[WO-475] give backbutton on android sane behavior

.jshintrc

@@ -21,6 +21,7 @@
 			"console",
 			"importScripts",
 			"process",
+			"Event",
 			"QUnit",
 			"test",
 			"asyncTest",

src/js/app-controller.js

@@ -24,6 +24,7 @@ define(function(require) {
         InvitationDAO = require('js/dao/invitation-dao'),
         DeviceStorageDAO = require('js/dao/devicestorage-dao'),
         UpdateHandler = require('js/util/update/update-handler'),
+        backBtnHandler = require('js/util/backbutton-handler'),
         config = appConfig.config,
         str = appConfig.string;
 
@@ -54,6 +55,7 @@ define(function(require) {
         function onDeviceReady() {
             axe.debug('Starting app.');
 
+            backBtnHandler.start();
             self.buildModules();
 
             // Handle offline and online gracefully

src/js/app.js

@@ -23,6 +23,7 @@ requirejs([
     'js/controller/navigation',
     'js/crypto/util',
     'js/util/error',
+    'js/util/backbutton-handler',
     'fastclick',
     'angularRoute',
     'angularAnimate',
@@ -49,6 +50,7 @@ requirejs([
     NavigationCtrl,
     util,
     errorUtil,
+    backButtonUtil,
     FastClick
 ) {
     'use strict';
@@ -113,8 +115,13 @@ requirejs([
     app.run(function($rootScope) {
         // global state... inherited to all child scopes
         $rootScope.state = {};
+
         // attach global error handler
         errorUtil.attachHandler($rootScope);
+
+        // attach the back button handler to the root scope
+        backButtonUtil.attachHandler($rootScope);
+
         // attach fastclick
         FastClick.attach(document.body);
     });

src/js/util/backbutton-handler.js

@@ -0,0 +1,58 @@
+define(function(require) {
+    'use strict';
+
+    var axe = require('axe'),
+        DEBUG_TAG = 'backbutton handler';
+
+    /**
+     * The back button handler introduces meaningful behavior fo rthe back button:
+     * if there's an open lightbox, close it;
+     * if the reader is open in mobile mode, close it;
+     * if the navigation is open, close it;
+     * if there's nothing else open, shut down the app;
+     *
+     * @type {Object}
+     */
+    var backBtnHandler = {
+        attachHandler: function(scope) {
+            this.scope = scope;
+        },
+        start: function() {
+            document.addEventListener("backbutton", handleBackButton, false);
+        },
+        stop: function() {
+            document.removeEventListener("backbutton", handleBackButton, false);
+        }
+    };
+
+    function handleBackButton(event) {
+        axe.debug(DEBUG_TAG, 'back button pressed');
+
+        // this disarms the default behavior which we NEVER want
+        event.preventDefault();
+        event.stopPropagation();
+
+        if (backBtnHandler.scope.state.lightbox) {
+            // closes the lightbox (error msgs, writer, ...)
+            backBtnHandler.scope.state.lightbox = undefined;
+            axe.debug(DEBUG_TAG, 'lightbox closed');
+            backBtnHandler.scope.$apply();
+        } else if (backBtnHandler.scope.state.read && backBtnHandler.scope.state.read.open) {
+            // closes the reader
+            backBtnHandler.scope.state.read.toggle(false);
+            axe.debug(DEBUG_TAG, 'reader closed');
+            backBtnHandler.scope.$apply();
+        } else if (backBtnHandler.scope.state.nav && backBtnHandler.scope.state.nav.open) {
+            // closes the navigation
+            backBtnHandler.scope.state.nav.toggle(false);
+            axe.debug(DEBUG_TAG, 'navigation closed');
+            backBtnHandler.scope.$apply();
+        } else {
+            // exits the app
+            navigator.app.exitApp();
+        }
+    }
+
+
+    return backBtnHandler;
+});

test/unit/backbutton-handler-test.js

@@ -0,0 +1,67 @@
+define(function(require) {
+    'use strict';
+
+    var btnHandler = require('js/util/backbutton-handler'),
+        expect = chai.expect;
+
+    describe('Backbutton Handler', function() {
+        chai.Assertion.includeStack = true;
+
+        var scope, event;
+
+        beforeEach(function() {
+            scope = {
+                state: {},
+                $apply: function() {}
+            };
+
+            event = new CustomEvent('backbutton');
+
+            // this is a precondition for the test. throw an exception
+            // if this would produce side effects
+            expect(navigator.app).to.not.exist;
+            navigator.app = {};
+
+            btnHandler.attachHandler(scope);
+            btnHandler.start();
+        });
+
+        afterEach(function() {
+            btnHandler.stop();
+            delete navigator.app;
+        });
+
+        it('should close lightbox', function() {
+            scope.state.lightbox = 'asd';
+            document.dispatchEvent(event);
+            expect(scope.state.lightbox).to.be.undefined;
+        });
+
+        it('should close reader', function() {
+            scope.state.read = {
+                open: true,
+                toggle: function(state) {
+                    scope.state.read.open = state;
+                }
+            };
+            document.dispatchEvent(event);
+            expect(scope.state.read.open).to.be.false;
+        });
+
+        it('should close navigation', function() {
+            scope.state.nav = {
+                open: true,
+                toggle: function(state) {
+                    scope.state.nav.open = state;
+                }
+            };
+            document.dispatchEvent(event);
+            expect(scope.state.nav.open).to.be.false;
+        });
+
+        it('should close app', function(done) {
+            navigator.app.exitApp = done;
+            document.dispatchEvent(event);
+        });
+    });
+});

test/unit/main.js

@@ -22,6 +22,24 @@ if (!Function.prototype.bind) {
 	};
 }
 
+// a warm round of applause for phantomjs for missing events
+(function() {
+	function CustomEvent(event, params) {
+		params = params || {
+			bubbles: false,
+			cancelable: false,
+			detail: undefined
+		};
+		var evt = document.createEvent('CustomEvent');
+		evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
+		return evt;
+	}
+
+	CustomEvent.prototype = window.Event.prototype;
+
+	window.CustomEvent = CustomEvent;
+})();
+
 require(['../../src/require-config'], function() {
 	require.config({
 		baseUrl: '../../src/lib',
@@ -59,6 +77,7 @@ function startTests() {
 			'test/unit/app-controller-test',
 			'test/unit/pgp-test',
 			'test/unit/crypto-test',
+			'test/unit/backbutton-handler-test',
 			'test/unit/rest-dao-test',
 			'test/unit/publickey-dao-test',
 			'test/unit/privatekey-dao-test',