module ChronoTest::Matchers

  module Column
    class HaveColumns < ChronoTest::Matchers::Base
      def initialize(columns, schema = 'public')
        @columns = columns
        @schema  = schema
      end

      def description
        'have columns'
      end

      def matches?(table)
        super(table)

        @matches = @columns.inject({}) do |h, (name, type)|
          h.update([name, type] => has_column?(name, type))
        end

        @matches.values.all?
      end

      def failure_message
        message_matches("expected #{@schema}.#{table} to have")
      end

      def failure_message_when_negated
        message_matches("expected #{@schema}.#{table} to not have")
      end

      protected
        def has_column?(name, type)
          column_type(name) == [name, type]
        end

        def column_type(name)
          table = "#{@schema}.#{self.table}"

          select_rows(<<-SQL, [table, name], 'Check column').first
            SELECT attname, FORMAT_TYPE(atttypid, atttypmod)
              FROM pg_attribute
             WHERE attrelid = ?::regclass::oid
               AND attname = ?
          SQL
        end

      private
        def message_matches(message)
          (message << ' ').tap do |message|
            message << @matches.map do |(name, type), match|
              "a #{name}(#{type}) column" unless match
            end.compact.to_sentence
          end
        end
    end

    def have_columns(*args)
      HaveColumns.new(*args)
    end


    class HaveTemporalColumns < HaveColumns
      def initialize(columns)
        super(columns, temporal_schema)
      end
    end

    def have_temporal_columns(*args)
      HaveTemporalColumns.new(*args)
    end


    class HaveHistoryColumns < HaveColumns
      def initialize(columns)
        super(columns, history_schema)
      end
    end

    def have_history_columns(*args)
      HaveHistoryColumns.new(*args)
    end


    class HaveHistoryExtraColumns < HaveColumns
      def initialize
        super([
          ['validity',    'tsrange'],
          ['recorded_at', 'timestamp without time zone'],
          ['hid',         'integer']
        ], history_schema)
      end
    end

    def have_history_extra_columns
      HaveHistoryExtraColumns.new
    end
  end
end