import os
import io
import uvicorn

from pathlib                    import Path
from fastapi                    import FastAPI, Header
from fastapi.responses          import StreamingResponse
from fastapi.middleware.cors    import CORSMiddleware
from fastapi.staticfiles        import StaticFiles
from config                     import ServerConfig


app = FastAPI()
app.mount('/home', StaticFiles(directory="static", html=True), name="static")
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"]
)


@app.get("/fetch/{id}")
async def fetch_file(id: str, range: str = Header(None)) -> StreamingResponse:
    video_path: Path = Path(os.path.join(ServerConfig.video_play_path, id + '.mp4'))
    video_size: int  = video_path.stat().st_size
    start            = 0
    end              = video_size - 1
    chunk_size       = min(video_size, ServerConfig.video_chunk_size)
    headers          = { 
                         'Content-Type': 'video/mp4', 
                         'Content-Disposition': f'attachment; filename="{id}.mp4"',
                       }
    if range:
        start, end       = range.replace('bytes=', '').split('-')
        start            = int(start)
        end              = int(end) if end else video_size - 1
        chunk_size: int  = min(end - start + 1, ServerConfig.video_chunk_size)
        headers['Content-Range']        = f'bytes {start}-{end}/{video_size}'
        headers['Accept-Ranges']        = 'bytes'
        headers['Content-Disposition']  = 'inline'
    def file_reader():
        with open(video_path, 'rb') as video:
            video.seek(start)
            while True:
                data = video.read(chunk_size)
                if not data:
                    break
                yield data
    return StreamingResponse(file_reader(), status_code=206, headers=headers, media_type='video/mp4')





if __name__ == "__main__":
    uvicorn.run(app=app)