from fastapi import FastAPI, UploadFile, File, Form, HTTPException
from fastapi.responses import StreamingResponse, JSONResponse
from core.renderer import ExcelRenderer
import io
import logging

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

app = FastAPI(
    title="Excel2Pic API",
    description="A lightweight service to convert Excel sheets to images.",
    version="0.1.0"
)

@app.post("/api/v1/convert", summary="Convert Excel to Image")
async def convert_excel(
    file: UploadFile = File(..., description="The Excel file to convert"),
    sheet_name: str = Form(None, description="Name of the sheet to convert (optional, defaults to active sheet)"),
    scale: int = Form(3, description="Scaling factor for high-DPI rendering (default 3, best for mobile/retina screens)"),
):
    """
    Convert an uploaded Excel file to a PNG image.
    """
    # Validation
    if not file.filename.endswith(('.xlsx', '.xls')):
        raise HTTPException(status_code=400, detail="Invalid file format. Please upload .xlsx or .xls file.")

    try:
        # Read file content
        contents = await file.read()
        
        # Initialize Renderer
        # Note: In a real deployment, font paths might come from env vars
        renderer = ExcelRenderer(contents)
        
        # Render
        # Use scale parameter
        image_bytes = renderer.render_to_bytes(sheet_name=sheet_name, scale=scale)
        
        # Return as streaming response
        # Handle Chinese filenames in Content-Disposition
        from urllib.parse import quote
        filename = file.filename.split('.')[0] + ".png"
        encoded_filename = quote(filename)
        
        return StreamingResponse(
            io.BytesIO(image_bytes), 
            media_type="image/png",
            headers={"Content-Disposition": f"inline; filename*=utf-8''{encoded_filename}"}
        )

    except ValueError as ve:
        # Often raised when sheet name is not found
        logger.warning(f"Value Error: {str(ve)}")
        raise HTTPException(status_code=400, detail=str(ve))
    except Exception as e:
        logger.error(f"Internal Server Error: {str(e)}", exc_info=True)
        raise HTTPException(status_code=500, detail=f"An error occurred during conversion: {str(e)}")

@app.get("/health", summary="Health Check")
def health_check():
    return {"status": "ok"}