'use strict';

const fs = require('fs');
const settingsVersion = 1;

function merge(base, target) {
  return Object.assign({}, base, target);
}

function loadDefault(version, spellCheckerLocale) {
  var ver = version;
  if (version == null) {
    ver = settingsVersion;
  }
  switch (ver) {
  case 1:
    return {
      teams: [],
      showTrayIcon: false,
      trayIconTheme: 'light',
      minimizeToTray: false,
      version: 1,
      notifications: {
        flashWindow: 0 // 0 = flash never, 1 = only when idle (after 10 seconds), 2 = always
      },
      showUnreadBadge: true,
      useSpellChecker: false,
      spellCheckerLocale: spellCheckerLocale || 'en-US'
    };
  default:
    return {};
  }
}

function upgradeV0toV1(configV0) {
  var config = loadDefault(1);
  config.teams.push({
    name: 'Primary team',
    url: configV0.url
  });
  return config;
}

function upgrade(config, newAppVersion) {
  var configVersion = config.version ? config.version : 0;
  if (newAppVersion) {
    config.lastMattermostVersion = newAppVersion;
  }
  switch (configVersion) {
  case 0:
    return upgrade(upgradeV0toV1(config));
  default:
    return config;
  }
}

module.exports = {
  version: settingsVersion,

  upgrade,

  readFileSync(configFile) {
    var config = JSON.parse(fs.readFileSync(configFile, 'utf8'));
    if (config.version === settingsVersion) {
      var defaultConfig = this.loadDefault();
      config = merge(defaultConfig, config);
    }
    return config;
  },

  writeFile(configFile, config, callback) {
    if (config.version !== settingsVersion) {
      throw new Error('version ' + config.version + ' is not equal to ' + settingsVersion);
    }
    var data = JSON.stringify(config, null, '  ');
    fs.writeFile(configFile, data, 'utf8', callback);
  },

  writeFileSync(configFile, config) {
    if (config.version !== settingsVersion) {
      throw new Error('version ' + config.version + ' is not equal to ' + settingsVersion);
    }
    var data = JSON.stringify(config, null, '  ');
    fs.writeFileSync(configFile, data, 'utf8');
  },

  loadDefault
};