[WIP] beautify code blocks in markdown

package.json

@@ -171,6 +171,7 @@
     "event-kit": "^2.3.0",
     "expand-home-dir": "0.0.3",
     "extend": "^3.0.1",
+    "gfm-code-blocks": "^1.0.0",
     "gherkin": "^2.12.2",
     "handlebars": "^4.0.10",
     "js-beautify": "^1.6.14",

src/beautifier.coffee

@@ -0,0 +1,2 @@
+Beautifiers = require("./beautifiers")
+module.exports = new Beautifiers()

src/beautifiers/markdown-blocks/index.coffee

@@ -0,0 +1,52 @@
+module.exports = (text, logger) ->
+  return new @Promise((resolve, reject) ->
+    extractCodeBlocks = require 'gfm-code-blocks'
+    beautifier = require '../../beautifier'
+    cleanMarkdown = text
+    codeBlocks = extractCodeBlocks(cleanMarkdown)
+    beautifyBlockPromises = []
+    for codeBlock in codeBlocks
+      codeLanguage = codeBlock.lang.match(/^[\w\d]+/)?[0]
+      logger.verbose "Beautify code block #{codeLanguage}"
+      if !codeLanguage
+        beautifyBlockPromises.push(null)
+      else
+        beautifyBlockPromises.push(new @Promise((resolve, reject) ->
+          linesInBlock = codeBlock.block.split('\n')
+          codePrefix = linesInBlock[0]
+          codeSuffix = linesInBlock[linesInBlock.length - 1]
+          code = linesInBlock.slice(1, linesInBlock.length - 1).join('\n')
+          filePath = 'fakepath.' + codeLanguage
+          grammar = atom.grammars.selectGrammar(filePath, code)
+          grammarName = grammar.name
+          allOptions = beautifier.getOptionsForPath(filePath)
+          originalStart = codeBlock.start
+          originalEnd = codeBlock.end
+          if grammarName == 'Null Grammar'
+            resolve(null)
+          else
+            beautifier.beautify(code, allOptions, grammarName, filePath)
+              .then((cleanCode) =>
+                  if cleanCode
+                    resolve({
+                      block: [codePrefix, cleanCode, codeSuffix].join('\n')
+                      originalStart: originalStart
+                      originalEnd: originalEnd
+                    })
+                  else
+                    resolve(null)
+              )
+              .catch((e) =>
+                logger.verbose "error while beautifying #{code.substring(0, 200)}...", e
+                resolve(null)
+              )
+          ))
+    Promise.all(beautifyBlockPromises).then((cleanCodeBlocks) =>
+      cleanCodeBlocks.reverse((b) -> !!b).forEach((codeBlock) =>
+        if (codeBlock)
+          cleanMarkdown = cleanMarkdown.substring(0, codeBlock.originalStart) + codeBlock.block + cleanMarkdown.substring(codeBlock.originalEnd)
+      )
+    ).then(->
+      resolve(cleanMarkdown)
+    )
+  )

src/beautifiers/remark.coffee

@@ -1,5 +1,6 @@
 "use strict"
 Beautifier = require('./beautifier')
+beautifyCodeBlocks = require './markdown-blocks'
 
 module.exports = class Remark extends Beautifier
   name: "Remark"
@@ -28,16 +29,23 @@ module.exports = class Remark extends Beautifier
       strong: true
       emphasis: true
       position: true
+      beautifyCodeBlocks: true
     }
     Markdown: true
   }
 
   beautify: (text, language, options) ->
+    logger = @logger;
     return new @Promise((resolve, reject) ->
       try
         remark = require 'remark'
         cleanMarkdown = remark().process(text, options).toString()
-        resolve cleanMarkdown
+        if options.beautifyCodeBlocks
+          beautifyCodeBlocks(cleanMarkdown, logger)
+            .then((t) => resolve(t))
+            .catch((e) => reject(e))
+        else
+          resolve cleanMarkdown
       catch err
         @error("Remark error: #{err}")
         reject(err)

src/beautifiers/tidy-markdown.coffee

@@ -1,16 +1,26 @@
 "use strict"
 Beautifier = require('./beautifier')
+beautifyCodeBlocks = require './markdown-blocks'
 
 module.exports = class TidyMarkdown extends Beautifier
   name: "Tidy Markdown"
   link: "https://github.com/slang800/tidy-markdown"
   options: {
-    Markdown: false
+    _: {
+      beautifyCodeBlocks: true
+    }
+    Markdown: true
   }
 
   beautify: (text, language, options) ->
+    logger = @logger;
     return new @Promise((resolve, reject) ->
       tidyMarkdown = require 'tidy-markdown'
-      cleanMarkdown = tidyMarkdown(text)
-      resolve(cleanMarkdown)
+      cleanMarkdown = tidyMarkdown(text, logger)
+      if options.beautifyCodeBlocks
+        beautifyCodeBlocks(cleanMarkdown)
+          .then((t) => resolve(t))
+          .catch((e) => reject(e))
+      else
+        resolve(cleanMarkdown)
     )

src/beautify.coffee

@@ -1,13 +1,12 @@
 # global atom
 "use strict"
 pkg = require('../package')
+beautifier = require('./beautifier')
 
 # Dependencies
 plugin = module.exports
 {CompositeDisposable} = require 'event-kit'
 _ = require("lodash")
-Beautifiers = require("./beautifiers")
-beautifier = new Beautifiers()
 defaultLanguageOptions = beautifier.options
 logger = require('./logger')(__filename)
 Promise = require('bluebird')

src/languages/markdown.coffee

@@ -33,4 +33,8 @@ module.exports = {
       type: 'boolean'
       default: false
       description: 'Allows and disallows several constructs.'
+    beautifyCodeBlocks:
+      type: 'boolean'
+      default: false
+      description: 'Look for fenced code blocks (e.g. ```js) and beautify them using corresponding language rules'
 }

src/options.json

@@ -4686,6 +4686,21 @@
           "namespace": "markdown"
         }
       },
+      "beautifyCodeBlocks": {
+        "type": "boolean",
+        "default": false,
+        "description": "Look for fenced code blocks (e.g. ```js) and beautify them using corresponding language rules (Supported by Remark, Tidy Markdown)",
+        "title": "Beautify Code Blocks",
+        "beautifiers": [
+          "Remark",
+          "Tidy Markdown"
+        ],
+        "key": "beautifyCodeBlocks",
+        "language": {
+          "name": "Markdown",
+          "namespace": "markdown"
+        }
+      },
       "disabled": {
         "title": "Disable Beautifying Language",
         "order": -3,