begin
  require 'active_support/core_ext/string/strip'
rescue LoadError
  $stderr.puts 'You need to install the "activesupport"-gem to make that rake task work.'
  exit 1 
end

begin
  require 'erubis'
rescue LoadError
  $stderr.puts 'You need to install the "erubis"-gem to make that rake task work.'
  exit 1 
end

require 'forwardable'

require_relative 'rubygem_version_file_parser'
require_relative 'version_builder'
require_relative 'library_builder'

module FeduxOrg
  module Stdlib
    module VersionManagement

      class RubygemVersionFile
        extend Forwardable
        def_delegators :@version, :bump

        def initialize( version, library )
          @version = version
          @library = library
        end

        def version
          @version.to_s
        end

        def version=(v)
          @version.update( v )
        end

        def write(path)
          File.write( path, to_s )
        end
        
        def self.read( path, parser=RubygemVersionFileParser.new,version_builder=VersionBuilder.new, library_builder=LibraryBuilder.new )
          parser.parse( path )

          version = version_builder.build_from( parser.version )
          library = library_builder.build_from( parser.modules )

          RubygemVersionFile.new( version, library )
        end

        def to_s
          klass = Class.new do 
            attr_reader :version, :library

            def initialize( version, module_names )
              @version      = version
              @module_names = module_names
            end

            def prefix(n)
              ' ' * 2 * n
            end
          end

          Erubis::Eruby.new(template).evaluate( klass.new( @version, @library.module_names ) )
        end

        private

        def template
          <<-EOF.strip_heredoc
            #main <%= @module_names.first %>
            <% @module_names.each_with_index do |m,i| -%>
            <%= prefix( i ) %>module <%= m %>
            <% end -%>
            <%= prefix( @module_names.size ) %>VERSION = '<%= @version %>'
            <% ( @module_names.size - 1 ).downto(0) do |i| -%>
            <%= prefix( i ) %>end
            <% end -%>
          EOF
        end

      end
    end
  end
end