'use strict';

if (process.electronBinding('features').isExtensionsEnabled()) {
  throw new Error('Attempted to load JS chrome-extension polyfill with //extensions support enabled');
}

const { app, webContents, BrowserWindow } = require('electron');
const { getAllWebContents } = process.electronBinding('web_contents');
const { ipcMainInternal } = require('@electron/internal/browser/ipc-main-internal');
const ipcMainUtils = require('@electron/internal/browser/ipc-main-internal-utils');

const { Buffer } = require('buffer');
const fs = require('fs');
const path = require('path');
const url = require('url');
const util = require('util');

// Mapping between extensionId(hostname) and manifest.
const manifestMap = {}; // extensionId => manifest
const manifestNameMap = {}; // name => manifest
const devToolsExtensionNames = new Set();

const generateExtensionIdFromName = function (name) {
  return name.replace(/[\W_]+/g, '-').toLowerCase();
};

const isWindowOrWebView = function (webContents) {
  const type = webContents.getType();
  return type === 'window' || type === 'webview';
};

const isBackgroundPage = function (webContents) {
  return webContents.getType() === 'backgroundPage';
};

// Create or get manifest object from |srcDirectory|.
const getManifestFromPath = function (srcDirectory) {
  let manifest;
  let manifestContent;

  try {
    manifestContent = fs.readFileSync(path.join(srcDirectory, 'manifest.json'));
  } catch (readError) {
    console.warn(`Reading ${path.join(srcDirectory, 'manifest.json')} failed.`);
    console.warn(readError.stack || readError);
    throw readError;
  }

  try {
    manifest = JSON.parse(manifestContent);
  } catch (parseError) {
    console.warn(`Parsing ${path.join(srcDirectory, 'manifest.json')} failed.`);
    console.warn(parseError.stack || parseError);
    throw parseError;
  }

  if (!manifestNameMap[manifest.name]) {
    const extensionId = generateExtensionIdFromName(manifest.name);
    manifestMap[extensionId] = manifestNameMap[manifest.name] = manifest;

    let extensionURL = url.format({
      protocol: 'chrome-extension',
      slashes: true,
      hostname: extensionId,
      pathname: manifest.devtools_page
    });

    // Chromium requires that startPage matches '([^:]+:\/\/[^/]*)\/'
    // We also can't use the file:// protocol here since that would make Chromium
    // treat all extension resources as being relative to root which we don't want.
    if (!manifest.devtools_page) extensionURL += '/';

    Object.assign(manifest, {
      srcDirectory: srcDirectory,
      extensionId: extensionId,
      startPage: extensionURL
    });

    return manifest;
  } else if (manifest && manifest.name) {
    console.warn(`Attempted to load extension "${manifest.name}" that has already been loaded.`);
    return manifest;
  }
};

// Manage the background pages.
const backgroundPages = {};

const startBackgroundPages = function (manifest) {
  if (backgroundPages[manifest.extensionId] || !manifest.background) return;

  let html;
  let name;
  if (manifest.background.page) {
    name = manifest.background.page;
    html = fs.readFileSync(path.join(manifest.srcDirectory, manifest.background.page));
  } else {
    name = '_generated_background_page.html';
    const scripts = manifest.background.scripts.map((name) => {
      return `<script src="${name}"></script>`;
    }).join('');
    html = Buffer.from(`<html><body>${scripts}</body></html>`);
  }

  const contents = webContents.create({
    partition: 'persist:__chrome_extension',
    type: 'backgroundPage',
    sandbox: true,
    enableRemoteModule: false
  });
  backgroundPages[manifest.extensionId] = { html: html, webContents: contents, name: name };
  contents.loadURL(url.format({
    protocol: 'chrome-extension',
    slashes: true,
    hostname: manifest.extensionId,
    pathname: name
  }));
};

const removeBackgroundPages = function (manifest) {
  if (!backgroundPages[manifest.extensionId]) return;

  backgroundPages[manifest.extensionId].webContents.destroy();
  delete backgroundPages[manifest.extensionId];
};

const sendToBackgroundPages = function (...args) {
  for (const page of Object.values(backgroundPages)) {
    if (!page.webContents.isDestroyed()) {
      page.webContents._sendInternalToAll(...args);
    }
  }
};

// Dispatch web contents events to Chrome APIs
const hookWebContentsEvents = function (webContents) {
  const tabId = webContents.id;

  sendToBackgroundPages('CHROME_TABS_ONCREATED');

  webContents.on('will-navigate', (event, url) => {
    sendToBackgroundPages('CHROME_WEBNAVIGATION_ONBEFORENAVIGATE', {
      frameId: 0,
      parentFrameId: -1,
      processId: webContents.getProcessId(),
      tabId: tabId,
      timeStamp: Date.now(),
      url: url
    });
  });

  webContents.on('did-navigate', (event, url) => {
    sendToBackgroundPages('CHROME_WEBNAVIGATION_ONCOMPLETED', {
      frameId: 0,
      parentFrameId: -1,
      processId: webContents.getProcessId(),
      tabId: tabId,
      timeStamp: Date.now(),
      url: url
    });
  });

  webContents.once('destroyed', () => {
    sendToBackgroundPages('CHROME_TABS_ONREMOVED', tabId);
  });
};

// Handle the chrome.* API messages.
let nextId = 0;

ipcMainUtils.handleSync('CHROME_RUNTIME_CONNECT', function (event, extensionId, connectInfo) {
  if (isBackgroundPage(event.sender)) {
    throw new Error('chrome.runtime.connect is not supported in background page');
  }

  const page = backgroundPages[extensionId];
  if (!page || page.webContents.isDestroyed()) {
    throw new Error(`Connect to unknown extension ${extensionId}`);
  }

  const tabId = page.webContents.id;
  const portId = ++nextId;

  event.sender.once('render-view-deleted', () => {
    if (page.webContents.isDestroyed()) return;
    page.webContents._sendInternalToAll(`CHROME_PORT_DISCONNECT_${portId}`);
  });
  page.webContents._sendInternalToAll(`CHROME_RUNTIME_ONCONNECT_${extensionId}`, event.sender.id, portId, connectInfo);

  return { tabId, portId };
});

ipcMainUtils.handleSync('CHROME_EXTENSION_MANIFEST', function (event, extensionId) {
  const manifest = manifestMap[extensionId];
  if (!manifest) {
    throw new Error(`Invalid extensionId: ${extensionId}`);
  }
  return manifest;
});

ipcMainInternal.handle('CHROME_RUNTIME_SEND_MESSAGE', async function (event, extensionId, message) {
  if (isBackgroundPage(event.sender)) {
    throw new Error('chrome.runtime.sendMessage is not supported in background page');
  }

  const page = backgroundPages[extensionId];
  if (!page || page.webContents.isDestroyed()) {
    throw new Error(`Connect to unknown extension ${extensionId}`);
  }

  return ipcMainUtils.invokeInWebContents(page.webContents, true, `CHROME_RUNTIME_ONMESSAGE_${extensionId}`, event.sender.id, message);
});

ipcMainInternal.handle('CHROME_TABS_SEND_MESSAGE', async function (event, tabId, extensionId, message) {
  const contents = webContents.fromId(tabId);
  if (!contents) {
    throw new Error(`Sending message to unknown tab ${tabId}`);
  }

  const senderTabId = isBackgroundPage(event.sender) ? null : event.sender.id;

  return ipcMainUtils.invokeInWebContents(contents, true, `CHROME_RUNTIME_ONMESSAGE_${extensionId}`, senderTabId, message);
});

const getLanguage = () => {
  return app.getLocale().replace(/-.*$/, '').toLowerCase();
};

const getMessagesPath = (extensionId) => {
  const metadata = manifestMap[extensionId];
  if (!metadata) {
    throw new Error(`Invalid extensionId: ${extensionId}`);
  }

  const localesDirectory = path.join(metadata.srcDirectory, '_locales');
  const language = getLanguage();

  try {
    const filename = path.join(localesDirectory, language, 'messages.json');
    fs.accessSync(filename, fs.constants.R_OK);
    return filename;
  } catch {
    const defaultLocale = metadata.default_locale || 'en';
    return path.join(localesDirectory, defaultLocale, 'messages.json');
  }
};

ipcMainUtils.handleSync('CHROME_GET_MESSAGES', async function (event, extensionId) {
  const messagesPath = getMessagesPath(extensionId);
  return fs.promises.readFile(messagesPath, 'utf8');
});

const validStorageTypes = new Set(['sync', 'local']);

const getChromeStoragePath = (storageType, extensionId) => {
  if (!validStorageTypes.has(storageType)) {
    throw new Error(`Invalid storageType: ${storageType}`);
  }

  if (!manifestMap[extensionId]) {
    throw new Error(`Invalid extensionId: ${extensionId}`);
  }

  return path.join(app.getPath('userData'), `/Chrome Storage/${extensionId}-${storageType}.json`);
};

ipcMainInternal.handle('CHROME_STORAGE_READ', async function (event, storageType, extensionId) {
  const filePath = getChromeStoragePath(storageType, extensionId);

  try {
    return await fs.promises.readFile(filePath, 'utf8');
  } catch (error) {
    if (error.code === 'ENOENT') {
      return null;
    } else {
      throw error;
    }
  }
});

ipcMainInternal.handle('CHROME_STORAGE_WRITE', async function (event, storageType, extensionId, data) {
  const filePath = getChromeStoragePath(storageType, extensionId);

  try {
    await fs.promises.mkdir(path.dirname(filePath), { recursive: true });
  } catch {
    // we just ignore the errors of mkdir
  }

  return fs.promises.writeFile(filePath, data, 'utf8');
});

const isChromeExtension = function (pageURL) {
  const { protocol } = url.parse(pageURL);
  return protocol === 'chrome-extension:';
};

const assertChromeExtension = function (contents, api) {
  const pageURL = contents._getURL();
  if (!isChromeExtension(pageURL)) {
    console.error(`Blocked ${pageURL} from calling ${api}`);
    throw new Error(`Blocked ${api}`);
  }
};

ipcMainInternal.handle('CHROME_TABS_EXECUTE_SCRIPT', async function (event, tabId, extensionId, details) {
  assertChromeExtension(event.sender, 'chrome.tabs.executeScript()');

  const contents = webContents.fromId(tabId);
  if (!contents) {
    throw new Error(`Sending message to unknown tab ${tabId}`);
  }

  let code, url;
  if (details.file) {
    const manifest = manifestMap[extensionId];
    code = String(fs.readFileSync(path.join(manifest.srcDirectory, details.file)));
    url = `chrome-extension://${extensionId}${details.file}`;
  } else {
    code = details.code;
    url = `chrome-extension://${extensionId}/${String(Math.random()).substr(2, 8)}.js`;
  }

  return ipcMainUtils.invokeInWebContents(contents, false, 'CHROME_TABS_EXECUTE_SCRIPT', extensionId, url, code);
});

exports.getContentScripts = () => {
  return Object.values(contentScripts);
};

// Transfer the content scripts to renderer.
const contentScripts = {};

const injectContentScripts = function (manifest) {
  if (contentScripts[manifest.name] || !manifest.content_scripts) return;

  const readArrayOfFiles = function (relativePath) {
    return {
      url: `chrome-extension://${manifest.extensionId}/${relativePath}`,
      code: String(fs.readFileSync(path.join(manifest.srcDirectory, relativePath)))
    };
  };

  const contentScriptToEntry = function (script) {
    return {
      matches: script.matches,
      js: script.js ? script.js.map(readArrayOfFiles) : [],
      css: script.css ? script.css.map(readArrayOfFiles) : [],
      runAt: script.run_at || 'document_idle',
      allFrames: script.all_frames || false
    };
  };

  try {
    const entry = {
      extensionId: manifest.extensionId,
      contentScripts: manifest.content_scripts.map(contentScriptToEntry)
    };
    contentScripts[manifest.name] = entry;
  } catch (e) {
    console.error('Failed to read content scripts', e);
  }
};

const removeContentScripts = function (manifest) {
  if (!contentScripts[manifest.name]) return;

  delete contentScripts[manifest.name];
};

// Transfer the |manifest| to a format that can be recognized by the
// |DevToolsAPI.addExtensions|.
const manifestToExtensionInfo = function (manifest) {
  return {
    startPage: manifest.startPage,
    srcDirectory: manifest.srcDirectory,
    name: manifest.name,
    exposeExperimentalAPIs: true
  };
};

// Load the extensions for the window.
const loadExtension = function (manifest) {
  startBackgroundPages(manifest);
  injectContentScripts(manifest);
};

const loadDevToolsExtensions = function (win, manifests) {
  if (!win.devToolsWebContents) return;

  manifests.forEach(loadExtension);

  const extensionInfoArray = manifests.map(manifestToExtensionInfo);
  extensionInfoArray.forEach((extension) => {
    win.devToolsWebContents._grantOriginAccess(extension.startPage);
  });

  extensionInfoArray.forEach((extensionInfo) => {
    const info = JSON.stringify(extensionInfo);
    win.devToolsWebContents.executeJavaScript(`Extensions.extensionServer._addExtension(${info})`);
  });
};

app.on('web-contents-created', function (event, webContents) {
  if (!isWindowOrWebView(webContents)) return;

  hookWebContentsEvents(webContents);
  webContents.on('devtools-opened', function () {
    loadDevToolsExtensions(webContents, Object.values(manifestMap));
  });
});

// The chrome-extension: can map a extension URL request to real file path.
const chromeExtensionHandler = function (request, callback) {
  const parsed = url.parse(request.url);
  if (!parsed.hostname || !parsed.path) return callback();

  const manifest = manifestMap[parsed.hostname];
  if (!manifest) return callback();

  const page = backgroundPages[parsed.hostname];
  if (page && parsed.path === `/${page.name}`) {
    // Disabled due to false positive in StandardJS
    // eslint-disable-next-line standard/no-callback-literal
    return callback({
      mimeType: 'text/html',
      data: page.html
    });
  }

  fs.readFile(path.join(manifest.srcDirectory, parsed.path), function (err, content) {
    if (err) {
      // Disabled due to false positive in StandardJS
      // eslint-disable-next-line standard/no-callback-literal
      return callback(-6); // FILE_NOT_FOUND
    } else {
      return callback(content);
    }
  });
};

app.on('session-created', function (ses) {
  ses.protocol.registerBufferProtocol('chrome-extension', chromeExtensionHandler);
});

// The persistent path of "DevTools Extensions" preference file.
let loadedDevToolsExtensionsPath = null;

app.on('will-quit', function () {
  try {
    const loadedDevToolsExtensions = Array.from(devToolsExtensionNames)
      .map(name => manifestNameMap[name].srcDirectory);
    if (loadedDevToolsExtensions.length > 0) {
      try {
        fs.mkdirSync(path.dirname(loadedDevToolsExtensionsPath));
      } catch {
        // Ignore error
      }
      fs.writeFileSync(loadedDevToolsExtensionsPath, JSON.stringify(loadedDevToolsExtensions));
    } else {
      fs.unlinkSync(loadedDevToolsExtensionsPath);
    }
  } catch {
    // Ignore error
  }
});

// We can not use protocol or BrowserWindow until app is ready.
app.whenReady().then(function () {
  // The public API to add/remove extensions.
  BrowserWindow.addExtension = function (srcDirectory) {
    const manifest = getManifestFromPath(srcDirectory);
    if (manifest) {
      loadExtension(manifest);
      for (const webContents of getAllWebContents()) {
        if (isWindowOrWebView(webContents)) {
          loadDevToolsExtensions(webContents, [manifest]);
        }
      }
      return manifest.name;
    }
  };

  BrowserWindow.removeExtension = function (name) {
    const manifest = manifestNameMap[name];
    if (!manifest) return;

    removeBackgroundPages(manifest);
    removeContentScripts(manifest);
    delete manifestMap[manifest.extensionId];
    delete manifestNameMap[name];
  };

  BrowserWindow.getExtensions = function () {
    const extensions = {};
    Object.keys(manifestNameMap).forEach(function (name) {
      const manifest = manifestNameMap[name];
      extensions[name] = { name: manifest.name, version: manifest.version };
    });
    return extensions;
  };

  BrowserWindow.addDevToolsExtension = function (srcDirectory) {
    const manifestName = BrowserWindow.addExtension(srcDirectory);
    if (manifestName) {
      devToolsExtensionNames.add(manifestName);
    }
    return manifestName;
  };

  BrowserWindow.removeDevToolsExtension = function (name) {
    BrowserWindow.removeExtension(name);
    devToolsExtensionNames.delete(name);
  };

  BrowserWindow.getDevToolsExtensions = function () {
    const extensions = BrowserWindow.getExtensions();
    const devExtensions = {};
    Array.from(devToolsExtensionNames).forEach(function (name) {
      if (!extensions[name]) return;
      devExtensions[name] = extensions[name];
    });
    return devExtensions;
  };

  // Load persisted extensions.
  loadedDevToolsExtensionsPath = path.join(app.getPath('userData'), 'DevTools Extensions');
  try {
    const loadedDevToolsExtensions = JSON.parse(fs.readFileSync(loadedDevToolsExtensionsPath));
    if (Array.isArray(loadedDevToolsExtensions)) {
      for (const srcDirectory of loadedDevToolsExtensions) {
        // Start background pages and set content scripts.
        BrowserWindow.addDevToolsExtension(srcDirectory);
      }
    }
  } catch (error) {
    if (process.env.ELECTRON_ENABLE_LOGGING && error.code !== 'ENOENT') {
      console.error('Failed to load browser extensions from directory:', loadedDevToolsExtensionsPath);
      console.error(error);
    }
  }
});
