fix: avoid setting up multiple tc timeouts

lib/brain.js

@@ -140,6 +140,7 @@ const Brain = function (config) {
   this.scannerTimeout = null
   this.manualTriggersDataProvided = _.zipObject(AUTOMATABLE_REQUIREMENTS, Array(AUTOMATABLE_REQUIREMENTS.length).fill(false))
   this.txBlockedByManualTrigger = false
+  this.termsAcceptButtonPressed = false
 
   this.numberOfCassettes = _.isFinite(parseInt(deviceConfig.billDispenser.cassettes))
     ? deviceConfig.billDispenser.cassettes
@@ -2291,6 +2292,9 @@ Brain.prototype.completeBillHandling = function completeBillHandling (blockedCus
 Brain.prototype.startScreen = function startScreen () {
   const direction = this.tx.direction
 
+  // reset T&C accept button flag
+  this.termsAcceptButtonPressed = false
+
   // check if terms screen is enabled
   // and user still need to accept terms
   if (this.mustAcceptTerms()) {
@@ -2318,14 +2322,20 @@ Brain.prototype.mustAcceptTerms = function mustAcceptTerms () {
 
 Brain.prototype.acceptTerms = function acceptTerms () {
   if (this.scanner.isOpened()) this.scanner.cancel()
+  // disable accept button after one click
+  this.browser().send({ terms: _.assign(this.trader.terms, { acceptDisabled: true }) })
+  if (!this.termsAcceptButtonPressed) {
   // timeout is a safety net to ensure that we close
   // the camera before opening it for another task
-  setTimeout(() => {
-    // mark terms as accepted
-    // and redirect user to start screen
-    this.tx = Tx.update(this.tx, { termsAccepted: true })
-    this.startScreen()
-  }, 1000)
+    setTimeout(() => {
+      // mark terms as accepted
+      // and redirect user to start screen
+      this.tx = Tx.update(this.tx, { termsAccepted: true })
+      this.startScreen()
+    }, 1000)
+  }
+  // avoid setting multiple timeouts
+  this.termsAcceptButtonPressed = true
 }
 
 function chooseBillDispenser (config) {

ui/src/app.js

@@ -1198,9 +1198,19 @@ function setTermsScreen (data) {
   $screen.find('.js-terms-cancel-button').html(data.cancel)
   $screen.find('.js-terms-accept-button').html(data.accept)
   setTermsConditionsTimeout()
+  setAcceptButtonDisabled($screen, data)
   setTermsConditionsAcceptanceDelay($screen, data)
 }
 
+function setAcceptButtonDisabled (screen, data) {
+  var acceptButton = screen.find('.js-terms-accept-button');
+  if (!data.acceptDisabled) {
+    acceptButton.prop('disabled', false);
+  } else {
+    acceptButton.prop('disabled', true);
+  }
+}
+
 function clearTermsConditionsTimeout () {
   clearTimeout(termsConditionsTimeout)
 }