import vault from "vault-storage";
import type { Chat, Message } from "@/lib/types";

const initializeChats = async () => {
  const newChatHistory = new Array<Chat>();
  await vault.setItem("chats", newChatHistory);
  return newChatHistory;
};

const getAllChats: () => Promise<Chat[]> = async () => {
  let chats = await vault.getItem("chats");
  if (!chats) {
    chats = await initializeChats();
  }
  return chats;
};

const readChat = async (id: string): Promise<Chat | undefined> => {
  const chats = await getAllChats();
  return chats.find((chat) => chat.id === id);
};

const createChat = async (
  title: string,
  messages: Array<Message>
): Promise<Chat> => {
  const chats = await getAllChats();
  const newChat: Chat = {
    id: Date.now().toString(),
    title,
    messages,
    date: new Date().toDateString(),
  };

  chats.push(newChat);
  await vault.setItem("chats", chats);
  return newChat;
};

const updateChat = async (
  id: string,
  updates: Partial<Chat>
): Promise<Chat | undefined> => {
  const chats = await getAllChats();
  const index = chats.findIndex((chat) => chat.id === id);

  if (index === -1) return undefined;

  chats[index] = { ...chats[index], ...updates };
  await vault.setItem("chats", chats);
  return chats[index];
};

const deleteChat = async (id: string): Promise<boolean> => {
  const chats = await getAllChats();
  const filteredChats = chats.filter((chat) => chat.id !== id);

  if (filteredChats.length === chats.length) return false;

  await vault.setItem("chats", filteredChats);
  return true;
};

const deleteAllChats = async (): Promise<void> => {
  await initializeChats();
};

const addMessage = async (
  chatId: string,
  message: Omit<Message, "id">
): Promise<Chat | undefined> => {
  const chats = await getAllChats();
  const chatIndex = chats.findIndex((chat) => chat.id === chatId);

  if (chatIndex === -1) return undefined;
  const id = Date.now().toString();
  const newMessage: Message = {
    ...message,
    id: id,
  };

  chats[chatIndex].messages.push(newMessage);
  await vault.setItem("chats", chats);
  return chats[chatIndex];
};

const removeMessage = async (
  chatId: string,
  messageId: string
): Promise<Chat | undefined> => {
  const chats = await getAllChats();
  const chatIndex = chats.findIndex((chat) => chat.id === chatId);

  if (chatIndex === -1) return undefined;

  const messageIndex = chats[chatIndex].messages.findIndex(
    (message) => message.id === messageId
  );

  if (messageIndex === -1) return undefined;

  chats[chatIndex].messages.splice(messageIndex, 1);
  await vault.setItem("chats", chats);
  return chats[chatIndex];
};

const updateChatName = async (
  chatId: string,
  name: string
): Promise<boolean> => {
  const chat = await readChat(chatId);
  if (!chat) return false;

  const updatedChat = { ...chat, title: name };
  await updateChat(chatId, updatedChat);
  return true;
};

export {
  getAllChats,
  createChat,
  readChat,
  updateChat,
  deleteChat,
  deleteAllChats,
  addMessage,
  updateChatName,
  removeMessage,
};