from fastapi import APIRouter, Depends, UploadFile, File, HTTPException
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session
import uuid
import shutil
from pathlib import Path

from app.db import get_db
from app.auth.dependencies import get_current_user
from app.config import settings

router = APIRouter(prefix="/documents", tags=["Assets"])

def get_asset_path(document_id: str, ref: str) -> Path:
    # Ensure directory exists
    dir_path = settings.PDF_STORAGE_PATH / "assets" / document_id
    dir_path.mkdir(parents=True, exist_ok=True)
    return dir_path / ref

@router.post("/{id}/assets")
async def upload_asset(
    id: str,
    file: UploadFile = File(...),
    user_id: int = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Upload a binary asset (like an image or signature) for a document."""
    # In a real app we'd verify the user owns the document here
    # For this single-user app, we trust the ID

    if not file.content_type or not file.content_type.startswith("image/"):
        raise HTTPException(status_code=400, detail="Only image assets are supported")

    ref = str(uuid.uuid4())
    filepath = get_asset_path(id, ref)
    
    try:
        with open(filepath, "wb") as f:
            shutil.copyfileobj(file.file, f)
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to save asset: {e}")

    return {
        "ref": ref,
        "url": f"/api/v1/documents/{id}/assets/{ref}"
    }

@router.get("/{id}/assets/{ref}")
async def get_asset(
    id: str,
    ref: str,
):
    """Serve a binary asset."""
    filepath = get_asset_path(id, ref)
    if not filepath.exists() or not filepath.is_file():
        raise HTTPException(status_code=404, detail="Asset not found")
        
    return FileResponse(filepath)