Update auto-logout to recognize idle time in background (#6593)

* Fix wording of autoLogoutTimeLimitDescription

* AppStateController and update auto-logout functionality

3 files changed, 86 insertions, 1 deletions

diff --git a/app/_locales/en/messages.json b/app/_locales/en/messages.json
index 254bfdfb9..bef278f79 100644
--- a/app/_locales/en/messages.json
+++ b/app/_locales/en/messages.json
@@ -161,7 +161,7 @@
     "message": "Auto-Logout Timer (minutes)"
   },
   "autoLogoutTimeLimitDescription": {
-    "message": "Set the number of idle time in minutes before Metamask automatically log out"
+    "message": "Set the idle time in minutes before MetaMask will automatically log out"
   },
   "available": {
     "message": "Available"
diff --git a/app/scripts/controllers/app-state.js b/app/scripts/controllers/app-state.js
new file mode 100644
index 000000000..9533fd458
--- /dev/null
+++ b/app/scripts/controllers/app-state.js
@@ -0,0 +1,73 @@
+const ObservableStore = require('obs-store')
+const extend = require('xtend')
+
+class AppStateController {
+  /**
+   * @constructor
+   * @param opts
+   */
+  constructor (opts = {}) {
+    const {initState, onInactiveTimeout, preferencesStore} = opts
+    const {preferences} = preferencesStore.getState()
+
+    this.onInactiveTimeout = onInactiveTimeout || (() => {})
+    this.store = new ObservableStore(extend({
+      timeoutMinutes: 0,
+    }, initState))
+    this.timer = null
+
+    preferencesStore.subscribe(state => {
+      this._setInactiveTimeout(state.preferences.autoLogoutTimeLimit)
+    })
+
+    this._setInactiveTimeout(preferences.autoLogoutTimeLimit)
+  }
+
+  /**
+   * Sets the last active time to the current time
+   * @return {void}
+   */
+  setLastActiveTime () {
+    this._resetTimer()
+  }
+
+  /**
+   * Sets the inactive timeout for the app
+   * @param {number} timeoutMinutes the inactive timeout in minutes
+   * @return {void}
+   * @private
+   */
+  _setInactiveTimeout (timeoutMinutes) {
+    this.store.putState({
+      timeoutMinutes,
+    })
+
+    this._resetTimer()
+  }
+
+  /**
+   * Resets the internal inactive timer
+   *
+   * If the {@code timeoutMinutes} state is falsy (i.e., zero) then a new
+   * timer will not be created.
+   *
+   * @return {void}
+   * @private
+   */
+  _resetTimer () {
+    const {timeoutMinutes} = this.store.getState()
+
+    if (this.timer) {
+      clearTimeout(this.timer)
+    }
+
+    if (!timeoutMinutes) {
+      return
+    }
+
+    this.timer = setTimeout(() => this.onInactiveTimeout(), timeoutMinutes * 60 * 1000)
+  }
+}
+
+module.exports = AppStateController
+
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index bdfff9827..07054f84b 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -25,6 +25,7 @@ const {setupMultiplex} = require('./lib/stream-utils.js')
 const KeyringController = require('eth-keyring-controller')
 const NetworkController = require('./controllers/network')
 const PreferencesController = require('./controllers/preferences')
+const AppStateController = require('./controllers/app-state')
 const CurrencyController = require('./controllers/currency')
 const ShapeShiftController = require('./controllers/shapeshift')
 const InfuraController = require('./controllers/infura')
@@ -101,6 +102,12 @@ module.exports = class MetamaskController extends EventEmitter {
       network: this.networkController,
     })
 
+    // app-state controller
+    this.appStateController = new AppStateController({
+      preferencesStore: this.preferencesController.store,
+      onInactiveTimeout: () => this.setLocked(),
+    })
+
     // currency controller
     this.currencyController = new CurrencyController({
       initState: initState.CurrencyController,
@@ -252,6 +259,7 @@ module.exports = class MetamaskController extends EventEmitter {
     })
 
     this.store.updateStructure({
+      AppStateController: this.appStateController.store,
       TransactionController: this.txController.store,
       KeyringController: this.keyringController.store,
       PreferencesController: this.preferencesController.store,
@@ -264,6 +272,7 @@ module.exports = class MetamaskController extends EventEmitter {
     })
 
     this.memStore = new ComposableObservableStore(null, {
+      AppStateController: this.appStateController.store,
       NetworkController: this.networkController.store,
       AccountTracker: this.accountTracker.store,
       TxController: this.txController.memStore,
@@ -462,6 +471,9 @@ module.exports = class MetamaskController extends EventEmitter {
       // AddressController
       setAddressBook: this.addressBookController.set.bind(this.addressBookController),
 
+      // AppStateController
+      setLastActiveTime: nodeify(this.appStateController.setLastActiveTime, this.appStateController),
+
       // KeyringController
       setLocked: nodeify(this.setLocked, this),
       createNewVaultAndKeychain: nodeify(this.createNewVaultAndKeychain, this),