require 'erb'
require 'fileutils'

module GGem
  class Template

    def initialize(ggem)
      @gem = ggem
    end

    def save
      save_folder # (gem root path)
      save_folder "lib/#{@gem.ruby_name}"
      save_folder "test/support"
      save_folder "test/system"
      save_folder "test/unit"
      save_folder "log"
      save_folder "tmp"

      save_file('gitignore.erb',   '.gitignore')
      save_file('Gemfile.erb',     'Gemfile')
      save_file('gemspec.erb',     "#{@gem.name}.gemspec")
      save_file('Rakefile.erb',    'Rakefile')
      save_file('README.md.erb',   'README.md')
      save_file('LICENSE.txt.erb', 'LICENSE.txt')

      save_file('lib.rb.erb',         "lib/#{@gem.ruby_name}.rb")
      save_file('lib_version.rb.erb', "lib/#{@gem.ruby_name}/version.rb")

      save_file('test_helper.rb.erb', 'test/helper.rb')

      save_empty_file('log/.gitkeep')
      save_empty_file('tmp/.gitkeep')
    end

    def init
      cmd = "cd #{@gem.path} &&"\
            " git init && git add --all &&"\
            " git add -f log/.gitkeep && git add -f tmp/.gitkeep"
      `#{cmd}`
    end

    private

    def save_folder(relative_path=nil)
      path = File.join([@gem.path, relative_path].compact)
      FileUtils.mkdir_p(path)
    end

    def save_empty_file(relative_path)
      path = File.join(@gem.path, relative_path)
      FileUtils.touch(path)
    end

    def save_file(source, output)
      source_file = File.join(File.dirname(__FILE__), 'template_file', source)
      output_file = File.join(@gem.root_path, @gem.name, output)

      if File.exists?(source_file)
        FileUtils.mkdir_p(File.dirname(output_file))
        erb = ERB.new(File.read(source_file))
        File.open(output_file, 'w') {|f| f << erb.result(binding) }
      else
        raise ArgumentError, "the source file '#{source_file}' does not exist"
      end
    end

  end
end