const fs = require('fs');
const path = require('path');

const TelegramBot = require('node-telegram-bot-api');

const config = require('./config');

let admin_chatId = null;
let authorizedUsers;

const SLIDESHOW_LOCATION = config.slideShowFolderPath;

// Functions
function storeFile(fileId, callback) {
  telegram.downloadFile(fileId, SLIDESHOW_LOCATION)
    .then((filePath) => {
      let message = config.messages.sendieResponse.fileSuccessfullySaved;
      message = message.replace('{fileLocation}', filePath);
      callback(null, filePath);
    })
    .catch((err) => {
      callback(err);
    });
}

let storeFileCallback = (err, filePath, chatId, photoId) => {
  let response;
  if (err) {
    response = config.messages.sendieResponse.failedToSaveFile;
    response = response.replace('{error}', err);
    telegram.sendMessage(chatId, response);
    response = config.messages.sendieResponse.failedToSaveFile;
    response = response.replace('{error}', err);
    if (admin_chatId !== chatId) notifyAdmin(response, photoId);
  } else {
    response = config.messages.sendieResponse.fileSuccessfullySaved;
    response = message.replace('{fileLocation}', filePath);
    telegram.sendMessage(chatId, response);
    response = config.messages.adminNotifications.fileSuccessfullySaved;
    response = message.replace('{fileLocation}', filePath);
    if (admin_chatId !== chatId) notifyAdmin(response, photoId);
  }
};

let handleMessage = (msg) => {
  const chatId = msg.chat.id;
  if (msg.photo || (msg.document && msg.document.mime_type.indexOf('image/') === 0)) { // Handle Images
    if (msg.photo) {
      storeFile(msg.photo[msg.photo.length - 1].file_id, (err, filePath) => {
        storeFileCallback(err, filePath, chatId, msg.photo[msg.photo.length - 1].file_id);
      });
    } else { // document - uncompressed photo
      storeFile(msg.document.file_id, (err, filePath) => {
        storeFileCallback(err, filePath, chatId, msg.document.file_id);
      });
    }
  } else if (msg.contact) { // Handle Contact
    addRemoveUser(msg.contact, msg.from);
  } else {
    // send a message to the chat acknowledging receipt of their message
    let message = config.messages.sendieResponse.unableToDoThat;
    message = message.replace('{username}', msg.from.username);
    telegram.sendMessage(chatId, message);
  }
};

let userAllowd = (msg) => {
  if (msg.from.id === config.admin.id) {
    admin_chatId = msg.chat.id;
    return true;
  }
  if (config.permissions.allowAll) return true;
  if (authorizedUsers.indexOf(msg.from.id) >= 0) return true;
  return false;
};

let notifyAdmin = (msg, photo_id) => {
  if (admin_chatId != null && config.admin.notifyActivity) {
    telegram.sendMessage(admin_chatId, msg);
    if (photo_id && config.admin.sendPhotoOnSave) telegram.sendPhoto(admin_chatId, photo_id);
  }
};

let addRemoveUser = (contact, from) => {
  if(!config.permissions.allowAddingUsers){
    // Ignore...
    console.warn('Attempt to add/remove a user. this functionality is disabled.');
    return;
  }else{
    if(from.id != config.admin.id && !config.permissions.allowNonAdminToAddUsers){
      telegram.sendMessage(from.id, config.messages.sendieResponse.noPermissions);
      console.warn('Attempt to add/remove a user from an unpermited user. id: ',from.id);
      return;
    }
  }
  let toAdd = true;
  if(authorizedUsers.indexOf(contact.user_id) < 0){
    // Add user
    authorizedUsers.push(contact.user_id);
  }else{
    // remove user
    toAdd = false;
    authorizedUsers.splice(authorizedUsers.indexOf(contact.user_id), 1);
  }
  if(saveToDB()){
    let message;
    if(toAdd) message = config.messages.sendieResponse.userAdded;
    else message = config.messages.sendieResponse.userRemoved;
    message = message.replace('{username}', contact.first_name);
    telegram.sendMessage(from.id, message); // response to the user that added the new one
    if(toAdd) message = config.messages.userAdded.added;
    else message = config.messages.userRemoved.removed;
    message = message.replace('{username_add_rem}', contact.first_name);
    message = message.replace('{username}', from.first_name);
    telegram.sendMessage(contact.user_id, message); // Notify the new/old user
    if(toAdd) message = config.messages.adminNotifications.userAdded;
    else message = config.messages.adminNotifications.userRemoved;
    message = message.replace('{username_add_rem}', contact.first_name);
    message = message.replace('{username}', from.first_name);
    if(from.id != config.admin.id) notifyAdmin(message); // notifyAdmin
  }else{
    console.log('Failed to save DB!!!');
  }
}

let loadDB = () => {
  let dbLocation = config.DBLocation;
  if (dbLocation[dbLocation.length - 1] != '/') dbLocation += '/users.json';
  else dbLocation += 'users.json';
  try{
    data = fs.readFileSync(path.resolve(dbLocation));
    try{
      authorizedUsers = JSON.parse(data.toString());
      console.log('DB loaded. AuthorizedUsers: ', authorizedUsers);
    }catch(err){
      console.error('DB file is corrupted. Please delete the file', dbLocation, 'And rerun this service');
      process.exit(1);
    }
  }catch(err){
    authorizedUsers = [];
    if(saveToDB()){
      console.log('DB was created. Everything is Okay.');
    }else{
      console.error('Unable to read from DB. Error:\n', err);
      process.exit(1);
    }
  }
}

let saveToDB = () => {
  let dbLocation = config.DBLocation;
  if (dbLocation[dbLocation.length - 1] != '/') dbLocation += '/users.json';
  else dbLocation += 'users.json';
  try{
    fs.writeFileSync(dbLocation, JSON.stringify(authorizedUsers));
    return true;
  }catch(err){
    console.error('Failed to save to DB... ERROR:\n', err);
    return false;
  }
}
/****** Run script ******/
loadDB();

let telegram = new TelegramBot(config.botId, {
  polling: true
});
telegram.on('message', (msg) => {
  const chatId = msg.chat.id;
  if(process.argv.indexOf('--printMessage') > 0){
    console.log(JSON.stringify(msg, null, 2));
    process.exit(0);
  }
  if (userAllowd(msg)) {
    handleMessage(msg);
  } else {
    let message = config.messages.sendieResponse.unauthorizedUser;
    message = message.replace('{username}', msg.from.username);
    message = message.replace('{messageObj}', JSON.stringify(msg, null, 2));
    telegram.sendMessage(chatId, message);
    message = config.messages.adminNotifications.unauthorizedUser;
    message = message.replace('{username}', msg.from.username);
    message = message.replace('{messageObj}', JSON.stringify(msg, null, 2));
    console.warn(message);
    notifyAdmin(message);
  }

});