from __future__ import annotations

import os
from pathlib import Path

from src.llm.gemma_client import generate_slides_json
from src.ppt.deck_generator import compile_presentation
from src.ppt.template_loader import parse_template_style
from src.utils.validators import validate_template


def _resolve_template_path(template_input) -> Path:
    if template_input is None:
        raise ValueError("Please upload a `.pptx` template file.")

    if isinstance(template_input, (str, Path)):
        return validate_template(template_input)

    # Gradio file objects generally expose `.name` with the temp file path.
    file_name = getattr(template_input, "name", None)
    if file_name:
        return validate_template(file_name)

    raise ValueError("Unsupported template input format. Upload a `.pptx` file.")


def customize_presentation(template_input, user_input: str) -> str:
    if not user_input or not user_input.strip():
        raise ValueError("Please provide presentation topic/content notes.")

    template_path = _resolve_template_path(template_input)

    style_profile = parse_template_style(template_path)
    backend = os.getenv("MODEL_BACKEND", "transformers")
    slides_json = generate_slides_json(user_input.strip(), backend=backend)

    output_path = compile_presentation(
        slides_payload=slides_json,
        template_path=template_path,
        style_profile=style_profile,
    )
    return output_path