enigFM/backend/app/routers/tracks.py

import uuid
from urllib.parse import quote
from fastapi import APIRouter, Depends, HTTPException, status, UploadFile, File, Form, Request
from fastapi.responses import StreamingResponse
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func
from mutagen.mp3 import MP3
from io import BytesIO
from ..database import get_db
from ..models.user import User
from ..models.track import Track
from ..schemas.track import TrackResponse, TrackWithUrl
from ..services.auth import get_current_user
from ..services.s3 import upload_file, delete_file, generate_presigned_url, can_upload_file, get_file_size, stream_file_chunks
from ..config import get_settings

settings = get_settings()
router = APIRouter(prefix="/api/tracks", tags=["tracks"])


@router.get("", response_model=list[TrackResponse])
async def get_tracks(db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(Track).order_by(Track.created_at.desc()))
    return result.scalars().all()


@router.post("/upload", response_model=TrackResponse)
async def upload_track(
    file: UploadFile = File(...),
    title: str = Form(None),
    artist: str = Form(None),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    # Check file type
    if not file.content_type or not file.content_type.startswith("audio/"):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="File must be an audio file",
        )

    # Read file content
    content = await file.read()
    file_size = len(content)

    # Check file size
    max_size = settings.max_file_size_mb * 1024 * 1024
    if file_size > max_size:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"File size exceeds {settings.max_file_size_mb}MB limit",
        )

    # Check storage limit
    if not await can_upload_file(file_size):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Storage limit exceeded",
        )

    # Get duration and metadata from MP3
    try:
        audio = MP3(BytesIO(content))
        duration = int(audio.info.length * 1000)  # Convert to milliseconds

        # Extract ID3 tags if title/artist not provided
        if not title or not artist:
            tags = audio.tags
            if tags:
                # TIT2 = Title, TPE1 = Artist
                if not title and tags.get("TIT2"):
                    title = str(tags.get("TIT2"))
                if not artist and tags.get("TPE1"):
                    artist = str(tags.get("TPE1"))

        # Fallback to filename if still no title
        if not title:
            title = file.filename.rsplit(".", 1)[0] if file.filename else "Unknown"
        if not artist:
            artist = "Unknown"

    except Exception:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Could not read audio file",
        )

    # Upload to S3
    s3_key = f"tracks/{uuid.uuid4()}.mp3"
    await upload_file(content, s3_key)

    # Create track record
    track = Track(
        title=title,
        artist=artist,
        duration=duration,
        s3_key=s3_key,
        file_size=file_size,
        uploaded_by=current_user.id,
    )
    db.add(track)
    await db.flush()

    return track


@router.get("/{track_id}", response_model=TrackWithUrl)
async def get_track(track_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(Track).where(Track.id == track_id))
    track = result.scalar_one_or_none()

    if not track:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Track not found")

    url = generate_presigned_url(track.s3_key)
    return TrackWithUrl(
        id=track.id,
        title=track.title,
        artist=track.artist,
        duration=track.duration,
        file_size=track.file_size,
        uploaded_by=track.uploaded_by,
        created_at=track.created_at,
        url=url,
    )


@router.delete("/{track_id}")
async def delete_track(
    track_id: uuid.UUID,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(select(Track).where(Track.id == track_id))
    track = result.scalar_one_or_none()

    if not track:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Track not found")

    if track.uploaded_by != current_user.id:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not track owner")

    # Delete from S3
    await delete_file(track.s3_key)

    # Delete from DB
    await db.delete(track)

    return {"status": "deleted"}


@router.get("/storage/info")
async def get_storage_info(db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(func.sum(Track.file_size)))
    total_size = result.scalar() or 0
    max_size = settings.max_storage_gb * 1024 * 1024 * 1024

    return {
        "used_bytes": total_size,
        "max_bytes": max_size,
        "used_gb": round(total_size / (1024 * 1024 * 1024), 2),
        "max_gb": settings.max_storage_gb,
    }


@router.get("/{track_id}/stream")
async def stream_track(track_id: uuid.UUID, request: Request, db: AsyncSession = Depends(get_db)):
    """Stream audio file through backend with Range support (bypasses S3 SSL issues)"""
    result = await db.execute(select(Track).where(Track.id == track_id))
    track = result.scalar_one_or_none()

    if not track:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Track not found")

    # Get file size from S3 (without downloading)
    file_size = get_file_size(track.s3_key)

    # Encode filename for non-ASCII characters
    encoded_filename = quote(f"{track.title}.mp3")

    # Parse Range header
    range_header = request.headers.get("range")

    if range_header:
        # Parse "bytes=start-end"
        range_match = range_header.replace("bytes=", "").split("-")
        start = int(range_match[0]) if range_match[0] else 0
        end = int(range_match[1]) if range_match[1] else file_size - 1

        # Ensure valid range
        if start >= file_size:
            raise HTTPException(status_code=416, detail="Range not satisfiable")

        end = min(end, file_size - 1)
        content_length = end - start + 1

        return StreamingResponse(
            stream_file_chunks(track.s3_key, start, end),
            status_code=206,
            media_type="audio/mpeg",
            headers={
                "Content-Range": f"bytes {start}-{end}/{file_size}",
                "Accept-Ranges": "bytes",
                "Content-Length": str(content_length),
                "Content-Disposition": f"inline; filename*=UTF-8''{encoded_filename}",
                "X-Accel-Buffering": "no",
                "Cache-Control": "no-cache",
            }
        )

    # No range - stream full file
    return StreamingResponse(
        stream_file_chunks(track.s3_key),
        media_type="audio/mpeg",
        headers={
            "Accept-Ranges": "bytes",
            "Content-Length": str(file_size),
            "Content-Disposition": f"inline; filename*=UTF-8''{encoded_filename}",
            "X-Accel-Buffering": "no",
            "Cache-Control": "no-cache",
        }
    )