app/api/routers/v1/background_edit.py

from fastapi import APIRouter, File, UploadFile, HTTPException, Form
from fastapi.responses import StreamingResponse
from app.services.image_generation_service import generate_image_from_files_and_prompt
from app.services.prompt_factory import BACKGROUND_EDIT_TEMPLATE 
from app.schemas.common_schemas import ModelSchema, CameraSchema,GarmentType,SurfaceType
import io
from typing import List, Annotated

router = APIRouter()

@router.post("/background_edit", tags=["Background_edit"])
async def background_edit(
    garment_type: Annotated[str, Form()],
    surface_type: Annotated[str, Form()],
    camera_view_angle: Annotated[str, Form()],
    camera_distance_meters: Annotated[float, Form()],
    camera_focal_length_mm: Annotated[float, Form()],
    camera_aperture_f_number: Annotated[float, Form()],
    camera_lighting_condition: Annotated[str, Form()],
    camera_background: Annotated[str, Form()],
    garment_images: List[UploadFile] = File(..., description="Exactly one image of the garments (e.g., dress /bag/shoes).", min_items=1, max_items=1),
):
    """
    Generate a try-on image based on garment images, model characteristics, and camera settings.
    """
    try:
        garment=GarmentType(garment_type=garment_type)
        surface=SurfaceType(surface_type=surface_type)
        camera_settings = CameraSchema(
            view_angle=camera_view_angle,
            distance_meters=camera_distance_meters,
            focal_length_mm=camera_focal_length_mm,
            aperture_f_number=camera_aperture_f_number,
            lighting_condition=camera_lighting_condition,
            background=camera_background
        )
    except Exception as e:
        raise HTTPException(status_code=400, detail=f"Invalid model or camera attributes: {e}")

    # Validation for exactly two files (FastAPI also handles min_items/max_items for File, but explicit check is fine)
    if not garment_images or len(garment_images) != 1:
        raise HTTPException(status_code=400, detail="Exactly one garment images are required for outfit match.")

    image_bytes_list = []
    for image_file in garment_images: # No need to check if garment_images is None here
        if not image_file.content_type.startswith("image/"):
            raise HTTPException(status_code=400, detail=f"Invalid file type for garment: {image_file.filename}. Must be an image.")
        content = await image_file.read()
        image_bytes_list.append((content, image_file.filename)) # Store as tuple (bytes, filename)
    
    prompt=BACKGROUND_EDIT_TEMPLATE.format(
            garment_type=garment.garment_type,
            surface_type=surface.surface_type,
            camera_view_angle=camera_settings.view_angle,
            camera_distance_meters=camera_settings.distance_meters,
            camera_focal_length_mm=camera_settings.focal_length_mm,
            camera_aperture_f_number=camera_settings.aperture_f_number,
            camera_lighting_condition=camera_settings.lighting_condition,
            camera_background=camera_settings.background
        )

    generated_image_data = await generate_image_from_files_and_prompt(
        image_files=image_bytes_list, 
        prompt=prompt
    )

    if generated_image_data:
        return StreamingResponse(io.BytesIO(generated_image_data), media_type="image/png")
    else:
        raise HTTPException(status_code=500, detail="Failed to generate image. Check service logs.")