import os
import tempfile
import uuid
from typing import Optional

from fastapi import APIRouter, Depends, File, Form, HTTPException, UploadFile
from fastapi.responses import FileResponse

from api.middlewares.rate_limit_middleware import limiter
from models.sql.user import UserModel
from services.template_codegen_service import generate_pptx_from_template
from utils.auth_dependencies import get_current_user
from fastapi import Request

TEMPLATE_CODEGEN_ROUTER = APIRouter(prefix="/template-codegen", tags=["Template CodeGen"])


@TEMPLATE_CODEGEN_ROUTER.post("/generate")
@limiter.limit("3/minute")
async def generate_from_template(
    request: Request,
    presentation_id: str = Form(...),
    template_file: UploadFile = File(...),
    custom_prompt: Optional[str] = Form(None),
    _current_user: UserModel = Depends(get_current_user),
):
    """
    Generate a populated PPTX from a branded template file and existing presentation content.
    Accepts: multipart/form-data with presentation_id, template_file (.pptx), custom_prompt (optional)
    Returns: PPTX file download
    """
    # Validate file type
    filename = template_file.filename or ""
    if not filename.lower().endswith(".pptx"):
        raise HTTPException(status_code=400, detail="Template file must be a .pptx file")

    # Save uploaded template to temp
    tmp_dir = os.environ.get("TEMP_DIRECTORY", tempfile.gettempdir())
    template_path = os.path.join(tmp_dir, f"template_{uuid.uuid4().hex}.pptx")
    output_path = os.path.join(tmp_dir, f"output_{uuid.uuid4().hex}.pptx")

    try:
        content = await template_file.read()
        with open(template_path, "wb") as f:
            f.write(content)

        result = await generate_pptx_from_template(
            template_path=template_path,
            presentation_id=presentation_id,
            custom_prompt=custom_prompt or "",
            output_path=output_path,
        )

        return FileResponse(
            path=result["output_path"],
            media_type="application/vnd.openxmlformats-officedocument.presentationml.presentation",
            filename="presentation-from-template.pptx",
            background=None,
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except RuntimeError as e:
        raise HTTPException(status_code=500, detail=str(e))
    finally:
        # Clean up template file
        try:
            os.unlink(template_path)
        except Exception:
            pass