module ActiveRecord #:nodoc:
  module ConnectionAdapters #:nodoc:
    module OracleEnhancedColumnDumper #:nodoc:

      def self.included(base) #:nodoc:
        base.class_eval do
          private
          alias_method_chain :column_spec,            :oracle_enhanced
          alias_method_chain :prepare_column_options, :oracle_enhanced
          alias_method_chain :migration_keys,         :oracle_enhanced

          def oracle_enhanced_adapter?
          # return original method if not using 'OracleEnhanced'
            if (rails_env = defined?(Rails.env) ? Rails.env : (defined?(RAILS_ENV) ? RAILS_ENV : nil)) &&
                ActiveRecord::Base.configurations[rails_env] &&
                ActiveRecord::Base.configurations[rails_env]['adapter'] != 'oracle_enhanced'
              return false
            else
              return true
            end
          end
        end
      end

      def column_spec_with_oracle_enhanced(column, types)
        # return original method if not using 'OracleEnhanced'
        return column_spec_without_oracle_enhanced(column, types) unless oracle_enhanced_adapter?
        
        spec = prepare_column_options(column, types)
        (spec.keys - [:name, :type]).each do |k|
          key_s = (k == :virtual_type ? "type: " : "#{k.to_s}: ")
          spec[k] = key_s + spec[k]
        end
        spec
      end

      def prepare_column_options_with_oracle_enhanced(column, types)
        # return original method if not using 'OracleEnhanced'
        return prepare_column_options_without_oracle_enhanced(column, types) unless oracle_enhanced_adapter?

        spec = {}

        spec[:name]      = column.name.inspect
        spec[:type]      = column.virtual? ? 'virtual' : column.type.to_s
        spec[:limit]     = column.limit.inspect if column.limit != types[column.type][:limit] && column.type != :decimal
        spec[:precision] = column.precision.inspect if !column.precision.nil?
        spec[:scale]     = column.scale.inspect if !column.scale.nil?
        spec[:null]      = 'false' if !column.null
        spec[:as]        = column.virtual_column_data_default if column.virtual?
        spec[:default]   = default_string(column.default) if column.has_default? && !column.virtual?

        if column.virtual?
          # Supports backwards compatibility with older OracleEnhancedAdapter versions where 'NUMBER' virtual column type is not included in dump
          if column.sql_type != "NUMBER" || ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.number_datatype_coercion != :decimal
            spec[:virtual_type] = column.type.inspect
          end
        end

        spec
      end

      def migration_keys_with_oracle_enhanced
        # TODO `& column_specs.map(&:keys).flatten` should be exetuted here
        # return original method if not using 'OracleEnhanced'
        return migration_keys_without_oracle_enhanced unless oracle_enhanced_adapter?

        [:name, :limit, :precision, :scale, :default, :null, :as, :virtual_type]
      end


    end
  end
end

ActiveRecord::ConnectionAdapters::ColumnDumper.class_eval do
  include ActiveRecord::ConnectionAdapters::OracleEnhancedColumnDumper
end