From 4368d8a7379ddb2620a326ebae63cdb209370462 Mon Sep 17 00:00:00 2001
From: Oliver Hamlet <oliver.hamlet@gmail.com>
Date: Fri, 27 May 2016 21:35:35 +0100
Subject: [PATCH] Start to implement a UI finite state machine

Using it should help abstract out UI state changes and avoid situations
where operations leave the UI in a muddled state. It also provides a
foundation to help make operations transactional.
---
 src/gui/html/index.html             |   1 +
 src/gui/html/js/events.js           |  47 +----
 src/gui/html/js/state.js            | 125 +++++++++++++
 src/tests/gui/html/js/test.html     |   3 +
 src/tests/gui/html/js/test_state.js | 271 ++++++++++++++++++++++++++++
 5 files changed, 405 insertions(+), 42 deletions(-)
 create mode 100644 src/gui/html/js/state.js
 create mode 100644 src/tests/gui/html/js/test_state.js

diff --git a/src/gui/html/index.html b/src/gui/html/index.html
index d4cac4e0..e8e010cd 100644
--- a/src/gui/html/index.html
+++ b/src/gui/html/index.html
@@ -463,6 +463,7 @@
   <script src="js/l10n.js"></script>
   <script src="js/plugin.js"></script>
   <script src="js/query.js"></script>
+  <script src="js/state.js"></script>
   <script src="js/translator.js"></script>
   <script src="js/init.js"></script>
   <script>
diff --git a/src/gui/html/js/events.js b/src/gui/html/js/events.js
index 0782a4d7..6baeacb7 100644
--- a/src/gui/html/js/events.js
+++ b/src/gui/html/js/events.js
@@ -147,15 +147,8 @@ function onSortPlugins() {
     loot.game.plugins = loot.game.loadOrder;
     filterPluginData(loot.game.plugins, loot.filters);
 
-    /* Now hide the masterlist update buttons, and display the accept and
-       cancel sort buttons. */
-    loot.dom.show('updateMasterlistButton', false);
-    loot.dom.show('sortButton', false);
-    loot.dom.show('applySortButton');
-    loot.dom.show('cancelSortButton');
+    loot.state.enterSortingState();
 
-    /* Disable changing game. */
-    loot.dom.enable('gameMenu', false);
     loot.Dialog.closeProgress();
   }).catch(handlePromiseError);
 }
@@ -168,15 +161,7 @@ function onApplySort() {
     delete loot.game.loadOrder;
     delete loot.game.oldLoadOrder;
 
-    /* Now show the masterlist update buttons, and hide the accept and
-       cancel sort buttons. */
-    loot.dom.show('updateMasterlistButton');
-    loot.dom.show('sortButton');
-    loot.dom.show('applySortButton', false);
-    loot.dom.show('cancelSortButton', false);
-
-    /* Enable changing game. */
-    loot.dom.enable('gameMenu');
+    loot.state.exitSortingState();
   }).catch(handlePromiseError);
 }
 function onCancelSort() {
@@ -190,15 +175,7 @@ function onCancelSort() {
     /* Update general messages */
     loot.game.globalMessages = messages;
 
-    /* Now show the masterlist update buttons, and hide the accept and
-       cancel sort buttons. */
-    loot.dom.show('updateMasterlistButton');
-    loot.dom.show('sortButton');
-    loot.dom.show('applySortButton', false);
-    loot.dom.show('cancelSortButton', false);
-
-    /* Enable changing game. */
-    loot.dom.enable('gameMenu');
+    loot.state.exitSortingState();
   }).catch(handlePromiseError);
 }
 
@@ -431,14 +408,7 @@ function onEditorOpen(evt) {
     elements[i].addEventListener('dragstart', elements[i].onDragStart);
   }
 
-  /* Disable the toolbar elements. */
-  loot.dom.enable('wipeUserlistButton', false);
-  loot.dom.enable('copyContentButton', false);
-  loot.dom.enable('refreshContentButton', false);
-  loot.dom.enable('settingsButton', false);
-  loot.dom.enable('gameMenu', false);
-  loot.dom.enable('updateMasterlistButton', false);
-  loot.dom.enable('sortButton', false);
+  loot.state.enterEditingState();
 
   return loot.query('editorOpened').catch(handlePromiseError);
 }
@@ -488,14 +458,7 @@ function onEditorClose(evt) {
       elements[i].removeEventListener('dragstart', elements[i].onDragStart);
     }
 
-    /* Re-enable toolbar elements. */
-    loot.dom.enable('wipeUserlistButton');
-    loot.dom.enable('copyContentButton');
-    loot.dom.enable('refreshContentButton');
-    loot.dom.enable('settingsButton');
-    loot.dom.enable('gameMenu');
-    loot.dom.enable('updateMasterlistButton');
-    loot.dom.enable('sortButton');
+    loot.state.exitEditingState();
   }).catch(handlePromiseError);
 }
 function undoConflictsFilter() {
diff --git a/src/gui/html/js/state.js b/src/gui/html/js/state.js
new file mode 100644
index 00000000..5a8e9d6a
--- /dev/null
+++ b/src/gui/html/js/state.js
@@ -0,0 +1,125 @@
+'use strict';
+(function exportModule(root, factory) {
+  if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define([], factory);
+  } else {
+    // Browser globals
+    root.loot = root.loot || {};
+    root.loot.State = factory(root.loot.dom);
+    root.loot.state = new root.loot.State();
+  }
+}(this, (dom) => {
+  return class State {
+
+    static get DEFAULT_STATE() {
+      return 0;
+    }
+
+    static get SORTING_STATE() {
+      return 1;
+    }
+
+    static get EDITING_STATE() {
+      return 2;
+    }
+
+    constructor() {
+      this.currentState = State.DEFAULT_STATE;
+    }
+
+    isInDefaultState() {
+      return this.currentState === State.DEFAULT_STATE;
+    }
+
+    isInEditingState() {
+      return this.currentState === State.EDITING_STATE;
+    }
+
+    isInSortingState() {
+      return this.currentState === State.SORTING_STATE;
+    }
+
+    enterSortingState() {
+      if (this.isInSortingState()) {
+        return;
+      }
+      if (this.isInEditingState()) {
+        throw new Error('Cannot enter sorting state from editing state');
+      }
+
+      /* Hide the masterlist update buttons, and display the accept and
+         cancel sort buttons. */
+      loot.dom.show('updateMasterlistButton', false);
+      loot.dom.show('sortButton', false);
+      loot.dom.show('applySortButton');
+      loot.dom.show('cancelSortButton');
+
+      /* Disable changing game. */
+      loot.dom.enable('gameMenu', false);
+
+      this.currentState = State.SORTING_STATE;
+    }
+
+    exitSortingState() {
+      if (this.isInDefaultState()) {
+        return;
+      }
+      if (this.isInEditingState()) {
+        throw new Error('Cannot exit sorting state from editing state');
+      }
+
+      /* Show the masterlist update buttons, and hide the accept and
+         cancel sort buttons. */
+      loot.dom.show('updateMasterlistButton');
+      loot.dom.show('sortButton');
+      loot.dom.show('applySortButton', false);
+      loot.dom.show('cancelSortButton', false);
+
+      /* Enable changing game. */
+      loot.dom.enable('gameMenu');
+
+      this.currentState = State.DEFAULT_STATE;
+    }
+
+    enterEditingState() {
+      if (this.isInEditingState()) {
+        return;
+      }
+      if (this.isInSortingState()) {
+        throw new Error('Cannot enter editing state from sorting state');
+      }
+
+      /* Disable the toolbar elements. */
+      loot.dom.enable('wipeUserlistButton', false);
+      loot.dom.enable('copyContentButton', false);
+      loot.dom.enable('refreshContentButton', false);
+      loot.dom.enable('settingsButton', false);
+      loot.dom.enable('gameMenu', false);
+      loot.dom.enable('updateMasterlistButton', false);
+      loot.dom.enable('sortButton', false);
+
+      this.currentState = State.EDITING_STATE;
+    }
+
+    exitEditingState() {
+      if (this.isInDefaultState()) {
+        return;
+      }
+      if (this.isInSortingState()) {
+        throw new Error('Cannot exit editing state from sorting state');
+      }
+
+      /* Re-enable toolbar elements. */
+      loot.dom.enable('wipeUserlistButton');
+      loot.dom.enable('copyContentButton');
+      loot.dom.enable('refreshContentButton');
+      loot.dom.enable('settingsButton');
+      loot.dom.enable('gameMenu');
+      loot.dom.enable('updateMasterlistButton');
+      loot.dom.enable('sortButton');
+
+      this.currentState = State.DEFAULT_STATE;
+    }
+  };
+}));
diff --git a/src/tests/gui/html/js/test.html b/src/tests/gui/html/js/test.html
index 11efd275..4391d854 100644
--- a/src/tests/gui/html/js/test.html
+++ b/src/tests/gui/html/js/test.html
@@ -12,15 +12,18 @@
 <script src="../../../../../bower_components/lodash/dist/lodash.core.min.js"></script>
 
 <script>mocha.setup('bdd')</script>
+<script src="../../../../gui/html/js/dom.js"></script>
 <script src="../../../../gui/html/js/filters.js"></script>
 <script src="../../../../gui/html/js/game.js"></script>
 <script src="../../../../gui/html/js/plugin.js"></script>
 <script src="../../../../gui/html/js/query.js"></script>
+<script src="../../../../gui/html/js/state.js"></script>
 <script src="../../../../gui/html/js/translator.js"></script>
 <script src="test_filters.js"></script>
 <script src="test_game.js"></script>
 <script src="test_plugin.js"></script>
 <script src="test_query.js"></script>
+<script src="test_state.js"></script>
 <script src="test_translator.js"></script>
 <script>
   onload = function(){
diff --git a/src/tests/gui/html/js/test_state.js b/src/tests/gui/html/js/test_state.js
new file mode 100644
index 00000000..2ff6b7cb
--- /dev/null
+++ b/src/tests/gui/html/js/test_state.js
@@ -0,0 +1,271 @@
+'use strict';
+
+/* Mock the DOM interactions */
+loot.dom = {
+  elementShownStates: new Map(),
+  elementEnabledStates: new Map(),
+
+  show(elementId, showElement = true) {
+    this.elementShownStates.set(elementId, showElement);
+  },
+
+  enable(elementId, enableElement = true) {
+    this.elementEnabledStates.set(elementId, enableElement);
+  },
+};
+
+function getShown(elementId) {
+  return loot.dom.elementShownStates.get(elementId);
+}
+
+function getEnabled(elementId) {
+  return loot.dom.elementEnabledStates.get(elementId);
+}
+
+beforeEach(() => {
+  loot.dom.elementShownStates.clear();
+  loot.dom.elementEnabledStates.clear();
+});
+
+describe('State', () => {
+  describe('State()', () => {
+    it('should set the current state to DEFAULT_STATE', () => {
+      const state = new loot.State();
+      state.currentState.should.equal(loot.State.DEFAULT_STATE);
+    });
+  });
+
+  describe('DEFAULT_STATE', () => {
+    it('should not equal EDITING_STATE', () => {
+      loot.State.DEFAULT_STATE.should.not.equal(loot.State.EDITING_STATE);
+    });
+
+    it('should not equal SORTING_STATE', () => {
+      loot.State.DEFAULT_STATE.should.not.equal(loot.State.SORTING_STATE);
+    });
+  });
+
+  describe('EDITING_STATE', () => {
+    it('should not equal SORTING_STATE', () => {
+      loot.State.EDITING_STATE.should.not.equal(loot.State.SORTING_STATE);
+    });
+  });
+
+  describe('isInDefaultState()', () => {
+    it('should return true if the default state is the current state', () => {
+      const state = new loot.State();
+
+      state.isInDefaultState().should.be.true();
+    });
+
+    it('should return false if the editing state is the current state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      state.isInDefaultState().should.be.false();
+    });
+
+    it('should return false if the sorting state is the current state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      state.isInDefaultState().should.be.false();
+    });
+  });
+
+  describe('isInEditingState()', () => {
+    it('should return true if the editing state is the current state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      state.isInEditingState().should.be.true();
+    });
+
+    it('should return false if the default state is the current state', () => {
+      const state = new loot.State();
+
+      state.isInEditingState().should.be.false();
+    });
+
+    it('should return false if the sorting state is the current state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      state.isInEditingState().should.be.false();
+    });
+  });
+
+  describe('isInSortingState()', () => {
+    it('should return true if the sorting state is the current state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      state.isInSortingState().should.be.true();
+    });
+
+    it('should return false if the editing state is the current state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      state.isInSortingState().should.be.false();
+    });
+
+    it('should return false if the default state is the current state', () => {
+      const state = new loot.State();
+
+      state.isInSortingState().should.be.false();
+    });
+  });
+
+  describe('enterSortingState()', () => {
+    it('should change state to the sorting state from the default state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      state.currentState.should.equal(loot.State.SORTING_STATE);
+
+      getShown('updateMasterlistButton').should.be.false();
+      getShown('sortButton').should.be.false();
+      getShown('applySortButton').should.be.true();
+      getShown('cancelSortButton').should.be.true();
+      getEnabled('gameMenu').should.be.false();
+    });
+
+    it('should throw an error if called in the editing state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      should.throws(() => { state.enterSortingState(); }, Error);
+    });
+
+    it('should have no effect if already in the sorting state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+      state.enterSortingState();
+
+      state.currentState.should.equal(loot.State.SORTING_STATE);
+
+      getShown('updateMasterlistButton').should.be.false();
+      getShown('sortButton').should.be.false();
+      getShown('applySortButton').should.be.true();
+      getShown('cancelSortButton').should.be.true();
+      getEnabled('gameMenu').should.be.false();
+    });
+  });
+
+  describe('exitSortingState()', () => {
+    it('should change state to the default state from the sorting state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+      state.exitSortingState();
+
+      state.currentState.should.equal(loot.State.DEFAULT_STATE);
+
+      getShown('updateMasterlistButton').should.be.true();
+      getShown('sortButton').should.be.true();
+      getShown('applySortButton').should.be.false();
+      getShown('cancelSortButton').should.be.false();
+      getEnabled('gameMenu').should.be.true();
+    });
+
+    it('should throw an error if called in the editing state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      should.throws(() => { state.exitSortingState(); }, Error);
+    });
+
+    it('should have no effect if already in the default state', () => {
+      const state = new loot.State();
+      state.exitSortingState();
+
+      state.currentState.should.equal(loot.State.DEFAULT_STATE);
+
+      should(getShown('updateMasterlistButton')).be.undefined();
+      should(getShown('sortButton')).be.undefined();
+      should(getShown('applySortButton')).be.undefined();
+      should(getShown('cancelSortButton')).be.undefined();
+      should(getEnabled('gameMenu')).be.undefined();
+    });
+  });
+
+  describe('enterEditingState()', () => {
+    it('should change state to the editing state from the default state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+
+      state.currentState.should.equal(loot.State.EDITING_STATE);
+
+      getEnabled('wipeUserlistButton').should.be.false();
+      getEnabled('copyContentButton').should.be.false();
+      getEnabled('refreshContentButton').should.be.false();
+      getEnabled('settingsButton').should.be.false();
+      getEnabled('gameMenu').should.be.false();
+      getEnabled('updateMasterlistButton').should.be.false();
+      getEnabled('sortButton').should.be.false();
+    });
+
+    it('should throw an error if called in the sorting state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      should.throws(() => { state.enterEditingState(); }, Error);
+    });
+
+    it('should have no effect if already in the editing state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+      state.enterEditingState();
+
+      state.currentState.should.equal(loot.State.EDITING_STATE);
+
+      getEnabled('wipeUserlistButton').should.be.false();
+      getEnabled('copyContentButton').should.be.false();
+      getEnabled('refreshContentButton').should.be.false();
+      getEnabled('settingsButton').should.be.false();
+      getEnabled('gameMenu').should.be.false();
+      getEnabled('updateMasterlistButton').should.be.false();
+      getEnabled('sortButton').should.be.false();
+    });
+  });
+
+  describe('exitEditingState()', () => {
+    it('should change state to the default state from the editing state', () => {
+      const state = new loot.State();
+      state.enterEditingState();
+      state.exitEditingState();
+
+      state.currentState.should.equal(loot.State.DEFAULT_STATE);
+
+      getEnabled('wipeUserlistButton').should.be.true();
+      getEnabled('copyContentButton').should.be.true();
+      getEnabled('refreshContentButton').should.be.true();
+      getEnabled('settingsButton').should.be.true();
+      getEnabled('gameMenu').should.be.true();
+      getEnabled('updateMasterlistButton').should.be.true();
+      getEnabled('sortButton').should.be.true();
+    });
+
+    it('should throw an error if called in the sorting state', () => {
+      const state = new loot.State();
+      state.enterSortingState();
+
+      should.throws(() => { state.exitEditingState(); }, Error);
+    });
+
+    it('should have no effect if already in the default state', () => {
+      const state = new loot.State();
+      state.exitEditingState();
+
+      state.currentState.should.equal(loot.State.DEFAULT_STATE);
+
+      should(getEnabled('wipeUserlistButton')).be.undefined();
+      should(getEnabled('copyContentButton')).be.undefined();
+      should(getEnabled('refreshContentButton')).be.undefined();
+      should(getEnabled('settingsButton')).be.undefined();
+      should(getEnabled('gameMenu')).be.undefined();
+      should(getEnabled('updateMasterlistButton')).be.undefined();
+      should(getEnabled('sortButton')).be.undefined();
+    });
+  });
+});