From ad8ed0d9f60fc1d1060d4f027593ba4e4b153afe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20H=C3=A4usler?= <hfelix@protonmail.ch>
Date: Tue, 26 May 2020 12:07:13 +0200
Subject: [PATCH] Add GitLab math block support

---
 src/main/preferences/schema.json              |  5 ++
 src/muya/lib/config/index.js                  |  3 +-
 src/muya/lib/contentState/codeBlockCtrl.js    |  3 ++
 src/muya/lib/contentState/containerCtrl.js    | 49 +++++++++++++++++--
 src/muya/lib/contentState/copyCutCtrl.js      | 12 +++--
 src/muya/lib/contentState/paragraphCtrl.js    |  8 ++-
 src/muya/lib/index.js                         |  4 +-
 src/muya/lib/parser/marked/blockRules.js      |  1 +
 src/muya/lib/parser/marked/lexer.js           | 24 ++++++++-
 src/muya/lib/parser/marked/options.js         |  3 +-
 src/muya/lib/prism/languages.json             |  3 ++
 src/muya/lib/utils/exportHtml.js              |  1 +
 src/muya/lib/utils/exportMarkdown.js          | 15 ++++--
 src/muya/lib/utils/importMarkdown.js          | 22 ++++++---
 .../components/editorWithTabs/editor.vue      | 10 ++++
 .../prefComponents/markdown/index.vue         |  8 +++
 src/renderer/store/preferences.js             |  1 +
 static/preference.json                        |  1 +
 18 files changed, 146 insertions(+), 27 deletions(-)

diff --git a/src/main/preferences/schema.json b/src/main/preferences/schema.json
index b3b1053d0..dd5d3bbbf 100644
--- a/src/main/preferences/schema.json
+++ b/src/main/preferences/schema.json
@@ -289,6 +289,11 @@
     "type": "boolean",
     "default": false
   },
+  "isGitlabCompatibilityEnabled": {
+    "description": "Markdown-Enable GitLab compatibility mode.",
+    "type": "boolean",
+    "default": false
+  },
   "sequenceTheme": {
     "description": "Markdown--Sequence diagram theme",
     "enum": [
diff --git a/src/muya/lib/config/index.js b/src/muya/lib/config/index.js
index 3c409ea13..c5405eb7a 100644
--- a/src/muya/lib/config/index.js
+++ b/src/muya/lib/config/index.js
@@ -280,7 +280,8 @@ export const MUYA_DEFAULT_OPTION = {
 
   // Markdown extensions
   superSubScript: false,
-  footnote: false
+  footnote: false,
+  isGitlabCompatibilityEnabled: false
 }
 
 // export const DIAGRAM_TEMPLATE = {
diff --git a/src/muya/lib/contentState/codeBlockCtrl.js b/src/muya/lib/contentState/codeBlockCtrl.js
index 3cd6ae1e1..078dbc2b0 100644
--- a/src/muya/lib/contentState/codeBlockCtrl.js
+++ b/src/muya/lib/contentState/codeBlockCtrl.js
@@ -35,6 +35,9 @@ const codeBlockCtrl = ContentState => {
 
   ContentState.prototype.selectLanguage = function (paragraph, lang) {
     const block = this.getBlock(paragraph.id)
+    if (lang === 'math' && this.isGitlabCompatibilityEnabled && this.updateMathBlock(block)) {
+      return
+    }
     this.updateCodeLanguage(block, lang)
   }
 
diff --git a/src/muya/lib/contentState/containerCtrl.js b/src/muya/lib/contentState/containerCtrl.js
index eebf0bffe..0b0973b37 100644
--- a/src/muya/lib/contentState/containerCtrl.js
+++ b/src/muya/lib/contentState/containerCtrl.js
@@ -8,11 +8,18 @@ const FUNCTION_TYPE_LANG = {
 }
 
 const containerCtrl = ContentState => {
-  ContentState.prototype.createContainerBlock = function (functionType, value = '') {
+  ContentState.prototype.createContainerBlock = function (functionType, value = '', style = undefined) {
     const figureBlock = this.createBlock('figure', {
       functionType
     })
 
+    if (functionType === 'multiplemath') {
+      if (style === undefined) {
+        figureBlock.mathStyle = this.isGitlabCompatibilityEnabled ? 'gitlab' : ''
+      }
+      figureBlock.mathStyle = style
+    }
+
     const { preBlock, preview } = this.createPreAndPreview(functionType, value)
     this.appendChild(figureBlock, preBlock)
     this.appendChild(figureBlock, preview)
@@ -56,11 +63,18 @@ const containerCtrl = ContentState => {
     return { preBlock, preview }
   }
 
-  ContentState.prototype.initContainerBlock = function (functionType, block) { // p block
+  ContentState.prototype.initContainerBlock = function (functionType, block, style = undefined) { // p block
     block.type = 'figure'
     block.functionType = functionType
     block.children = []
 
+    if (functionType === 'multiplemath') {
+      if (style === undefined) {
+        block.mathStyle = this.isGitlabCompatibilityEnabled ? 'gitlab' : ''
+      }
+      block.mathStyle = style
+    }
+
     const { preBlock, preview } = this.createPreAndPreview(functionType)
 
     this.appendChild(block, preBlock)
@@ -84,11 +98,36 @@ const containerCtrl = ContentState => {
   }
 
   ContentState.prototype.updateMathBlock = function (block) {
+    const functionType = 'multiplemath'
     const { type } = block
-    if (type !== 'p') return false
+
+    // TODO(GitLab): Allow "functionType" 'languageInput' to convert an existing
+    //   code block into math block.
+    if (type === 'span' && block.functionType === 'paragraphContent') {
+      const isMathBlock = !!block.text.match(/^`{3,}math\s*/)
+      if (isMathBlock) {
+        const result = this.initContainerBlock(functionType, block, 'gitlab')
+        if (result) {
+          // Set cursor at the first line
+          const { key } = result
+          const offset = 0
+          this.cursor = {
+            start: { key, offset },
+            end: { key, offset }
+          }
+
+          // Force render
+          this.partialRender()
+          return result
+        }
+      }
+      return false
+    } else if (type !== 'p') {
+      return false
+    }
+
     const { text } = block.children[0]
-    const functionType = 'multiplemath'
-    return text.trim() === '$$' ? this.initContainerBlock(functionType, block) : false
+    return text.trim() === '$$' ? this.initContainerBlock(functionType, block, '') : false
   }
 }
 
diff --git a/src/muya/lib/contentState/copyCutCtrl.js b/src/muya/lib/contentState/copyCutCtrl.js
index 3769e93ab..a467c4af8 100644
--- a/src/muya/lib/contentState/copyCutCtrl.js
+++ b/src/muya/lib/contentState/copyCutCtrl.js
@@ -244,8 +244,8 @@ const copyCutCtrl = ContentState => {
 
       const table = this.createTableInFigure({ rows: row, columns: column }, tableContents)
       this.appendChild(figureBlock, table)
-      const listIndentation = this.listIndentation
-      const markdown = new ExportMarkdown([figureBlock], listIndentation).generate()
+      const { isGitlabCompatibilityEnabled, listIndentation } = this
+      const markdown = new ExportMarkdown([figureBlock], listIndentation, isGitlabCompatibilityEnabled).generate()
 
       event.clipboardData.setData('text/html', '')
       event.clipboardData.setData('text/plain', markdown)
@@ -281,7 +281,9 @@ const copyCutCtrl = ContentState => {
       case 'copyAsHtml': {
         event.clipboardData.setData('text/html', '')
         event.clipboardData.setData('text/plain', getSanitizeHtml(text, {
-          superSubScript: this.muya.options.superSubScript
+          superSubScript: this.muya.options.superSubScript,
+          footnote: this.muya.options.footnote,
+          isGitlabCompatibilityEnabled: this.muya.options.isGitlabCompatibilityEnabled
         }))
         break
       }
@@ -290,8 +292,8 @@ const copyCutCtrl = ContentState => {
         const block = typeof copyInfo === 'string' ? this.getBlock(copyInfo) : copyInfo
         if (!block) return
         const anchor = this.getAnchor(block)
-        const listIndentation = this.listIndentation
-        const markdown = new ExportMarkdown([anchor], listIndentation).generate()
+        const { isGitlabCompatibilityEnabled, listIndentation } = this
+        const markdown = new ExportMarkdown([anchor], listIndentation, isGitlabCompatibilityEnabled).generate()
         event.clipboardData.setData('text/html', '')
         event.clipboardData.setData('text/plain', markdown)
         break
diff --git a/src/muya/lib/contentState/paragraphCtrl.js b/src/muya/lib/contentState/paragraphCtrl.js
index dcdb9dd36..099df5c7f 100644
--- a/src/muya/lib/contentState/paragraphCtrl.js
+++ b/src/muya/lib/contentState/paragraphCtrl.js
@@ -321,8 +321,12 @@ const paragraphCtrl = ContentState => {
           lang
         })
 
-        const listIndentation = this.listIndentation
-        const markdown = new ExportMarkdown(children.slice(startIndex, endIndex + 1), listIndentation).generate()
+        const { isGitlabCompatibilityEnabled, listIndentation } = this
+        const markdown = new ExportMarkdown(
+          children.slice(startIndex, endIndex + 1),
+          listIndentation,
+          isGitlabCompatibilityEnabled
+        ).generate()
         const codeContent = this.createBlock('span', {
           text: markdown,
           lang,
diff --git a/src/muya/lib/index.js b/src/muya/lib/index.js
index 57e4d2e13..5fb130edd 100644
--- a/src/muya/lib/index.js
+++ b/src/muya/lib/index.js
@@ -127,8 +127,8 @@ class Muya {
 
   getMarkdown () {
     const blocks = this.contentState.getBlocks()
-    const listIndentation = this.contentState.listIndentation
-    return new ExportMarkdown(blocks, listIndentation).generate()
+    const { isGitlabCompatibilityEnabled, listIndentation } = this.contentState
+    return new ExportMarkdown(blocks, listIndentation, isGitlabCompatibilityEnabled).generate()
   }
 
   getHistory () {
diff --git a/src/muya/lib/parser/marked/blockRules.js b/src/muya/lib/parser/marked/blockRules.js
index 99774b2b1..a9a263338 100644
--- a/src/muya/lib/parser/marked/blockRules.js
+++ b/src/muya/lib/parser/marked/blockRules.js
@@ -36,6 +36,7 @@ export const block = {
   // extra
   frontmatter: /^(?:(?:---\n([\s\S]+?)---)|(?:\+\+\+\n([\s\S]+?)\+\+\+)|(?:;;;\n([\s\S]+?);;;)|(?:\{\n([\s\S]+?)\}))(?:\n{2,}|\n{1,2}$)/,
   multiplemath: /^\$\$\n([\s\S]+?)\n\$\$(?:\n+|$)/,
+  multiplemathGitlab: /^ {0,3}(`{3,})math\n(?:(|[\s\S]*?)\n)(?: {0,3}\1`* *(?:\n+|$)|$)/, // Math inside a code block (GitLab display math)
   footnote: /^\[\^([^\^\[\]\s]+?)\]:[\s\S]+?(?=\n *\n {0,3}[^ ]+|$)/
 }
 
diff --git a/src/muya/lib/parser/marked/lexer.js b/src/muya/lib/parser/marked/lexer.js
index 31965b279..aaac02155 100644
--- a/src/muya/lib/parser/marked/lexer.js
+++ b/src/muya/lib/parser/marked/lexer.js
@@ -64,7 +64,12 @@ Lexer.prototype.lex = function (src) {
  */
 
 Lexer.prototype.token = function (src, top) {
-  const { frontMatter, math, footnote } = this.options
+  const {
+    footnote,
+    frontMatter,
+    isGitlabCompatibilityEnabled,
+    math
+  } = this.options
   src = src.replace(/^ +$/gm, '')
 
   let loose
@@ -149,10 +154,25 @@ Lexer.prototype.token = function (src, top) {
         src = src.substring(cap[0].length)
         this.tokens.push({
           type: 'multiplemath',
-          text: cap[1]
+          text: cap[1],
+          mathStyle: ''
         })
         continue
       }
+
+      // match GitLab display math blocks (```math)
+      if (isGitlabCompatibilityEnabled) {
+        cap = this.rules.multiplemathGitlab.exec(src)
+        if (cap) {
+          src = src.substring(cap[0].length)
+          this.tokens.push({
+            type: 'multiplemath',
+            text: cap[2] || '',
+            mathStyle: 'gitlab'
+          })
+          continue
+        }
+      }
     }
 
     if (footnote) {
diff --git a/src/muya/lib/parser/marked/options.js b/src/muya/lib/parser/marked/options.js
index 3d3a81586..4c1399cd6 100644
--- a/src/muya/lib/parser/marked/options.js
+++ b/src/muya/lib/parser/marked/options.js
@@ -29,5 +29,6 @@ export default {
   math: true,
   frontMatter: true,
   superSubScript: false,
-  footnote: false
+  footnote: false,
+  isGitlabCompatibilityEnabled: false
 }
diff --git a/src/muya/lib/prism/languages.json b/src/muya/lib/prism/languages.json
index fabb18d05..c88bd7f76 100644
--- a/src/muya/lib/prism/languages.json
+++ b/src/muya/lib/prism/languages.json
@@ -564,6 +564,9 @@
   },
   "latex": {
     "title": "LaTeX",
+    "alias": [
+      "math"
+    ],
     "ext": [
       "text",
       "ltx",
diff --git a/src/muya/lib/utils/exportHtml.js b/src/muya/lib/utils/exportHtml.js
index 230f3d00e..01a259384 100644
--- a/src/muya/lib/utils/exportHtml.js
+++ b/src/muya/lib/utils/exportHtml.js
@@ -114,6 +114,7 @@ class ExportHtml {
     let html = marked(this.markdown, {
       superSubScript: this.muya ? this.muya.options.superSubScript : false,
       footnote: this.muya ? this.muya.options.footnote : false,
+      isGitlabCompatibilityEnabled: this.muya ? this.muya.options.isGitlabCompatibilityEnabled : false,
       highlight (code, lang) {
         // Language may be undefined (GH#591)
         if (!lang) {
diff --git a/src/muya/lib/utils/exportMarkdown.js b/src/muya/lib/utils/exportMarkdown.js
index da4453985..f6e63b693 100644
--- a/src/muya/lib/utils/exportMarkdown.js
+++ b/src/muya/lib/utils/exportMarkdown.js
@@ -10,11 +10,12 @@
  */
 
 class ExportMarkdown {
-  constructor (blocks, listIndentation = 1) {
+  constructor (blocks, listIndentation = 1, isGitlabCompatibilityEnabled = false) {
     this.blocks = blocks
     this.listType = [] // 'ul' or 'ol'
     // helper to translate the first tight item in a nested list
     this.isLooseParentList = true
+    this.isGitlabCompatibilityEnabled = !!isGitlabCompatibilityEnabled
 
     // set and validate settings
     this.listIndentation = 'number'
@@ -229,12 +230,20 @@ class ExportMarkdown {
   }
 
   normalizeMultipleMath (block, /* figure */ indent) {
+    const { isGitlabCompatibilityEnabled } = this
+    let startToken = '$$'
+    let endToken = '$$'
+    if (isGitlabCompatibilityEnabled && block.mathStyle === 'gitlab') {
+      startToken = '```math'
+      endToken = '```'
+    }
+
     const result = []
-    result.push(`${indent}$$\n`)
+    result.push(`${indent}${startToken}\n`)
     for (const line of block.children[0].children[0].children) {
       result.push(`${indent}${line.text}\n`)
     }
-    result.push(`${indent}$$\n`)
+    result.push(`${indent}${endToken}\n`)
     return result.join('')
   }
 
diff --git a/src/muya/lib/utils/importMarkdown.js b/src/muya/lib/utils/importMarkdown.js
index bb632b756..254be1991 100644
--- a/src/muya/lib/utils/importMarkdown.js
+++ b/src/muya/lib/utils/importMarkdown.js
@@ -77,9 +77,19 @@ const importRegister = ContentState => {
       nextSibling: null,
       children: []
     }
-
-    const { trimUnnecessaryCodeBlockEmptyLines, footnote } = this.muya.options
-    const tokens = new Lexer({ disableInline: true, footnote }).lex(markdown)
+    const {
+      footnote,
+      isGitlabCompatibilityEnabled,
+      superSubScript,
+      trimUnnecessaryCodeBlockEmptyLines
+    } = this.muya.options
+
+    const tokens = new Lexer({
+      disableInline: true,
+      footnote,
+      isGitlabCompatibilityEnabled,
+      superSubScript
+    }).lex(markdown)
 
     let token
     let block
@@ -152,7 +162,7 @@ const importRegister = ContentState => {
 
         case 'multiplemath': {
           value = token.text
-          block = this.createContainerBlock(token.type, value)
+          block = this.createContainerBlock(token.type, value, token.mathStyle)
           this.appendChild(parentList[0], block)
           break
         }
@@ -457,8 +467,8 @@ const importRegister = ContentState => {
       focusBlock.text = focusText.substring(0, focus.offset) + CURSOR_FOCUS_DNA + focusText.substring(focus.offset)
     }
 
-    const listIndentation = this.listIndentation
-    const markdown = new ExportMarkdown(blocks, listIndentation).generate()
+    const { isGitlabCompatibilityEnabled, listIndentation } = this
+    const markdown = new ExportMarkdown(blocks, listIndentation, isGitlabCompatibilityEnabled).generate()
     const cursor = markdown.split('\n').reduce((acc, line, index) => {
       const ach = line.indexOf(CURSOR_ANCHOR_DNA)
       const fch = line.indexOf(CURSOR_FOCUS_DNA)
diff --git a/src/renderer/components/editorWithTabs/editor.vue b/src/renderer/components/editorWithTabs/editor.vue
index 68d28ae08..18d17fd84 100644
--- a/src/renderer/components/editorWithTabs/editor.vue
+++ b/src/renderer/components/editorWithTabs/editor.vue
@@ -140,6 +140,7 @@ export default {
       frontmatterType: state => state.preferences.frontmatterType,
       superSubScript: state => state.preferences.superSubScript,
       footnote: state => state.preferences.footnote,
+      isGitlabCompatibilityEnabled: state => state.preferences.isGitlabCompatibilityEnabled,
       lineHeight: state => state.preferences.lineHeight,
       fontSize: state => state.preferences.fontSize,
       codeFontSize: state => state.preferences.codeFontSize,
@@ -284,6 +285,13 @@ export default {
       }
     },
 
+    isGitlabCompatibilityEnabled: function (value, oldValue) {
+      const { editor } = this
+      if (value !== oldValue && editor) {
+        editor.setOptions({ isGitlabCompatibilityEnabled: value }, true)
+      }
+    },
+
     hideQuickInsertHint: function (value, oldValue) {
       const { editor } = this
       if (value !== oldValue && editor) {
@@ -517,6 +525,7 @@ export default {
         frontmatterType,
         superSubScript,
         footnote,
+        isGitlabCompatibilityEnabled,
         hideQuickInsertHint,
         editorLineWidth,
         theme,
@@ -564,6 +573,7 @@ export default {
         frontmatterType,
         superSubScript,
         footnote,
+        isGitlabCompatibilityEnabled,
         hideQuickInsertHint,
         hideLinkPopup,
         autoCheck,
diff --git a/src/renderer/prefComponents/markdown/index.vue b/src/renderer/prefComponents/markdown/index.vue
index 572bfbe13..cd810aefb 100644
--- a/src/renderer/prefComponents/markdown/index.vue
+++ b/src/renderer/prefComponents/markdown/index.vue
@@ -61,6 +61,13 @@
       more="https://pandoc.org/MANUAL.html#footnotes"
     ></bool>
     <separator></separator>
+    <h5>Compatibility</h5>
+    <bool
+      description="Enable GitLab compatibility mode."
+      :bool="isGitlabCompatibilityEnabled"
+      :onChange="value => onSelectChange('isGitlabCompatibilityEnabled', value)"
+    ></bool>
+    <separator></separator>
     <h5>Diagram theme</h5>
     <cus-select
       description="Sequence diagram theme"
@@ -114,6 +121,7 @@ export default {
       frontmatterType: state => state.preferences.frontmatterType,
       superSubScript: state => state.preferences.superSubScript,
       footnote: state => state.preferences.footnote,
+      isGitlabCompatibilityEnabled: state => state.preferences.isGitlabCompatibilityEnabled,
       sequenceTheme: state => state.preferences.sequenceTheme
     })
   },
diff --git a/src/renderer/store/preferences.js b/src/renderer/store/preferences.js
index c2b23e17f..2c0e13b6c 100644
--- a/src/renderer/store/preferences.js
+++ b/src/renderer/store/preferences.js
@@ -47,6 +47,7 @@ const state = {
   frontmatterType: '-',
   superSubScript: false,
   footnote: false,
+  isGitlabCompatibilityEnabled: false,
   sequenceTheme: 'hand',
 
   theme: 'light',
diff --git a/static/preference.json b/static/preference.json
index 019de8912..5f687534e 100644
--- a/static/preference.json
+++ b/static/preference.json
@@ -43,6 +43,7 @@
   "frontmatterType": "-",
   "superSubScript": false,
   "footnote": false,
+  "isGitlabCompatibilityEnabled": false,
   "sequenceTheme": "hand",
 
   "theme": "light",