import { v4 as uuidv4 } from 'uuid';

let messages = [];
let searchQueue = [];
let users = [];
let currentChats = [];

export const getMessages = (toId, fromId) => {
  const userChats = currentChats.filter(chat => chat.includes(toId) && chat.includes(fromId));
  if (userChats.length === 0) {
    fromId = '';
  }
  const userMessages = messages.filter(message => message.to = toId && ["system", fromId].includes(message.from));
  messages = messages.filter(message => message.to === toId && ["system", fromId].includes(message.from));
  return userMessages;
};

export const addMessage = (from, to, text) => {
  const userChats = currentChats.filter(chat => chat.includes(from) && chat.includes(to));
  if (userChats.length === 0) {
    return;
  }
  messages.push({ from: from, to: to, text: text });
  return { text: text };
};

export const findMatch = (genders, age, id) => {
  const currentUsersChat = currentChats.filter(chat => chat.includes(id));
  if (currentUsersChat.length > 0) {
    return findUser(currentUsersChat[0][0] === id ? currentUsersChat[0][1] : currentUsersChat[0][0]);
  }
  let filteredSearchQueue = users.filter(user =>
    searchQueue.some(sq => sq.id === user.id) && user.id !== id
    && currentChats.filter(chat => chat.includes(user.id)).length === 0
  ).sort(() => Math.random() - 0.5);
  for (let i = 0; i < filteredSearchQueue.length; i++) {
    const user = filteredSearchQueue[i];
    const ageMatch = user.age >= age.min && user.age <= age.max;
    const genderMatch = genders.includes(user.gender);
    if (ageMatch && genderMatch) {
      for (let j = searchQueue.length - 1; j >= 0; j--) {
        if ([id, user.id].includes(searchQueue[j].id)) {
          searchQueue.splice(j, 1);
        }
      }
      currentChats.push([user.id, id]);
      return user;
    }
  }
  if (!searchQueue.find(user => user.id === id)) {
    searchQueue.push({ id, genders, age });
  }
  return null;
};

const findUser = (id) => {
  return users.find(user => user.id === id);
};

export const registerUser = (gender, age) => {
  const id = uuidv4();
  users.push({ gender, age, id });
  return id;
};

export const removeUser = (id) => {
  searchQueue = searchQueue.filter(user => user.id !== id);
  users = users.filter(user => user.id !== id);
  currentChats = currentChats.filter(pair => pair[0] === id || pair[1] === id);
  messages = messages.filter(message => message.from === id || message.to === id);
};

export const endChat = (userId) => {
  currentChats = currentChats.filter(chat => !chat.includes(userId));
  messages.push({ to: userId, from: 'system', activity: 'otheruserleft'})
}