# encoding: utf-8
require 'fedux_org_stdlib/require_files'
require_library %w{ erubis forwardable active_support/core_ext/string/strip active_support/core_ext/object/blank }

require 'fedux_org_stdlib/version_management/rubygem_version_file_parser'
require 'fedux_org_stdlib/version_management/version_builder'
require 'fedux_org_stdlib/version_management/library_builder'
require 'fedux_org_stdlib/version_management/exceptions'

module FeduxOrgStdlib
  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
            # encoding: utf-8
            # <%= @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