module Assetify

  class DSL
    attr_reader :assets

    #
    # Makes a pkg, a gz/tar/zip asset/
    #
    # pkg :foo, "http://to.tgz" do
    # end
    #
    def pkg name, url, opts = {}, &block
      @pkg = Pkg.new name, url
      if block_given?
        set_namespace name unless opts[:shallow]
        instance_exec &block
      else
        @pkg.unpack_all
      end
      assets
    ensure
      @ns = @pkg = nil
    end

    #
    # Makes a group, a namespace for the assets.
    #
    # group :foo do
    # end
    #
    def group name, &block
      set_namespace name
      instance_exec &block
      @ns = nil
      assets
    ensure
      @ns = nil
    end

    #
    # Makes assets out of the entire directory
    #
    # pkg :foo do
    #   dir "images/*"
    #   dir "images/*jpg"
    # end
    #
    def dir regex, params = {}
      to = params[:to]
      if @pkg
        @pkg.get(regex).each do |path, data|
          next if path =~ /\/$/ # dont let dirs get in... ugly
          ext, *name = path.split(".").reverse
          name = name.reverse.join(".").split("/").last
          create_asset(ext, name, path, nil, { :to => to } )
        end
      end
    end

    #
    # Parse the assets.
    #
    # js "foo", "http://foo.com"
    # js "foo", "http://foo.com", :to => "/other/place"
    #
    def method_missing method, name, uri, *params
      params, ver = params.partition { |param| param.is_a?(Hash) }
      opts = {}
      params.each { |hsh| opts.merge! hsh }
      ver = ver[0]
      create_asset(method.to_sym, name, uri, ver, opts)
    end

    #
    # Global command, detects the filetype
    #
    #    a "jquery", "http://...jquery.js"
    #
    def a name, url, *params
      extension = url.split(".").last
      send(extension, name, url)
    end
    alias :asset :a

    #
    # Creates Assetfile assets path setters
    #
    # javascript "new/path"
    # ...
    Assetify::ASSETS.each do |asset|
      define_method asset do |path|
        Opt[asset] = path
      end
    end

    private

    #
    # Helper to create asset with correct options
    #
    def create_asset(ext, name, path, ver, opts = {})
      opts.merge! ({pkg: @pkg, ns: @ns })
      @assets ||= []
      @assets << Asset.new(ext, name, path, ver, opts)
    end


    def set_namespace name
      @ns = @ns.nil? ? name : "#{@ns}/#{name}"
    end

    #
    # DSL.parse()
    #
    def self.parse chunk
      # puts "Assetify - Error Parsing 'Assetfile'."
      # Instance eval with 2nd, 3rd args to the rescue
      new.instance_eval(chunk, "Assetfile", 1)
    end

  end

end