1 files changed, 92 insertions, 0 deletions
diff --git a/app/assets/javascripts/blob/template_selector.js b/app/assets/javascripts/blob/template_selector.js
new file mode 100644
index 00000000000..d7c1c32efbd
--- /dev/null
+++ b/app/assets/javascripts/blob/template_selector.js
@@ -0,0 +1,92 @@
+/* eslint-disable class-methods-use-this, no-unused-vars */
+
+export default class TemplateSelector {
+  constructor({ dropdown, data, pattern, wrapper, editor, $input } = {}) {
+    this.pattern = pattern;
+    this.editor = editor;
+    this.dropdown = dropdown;
+    this.$dropdownContainer = wrapper;
+    this.$filenameInput = $input || $('#file_name');
+    this.$dropdownIcon = $('.fa-chevron-down', dropdown);
+
+    this.initDropdown(dropdown, data);
+    this.listenForFilenameInput();
+    this.renderMatchedDropdown();
+    this.initAutosizeUpdateEvent();
+  }
+
+  initDropdown(dropdown, data) {
+    return $(dropdown).glDropdown({
+      data,
+      filterable: true,
+      selectable: true,
+      toggleLabel: item => item.name,
+      search: {
+        fields: ['name'],
+      },
+      clicked: (item, el, e) => this.fetchFileTemplate(item, el, e),
+      text: item => item.name,
+    });
+  }
+
+  initAutosizeUpdateEvent() {
+    this.autosizeUpdateEvent = document.createEvent('Event');
+    this.autosizeUpdateEvent.initEvent('autosize:update', true, false);
+  }
+
+  listenForFilenameInput() {
+    return this.$filenameInput.on('keyup blur', e => this.renderMatchedDropdown(e));
+  }
+
+  renderMatchedDropdown() {
+    if (!this.$filenameInput.length) {
+      return null;
+    }
+
+    const filenameMatches = this.pattern.test(this.$filenameInput.val().trim());
+
+    if (!filenameMatches) {
+      return this.$dropdownContainer.addClass('hidden');
+    }
+    return this.$dropdownContainer.removeClass('hidden');
+  }
+
+  fetchFileTemplate(item, el, e) {
+    e.preventDefault();
+    return this.requestFile(item);
+  }
+
+  requestFile(item) {
+    // This `requestFile` method is an abstract method that should
+    // be added by all subclasses.
+  }
+
+  // To be implemented on the extending class
+  // e.g. Api.gitlabCiYml(query.name, file => this.setEditorContent(file));
+
+  setEditorContent(file, { skipFocus } = {}) {
+    if (!file) return;
+
+    const newValue = file.content;
+
+    this.editor.setValue(newValue, 1);
+
+    if (!skipFocus) this.editor.focus();
+
+    if (this.editor instanceof jQuery) {
+      this.editor.get(0).dispatchEvent(this.autosizeUpdateEvent);
+    }
+  }
+
+  startLoadingSpinner() {
+    this.$dropdownIcon
+      .addClass('fa-spinner fa-spin')
+      .removeClass('fa-chevron-down');
+  }
+
+  stopLoadingSpinner() {
+    this.$dropdownIcon
+      .addClass('fa-chevron-down')
+      .removeClass('fa-spinner fa-spin');
+  }
+}