# multimarkdown renderer for jekyll
#
# adapted from: http://git.io/9-RWUg


module Jekyll
  require 'multimarkdown'

  class MultimarkdownConverter < Converter
    safe false
    priority :low

    def matches(ext)
      ext =~ /multimarkdown/i
    end

    def output_ext(ext)
      ".html"
    end

    def convert(content)
      #puts MultiMarkdown.new(knit(content)).to_html
      MultiMarkdown.new(content).to_html
    end

  end
end

require 'tempfile'

module Jekyll

  require_relative 'post_filters'

  # A filter to pass mmd files through knitr
  class KnitrPost < PostFilter

    KNITR_PATH = File.join(File.dirname(__FILE__), "knit_markdown.R")

    unless File.exists?(KNITR_PATH) and File.executable?(KNITR_PATH)
      throw "knit_markdown.R is not found and executable"
    end

    def pre_render(post)
      if post.is_post?
        if post.ext == '.multimarkdown'
          postname = post.name[0..-post.ext.length-1]
          post.content = knit(postname, post.content)
        end
      end
    end

    # runs everything through knitr
    def knit(name, content)
      #knit_content, status = Open3.capture2(KNITR_PATH, name,
                                            #:stdin_data=>content)
      # set up the tempfiles to do the translation
      src_file = Tempfile.new('srcfile')
      src_file.write(content)
      src_file.close
      dst_file = Tempfile.new('dstfile')
      dst_file.close

      # execute!
      `#{KNITR_PATH} #{name} #{src_file.path} #{dst_file.path}`

      # read back in the processed file
      dst_file.open
      knit_content = dst_file.read
      dst_file.close

      # remove the files
      src_file.unlink
      dst_file.unlink

      # This is a hack to get the double backslashes in latex math
      # working with liquid templates
      knit_content.gsub(/\\\\$/){"\\\\\\\\"}
    end
  end
end

#!/usr/bin/Rscript

library(knitr)

args <- commandArgs(trailingOnly=TRUE)

# the file name generating this R code
# needed so we can put separate cache and image links
post.name <- args[1]
store.prefix <- if(is.na(post.name)) "" else post.name
cache.path <- paste('cache', store.prefix, "", sep='/')
image.save.path <- paste('source/images/knitr', store.prefix, "", sep='/')
image.load.path <- paste('/images/knitr', store.prefix, "", sep='/')
opts_chunk$set(cache.path=cache.path)
opts_chunk$set(fig.path=image.save.path)

# also get the input and output files
in.file <- if(is.na(args[2])) file("stdin") else args[2]
out.file <- if(is.na(args[3])) stdout() else args[3]

pic.sample <- function() {
  sample(1000,1)
}

# hook to force marked to reload output images
# uses a random query element on the image
# also supports creating animations
query_plot_hook <- function(x, options) {
  # pull out all the relevant plot options
  animate <- options$fig.show == 'animate'
  fig.num <- options$fig.num
  fig.cur <- options$fig.cur
  if(is.null(fig.cur)) fig.cur <- 0

  # Don't print out intermediate plots if we're animating
  if(animate && fig.cur < fig.num) return('')

  base <- opts_knit$get('base.url')
  if (is.null(base)) base <- ''
  # adjust the base for the base path
  filename <- paste(image.load.path, basename(paste(x,collapse='.')), sep='')
  if(options$fig.show == 'animate') {
    # set up the ffmpeg run
    ffmpeg.opts <- options$aniopts
    fig.fname <- paste(sub(paste(fig.num, '$',sep=''), '', x[1]), "%d.png", sep="")
    mov.fname <- paste(sub(paste(fig.num, '$',sep=''), '', x[1]), ".mp4", sep="")
    mov.linkname <- paste(image.load.path, basename(mov.fname), sep='')
    if(is.na(ffmpeg.opts)) ffmpeg.opts <- NULL

    ffmpeg.cmd <- paste("ffmpeg", "-y", "-r", 1/options$interval,
                        "-i", fig.fname, mov.fname)
    system(ffmpeg.cmd, ignore.stdout=TRUE)

    # figure out the options for the movie itself
    mov.opts <- strsplit(options$aniopts, ';')[[1]]
    opt.str <- paste(
      " ",
      if(!is.null(options$out.width)) sprintf('width=%s', options$out.width),
      if(!is.null(options$out.height)) sprintf('height=%s', options$out.height),
      if('controls' %in% mov.opts) 'controls="controls"',
      if('loop' %in% mov.opts) 'loop="loop"')
    sprintf('<video %s><source src="%s?%d" type="video/mp4" />video of chunk %s</video>', opt.str, mov.linkname, pic.sample(), options$label)
  } else {
    sprintf('![plot of chunk %s](%s%s?%d) ',
            options$label, base, filename, pic.sample())
  }
}

# highlight R code on output
code_hook <- function(x, options) {
  print(options)
  prefix <- sprintf("\n\n{{ "{%%" }} codeblock %s lang:r %%}", options$label)
  suffix <- "{{ "{%" }} endcodeblock %}\n\n"
  paste(prefix, x, suffix, sep="\n")
}

# hack render_markdown so it doesn't override my custom hook
render_custom <- function() {
  render_markdown(strict=TRUE)
  knit_hooks$set(plot=query_plot_hook,
                 source=code_hook)
}

# need to read everything through stdin and stdout
pat_html()
render_custom()
opts_knit$set(progress=FALSE)
#opts_knit$set(dev='png')
opts_knit$set(out.format='custom')
opts_knit$set(input.dir=getwd())
knit(in.file, out.file)