module ActiveRecord
  module ConnectionAdapters
    module MySQL
      module ColumnDumper
        def column_spec_for_primary_key(column)
          spec = super
          if [:integer, :bigint].include?(schema_type(column)) && !column.auto_increment?
            spec[:default] ||= schema_default(column) || "nil"
          end
          spec[:unsigned] = "true" if column.unsigned?
          spec
        end

        def prepare_column_options(column)
          spec = super
          spec[:unsigned] = "true" if column.unsigned?
          spec
        end

        def migration_keys
          super + [:unsigned]
        end

        private

          def default_primary_key?(column)
            super && column.auto_increment?
          end

          def schema_type(column)
            if column.sql_type == "tinyblob"
              :blob
            else
              super
            end
          end

          def schema_precision(column)
            super unless /time/.match?(column.sql_type) && column.precision == 0
          end

          def schema_collation(column)
            if column.collation && table_name = column.table_name
              @table_collation_cache ||= {}
              @table_collation_cache[table_name] ||= select_one("SHOW TABLE STATUS LIKE '#{table_name}'")["Collation"]
              column.collation.inspect if column.collation != @table_collation_cache[table_name]
            end
          end
      end
    end
  end
end