Add markdown buttons to file editor

Currently, we have markdown files in many places (e.g. comments, new
issues, etc.). This Merge Request detects if the file being edited is a
markdown file and adds markdown buttons and their functionality to the
single file editor (Not the web IDE)

9 files changed, 179 insertions, 50 deletions

diff --git a/app/assets/javascripts/blob_edit/blob_bundle.js b/app/assets/javascripts/blob_edit/blob_bundle.js
index b07f951346e..5f64175362d 100644
--- a/app/assets/javascripts/blob_edit/blob_bundle.js
+++ b/app/assets/javascripts/blob_edit/blob_bundle.js
@@ -16,6 +16,7 @@ export default () => {
     const filePath = editBlobForm.data('blobFilename');
     const currentAction = $('.js-file-title').data('currentAction');
     const projectId = editBlobForm.data('project-id');
+    const isMarkdown = editBlobForm.data('is-markdown');
     const commitButton = $('.js-commit-button');
     const cancelLink = $('.btn.btn-cancel');
 
@@ -27,7 +28,13 @@ export default () => {
       window.onbeforeunload = null;
     });
 
-    new EditBlob(`${urlRoot}${assetsPath}`, filePath, currentAction, projectId);
+    new EditBlob({
+      assetsPath: `${urlRoot}${assetsPath}`,
+      filePath,
+      currentAction,
+      projectId,
+      isMarkdown,
+    });
     new NewCommitForm(editBlobForm);
 
     // returning here blocks page navigation
diff --git a/app/assets/javascripts/blob_edit/edit_blob.js b/app/assets/javascripts/blob_edit/edit_blob.js
index 6e19548eed2..011898a5e7a 100644
--- a/app/assets/javascripts/blob_edit/edit_blob.js
+++ b/app/assets/javascripts/blob_edit/edit_blob.js
@@ -6,22 +6,31 @@ import createFlash from '~/flash';
 import { __ } from '~/locale';
 import TemplateSelectorMediator from '../blob/file_template_mediator';
 import getModeByFileExtension from '~/lib/utils/ace_utils';
+import { addEditorMarkdownListeners } from '~/lib/utils/text_markdown';
 
 export default class EditBlob {
-  constructor(assetsPath, aceMode, currentAction, projectId) {
-    this.configureAceEditor(aceMode, assetsPath);
+  // The options object has:
+  // assetsPath, filePath, currentAction, projectId, isMarkdown
+  constructor(options) {
+    this.options = options;
+    this.configureAceEditor();
     this.initModePanesAndLinks();
     this.initSoftWrap();
-    this.initFileSelectors(currentAction, projectId);
+    this.initFileSelectors();
   }
 
-  configureAceEditor(filePath, assetsPath) {
+  configureAceEditor() {
+    const { filePath, assetsPath, isMarkdown } = this.options;
     ace.config.set('modePath', `${assetsPath}/ace`);
     ace.config.loadModule('ace/ext/searchbox');
     ace.config.loadModule('ace/ext/modelist');
 
     this.editor = ace.edit('editor');
 
+    if (isMarkdown) {
+      addEditorMarkdownListeners(this.editor);
+    }
+
     // This prevents warnings re: automatic scrolling being logged
     this.editor.$blockScrolling = Infinity;
 
@@ -32,7 +41,8 @@ export default class EditBlob {
     }
   }
 
-  initFileSelectors(currentAction, projectId) {
+  initFileSelectors() {
+    const { currentAction, projectId } = this.options;
     this.fileTemplateMediator = new TemplateSelectorMediator({
       currentAction,
       editor: this.editor,
diff --git a/app/assets/javascripts/lib/utils/text_markdown.js b/app/assets/javascripts/lib/utils/text_markdown.js
index 1254ec798a6..84a617acb42 100644
--- a/app/assets/javascripts/lib/utils/text_markdown.js
+++ b/app/assets/javascripts/lib/utils/text_markdown.js
@@ -8,6 +8,10 @@ function selectedText(text, textarea) {
   return text.substring(textarea.selectionStart, textarea.selectionEnd);
 }
 
+function addBlockTags(blockTag, selected) {
+  return `${blockTag}\n${selected}\n${blockTag}`;
+}
+
 function lineBefore(text, textarea) {
   var split;
   split = text
@@ -24,19 +28,45 @@ function lineAfter(text, textarea) {
     .split('\n')[0];
 }
 
+function editorBlockTagText(text, blockTag, selected, editor) {
+  const lines = text.split('\n');
+  const selectionRange = editor.getSelectionRange();
+  const shouldRemoveBlock =
+    lines[selectionRange.start.row - 1] === blockTag &&
+    lines[selectionRange.end.row + 1] === blockTag;
+
+  if (shouldRemoveBlock) {
+    if (blockTag !== null) {
+      // ace is globally defined
+      // eslint-disable-next-line no-undef
+      const { Range } = ace.require('ace/range');
+      const lastLine = lines[selectionRange.end.row + 1];
+      const rangeWithBlockTags = new Range(
+        lines[selectionRange.start.row - 1],
+        0,
+        selectionRange.end.row + 1,
+        lastLine.length,
+      );
+      editor.getSelection().setSelectionRange(rangeWithBlockTags);
+    }
+    return selected;
+  }
+  return addBlockTags(blockTag, selected);
+}
+
 function blockTagText(text, textArea, blockTag, selected) {
-  const before = lineBefore(text, textArea);
-  const after = lineAfter(text, textArea);
-  if (before === blockTag && after === blockTag) {
+  const shouldRemoveBlock =
+    lineBefore(text, textArea) === blockTag && lineAfter(text, textArea) === blockTag;
+
+  if (shouldRemoveBlock) {
     // To remove the block tag we have to select the line before & after
     if (blockTag != null) {
       textArea.selectionStart = textArea.selectionStart - (blockTag.length + 1);
       textArea.selectionEnd = textArea.selectionEnd + (blockTag.length + 1);
     }
     return selected;
-  } else {
-    return blockTag + '\n' + selected + '\n' + blockTag;
   }
+  return addBlockTags(blockTag, selected);
 }
 
 function moveCursor({
@@ -46,33 +76,48 @@ function moveCursor({
   positionBetweenTags,
   removedLastNewLine,
   select,
+  editor,
+  editorSelectionStart,
+  editorSelectionEnd,
 }) {
   var pos;
-  if (!textArea.setSelectionRange) {
+  if (textArea && !textArea.setSelectionRange) {
     return;
   }
   if (select && select.length > 0) {
-    // calculate the part of the text to be selected
-    const startPosition = textArea.selectionStart - (tag.length - tag.indexOf(select));
-    const endPosition = startPosition + select.length;
-    return textArea.setSelectionRange(startPosition, endPosition);
-  }
-  if (textArea.selectionStart === textArea.selectionEnd) {
-    if (positionBetweenTags) {
-      pos = textArea.selectionStart - tag.length;
-    } else {
-      pos = textArea.selectionStart;
+    if (textArea) {
+      // calculate the part of the text to be selected
+      const startPosition = textArea.selectionStart - (tag.length - tag.indexOf(select));
+      const endPosition = startPosition + select.length;
+      return textArea.setSelectionRange(startPosition, endPosition);
+    } else if (editor) {
+      editor.navigateLeft(tag.length - tag.indexOf(select));
+      editor.getSelection().selectAWord();
+      return;
     }
+  }
+  if (textArea) {
+    if (textArea.selectionStart === textArea.selectionEnd) {
+      if (positionBetweenTags) {
+        pos = textArea.selectionStart - tag.length;
+      } else {
+        pos = textArea.selectionStart;
+      }
 
-    if (removedLastNewLine) {
-      pos -= 1;
-    }
+      if (removedLastNewLine) {
+        pos -= 1;
+      }
 
-    if (cursorOffset) {
-      pos -= cursorOffset;
-    }
+      if (cursorOffset) {
+        pos -= cursorOffset;
+      }
 
-    return textArea.setSelectionRange(pos, pos);
+      return textArea.setSelectionRange(pos, pos);
+    }
+  } else if (editor && editorSelectionStart.row === editorSelectionEnd.row) {
+    if (positionBetweenTags) {
+      editor.navigateLeft(tag.length);
+    }
   }
 }
 
@@ -85,6 +130,7 @@ export function insertMarkdownText({
   selected = '',
   wrap,
   select,
+  editor,
 }) {
   var textToInsert,
     selectedSplit,
@@ -92,11 +138,20 @@ export function insertMarkdownText({
     removedLastNewLine,
     removedFirstNewLine,
     currentLineEmpty,
-    lastNewLine;
+    lastNewLine,
+    editorSelectionStart,
+    editorSelectionEnd;
   removedLastNewLine = false;
   removedFirstNewLine = false;
   currentLineEmpty = false;
 
+  if (editor) {
+    const selectionRange = editor.getSelectionRange();
+
+    editorSelectionStart = selectionRange.start;
+    editorSelectionEnd = selectionRange.end;
+  }
+
   // check for link pattern and selected text is an URL
   // if so fill in the url part instead of the text part of the pattern.
   if (tag === LINK_TAG_PATTERN) {
@@ -119,14 +174,27 @@ export function insertMarkdownText({
   }
 
   // Remove the last newline
-  if (textArea.selectionEnd - textArea.selectionStart > selected.replace(/\n$/, '').length) {
-    removedLastNewLine = true;
-    selected = selected.replace(/\n$/, '');
+  if (textArea) {
+    if (textArea.selectionEnd - textArea.selectionStart > selected.replace(/\n$/, '').length) {
+      removedLastNewLine = true;
+      selected = selected.replace(/\n$/, '');
+    }
+  } else if (editor) {
+    if (editorSelectionStart.row !== editorSelectionEnd.row) {
+      removedLastNewLine = true;
+      selected = selected.replace(/\n$/, '');
+    }
   }
 
   selectedSplit = selected.split('\n');
 
-  if (!wrap) {
+  if (editor && !wrap) {
+    lastNewLine = editor.getValue().split('\n')[editorSelectionStart.row];
+
+    if (/^\s*$/.test(lastNewLine)) {
+      currentLineEmpty = true;
+    }
+  } else if (textArea && !wrap) {
     lastNewLine = textArea.value.substr(0, textArea.selectionStart).lastIndexOf('\n');
 
     // Check whether the current line is empty or consists only of spaces(=handle as empty)
@@ -135,13 +203,19 @@ export function insertMarkdownText({
     }
   }
 
-  startChar = !wrap && !currentLineEmpty && textArea.selectionStart > 0 ? '\n' : '';
+  const isBeginning =
+    (textArea && textArea.selectionStart === 0) ||
+    (editor && editorSelectionStart.column === 0 && editorSelectionStart.row === 0);
+
+  startChar = !wrap && !currentLineEmpty && !isBeginning ? '\n' : '';
 
   const textPlaceholder = '{text}';
 
   if (selectedSplit.length > 1 && (!wrap || (blockTag != null && blockTag !== ''))) {
     if (blockTag != null && blockTag !== '') {
-      textToInsert = blockTagText(text, textArea, blockTag, selected);
+      textToInsert = editor
+        ? editorBlockTagText(text, blockTag, selected, editor)
+        : blockTagText(text, textArea, blockTag, selected);
     } else {
       textToInsert = selectedSplit
         .map(function(val) {
@@ -170,7 +244,11 @@ export function insertMarkdownText({
     textToInsert += '\n';
   }
 
-  insertText(textArea, textToInsert);
+  if (editor) {
+    editor.insert(textToInsert);
+  } else {
+    insertText(textArea, textToInsert);
+  }
   return moveCursor({
     textArea,
     tag: tag.replace(textPlaceholder, selected),
@@ -178,6 +256,9 @@ export function insertMarkdownText({
     positionBetweenTags: wrap && selected.length === 0,
     removedLastNewLine,
     select,
+    editor,
+    editorSelectionStart,
+    editorSelectionEnd,
   });
 }
 
@@ -217,6 +298,25 @@ export function addMarkdownListeners(form) {
     });
 }
 
+export function addEditorMarkdownListeners(editor) {
+  $('.js-md')
+    .off('click')
+    .on('click', function(e) {
+      const { mdTag, mdBlock, mdPrepend, mdSelect } = $(e.currentTarget).data();
+
+      insertMarkdownText({
+        tag: mdTag,
+        blockTag: mdBlock,
+        wrap: !mdPrepend,
+        select: mdSelect,
+        selected: editor.getSelectedText(),
+        text: editor.getValue(),
+        editor,
+      });
+      editor.focus();
+    });
+}
+
 export function removeMarkdownListeners(form) {
   return $('.js-md', form).off('click');
 }
diff --git a/app/assets/stylesheets/framework/markdown_area.scss b/app/assets/stylesheets/framework/markdown_area.scss
index 5609a2086e6..eb191cf4d39 100644
--- a/app/assets/stylesheets/framework/markdown_area.scss
+++ b/app/assets/stylesheets/framework/markdown_area.scss
@@ -173,7 +173,7 @@
   svg {
     width: 14px;
     height: 14px;
-    margin-top: 3px;
+    vertical-align: middle;
     fill: $gl-text-color-secondary;
   }
 
diff --git a/app/assets/stylesheets/pages/editor.scss b/app/assets/stylesheets/pages/editor.scss
index f46ff360496..5a988b184b6 100644
--- a/app/assets/stylesheets/pages/editor.scss
+++ b/app/assets/stylesheets/pages/editor.scss
@@ -128,6 +128,10 @@
           width: 100%;
         }
       }
+
+      @media(max-width: map-get($grid-breakpoints, md)-1) {
+        clear: both;
+      }
     }
 
     .editor-ref {
diff --git a/app/helpers/blob_helper.rb b/app/helpers/blob_helper.rb
index 3dea0975beb..23d6684a8e6 100644
--- a/app/helpers/blob_helper.rb
+++ b/app/helpers/blob_helper.rb
@@ -177,7 +177,8 @@ module BlobHelper
       'relative-url-root' => Rails.application.config.relative_url_root,
       'assets-prefix' => Gitlab::Application.config.assets.prefix,
       'blob-filename' => @blob && @blob.path,
-      'project-id' => project.id
+      'project-id' => project.id,
+      'is-markdown' => @blob && @blob.path && Gitlab::MarkupHelper.gitlab_markdown?(@blob.path)
     }
   end
 
diff --git a/app/views/projects/_md_preview.html.haml b/app/views/projects/_md_preview.html.haml
index 0f709c65d0e..03ba1104507 100644
--- a/app/views/projects/_md_preview.html.haml
+++ b/app/views/projects/_md_preview.html.haml
@@ -18,17 +18,7 @@
           Preview
 
       %li.md-header-toolbar.active
-        = markdown_toolbar_button({ icon: "bold", data: { "md-tag" => "**" }, title: s_("MarkdownToolbar|Add bold text") })
-        = markdown_toolbar_button({ icon: "italic", data: { "md-tag" => "*" }, title: s_("MarkdownToolbar|Add italic text") })
-        = markdown_toolbar_button({ icon: "quote", data: { "md-tag" => "> ", "md-prepend" => true }, title: s_("MarkdownToolbar|Insert a quote") })
-        = markdown_toolbar_button({ icon: "code", data: { "md-tag" => "`", "md-block" => "```" }, title: s_("MarkdownToolbar|Insert code") })
-        = markdown_toolbar_button({ icon: "link", data: { "md-tag" => "[{text}](url)", "md-select" => "url" }, title: s_("MarkdownToolbar|Add a link") })
-        = markdown_toolbar_button({ icon: "list-bulleted", data: { "md-tag" => "* ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a bullet list") })
-        = markdown_toolbar_button({ icon: "list-numbered", data: { "md-tag" => "1. ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a numbered list") })
-        = markdown_toolbar_button({ icon: "task-done", data: { "md-tag" => "* [ ] ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a task list") })
-        = markdown_toolbar_button({ icon: "table", data: { "md-tag" => "| header | header |\n| ------ | ------ |\n| cell | cell |\n| cell | cell |", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a table") })
-        %button.toolbar-btn.toolbar-fullscreen-btn.js-zen-enter.has-tooltip{ type: "button", tabindex: -1, "aria-label": "Go full screen", title: s_("MarkdownToolbar|Go full screen"), data: { container: "body" } }
-          = sprite_icon("screen-full")
+        = render 'projects/blob/markdown_buttons', show_fullscreen_button: true
 
   .md-write-holder
     = yield
diff --git a/app/views/projects/blob/_editor.html.haml b/app/views/projects/blob/_editor.html.haml
index 3c1f33ea95e..a54460f1196 100644
--- a/app/views/projects/blob/_editor.html.haml
+++ b/app/views/projects/blob/_editor.html.haml
@@ -1,4 +1,6 @@
 - action = current_action?(:edit) || current_action?(:update) ? 'edit' : 'create'
+- file_name = params[:id].split("/").last ||= ""
+- is_markdown = Gitlab::MarkupHelper.gitlab_markdown?(file_name)
 
 .file-holder-bottom-radius.file-holder.file.append-bottom-default
   .js-file-title.file-title.clearfix{ data: { current_action: action } }
@@ -17,6 +19,8 @@
         required: true, class: 'form-control new-file-name js-file-path-name-input'
 
     .file-buttons
+      - if is_markdown
+        = render 'projects/blob/markdown_buttons', show_fullscreen_button: false
       = button_tag class: 'soft-wrap-toggle btn', type: 'button', tabindex: '-1' do
         %span.no-wrap
           = custom_icon('icon_no_wrap')
diff --git a/app/views/projects/blob/_markdown_buttons.html.haml b/app/views/projects/blob/_markdown_buttons.html.haml
new file mode 100644
index 00000000000..1d6acd86108
--- /dev/null
+++ b/app/views/projects/blob/_markdown_buttons.html.haml
@@ -0,0 +1,13 @@
+.md-header-toolbar.active
+  = markdown_toolbar_button({ icon: "bold", data: { "md-tag" => "**" }, title: s_("MarkdownToolbar|Add bold text") })
+  = markdown_toolbar_button({ icon: "italic", data: { "md-tag" => "*" }, title: s_("MarkdownToolbar|Add italic text") })
+  = markdown_toolbar_button({ icon: "quote", data: { "md-tag" => "> ", "md-prepend" => true }, title: s_("MarkdownToolbar|Insert a quote") })
+  = markdown_toolbar_button({ icon: "code", data: { "md-tag" => "`", "md-block" => "```" }, title: s_("MarkdownToolbar|Insert code") })
+  = markdown_toolbar_button({ icon: "link", data: { "md-tag" => "[{text}](url)", "md-select" => "url" }, title: s_("MarkdownToolbar|Add a link") })
+  = markdown_toolbar_button({ icon: "list-bulleted", data: { "md-tag" => "* ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a bullet list") })
+  = markdown_toolbar_button({ icon: "list-numbered", data: { "md-tag" => "1. ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a numbered list") })
+  = markdown_toolbar_button({ icon: "task-done", data: { "md-tag" => "* [ ] ", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a task list") })
+  = markdown_toolbar_button({ icon: "table", data: { "md-tag" => "| header | header |\n| ------ | ------ |\n| cell | cell |\n| cell | cell |", "md-prepend" => true }, title: s_("MarkdownToolbar|Add a table") })
+  - if show_fullscreen_button
+    %button.toolbar-btn.toolbar-fullscreen-btn.js-zen-enter.has-tooltip{ type: "button", tabindex: -1, "aria-label": "Go full screen", title: s_("MarkdownToolbar|Go full screen"), data: { container: "body" } }
+      = sprite_icon("screen-full")