/**

 * @file The entry point for the web extension singleton process.

 */

const urlUtil = require('url')

const endOfStream = require('end-of-stream')

const pump = require('pump')

const debounce = require('debounce-stream')

const log = require('loglevel')

const extension = require('extensionizer')

const LocalStorageStore = require('obs-store/lib/localStorage')

const LocalStore = require('./lib/local-store')

const storeTransform = require('obs-store/lib/transform')

const asStream = require('obs-store/lib/asStream')

const ExtensionPlatform = require('./platforms/extension')

const Migrator = require('./lib/migrator/') //初始化就是设置migrations有默认设置的就用默认的，否则就用最新版本的，不然就用0版本

const migrations = require('./migrations/') //Data (user data, config files etc.) is migrated from one version to another.从版本2一直到28，0为初始版本

const PortStream = require('./lib/port-stream.js')

const createStreamSink = require('./lib/createStreamSink')

const NotificationManager = require('./lib/notification-manager.js')

const MetamaskController = require('./metamask-controller')

const firstTimeState = require('./first-time-state')

const setupRaven = require('./lib/setupRaven')

const reportFailedTxToSentry = require('./lib/reportFailedTxToSentry')

const setupMetamaskMeshMetrics = require('./lib/setupMetamaskMeshMetrics')

const EdgeEncryptor = require('./edge-encryptor')

const getFirstPreferredLangCode = require('./lib/get-first-preferred-lang-code')

const getObjStructure = require('./lib/getObjStructure')

const ipfsContent = require('./lib/ipfsContent.js')

const {

  ENVIRONMENT_TYPE_POPUP,

  ENVIRONMENT_TYPE_NOTIFICATION,

  ENVIRONMENT_TYPE_FULLSCREEN,

} = require('./lib/enums')

const STORAGE_KEY = 'metamask-config'

const METAMASK_DEBUG = process.env.METAMASK_DEBUG

log.setDefaultLevel(process.env.METAMASK_DEBUG ? 'debug' : 'warn')

const platform = new ExtensionPlatform()

const notificationManager = new NotificationManager()

global.METAMASK_NOTIFIER = notificationManager

// setup sentry error reporting

const release = platform.getVersion()

const raven = setupRaven({ release })

// browser check if it is Edge - https://*.com/questions/9847580/how-to-detect-safari-chrome-ie-firefox-and-opera-browser

// Internet Explorer 6-11，即How to detect Safari, Chrome, IE, Firefox and Opera browser?

const isIE = !!document.documentMode //查看所使用的浏览器类型

// Edge 20+

const isEdge = !isIE && !!window.StyleMedia

let ipfsHandle

let popupIsOpen = false //弹出窗口是否打开

let notificationIsOpen = false //通知是否打开

const openMetamaskTabsIDs = {}

// state persistence

const diskStore = new LocalStorageStore({ storageKey: STORAGE_KEY }) //硬盘的存储

const localStore = new LocalStore() //本地的存储

let versionedData

// initialization flow

initialize().catch(log.error)

// setup metamask mesh testing container

setupMetamaskMeshMetrics()

/**

 * An object representing a transaction, in whatever state it is in.

 * @typedef TransactionMeta 交易中信息的意义

 *

 * @property {number} id - An internally unique tx identifier.

 * @property {number} time - Time the tx was first suggested, in unix epoch time (ms).

 * @property {string} status - The current transaction status (unapproved, signed, submitted, dropped, failed, rejected), as defined in `tx-state-manager.js`.

 * @property {string} metamaskNetworkId - The transaction's network ID, used for EIP-155 compliance.

 * @property {boolean} loadingDefaults - TODO: Document

 * @property {Object} txParams - The tx params as passed to the network provider.

 * @property {Object[]} history - A history of mutations to this TransactionMeta object.

 * @property {boolean} gasPriceSpecified - True if the suggesting dapp specified a gas price, prevents auto-estimation.

 * @property {boolean} gasLimitSpecified - True if the suggesting dapp specified a gas limit, prevents auto-estimation.

 * @property {string} estimatedGas - A hex string represented the estimated gas limit required to complete the transaction.

 * @property {string} origin - A string representing the interface that suggested the transaction.

 * @property {Object} nonceDetails - A metadata object containing information used to derive the suggested nonce, useful for debugging nonce issues.

 * @property {string} rawTx - A hex string of the final signed transaction, ready to submit to the network.

 * @property {string} hash - A hex string of the transaction hash, used to identify the transaction on the network.

 * @property {number} submittedTime - The time the transaction was submitted to the network, in Unix epoch time (ms).

 */

/**

 * The data emitted from the MetaMaskController.store EventEmitter, also used to initialize the MetaMaskController. Available in UI on React state as state.metamask.

 * @typedef MetaMaskState 存储信息

 * @property {boolean} isInitialized - Whether the first vault has been created. metamask是否初始化

 * @property {boolean} isUnlocked - Whether the vault is currently decrypted and accounts are available for selection. metamask是否没上锁

 * @property {boolean} isAccountMenuOpen - Represents whether the main account selection UI is currently displayed.

 * @property {boolean} isMascara - True if the current context is the extensionless MetaMascara project.

 * @property {boolean} isPopup - Returns true if the current view is an externally-triggered notification.

 * @property {string} rpcTarget - DEPRECATED - The URL of the current RPC provider.

 * @property {Object} identities - An object matching lower-case hex addresses to Identity objects with "address" and "name" (nickname) keys.

 * @property {Object} unapprovedTxs - An object mapping transaction hashes to unapproved transactions.

 * @property {boolean} noActiveNotices - False if there are notices the user should confirm before using the application.

 * @property {Array} frequentRpcList - A list of frequently used RPCs, including custom user-provided ones.

 * @property {Array} addressBook - A list of previously sent to addresses.

 * @property {address} selectedTokenAddress - Used to indicate if a token is globally selected. Should be deprecated in favor of UI-centric token selection.

 * @property {Object} tokenExchangeRates - Info about current token prices.

 * @property {Array} tokens - Tokens held by the current user, including their balances.

 * @property {Object} send - TODO: Document

 * @property {Object} coinOptions - TODO: Document

 * @property {boolean} useBlockie - Indicates preferred user identicon format. True for blockie, false for Jazzicon.

 * @property {Object} featureFlags - An object for optional feature flags.

 * @property {string} networkEndpointType - TODO: Document

 * @property {boolean} isRevealingSeedWords - True if seed words are currently being recovered, and should be shown to user.

 * @property {boolean} welcomeScreen - True if welcome screen should be shown.

 * @property {string} currentLocale - A locale string matching the user's preferred display language.这个语言的选择

 * @property {Object} provider - The current selected network provider.

 * @property {string} provider.rpcTarget - The address for the RPC API, if using an RPC API.

 * @property {string} provider.type - An identifier for the type of network selected, allows MetaMask to use custom provider strategies for known networks.

 * @property {string} network - A stringified number of the current network ID.

 * @property {Object} accounts - An object mapping lower-case hex addresses to objects with "balance" and "address" keys, both storing hex string values.

 * @property {hex} currentBlockGasLimit - The most recently seen block gas limit, in a lower case hex prefixed string.

 * @property {TransactionMeta[]} selectedAddressTxList - An array of transactions associated with the currently selected account.

 * @property {Object} unapprovedMsgs - An object of messages associated with the currently selected account, mapping a unique ID to the options.

 * @property {number} unapprovedMsgCount - The number of messages in unapprovedMsgs.

 * @property {Object} unapprovedPersonalMsgs - An object of messages associated with the currently selected account, mapping a unique ID to the options.

 * @property {number} unapprovedPersonalMsgCount - The number of messages in unapprovedPersonalMsgs.

 * @property {Object} unapprovedTypedMsgs - An object of messages associated with the currently selected account, mapping a unique ID to the options.

 * @property {number} unapprovedTypedMsgCount - The number of messages in unapprovedTypedMsgs.

 * @property {string[]} keyringTypes - An array of unique keyring identifying strings, representing available strategies for creating accounts.

 * @property {Keyring[]} keyrings - An array of keyring descriptions, summarizing the accounts that are available for use, and what keyrings they belong to.

 * @property {Object} computedBalances - Maps accounts to their balances, accounting for balance changes from pending transactions.

 * @property {string} currentAccountTab - A view identifying string for displaying the current displayed view, allows user to have a preferred tab in the old UI (between tokens and history).

 * @property {string} selectedAddress - A lower case hex string of the currently selected address.

 * @property {string} currentCurrency - A string identifying the user's preferred display currency, for use in showing conversion rates.

 * @property {number} conversionRate - A number representing the current exchange rate from the user's preferred currency to Ether.

 * @property {number} conversionDate - A unix epoch date (ms) for the time the current conversion rate was last retrieved.

 * @property {Object} infuraNetworkStatus - An object of infura network status checks.

 * @property {Block[]} recentBlocks - An array of recent blocks, used to calculate an effective but cheap gas price.

 * @property {Array} shapeShiftTxList - An array of objects describing shapeshift exchange attempts.

 * @property {Array} lostAccounts - TODO: Remove this feature. A leftover from the version-3 migration where our seed-phrase library changed to fix a bug where some accounts were mis-generated, but we recovered the old accounts as "lost" instead of losing them.

 * @property {boolean} forgottenPassword - Returns true if the user has initiated the password recovery screen, is recovering from seed phrase.

 */

/**

 * @typedef VersionedData

 * @property {MetaMaskState} data - The data emitted from MetaMask controller, or used to initialize it.

 * @property {Number} version - The latest migration version that has been run.

 */

/**

 * Initializes the MetaMask controller, and sets up all platform configuration.

 * @returns {Promise} Setup complete.

 */

async function initialize () {

  const initState = await loadStateFromPersistence() //得到state信息

  const initLangCode = await getFirstPreferredLangCode() //设置使用的语言

  await setupController(initState, initLangCode)//metamask控制器的创建

  log.debug('MetaMask initialization complete.')

  ipfsHandle = ipfsContent(initState.NetworkController.provider)

}

//

// State and Persistence

//

/**

 * Loads any stored data, prioritizing the latest storage strategy.加载所有存储数据，优先考虑最新的存储策略

 * Migrates that data schema in case it was last loaded on an older version.迁移该数据模式，以防最后一次加载到旧版本

 * @returns {Promise<MetaMaskState>} Last data emitted from previous instance of MetaMask.返回上次MetaMask实例发出的数据

 */

async function loadStateFromPersistence () {

  // migrations

  const migrator = new Migrator({ migrations })

  // read from disk

  // first from preferred, async API: 先从本地读取，没有则从硬盘读取，最后则是初始化生成

  versionedData = (await localStore.get()) ||

                  diskStore.getState() ||

                  migrator.generateInitialState(firstTimeState)

  // check if somehow state is empty 就是如果不知道为何state为空

  // this should never happen but new error reporting suggests that it has

  // for a small number of users

  // https://github.com/metamask/metamask-extension/issues/3919

  if (versionedData && !versionedData.data) {

    // try to recover from diskStore incase only localStore is bad

    const diskStoreState = diskStore.getState() //首先是试着从硬盘中的数据进行恢复，以免只是本地数据出现了问题

    if (diskStoreState && diskStoreState.data) {

      // we were able to recover (though it might be old)

      versionedData = diskStoreState

      const vaultStructure = getObjStructure(versionedData)

      raven.captureMessage('MetaMask - Empty vault found - recovered from diskStore', {

        // "extra" key is required by Sentry

        extra: { vaultStructure },

      })

    } else {//发现连硬盘中的数据也损坏了，那就没有办法恢复了

      // unable to recover, clear state

      versionedData = migrator.generateInitialState(firstTimeState)

      raven.captureMessage('MetaMask - Empty vault found - unable to recover')

    }

  }

  // report migration errors to sentry

  migrator.on('error', (err) => {

    // get vault structure without secrets

    const vaultStructure = getObjStructure(versionedData)

    raven.captureException(err, {

      // "extra" key is required by Sentry

      extra: { vaultStructure },

    })

  })

  // migrate data

  versionedData = await migrator.migrateData(versionedData)

  if (!versionedData) {

    throw new Error('MetaMask - migrator returned undefined')

  }

  // write to disk

  if (localStore.isSupported) {

    localStore.set(versionedData)

  } else {

    // throw in setTimeout so as to not block boot

    setTimeout(() => {

      throw new Error('MetaMask - Localstore not supported')

    })

  }

  // return just the data

  return versionedData.data

}

/**

 * Initializes the MetaMask Controller with any initial state and default language. 使用初始状态和默认语言来初始化metamask控制器

 * Configures platform-specific error reporting strategy. 配置特定于平台的错误报告策略

 * Streams emitted state updates to platform-specific storage strategy.流 向 特定于平台的存储策略发出状态更新

 * Creates platform listeners for new Dapps/Contexts, and sets up their data connections to the controller.为新的Dapps/上下文创建平台侦听器，并设置它们与控制器的数据连接

 *

 * @param {Object} initState - The initial state to start the controller with, matches the state that is emitted from the controller.

 * @param {String} initLangCode - The region code for the language preferred by the current user.

 * @returns {Promise} After setup is complete. 当设置完成后返回

 */

function setupController (initState, initLangCode) {

  //

  // MetaMask Controller

  //

  const controller = new MetamaskController({//metamask控制器的创建

    // User confirmation callbacks:

    showUnconfirmedMessage: triggerUi,

    unlockAccountMessage: triggerUi,

    showUnapprovedTx: triggerUi,

    // initial state

    initState,

    // initial locale code

    initLangCode,

    // platform specific api

    platform,

    encryptor: isEdge ? new EdgeEncryptor() : undefined,//EdgeEncryptor是一个特定于边缘的Microsoft加密类，它公开了eth-keykeyring-controller所期望的接口

  })

  global.metamaskController = controller

  controller.networkController.on('networkDidChange', () => { //如果网络变化则跟着变化

    ipfsHandle && ipfsHandle.remove()

    ipfsHandle = ipfsContent(controller.networkController.providerStore.getState())

  })

  // report failed transactions to Sentry 报告错误的交易

  controller.txController.on(`tx:status-update`, (txId, status) => {

    if (status !== 'failed') return

    const txMeta = controller.txController.txStateManager.getTx(txId)

    try {

      reportFailedTxToSentry({ raven, txMeta })

    } catch (e) {

      console.error(e)

    }

  })

  // setup state persistence

  pump(

    asStream(controller.store),

    debounce(),

    storeTransform(versionifyData),

    createStreamSink(persistData),

    (error) => {

      log.error('MetaMask - Persistence pipeline failed', error)

    }

  )

  /**

   * Assigns the given state to the versioned object (with metadata), and returns that.将给定状态分配给版本对象

   * @param {Object} state - The state object as emitted by the MetaMaskController.

   * @returns {VersionedData} The state object wrapped in an object that includes a metadata key.

   */

  function versionifyData (state) {

    versionedData.data = state

    return versionedData

  }

  async function persistData (state) {

    if (!state) {

      throw new Error('MetaMask - updated state is missing', state)

    }

    if (!state.data) {

      throw new Error('MetaMask - updated state does not have data', state)

    }

    if (localStore.isSupported) {

      try {

        await localStore.set(state)

      } catch (err) {

        // log error so we dont break the pipeline

        log.error('error setting state in local store:', err)

      }

    }

  }

  //

  // connect to other contexts

  //

  extension.runtime.onConnect.addListener(connectRemote)

  extension.runtime.onConnectExternal.addListener(connectExternal)

  const metamaskInternalProcessHash = {

    [ENVIRONMENT_TYPE_POPUP]: true,

    [ENVIRONMENT_TYPE_NOTIFICATION]: true,

    [ENVIRONMENT_TYPE_FULLSCREEN]: true,

  }

  const isClientOpenStatus = () => {

    return popupIsOpen || Boolean(Object.keys(openMetamaskTabsIDs).length) || notificationIsOpen

  }

  /**

   * A runtime.Port object, as provided by the browser:

   * @see https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/runtime/Port

   * @typedef Port

   * @type Object

   */

  /**

   * Connects a Port to the MetaMask controller via a multiplexed duplex stream.通过多路复用双流将端口连接到MetaMask控制器

   * This method identifies trusted (MetaMask) interfaces, and connects them differently from untrusted (web pages).此方法识别受信任(MetaMask)接口，并以不同于不受信任(web页面)的方式连接它们

   * @param {Port} remotePort - The port provided by a new context.

   */

  function connectRemote (remotePort) {

    const processName = remotePort.name

    const isMetaMaskInternalProcess = metamaskInternalProcessHash[processName]

    if (isMetaMaskInternalProcess) {//如果是内部进程，受信赖的，就相当于本地的浏览器跟metamask连接了，然后这时候浏览器的页面与metamask进行交互了

      const portStream = new PortStream(remotePort)

      // communication with popup

      controller.isClientOpen = true

      controller.setupTrustedCommunication(portStream, 'MetaMask')//用于通过远程端口连接用户界面

      if (processName === ENVIRONMENT_TYPE_POPUP) {//如果连接用户界面是一个弹出窗口，后面查查看这些常量是什么意思？？？？？

        popupIsOpen = true

        endOfStream(portStream, () => {

          popupIsOpen = false

          controller.isClientOpen = isClientOpenStatus()

        })

      }

      if (processName === ENVIRONMENT_TYPE_NOTIFICATION) { //如果是一个通知窗口

        notificationIsOpen = true

        endOfStream(portStream, () => {

          notificationIsOpen = false

          controller.isClientOpen = isClientOpenStatus()

        })

      }

      if (processName === ENVIRONMENT_TYPE_FULLSCREEN) {//如果是一个全屏

        const tabId = remotePort.sender.tab.id

        openMetamaskTabsIDs[tabId] = true

        endOfStream(portStream, () => {

          delete openMetamaskTabsIDs[tabId]

          controller.isClientOpen = isClientOpenStatus()

        })

      }

    } else {

      connectExternal(remotePort)//否则就使用不受信赖的联系方式

    }

  }

  // communication with page or other extension

  function connectExternal (remotePort) {

    const originDomain = urlUtil.parse(remotePort.sender.url).hostname

    const portStream = new PortStream(remotePort)

    controller.setupUntrustedCommunication(portStream, originDomain)//此方法用于将新web站点的web3 API连接到MetaMask的区块链连接。另外，originDomain可以用来阻止检测到的钓鱼网站

  }

  //

  // User Interface setup

  //

  updateBadge()

  controller.txController.on('update:badge', updateBadge)

  controller.messageManager.on('updateBadge', updateBadge)

  controller.personalMessageManager.on('updateBadge', updateBadge)

  /**

   * Updates the Web Extension's "badge" number, on the little fox in the toolbar.

   * The number reflects the current number of pending transactions or message signatures needing user approval.

   */

  function updateBadge () {

    var label = ''

    var unapprovedTxCount = controller.txController.getUnapprovedTxCount()

    var unapprovedMsgCount = controller.messageManager.unapprovedMsgCount

    var unapprovedPersonalMsgs = controller.personalMessageManager.unapprovedPersonalMsgCount

    var unapprovedTypedMsgs = controller.typedMessageManager.unapprovedTypedMessagesCount

    var count = unapprovedTxCount + unapprovedMsgCount + unapprovedPersonalMsgs + unapprovedTypedMsgs

    if (count) {

      label = String(count)

    }

    extension.browserAction.setBadgeText({ text: label })

    extension.browserAction.setBadgeBackgroundColor({ color: '#506F8B' })

  }

  return Promise.resolve()

}

//

// Etc...

//

/**

 * Opens the browser popup for user confirmation 就是打开浏览器的一个弹出窗口来用于metamask上进行的操作的确认

 */

function triggerUi () {

  extension.tabs.query({ active: true }, tabs => {

    const currentlyActiveMetamaskTab = Boolean(tabs.find(tab => openMetamaskTabsIDs[tab.id]))

    if (!popupIsOpen && !currentlyActiveMetamaskTab && !notificationIsOpen) {

      notificationManager.showPopup()

    }

  })

}

// On first install, open a window to MetaMask website to how-it-works.

extension.runtime.onInstalled.addListener(function (details) {

  if ((details.reason === 'install') && (!METAMASK_DEBUG)) {

    extension.tabs.create({url: 'https://metamask.io/#how-it-works'})

  }

})

  /**

   * Used to create a multiplexed stream for connecting to a trusted context,

   * like our own user interfaces, which have the provider APIs, but also

   * receive the exported API from this controller, which includes trusted

   * functions, like the ability to approve transactions or sign messages.

   *

   * @param {*} connectionStream - The duplex stream to connect to.

   * @param {string} originDomain - The domain requesting the connection,

   * used in logging and error reporting.

   */

  setupTrustedCommunication (connectionStream, originDomain) {

    // setup multiplexing

    const mux = setupMultiplex(connectionStream)

    // connect features

    this.setupControllerConnection(mux.createStream('controller'))

    this.setupProviderConnection(mux.createStream('provider'), originDomain)

  }

//=============================================================================

// SETUP

//=============================================================================

  /**

   * Used to create a multiplexed stream for connecting to an untrusted context

   * like a Dapp or other extension.

   * @param {*} connectionStream - The Duplex stream to connect to.

   * @param {string} originDomain - The domain requesting the stream, which

   * may trigger a blacklist reload.

   */

  setupUntrustedCommunication (connectionStream, originDomain) {

    // Check if new connection is blacklisted查黑名单看其是否为钓鱼网站，不是才连接

    if (this.blacklistController.checkForPhishing(originDomain)) {

      log.debug('MetaMask - sending phishing warning for', originDomain)

      this.sendPhishingWarning(connectionStream, originDomain)

      return

    }

    // setup multiplexing

    const mux = setupMultiplex(connectionStream)

    // connect features

    this.setupProviderConnection(mux.createStream('provider'), originDomain)

    this.setupPublicConfig(mux.createStream('publicConfig'))

  }