# /core.py
""" Core business logic for the code generation application. """
from typing import Dict, List, Optional, Tuple, Generator, Any
from config import (HTML_SYSTEM_PROMPT, GENERIC_SYSTEM_PROMPT, HTML_SYSTEM_PROMPT_WITH_SEARCH, 
                    GENERIC_SYSTEM_PROMPT_WITH_SEARCH, FollowUpSystemPrompt)
from services import llm_service, search_service
from extractor import extract_text_from_file, extract_website_content
from utils import (history_to_messages, remove_code_block, process_image_for_model, 
                   apply_search_replace_changes)

History = List[Tuple[Optional[str], Optional[str]]]

def _determine_system_prompt(language: str, enable_search: bool, history: History) -> Tuple[str, bool]:
    is_follow_up = bool(history and history[-1][1] and ("<html" in history[-1][1]))
    if is_follow_up: return FollowUpSystemPrompt, True

    if language == "html":
        return (HTML_SYSTEM_PROMPT_WITH_SEARCH if enable_search else HTML_SYSTEM_PROMPT), False
    else:
        base = GENERIC_SYSTEM_PROMPT_WITH_SEARCH if enable_search else GENERIC_SYSTEM_PROMPT
        return base.format(language=language), False

def _prepare_user_content(query: str, image_data: Optional[Any], file_path: Optional[str], website_url: Optional[str], enable_search: bool) -> Any:
    context_parts = [query]
    if file_path: context_parts.append(f"\n\n--- Reference File ---\n{extract_text_from_file(file_path)[:8000]}")
    if website_url: context_parts.append(f"\n\n--- Website to Redesign ---\n{extract_website_content(website_url)}")
    full_query = "".join(context_parts)
    if enable_search and search_service.is_available(): full_query += f"\n\n--- Web Search Results ---\n{search_service.search(full_query)}"
    
    if image_data is not None:
        return [{"type": "text", "text": full_query}, {"type": "image_url", "image_url": {"url": process_image_for_model(image_data)}}]
    return full_query

def generate_code(query: str, image_data: Optional[Any], file_path: Optional[str], website_url: Optional[str], history: History, 
                  model_config: Dict[str, str], enable_search: bool, language: str) -> Generator[Dict[str, Any], None, None]:
    system_prompt, is_follow_up = _determine_system_prompt(language, enable_search, history)
    messages = history_to_messages(history, system_prompt)
    user_content = _prepare_user_content(query, image_data, file_path, website_url, enable_search)
    messages.append({'role': 'user', 'content': user_content})

    content_stream = ""
    for chunk in llm_service.generate_code_stream(model_config['id'], messages):
        content_stream += chunk
        processed_code = apply_search_replace_changes(history[-1][1], content_stream) if is_follow_up else remove_code_block(content_stream)
        yield {"code_output": processed_code}

    final_code = apply_search_replace_changes(history[-1][1], content_stream) if is_follow_up else remove_code_block(content_stream)
    history.append((query, final_code))
    yield {"code_output": final_code, "history": history}