/* globals UAParser*/

'use strict';

var ua = {
  userAgent: '',
  appVersion: '',
  platform: '',
  vendor: ''
};

var onBeforeSendHeaders = ({requestHeaders}) => {
  for (let i = 0, name = requestHeaders[0].name; i < requestHeaders.length; i += 1, name = requestHeaders[i].name) {
    if (name === 'User-Agent' || name === 'user-agent') {
      requestHeaders[i].value = ua.userAgent;
      return {
        requestHeaders
      };
    }
  }
};

var onCommitted = ({frameId, url, tabId}) => {
  if (frameId === 0 && url && (url.startsWith('http') || url.startsWith('ftp'))) {
    chrome.tabs.executeScript(tabId, {
      runAt: 'document_start',
      allFrames: true,
      code: `{
        const script = document.createElement('script');
        script.textContent = \`{
          navigator.__defineGetter__('userAgent', () => '${ua.userAgent}');
          navigator.__defineGetter__('appVersion', () => '${ua.appVersion}');
          navigator.__defineGetter__('platform', () => '${ua.platform}');
          navigator.__defineGetter__('vendor', () => '${ua.vendor}');
        }\`;
        document.documentElement.appendChild(script);
      }`
    }, () => chrome.runtime.lastError);
  }
};

function update(str) {
  ua.userAgent = str;
  ua.appVersion = str
    .replace(/^Mozilla\//, '')
    .replace(/^Opera\//, '');
  if (str) {
    const p = new UAParser(str);
    ua.platform = p.getOS().name || '';
    ua.vendor = p.getDevice().vendor || '';

    chrome.webRequest.onBeforeSendHeaders.addListener(onBeforeSendHeaders, {
      'urls' : ['*://*/*']
    }, ['blocking', 'requestHeaders']);
    chrome.webNavigation.onCommitted.addListener(onCommitted);
  }
  else {
    chrome.webRequest.onBeforeSendHeaders.removeListener(onBeforeSendHeaders);
    chrome.webNavigation.onCommitted.removeListener(onCommitted);
  }
  chrome.browserAction.setIcon({
    path: {
      16: 'data/icons/' + (str ? 'active/' : '') + '16.png',
      32: 'data/icons/' + (str ? 'active/' : '') + '32.png',
      48: 'data/icons/' + (str ? 'active/' : '') + '48.png',
      64: 'data/icons/' + (str ? 'active/' : '') + '64.png'
    }
  });
  chrome.browserAction.setTitle({
    title: `UserAgent Switcher (${str ? 'enabled' : 'disabled'})

User-Agent String: ${str || navigator.userAgent}`
  });
}

chrome.storage.local.get({
  ua: ''
}, prefs => update(prefs.ua));
chrome.storage.onChanged.addListener(prefs => prefs.ua && update(prefs.ua.newValue));

// FAQs & Feedback
chrome.storage.local.get({
  'version': null,
  'faqs': navigator.userAgent.indexOf('Firefox')
}, prefs => {
  const version = chrome.runtime.getManifest().version;

  if (prefs.version ? (prefs.faqs && prefs.version !== version) : true) {
    chrome.storage.local.set({version}, () => {
      chrome.tabs.create({
        url: 'http://add0n.com/useragent-switcher.html?version=' + version +
          '&type=' + (prefs.version ? ('upgrade&p=' + prefs.version) : 'install')
      });
    });
  }
});

{
  const {name, version} = chrome.runtime.getManifest();
  chrome.runtime.setUninstallURL('http://add0n.com/feedback.html?name=' + name + '&version=' + version);
}