import fs from 'fs';
import path from 'path';

const CHAT_HISTORY_FILE = path.join(__dirname, 'chat_history.json');
const MAX_MESSAGES = 100;

export interface ChatMessage {
  id: string;
  user: string;
  message: string;
  timestamp: number;
}

// Initialize chat history file if it doesn't exist
function initializeChatHistory(): void {
  if (!fs.existsSync(CHAT_HISTORY_FILE)) {
    fs.writeFileSync(CHAT_HISTORY_FILE, JSON.stringify([], null, 2));
  }
}

export function saveMessage(message: ChatMessage): void {
  try {
    initializeChatHistory();
    let messages: ChatMessage[] = [];
    
    // Read existing messages
    const fileContent = fs.readFileSync(CHAT_HISTORY_FILE, 'utf-8');
    try {
      messages = JSON.parse(fileContent);
      if (!Array.isArray(messages)) {
        messages = [];
      }
    } catch (parseError) {
      console.error('Error parsing chat history file:', parseError);
      messages = [];
    }
    
    // Add new message
    messages.push(message);
    
    // Keep only the last MAX_MESSAGES
    if (messages.length > MAX_MESSAGES) {
      messages = messages.slice(-MAX_MESSAGES);
    }
    
    // Write back to file
    fs.writeFileSync(CHAT_HISTORY_FILE, JSON.stringify(messages, null, 2));
  } catch (error) {
    console.error('Error saving chat message:', error);
  }
}

export function loadRecentMessages(): ChatMessage[] {
  try {
    initializeChatHistory();
    const fileContent = fs.readFileSync(CHAT_HISTORY_FILE, 'utf-8');
    try {
      const messages: ChatMessage[] = JSON.parse(fileContent);
      if (!Array.isArray(messages)) {
        return [];
      }
      return messages.slice(-MAX_MESSAGES);
    } catch (parseError) {
      console.error('Error parsing chat history file:', parseError);
      return [];
    }
  } catch (error) {
    console.error('Error loading chat messages:', error);
    return [];
  }
}