markdowntomla.coffee

_           = require 'underscore'
md          = require('markdown').markdown
coffee      = require 'coffee-script'
PDFDocument = require 'pdfkit'

Array::first ?= -> @[0]

Array::last ?= -> @[@length - 1]

# process.chdir(__dirname)

# style definitions for markdown
styles =
  default:
    font: 'Times-Roman'
    fontSize: 12
    lineGap: 24
    align: 'left'
  meta:
    indent: 0
  title:
    align: 'center'
  para:
    indent: 72/2
  blockquote:
    indent: 0
    marginLeft: 72
    color: 'red'
    font: 'Times-Italic'
  em:
    font: 'Times-Italic'
  strong:
    font: 'Times-Bold'
  h1:
    font: 'Times-Bold'
  h2:
    font: 'Times-Italic'
  h3:
    font: 'Times-Bold'
    align: 'center'
  h4:
    font: 'Times-Italic'
    align: 'center'
  h5:
    underline: true
  citationHeader:
    align: 'center'
  citation:
    indent: -72/2
    marginLeft: 72/2

# syntax highlighting colors
# based on Github's theme
colors =
  keyword: '#cb4b16'
  atom: '#d33682'
  number: '#009999'
  def: '#2aa198'
  variable: '#108888'
  'variable-2': '#b58900'
  'variable-3': '#6c71c4'
  property: '#2aa198'
  operator: '#6c71c4'
  comment: '#999988'
  string: '#dd1144'
  'string-2': '#009926'
  meta: '#768E04'
  qualifier: '#b58900'
  builtin: '#d33682'
  bracket: '#cb4b16'
  tag: '#93a1a1'
  attribute: '#2aa198'
  header: '#586e75'
  quote: '#93a1a1'
  link: '#93a1a1'
  special: '#6c71c4'
  default: '#002b36'

codeBlocks = []
lastType = null

# This class represents a node in the markdown tree, and can render it to pdf
class Node
  constructor: (tree) ->
    # special case for text nodes
    if typeof tree is 'string'
      @type = 'text'
      @text = tree
      return

    @type = tree.shift()
    @attrs = {}

    if typeof tree[0] is 'object' and not Array.isArray tree[0]
      @attrs = tree.shift()

    switch @type
      when 'header'
        @type = 'h' + @attrs.level

      # when 'code_block'
      #   # use code mirror to syntax highlight the code block
      #   code = @content[0].text
      #   @content = []
      #   CodeMirror.runMode code, 'coffeescript', (text, style) =>
      #     color = colors[style] or colors.default
      #     opts =
      #       color: color
      #       continued: text isnt '\n'

      #     @content.push new Node ['code', opts, text]

      #   @content[@content.length - 1]?.attrs.continued = false
      #   codeBlocks.push code

      when 'img'
        # images are used to generate inline example output
        # compiles the coffeescript to JS so it can be run
        # in the render method
        @type = 'example'
        code = codeBlocks[@attrs.alt]
        @code = coffee.compile code if code
        @height = +@attrs.title or 0

    @style = _.extend({}, styles.default, styles[@type])

    # parse sub nodes
    @content = while tree.length
      child = new Node tree.shift()
      # blockquotes have an embedded paragraph; make sure the inner paragraph doesn't re-define
      # its indentation
      child.style?.indent = @style.indent if @style.indent?
      child

    # console.log "content =", @content
    # console.log "type =", @type


  # sets the styles on the document for this node
  setStyle: (doc) ->
    if @style.font
      doc.font @style.font

    if @style.fontSize
      doc.fontSize @style.fontSize

    if @style.color
      doc.fillColor @style.color
    else
      doc.fillColor 'black'

  # renders this node and its subnodes to the document
  render: (doc, continued = false) ->
    # console.log "rendering node: ", @
    if @style.marginLeft
      doc.x += @style.marginLeft

    switch @type
      when 'hr'
        doc.addPage()
      else
        # loop through subnodes and render them
        for fragment, index in @content
          if fragment.type is 'text'
            @setStyle doc

            # remove newlines unless this is code
            # unless @type is 'code'
            #   fragment.text = fragment.text.replace(/[\r\n]\s*/g, ' ')

            # console.log "rendering text. continued =", continued, 'attrs.continued =', @attrs.continued
            doc.text fragment.text, _.extend({}, @style, {continued: continued or index < @content.length - 1})
          else
            # console.log "rendering fragment #{fragment.type}"
            fragment.render doc, index < @content.length - 1 and @type isnt 'bulletlist'

          lastType = @type

    if @style.marginBottom
      doc.y += @style.marginBottom
    if @style.marginLeft
      doc.x -= @style.marginLeft

addPageNum = (doc, name) ->
  range = doc.bufferedPageRange() # => { start: 0, count: 2 }

  # todo: make more generic "draw text" function that sets the document properities based on provided styles
  doc.font styles.default.font
  for i in [range.start...range.start + range.count]
    doc.switchToPage(i)
    doc.y = 72/2
    doc.x = 72
    doc.text "#{name} #{i + 1}", _.extend({}, styles.default, {align: 'right'})

# reads and renders a markdown/literate coffeescript file to the document
render = (doc, tree) ->
  doc.font 'Times-Roman'
  doc.fontSize 12

  codeBlocks = []

  onWorksCited = false
  while tree.length
    node = new Node(tree.shift())
    # console.log "node =", node
    if node.type == "h1" && node.content?.first()?.text?.toLowerCase() == "works cited"
      onWorksCited = true
      node.style = _.extend({}, styles.default, styles.citationHeader)

    if onWorksCited && node.type == "para"
      node.style = _.extend({}, styles.default, styles.citation)

    node.render(doc)

  doc

# renders the title page of the guide
# renderTitlePage = (doc) ->
#   title = 'PDFKit Guide'
#   author = 'By Devon Govett'
#   version = 'Version ' + require('./package.json').version

#   doc.font 'fonts/AlegreyaSans-Light.ttf', 60
#   doc.y = doc.page.height / 2 - doc.currentLineHeight()
#   doc.text title, align: 'center'
#   w = doc.widthOfString(title)

#   doc.fontSize 20
#   doc.y -= 10
#   doc.text author,
#     align: 'center'
#     indent: w - doc.widthOfString(author)

#   doc.font styles.para.font, 10
#   doc.text version,
#     align: 'center'
#     indent: w - doc.widthOfString(version)

#   doc.addPage()

exports.extractMetadata = (text) ->
  body = ""
  metadata = {}

  metadata_pattern = /// ^
    ([\w.-]+) # key
    \:\       # colon
    \s*       # optional whitespace
    (.+)      # value
  $///

  for line in text.split("\n")
    if meta = line.match(metadata_pattern)
      key = meta[1]
      value = meta[2]
      metadata[key] = value
    else
      body += line + "\n"

  {metadata: metadata, body: body}

exports.createMLADocument = (body, metadata, stream) ->
  tree = md.parse body
  tree.shift() # ignore 'markdown' first element

  metadata.lastName ||= metadata.author?.split(" ").last()

  doc = new PDFDocument
    bufferPages: true

  doc.info.Title    = metadata.title
  doc.info.Author   = metadata.author
  doc.info.Creator = "markdowntomla by christian.gen.co"

  # add header
  doc.font 'Times-Roman'
  doc.fontSize 12
  doc.text(metadata.author,     _.extend({}, styles.default, styles.meta))
  doc.text(metadata.instructor, _.extend({}, styles.default, styles.meta))
  doc.text(metadata.course,     _.extend({}, styles.default, styles.meta))
  doc.text(metadata.date,       _.extend({}, styles.default, styles.meta))
  doc.text(metadata.title,      _.extend({}, styles.default, styles.title))

  doc.pipe(stream)
  render doc, tree
  addPageNum(doc, metadata.lastName)
  # doc.flushPages()
  doc.end()

# do ->
#   # command line
#   fs = require 'fs'
#   filename = "paper.md"
#   content  = fs.readFileSync(filename, 'utf8')
#   content  = extractMetadata(content)
#   body     = content.body
#   metadata = content.metadata
#   stream   = fs.createWriteStream("#{metadata.title} by #{metadata.author}.pdf")
#   createDocument(body, metadata, stream)