        select(PlaybackSession).where(
            PlaybackSession.id == session_id,
            PlaybackSession.user_id == current_user.id,
        )
    )
    session = result.scalar_one_or_none()
    if not session:
        raise HTTPException(status_code=404, detail="Session not found")

    current_time = float(body.get("currentTime", session.current_time))
    duration = float(body.get("duration", session.duration))
    session.current_time = current_time
    session.duration = duration
    session.updated_at = datetime.utcnow()

    progress_result = await db.execute(
        select(MediaProgress).where(
            MediaProgress.user_id == current_user.id,
            MediaProgress.library_item_id == session.library_item_id,
            MediaProgress.episode_id == session.episode_id,
        )
    )
    progress = progress_result.scalar_one_or_none()
    if not progress:
        progress = MediaProgress(
            user_id=current_user.id,
            library_item_id=session.library_item_id,
            episode_id=session.episode_id,
            duration=duration,
            started_at=datetime.utcnow(),
        )
        db.add(progress)

    progress.current_time = current_time
    progress.duration = duration
    progress.last_update = datetime.utcnow()
    is_finished = duration > 0 and (current_time / duration) >= 0.99
    if is_finished and not progress.is_finished:
        progress.is_finished = True
        progress.finished_at = datetime.utcnow()
    elif not is_finished:
        progress.is_finished = False

    await db.commit()
    return {"id": session_id, "currentTime": current_time}


@router.delete("/api/playback-session/{session_id}")
async def close_session(
    session_id: str,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(PlaybackSession).where(
            PlaybackSession.id == session_id,
            PlaybackSession.user_id == current_user.id,
        )
    )
    session = result.scalar_one_or_none()
    if not session:
        raise HTTPException(status_code=404, detail="Session not found")
    session.is_active = False
    await db.commit()
    return {"success": True}