module Jekyll

$minified_filename = ''

# use this as a workaround for getting cleaned up

# reference: https://gist.github.com/920651

class JsMinifyFile < StaticFile

def write(dest)

# do nothing

end

end

# minify js files

class JsMinifyGenerator < Generator

safe true

def generate(site)

config = Jekyll::JsMinifyGenerator.get_config

files_to_minify = config['files'] || get_js_files(site, config['js_source'])

last_modified = files_to_minify.reduce( Time.at(0) ) do |latest,filepath|

modified = File.mtime(filepath)

modified > latest ? modified : latest

end

# reset the minified filename

$minified_filename = last_modified.strftime("%Y%m%d%H%M") + '.min.js'

output_dir = File.join(site.config['destination'], config['js_destination'])

output_file = File.join(output_dir, $minified_filename)

# need to create destination dir if it doesn't exist

FileUtils.mkdir_p(output_dir)

minify_js(files_to_minify, output_file, site.source)

site.static_files << JsMinifyFile.new(site, site.source, config['js_destination'], $minified_filename)

end

# read the js dir for the js files to compile

def get_js_files(site, relative_dir)

# not sure if we need to do this, but keep track of the current dir

pwd = Dir.pwd

Dir.chdir(File.join(site.config['source'], relative_dir))

# read js files

js_files = Dir.glob('*.js').map{ |f| File.join(relative_dir, f) }

Dir.chdir(pwd)

return js_files

end

def minify_js(js_files, output_file, source)

js_files = js_files.join(' ')

juice_cmd = "juicer merge -s -f #{js_files} -o #{output_file} -d #{source}"

puts juice_cmd

if system(juice_cmd) == false

raise 'Juicer failed while minifying javascript.'

end

end

# Load configuration from JsMinify.yml

def self.get_config

if @config == nil

@config = {

'js_source' => 'javascripts', # relative to the route

'js_destination' => '/javascripts' # relative to site.config['destination']

}

config = YAML.load_file('JsMinify.yml') rescue nil

if config.is_a?(Hash)

@config = @config.merge(config)

end

end

return @config

end

end

class JsMinifyLinkTag < Liquid::Tag

def initialize(tag_name, text, tokens)

super

end

def render(context)

config = Jekyll::JsMinifyGenerator.get_config

File.join(config['js_destination'], $minified_filename)

end

end

end

Liquid::Template.register_tag('minified_js_file', Jekyll::JsMinifyLinkTag)