text: // @flow
  import { app, Menu, shell, BrowserWindow } from 'electron'
  
  export default class MenuBuilder {
    mainWindow: BrowserWindow;
  
    constructor(mainWindow: BrowserWindow) {
      this.mainWindow = mainWindow
    }
  
    buildMenu() {
      if (process.env.NODE_ENV === 'development' || process.env.DEBUG_PROD === 'true') {
        this.setupDevelopmentEnvironment()
      }
  
      const template = process.platform === 'darwin'
        ? this.buildDarwinTemplate()
        : this.buildDefaultTemplate()
  
      const menu = Menu.buildFromTemplate(template)
      Menu.setApplicationMenu(menu)
  
      return menu
    }
  
    setupDevelopmentEnvironment() {
      this.mainWindow.openDevTools()
      this.mainWindow.webContents.on('context-menu', (e, props) => {
        const { x, y } = props
  
        Menu
          .buildFromTemplate([{
            label: 'Inspect element',
            click: () => {
              this.mainWindow.inspectElement(x, y)
            },
          }])
          .popup(this.mainWindow)
      })
    }
  
    buildDarwinTemplate() {
      const subMenuAbout = {
        label: 'Electron',
        submenu: [
          { label: 'About ElectronReact', selector: 'orderFrontStandardAboutPanel:' },
          { type: 'separator' },
          { label: 'Services', submenu: [] },
          { type: 'separator' },
          { label: 'Hide ElectronReact', accelerator: 'Command+H', selector: 'hide:' },
          { label: 'Hide Others', accelerator: 'Command+Shift+H', selector: 'hideOtherApplications:' },
          { label: 'Show All', selector: 'unhideAllApplications:' },
          { type: 'separator' },
          { label: 'Quit', accelerator: 'Command+Q', click: () => { app.quit() } },
        ],
      }
      const subMenuEdit = {
        label: 'Edit',
        submenu: [
          { label: 'Undo', accelerator: 'Command+Z', selector: 'undo:' },
          { label: 'Redo', accelerator: 'Shift+Command+Z', selector: 'redo:' },
          { type: 'separator' },
          { label: 'Cut', accelerator: 'Command+X', selector: 'cut:' },
          { label: 'Copy', accelerator: 'Command+C', selector: 'copy:' },
          { label: 'Paste', accelerator: 'Command+V', selector: 'paste:' },
          { label: 'Select All', accelerator: 'Command+A', selector: 'selectAll:' },
        ],
      }
      const subMenuViewDev = {
        label: 'View',
        submenu: [
          { label: 'Reload', accelerator: 'Command+R', click: () => { this.mainWindow.webContents.reload() } },
          { label: 'Toggle Full Screen', accelerator: 'Ctrl+Command+F', click: () => { this.mainWindow.setFullScreen(!this.mainWindow.isFullScreen()) } },
          { label: 'Toggle Developer Tools', accelerator: 'Alt+Command+I', click: () => { this.mainWindow.toggleDevTools() } },
        ],
      }
      const subMenuViewProd = {
        label: 'View',
        submenu: [
          { label: 'Toggle Full Screen', accelerator: 'Ctrl+Command+F', click: () => { this.mainWindow.setFullScreen(!this.mainWindow.isFullScreen()) } },
        ],
      }
      const subMenuWindow = {
        label: 'Window',
        submenu: [
          { label: 'Minimize', accelerator: 'Command+M', selector: 'performMiniaturize:' },
          { label: 'Close', accelerator: 'Command+W', selector: 'performClose:' },
          { type: 'separator' },
          { label: 'Bring All to Front', selector: 'arrangeInFront:' },
        ],
      }
      const subMenuHelp = {
        label: 'Help',
        submenu: [
          { label: 'Learn More', click() { shell.openExternal('http://electron.atom.io') } },
          { label: 'Documentation', click() { shell.openExternal('https://github.com/atom/electron/tree/master/docs#readme') } },
          { label: 'Community Discussions', click() { shell.openExternal('https://discuss.atom.io/c/electron') } },
          { label: 'Search Issues', click() { shell.openExternal('https://github.com/atom/electron/issues') } },
        ],
      }
  
      const subMenuView = process.env.NODE_ENV === 'development'
        ? subMenuViewDev
        : subMenuViewProd
  
      return [
        subMenuAbout,
        subMenuEdit,
        subMenuView,
        subMenuWindow,
        subMenuHelp,
      ]
    }
  
    buildDefaultTemplate() {
      const templateDefault = [{
        label: '&File',
        submenu: [{
          label: '&Open',
          accelerator: 'Ctrl+O',
        }, {
          label: '&Close',
          accelerator: 'Ctrl+W',
          click: () => {
            this.mainWindow.close()
          },
        }],
      }, {
        label: '&View',
        submenu: (process.env.NODE_ENV === 'development') ? [{
          label: '&Reload',
          accelerator: 'Ctrl+R',
          click: () => {
            this.mainWindow.webContents.reload()
          },
        }, {
          label: 'Toggle &Full Screen',
          accelerator: 'F11',
          click: () => {
            this.mainWindow.setFullScreen(!this.mainWindow.isFullScreen())
          },
        }, {
          label: 'Toggle &Developer Tools',
          accelerator: 'Alt+Ctrl+I',
          click: () => {
            this.mainWindow.toggleDevTools()
          },
        }] : [{
          label: 'Toggle &Full Screen',
          accelerator: 'F11',
          click: () => {
            this.mainWindow.setFullScreen(!this.mainWindow.isFullScreen())
          },
        }],
      }, {
        label: 'Help',
        submenu: [{
          label: 'Learn More',
          click() {
            shell.openExternal('http://electron.atom.io')
          },
        }, {
          label: 'Documentation',
          click() {
            shell.openExternal('https://github.com/atom/electron/tree/master/docs#readme')
          },
        }, {
          label: 'Community Discussions',
          click() {
            shell.openExternal('https://discuss.atom.io/c/electron')
          },
        }, {
          label: 'Search Issues',
          click() {
            shell.openExternal('https://github.com/atom/electron/issues')
          },
        }],
      }]
  
      return templateDefault
    }
  }
  