module ActiveRecord #:nodoc:
  module ConnectionAdapters #:nodoc:
    module OracleEnhancedSchemaDumper #:nodoc:

      def self.included(base) #:nodoc:
        base.class_eval do
          private
          alias_method_chain :tables, :oracle_enhanced
          alias_method_chain :indexes, :oracle_enhanced
          alias_method_chain :foreign_keys, :oracle_enhanced
        end
      end

      private

      def ignore_table?(table)
        ['schema_migrations', ignore_tables].flatten.any? do |ignored|
          case ignored
          when String; remove_prefix_and_suffix(table) == ignored
          when Regexp; remove_prefix_and_suffix(table) =~ ignored
          else
            raise StandardError, 'ActiveRecord::SchemaDumper.ignore_tables accepts an array of String and / or Regexp values.'
          end
        end
      end

      def tables_with_oracle_enhanced(stream)
        return tables_without_oracle_enhanced(stream) unless @connection.respond_to?(:materialized_views)
        # do not include materialized views in schema dump - they should be created separately after schema creation
        sorted_tables = (@connection.tables - @connection.materialized_views).sort
        sorted_tables.each do |tbl|
          # add table prefix or suffix for schema_migrations
          next if ignore_table? tbl
          # change table name inspect method
          tbl.extend TableInspect
          oracle_enhanced_table(tbl, stream)
          # add primary key trigger if table has it
          primary_key_trigger(tbl, stream)
        end
        # following table definitions
        # add foreign keys if table has them
        sorted_tables.each do |tbl|
          next if ignore_table? tbl
          foreign_keys(tbl, stream)
        end

        # add synonyms in local schema
        synonyms(stream)
      end

      def primary_key_trigger(table_name, stream)
        if @connection.respond_to?(:has_primary_key_trigger?) && @connection.has_primary_key_trigger?(table_name)
          pk, pk_seq = @connection.pk_and_sequence_for(table_name)
          stream.print "  add_primary_key_trigger #{table_name.inspect}"
          stream.print ", primary_key: \"#{pk}\"" if pk != 'id'
          stream.print "\n\n"
        end
      end

      def foreign_keys_with_oracle_enhanced(table_name, stream)
        return foreign_keys_without_oracle_enhanced(table_name, stream)
      end

      def synonyms(stream)
        if @connection.respond_to?(:synonyms)
          syns = @connection.synonyms
          syns.each do |syn|
		        next if ignore_table? syn.name
            table_name = syn.table_name
            table_name = "#{syn.table_owner}.#{table_name}" if syn.table_owner
            table_name = "#{table_name}@#{syn.db_link}" if syn.db_link
            stream.print "  add_synonym #{syn.name.inspect}, #{table_name.inspect}, force: true"
            stream.puts
          end
          stream.puts unless syns.empty?
        end
      end

      def indexes_with_oracle_enhanced(table, stream)
        # return original method if not using oracle_enhanced
        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 indexes_without_oracle_enhanced(table, stream)
        end
        if (indexes = @connection.indexes(table)).any?
          add_index_statements = indexes.map do |index|
            case index.type
            when nil
              # use table.inspect as it will remove prefix and suffix
              statement_parts = [ ('add_index ' + table.inspect) ]
              statement_parts << index.columns.inspect
              statement_parts << ('name: ' + index.name.inspect)
              statement_parts << 'unique: true' if index.unique
              statement_parts << 'tablespace: ' + index.tablespace.inspect if index.tablespace
            when 'CTXSYS.CONTEXT'
              if index.statement_parameters
                statement_parts = [ ('add_context_index ' + table.inspect) ]
                statement_parts << index.statement_parameters
              else
                statement_parts = [ ('add_context_index ' + table.inspect) ]
                statement_parts << index.columns.inspect
                statement_parts << ('name: ' + index.name.inspect)
              end
            else
              # unrecognized index type
              statement_parts = ["# unrecognized index #{index.name.inspect} with type #{index.type.inspect}"]
            end
            '  ' + statement_parts.join(', ')
          end

          stream.puts add_index_statements.sort.join("\n")
          stream.puts
        end
      end

      def oracle_enhanced_table(table, stream)
        columns = @connection.columns(table)
        begin
          tbl = StringIO.new

          # first dump primary key column
          if @connection.respond_to?(:pk_and_sequence_for)
            pk, pk_seq = @connection.pk_and_sequence_for(table)
          elsif @connection.respond_to?(:primary_key)
            pk = @connection.primary_key(table)
          end
          
          tbl.print "  create_table #{table.inspect}"
          
          # addition to make temporary option work
          tbl.print ", temporary: true" if @connection.temporary_table?(table)
          
          if columns.detect { |c| c.name == pk }
            if pk != 'id'
              tbl.print %Q(, primary_key: "#{pk}")
            end
          else
            tbl.print ", id: false"
          end
          tbl.print ", force: :cascade"
          tbl.puts " do |t|"

          # then dump all non-primary key columns
          column_specs = columns.map do |column|
            raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" if @types[column.type].nil?
            next if column.name == pk
            @connection.column_spec(column, @types)
          end.compact

          # find all migration keys used in this table
          # 
          # TODO `& column_specs.map(&:keys).flatten` should be executed 
          # in migration_keys_with_oracle_enhanced
          keys = @connection.migration_keys & column_specs.map(&:keys).flatten

          # figure out the lengths for each column based on above keys
          lengths = keys.map{ |key| column_specs.map{ |spec| spec[key] ? spec[key].length + 2 : 0 }.max }

          # the string we're going to sprintf our values against, with standardized column widths
          format_string = lengths.map{ |len| "%-#{len}s" }

          # find the max length for the 'type' column, which is special
          type_length = column_specs.map{ |column| column[:type].length }.max

          # add column type definition to our format string
          format_string.unshift "    t.%-#{type_length}s "

          format_string *= ''

          column_specs.each do |colspec|
            values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
            values.unshift colspec[:type]
            tbl.print((format_string % values).gsub(/,\s*$/, ''))
            tbl.puts
          end

          tbl.puts "  end"
          tbl.puts
          
          indexes(table, tbl)

          tbl.rewind
          stream.print tbl.read
        rescue => e
          stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
          stream.puts "#   #{e.message}"
          stream.puts
        end
        
        stream
      end

      def remove_prefix_and_suffix(table)
        table.gsub(/^(#{ActiveRecord::Base.table_name_prefix})(.+)(#{ActiveRecord::Base.table_name_suffix})$/,  "\\2")
      end 
      
      # remove table name prefix and suffix when doing #inspect (which is used in tables method)
      module TableInspect #:nodoc:
        def inspect
          remove_prefix_and_suffix(self)
        end
        
        private
        def remove_prefix_and_suffix(table_name)
          if table_name =~ /\A#{ActiveRecord::Base.table_name_prefix.to_s.gsub('$','\$')}(.*)#{ActiveRecord::Base.table_name_suffix.to_s.gsub('$','\$')}\Z/
            "\"#{$1}\""
          else
            "\"#{table_name}\""
          end
        end
      end

    end
  end
end

ActiveRecord::SchemaDumper.class_eval do
  include ActiveRecord::ConnectionAdapters::OracleEnhancedSchemaDumper
end