# Slightly modified from https://raw.githubusercontent.com/GSI/jekyll_image_encode/master/lib/jekyll_image_encode.rb
require "mimemagic"

module ImageEncodeCache
  @@cached_base64_codes = Hash.new
  
  def cached_base64_codes
    @@cached_base64_codes
  end
  
  def cached_base64_codes= val
    @@cached_base64_codes = val
  end
end

module Jekyll
  module Tags
    class ImageEncodeTag < Liquid::Tag
      include ImageEncodeCache
          
      def initialize(tag_name, url, options)
        @url = url.strip
	@real_url = url
	uri = URI.parse(url)
	@isfile = uri.scheme != 'http' and uri.scheme != 'https'
        super
      end

      def render(context)
        if @isfile
          base_path = context.registers[:site].instance_variable_get("@source")
	  @url = File.join(base_path, @url)
        end
        encode_image
      end
      
      def encode_image
        require 'open-uri'
        require 'base64'
        
        encoded_image = ''
        image_handle = open(@url)

        if self.cached_base64_codes.has_key? @url
          encoded_image = self.cached_base64_codes[@url]
        else
          # p "Caching #{@url} as local base64 string ..."
          encoded_image = Base64.strict_encode64(image_handle.read)
          self.cached_base64_codes.merge!(@url => encoded_image)
        end
        
        data_type = MimeMagic.by_magic(image_handle)
        image_handle.close

        "data:#{data_type};base64, #{encoded_image}"
      end
    end
  end
end

Liquid::Template.register_tag('base64', Jekyll::Tags::ImageEncodeTag)