sass.gradle

import javax.script.ScriptEngineManager

task compileSass {

    ext.inputDir = project.file('src/main/sass')
    ext.outputDir = new File(project.buildDir, 'sass')
    ext.cacheLocation = new File(project.buildDir, 'sass-cache')

    // see http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#output_style for options
    ext.outputStyle = "expanded"


    doLast {

        def driverScript = '''
            require 'rubygems'
            require 'sass'

            Sass::Engine::DEFAULT_OPTIONS[:load_paths].tap do |load_paths|
                load_paths << $srcDir.path
            end

            #module Sass::Script::Functions
            #    def getDomain(string)
            #        Sass::Script::String.new("aas");
            #    end
            #    declare :getDomain, :args => [:string]
            #end

            $mappings.each do |src, dst|

                if $outputStyle == "compressed"
                    puts "using compressed stylesheets"
                    engine = Sass::Engine.for_file(src, {:cache_location => $cacheLocation, :style => :compressed})
                elsif $outputStyle == "expanded"
                    puts "using expanded stylesheets"
                    engine = Sass::Engine.for_file(src, {:cache_location => $cacheLocation, :style => :expanded})
                else
                    puts "using nested stylesheets"
                    engine = Sass::Engine.for_file(src, {:cache_location => $cacheLocation, :style => :nested})
                end

                #engine = Sass::Engine.for_file(src, {:cache_location => $cacheLocation, :style => style})
                css = engine.render
                File.open(dst, 'w') {|f| f.write(css) }
                puts "#{src} -> #{dst}"

            end
        '''

        def mappings = new TreeMap()

        inputDir.traverse(preDir: {if (it.isHidden()) return FileVisitResult.SKIP_SUBTREE}) { inputFile ->
            if (inputFile.isFile() && (inputFile.name.endsWith('.sass') || inputFile.name.endsWith('.scss'))) {
                def outputFile = new File(outputDir, relativePath(inputDir, inputFile) + '.css')
                outputFile.parentFile.mkdirs()
                mappings.put(inputFile.path, outputFile.path)
            }
        }

        def engine = new ScriptEngineManager().getEngineByName("jruby")
        engine.put("cacheLocation", cacheLocation.path)
        engine.put("mappings", mappings)
        engine.put("srcDir",inputDir)
        engine.put("outputStyle",outputStyle)
        engine.eval(driverScript)
    }
}

String relativePath(File root, File descendant) {
    def rootPath = root.absolutePath
    def descendantPath = descendant.absolutePath
    assert descendantPath.startsWith(rootPath)
    return descendantPath.substring(rootPath.length() + 1)
}

buildscript {
    repositories {
        mavenLocal()
        mavenCentral()
    }
    dependencies {
        classpath group: 'org.jruby', name: 'jruby-complete', version: '1.6.7.2'
        classpath group: 'me.n4u.sass', name: 'sass-gems', version: '3.2.1'
    }
}