from fastapi import APIRouter, HTTPException, Request
from fastapi.responses import Response

from app.services.backend_manager import get_backend

router = APIRouter()


def _validate_key(key: str) -> str:
    """Reject path traversal. Key may contain '/' for nested objects (e.g. user/doc.pdf)."""
    parts = key.split("/")
    if ".." in parts:
        raise HTTPException(status_code=400, detail="Invalid key: path traversal not allowed")
    return key


@router.put("/objects/{bucket}/{key:path}", status_code=204)
async def put_object(bucket: str, key: str, request: Request):
    """Upload raw bytes. Body is read as-is (application/octet-stream)."""
    _validate_key(key)
    data = await request.body()
    try:
        await get_backend().put(bucket, key, data)
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc))
    except Exception as exc:
        raise HTTPException(status_code=500, detail=str(exc))


@router.get("/objects/{bucket}/{key:path}")
async def get_object(bucket: str, key: str):
    """Download raw bytes."""
    _validate_key(key)
    try:
        data = await get_backend().get(bucket, key)
    except KeyError:
        raise HTTPException(status_code=404, detail="Object not found")
    except Exception as exc:
        raise HTTPException(status_code=500, detail=str(exc))
    return Response(content=data, media_type="application/octet-stream")


@router.delete("/objects/{bucket}/{key:path}", status_code=204)
async def delete_object(bucket: str, key: str):
    """Delete an object. No-op if it does not exist."""
    _validate_key(key)
    try:
        await get_backend().delete(bucket, key)
    except Exception as exc:
        raise HTTPException(status_code=500, detail=str(exc))


@router.get("/objects/{bucket}")
async def list_objects(bucket: str):
    """List all keys in a bucket."""
    try:
        keys = await get_backend().list_keys(bucket)
    except Exception as exc:
        raise HTTPException(status_code=500, detail=str(exc))
    return {"bucket": bucket, "keys": keys}