module Ably
  module RSpec
    # Generate Markdown Specification from the RSpec public API tests
    #
    class MarkdownSpecFormatter
      ::RSpec::Core::Formatters.register self, :start, :close,
                                               :example_group_started, :example_group_finished,
                                               :example_passed, :example_failed, :example_pending,
                                               :dump_summary

      def initialize(output)
        @output = if documenting_rest_only?
          File.open(File.expand_path('../../../../../../SPEC.md', __FILE__), 'w')
        else
          File.open(File.expand_path('../../../SPEC.md', __FILE__), 'w')
        end

        @indent  = 0
        @passed  = 0
        @pending = 0
        @failed  = 0
      end

      def start(notification)
        puts "\n\e[33m --> Creating SPEC.md <--\e[0m\n"
        scope = if defined?(Ably::Realtime)
          'Realtime & REST'
        else
          'REST'
        end
        output.write "# Ably #{scope} Client Library #{Ably::VERSION} Specification\n"
      end

      def close(notification)
        output.close
      end

      def example_group_started(notification)
        output.write "#{indent_prefix}#{notification.group.description}\n"
        output.write "_(see #{heading_location_path(notification)})_\n" if indent == 0
        @indent += 1
      end

      def example_group_finished(notification)
        @indent -= 1
      end

      def example_passed(notification)
        unless notification.example.metadata[:api_private]
          output.write "#{indent_prefix}#{example_name_and_link(notification)}\n"
          @passed += 1
        end
      end

      def example_failed(notification)
        unless notification.example.metadata[:api_private]
          output.write "#{indent_prefix}FAILED: ~~#{example_name_and_link(notification)}~~\n"
          @failed += 1
        end
      end

      def example_pending(notification)
        unless notification.example.metadata[:api_private]
          output.write "#{indent_prefix}PENDING: *#{example_name_and_link(notification)}*\n"
          @pending += 1
        end
      end

      def dump_summary(notification)
        output.write <<-EOF.gsub('        ', '')

          -------

          ## Test summary

          * Passing tests: #{@passed}
          * Pending tests: #{@pending}
          * Failing tests: #{@failed}
        EOF
      end

      private
      attr_reader :output, :indent

      def documenting_rest_only?
        File.exists?(File.expand_path('../../../../../../ably-rest.gemspec', __FILE__))
      end

      def example_name_and_link(notification)
        "[#{notification.example.metadata[:description]}](#{path_for(notification.example.location).gsub(/\:(\d+)/, '#L\1')})"
      end

      def heading_location_path(notification)
        "[#{notification.group.location.gsub(/\:(\d+)/, '').gsub(%r{^\.\/}, '')}](#{path_for(notification.group.location).gsub(/\:(\d+)/, '')})"
      end

      def path_for(location)
        if documenting_rest_only?
          "https://github.com/ably/ably-ruby/tree/#{submodule_sha}#{location.gsub(%r{^\./lib/submodules/ably-ruby}, '')}"
        else
          location
        end
      end

      def submodule_sha
        @sha ||= `git ls-tree HEAD:lib/submodules grep ably-ruby`[/^\w+\s+\w+\s+(\w+)/, 1]
      end

      def indent_prefix
        if indent > 0
          "#{'  ' * indent}* "
        else
          "\n### "
        end
      end
    end
  end
end