class Quivjek

# File lib/quivjek.rb, line 21
def initialize( site )
  self.showhelp('The qivjek plugin requires notebook_dir be set in your _config.yml file') unless site.config.key?('notebook_dir')

  @site         = site
  @jekyll_dir   = site.source
  @notebook_dir = site.config['notebook_dir']
  @post_dir     = File.join(@jekyll_dir, "/_posts/quiver")
  @img_dir      = File.join(@jekyll_dir, "/images/q")

end

# File lib/quivjek.rb, line 54
def copy_note(note_dir)
  # Load the quiver note meta.json file.
  metajson = load_meta_json(note_dir)

  # Skip this note if tagged with draft
  metajson["tags"].each do |tag|
    return if tag == 'draft'
  end

  # Copy the notes images to the jekyll directory
  imagepath    = File.join(note_dir, "resources")
  self.copy_note_images(imagepath) if File.exist?(imagepath)

  # Load the quiver note content.json file and merge its cells.
  contentjson = load_content_json(note_dir)
  content     = self.merge_cells(contentjson, '')

  # Parse out optional frontmatter from the content
  parsed      = FrontMatterParser::Parser.new(:md).call(content)
  fm          = parsed.front_matter
  content     = parsed.content

  # Set some default frontmatter and combine with content
  fm = set_default_frontmatter(fm, metajson)
  output = fm.to_yaml + "---\n" + content

  # Write the markdown file to the jekyll dir
  filename    = self.get_filename(fm)
  File.open(File.join(@post_dir, filename), "w") { |file| file.write(output) }

end

# File lib/quivjek.rb, line 102
def copy_note_images(imagepath)

  # copy all images from the note's resources dir to the jekyll images/q dir
  Dir.foreach(imagepath) do |item|
    next if item == '.' or item == '..'
    FileUtils.cp(File.join(imagepath, item), @img_dir)
  end

end

# File lib/quivjek.rb, line 112
def get_filename(fm)
  title = fm["title"].gsub(" ", "-").downcase
  date = DateTime.parse(fm["date"])

  day = "%02d" % date.day
  month = "%02d" % date.month
  year = date.year

  return "#{year}-#{month}-#{day}-#{title}.md"
end

# File lib/quivjek.rb, line 94
def load_content_json(dir)
  contentpath = File.join(dir, "content.json")
  showhelp(contentpath + "content.json doesn't exist") unless File.exist? contentpath
  contentjson = JSON.parse(File.read(contentpath))

  return contentjson
end

# File lib/quivjek.rb, line 86
def load_meta_json(dir)
  metapath    = File.join(dir, "meta.json")
  showhelp("meta.json doesn't exist") unless File.exist? metapath
  metajson = JSON.parse(File.read(metapath))

  return metajson
end

# File lib/quivjek.rb, line 32
def load_posts_from_quiver()

  Dir.mkdir(@post_dir) unless File.exists?(@post_dir)
  Dir.mkdir(@img_dir) unless File.exists?(@img_dir)

  # Clear out the _posts/quiver and images/q directories in case any posts or images have been renamed
  FileUtils.rm_rf Dir.glob(@post_dir + '/*')
  FileUtils.rm_rf Dir.glob(@img_dir + '/*')

  # Pass the path of each .qvnote to the copy_post method
  Dir.foreach(@notebook_dir) do |item|
    next if item == '.' or item == '..' or item == 'meta.json' or item == '.keep'
    self.copy_note(File.join(@notebook_dir, item))
  end

end

# File lib/quivjek.rb, line 139
def merge_cells(contentjson, output)
  contentjson["cells"].each do |cell|
    case cell["type"]
      when "code"
        output << "{% highlight #{cell["language"]} %}\n"
        output << "#{cell["data"]}\n"
        output << "{% endhighlight %}\n"
      when "markdown"

        c = cell["data"]

        # Scan the markdown cell for images
        images = c.scan(/!\[(.*)\]\(quiver-image-url\/(.*)\)/)
        images.each do |image|

          # Modify the image source to point to the alt tag in the images/q/ folder
          c = c.gsub(image[1], image[0])

          # Rename the image (since the image has already been copied from the qvnote folder)
          File.rename(File.join(@img_dir, image[1]), File.join(@img_dir, image[0]))
        end

        output << "#{c.gsub("quiver-image-url", "/images/q")}\n"
      else
        showhelp(frontmatter_title + " :all cells must be code or markdown types")
    end

    output << "\n"

    return output
  end
end

# File lib/quivjek.rb, line 123
def set_default_frontmatter(fm, metajson)

  # If certain frontmatter is missing default to quiver metadata
  fm['title'] = metajson['title']      unless fm['title']

  if !fm.key?("date")
    date = DateTime.strptime(metajson["created_at"].to_s, "%s")
    fm['date'] = date.strftime('%Y-%m-%d')
  end

  fm['tags']  = metajson["tags"]

  return fm

end

# File lib/quivjek.rb, line 49
def showhelp(message)
  puts message.red + "\n"
  exit
end