module Stastic::Generator
  module Jekyll
    extend self

    def desc
      "Jekyll Generator"
    end

    def detect
      FileTest.exists?('_config.yml') ||
      (FileTest.exists?('_site') && File.directory?('_site'))
    end

    def site_root
      Stastic::Config.site_root || "_site"
    end

    def build
      verify_gem
      system("jekyll")
    end

    def package
      Stastic::Generator.package(site_root)
    end

    def preview
      verify_gem
      system("jekyll --server")
    end

    private

      def gem_installed?
        begin
          gem "jekyll"
          true
        rescue LoadError
          false
        end
      end

      def verify_gem
        if !gem_installed?
          puts install_instructions
          exit
        end
      end

      def install_instructions
        <<-EOF
The Jekyll Gem can not be found on your GEM_PATH.
GEM_PATH=#{ENV['GEM_PATH']}

To Install Jekyll:
------------------

  sudo gem install jekyll

        EOF
      end 

      def jekyll_detection_instructions
        <<-EOF
A Jekyll Project was not detected in #{Dir.pwd}

Stastic looks of _config.yml or _site to detect Jekyll.

        EOF
      end
  end
end