import { useState, useEffect } from 'react';
import type { Conversation } from '../types';

export const useConversations = () => {
  const [conversations, setConversations] = useState<Conversation[]>([]);
  const [loading, setLoading] = useState(true);

  // Cargar conversaciones del localStorage (temporal hasta tener backend)
  useEffect(() => {
    loadConversations();
  }, []);

  const loadConversations = () => {
    try {
      const stored = localStorage.getItem('conversations');
      if (stored) {
        const parsed = JSON.parse(stored);
        setConversations(parsed.map((c: any) => ({
          ...c,
          createdAt: new Date(c.createdAt),
          updatedAt: new Date(c.updatedAt),
        })));
      }
    } catch (error) {
      console.error('Error loading conversations:', error);
    } finally {
      setLoading(false);
    }
  };

  const createConversation = (firstMessage: string): Conversation => {
    // Generar título del chat basado en el primer mensaje (máximo 50 caracteres)
    const title = firstMessage.length > 50
      ? firstMessage.substring(0, 47) + '...'
      : firstMessage;

    const newConversation: Conversation = {
      id: `conv_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
      title,
      createdAt: new Date(),
      updatedAt: new Date(),
      messageCount: 1,
    };

    const updated = [newConversation, ...conversations];
    setConversations(updated);
    saveConversations(updated);

    return newConversation;
  };

  const updateConversationTitle = (id: string, newTitle: string) => {
    const updated = conversations.map(conv =>
      conv.id === id
        ? { ...conv, title: newTitle, updatedAt: new Date() }
        : conv
    );
    setConversations(updated);
    saveConversations(updated);
  };

  const deleteConversation = (id: string) => {
    const updated = conversations.filter(conv => conv.id !== id);
    setConversations(updated);
    saveConversations(updated);

    // También eliminar mensajes asociados
    localStorage.removeItem(`messages_${id}`);
  };

  const saveConversations = (convs: Conversation[]) => {
    localStorage.setItem('conversations', JSON.stringify(convs));
  };

  return {
    conversations,
    loading,
    createConversation,
    updateConversationTitle,
    deleteConversation,
    refreshConversations: loadConversations,
  };
};