Add suggest menu for user mentions in text editor

2 files changed, 210 insertions, 0 deletions

diff --git a/assets/js/components/suggest-menu.js b/assets/js/components/suggest-menu.js
new file mode 100644
index 00000000..f0e6dfd1
--- /dev/null
+++ b/assets/js/components/suggest-menu.js
@@ -0,0 +1,206 @@
+KB.component('suggest-menu', function(containerElement, options) {
+
+    function onKeyDown(e) {
+        switch (e.keyCode) {
+            case 27:
+                destroy();
+                break;
+            case 38:
+                e.preventDefault();
+                e.stopImmediatePropagation();
+                moveUp();
+                break;
+            case 40:
+                e.preventDefault();
+                e.stopImmediatePropagation();
+                moveDown();
+                break;
+            case 13:
+                e.preventDefault();
+                e.stopImmediatePropagation();
+                insertSelectedItem();
+                break;
+        }
+    }
+
+    function onClick() {
+        insertSelectedItem();
+    }
+
+    function onMouseOver(element) {
+        if (KB.dom(element).hasClass('suggest-menu-item')) {
+            KB.find('.suggest-menu-item.active').removeClass('active');
+            KB.dom(element).addClass('active');
+        }
+    }
+
+    function insertSelectedItem() {
+        var element = KB.find('.suggest-menu-item.active');
+        var value = element.data('value');
+        var trigger = element.data('trigger');
+        var position = containerElement.value.lastIndexOf(trigger) + 1;
+        var content = containerElement.value.substring(0, position);
+
+        containerElement.value = content + value;
+        destroy();
+    }
+
+    function getParentElement() {
+        var selectors = ['.popover-form', '#popover-content', 'body'];
+
+        for (var i = 0; i < selectors.length; i++) {
+            var element = document.querySelector(selectors[i]);
+
+            if (element !== null) {
+                return element;
+            }
+        }
+
+        return null;
+    }
+
+    function resetSelection() {
+        var elements = document.querySelectorAll('.suggest-menu-item');
+
+        for (var i = 0; i < elements.length; i++) {
+            if (KB.dom(elements[i]).hasClass('active')) {
+                KB.dom(elements[i]).removeClass('active');
+                break;
+            }
+        }
+
+        return {items: elements, index: i};
+    }
+
+    function moveUp() {
+        var result = resetSelection();
+
+        if (result.index > 0) {
+            result.index = result.index - 1;
+        }
+
+        KB.dom(result.items[result.index]).addClass('active');
+    }
+
+    function moveDown() {
+        var result = resetSelection();
+
+        if (result.index < result.items.length - 1) {
+            result.index++;
+        }
+
+        KB.dom(result.items[result.index]).addClass('active');
+    }
+
+    function destroy() {
+        var element = KB.find('#suggest-menu');
+
+        if (element !== null) {
+            element.remove();
+        }
+
+        document.removeEventListener('keydown', onKeyDown, false);
+    }
+
+    function search(element) {
+        var text = element.value.substring(element.value.lastIndexOf(' ') + 1, element.selectionEnd);
+        var trigger = getTrigger(text, options.triggers);
+
+        destroy();
+
+        if (trigger !== null) {
+            fetchItems(trigger, text.substring(trigger.length), options.triggers[trigger]);
+        }
+    }
+
+    function getTrigger(text, triggers) {
+        for (var trigger in triggers) {
+            if (triggers.hasOwnProperty(trigger) && text.indexOf(trigger) === 0) {
+                return trigger;
+            }
+        }
+
+        return null;
+    }
+
+    function fetchItems(trigger, text, value) {
+        if (typeof value === 'string') {
+            KB.http.get(value).success(function (response) {
+                onItemFetched(trigger, text, response);
+            });
+        } else {
+            onItemFetched(trigger, text, value);
+        }
+    }
+
+    function onItemFetched(trigger, text, items) {
+        items = filterItems(text, items);
+
+        if (items.length > 0) {
+            renderMenu(buildItems(trigger, items));
+        }
+    }
+
+    function filterItems(text, items) {
+        var filteredItems = [];
+
+        if (text.length === 0) {
+            return items;
+        }
+
+        for (var i = 0; i < items.length; i++) {
+            if (items[i].value.toLowerCase().indexOf(text.toLowerCase()) === 0) {
+                filteredItems.push(items[i]);
+            }
+        }
+
+        return filteredItems;
+    }
+
+    function buildItems(trigger, items) {
+        var elements = [];
+
+        for (var i = 0; i < items.length; i++) {
+            var className = 'suggest-menu-item';
+
+            if (i === 0) {
+                className += ' active';
+            }
+
+            elements.push({
+                class: className,
+                html: items[i].html,
+                'data-value': items[i].value,
+                'data-trigger': trigger
+            });
+        }
+
+        return elements;
+    }
+
+    function renderMenu(items) {
+        var parentElement = getParentElement();
+        var caretPosition = getCaretCoordinates(containerElement, containerElement.selectionEnd);
+        var left = caretPosition.left + containerElement.offsetLeft;
+        var top = caretPosition.top + containerElement.offsetTop + 16;
+
+        document.addEventListener('keydown', onKeyDown, false);
+
+        var menu = KB.dom('ul')
+            .attr('id', 'suggest-menu')
+            .click(onClick)
+            .mouseover(onMouseOver)
+            .style('left', left + 'px')
+            .style('top', top + 'px')
+            .for('li', items)
+            .build();
+
+        parentElement.appendChild(menu);
+    }
+
+    this.render = function () {
+        containerElement.addEventListener('input', function () {
+            search(this);
+        });
+    };
+});
diff --git a/assets/js/components/text-editor.js b/assets/js/components/text-editor.js
index 2bf8109e..9b4be55c 100644
--- a/assets/js/components/text-editor.js
+++ b/assets/js/components/text-editor.js
@@ -55,6 +55,10 @@ KB.component('text-editor', function (containerElement, options) {
             .attr('placeholder', options.placeholder || null)
             .build();
 
+        if (options.mentionUrl) {
+            KB.getComponent('suggest-menu', textarea, {triggers: {'@': options.mentionUrl}}).render();
+        }
+
         return KB.dom('div')
             .attr('class', 'text-editor-write-mode')
             .add(toolbarElement)