module ActiveRecord
  module ConnectionAdapters
    module SchemaStatements
      def quote_column_names(column_name)
        Array(column_name).map { |e| quote_column_name(e) }.join(", ")
      end

      def add_primary_key(table_name, column_name, options = {})
        column_names = Array(column_name)
        quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ")
        execute "ALTER TABLE #{table_name} ADD PRIMARY KEY (#{quoted_column_names})"
      end

      def remove_primary_key(table_name)
        execute "ALTER TABLE #{table_name} DROP PRIMARY KEY"
      end

      def add_foreign_key(table_name, column_name, reftbl, refcol = nil)
        execute "ALTER TABLE #{table_name} ADD " +
	  "FOREIGN KEY (#{quote_column_names(column_name)}) " +
	  "REFERENCES #{reftbl} (#{quote_column_names(refcol || column_name)})"
      end

      def remove_foreign_key(table_name, column_name, reftbl, refcol = nil)
        execute "ALTER TABLE #{table_name} DROP " +
          "CONSTRAINT #{table_name}_#{column_name[0]}_fkey"
      end

      alias_method :old_options_include_default?, :options_include_default?

      def options_include_default?(options)
        return false if options[:options] =~ /AUTO_INCREMENT/i
        return old_options_include_default?(options)
      end

      alias_method :old_add_column_options!, :add_column_options!

      def add_column_options!(sql, options)
        sql << " UNSIGNED" if options[:unsigned]
        old_add_column_options!(sql, options)
        sql << " #{options[:options]}"
      end
    end

    class MysqlAdapter
      if MysqlAdapter.public_instance_methods(false).include?('native_database_types')
        alias_method :old_native_database_types, :native_database_types
      end

      def native_database_types
        types = old_native_database_types
        types[:bigint] = { :name => "bigint", :limit => 20 }
        types[:double] = { :name => "double" }
        types[:integer_pk] = { :name => "integer DEFAULT NULL auto_increment PRIMARY KEY" }
        types[:bigint_pk] = { :name => "bigint(20) DEFAULT NULL auto_increment PRIMARY KEY" }
        types[:bigint_pk_64] = { :name => "bigint(64) DEFAULT NULL auto_increment PRIMARY KEY" }
        types[:bigint_auto_64] = { :name => "bigint(64) DEFAULT NULL auto_increment" }
        types[:bigint_auto_11] = { :name => "bigint(11) DEFAULT NULL auto_increment" }
        types[:bigint_auto_20] = { :name => "bigint(20) DEFAULT NULL auto_increment" }
        types[:four_byte_unsigned] = { :name=> "integer unsigned" }
        types[:inet] = { :name=> "integer unsigned" }
        types
      end

      def change_column(table_name, column_name, type, options = {})
        unless options_include_default?(options)
          options[:default] = select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Default"]

          unless type == :string or type == :text
            options.delete(:default) if options[:default] = "";
          end
        end

        change_column_sql = "ALTER TABLE #{table_name} CHANGE #{column_name} #{column_name} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
        add_column_options!(change_column_sql, options)
        execute(change_column_sql) 
      end

      def myisam_table
        return { :id => false, :force => true, :options => "ENGINE=MyIsam" }
      end

      def innodb_table
        return { :id => false, :force => true, :options => "ENGINE=InnoDB" }
      end

      def innodb_option
        return "ENGINE=InnoDB"
      end

      def change_engine (table_name, engine)
        execute "ALTER TABLE #{table_name} ENGINE = #{engine}"
      end

      def add_fulltext_index (table_name, column)
        execute "CREATE FULLTEXT INDEX `#{table_name}_#{column}_idx` ON `#{table_name}` (`#{column}`)"
      end

      def alter_column_nwr_enum (table_name, column)
        execute "alter table #{table_name} change column #{column} #{column} enum('Node','Way','Relation');"
      end

      def alter_primary_key(table_name, new_columns)
        execute("alter table #{table_name} drop primary key, add primary key (#{new_columns.join(',')})")
      end

      def interval_constant(interval)
        "'#{interval}'"
      end
    end

    class PostgreSQLAdapter
      if PostgreSQLAdapter.public_instance_methods(false).include?('native_database_types')
        alias_method :old_native_database_types, :native_database_types
      end

      def native_database_types
        types = old_native_database_types
        types[:double] = { :name => "double precision" }
        types[:integer_pk] = { :name => "serial PRIMARY KEY" }
        types[:bigint_pk] = { :name => "bigserial PRIMARY KEY" }
        types[:bigint_pk_64] = { :name => "bigserial PRIMARY KEY" }
        types[:bigint_auto_64] = { :name => "bigint" } #fixme: need autoincrement?
        types[:bigint_auto_11] = { :name => "bigint" } #fixme: need autoincrement?
        types[:bigint_auto_20] = { :name => "bigint" } #fixme: need autoincrement?
        types[:four_byte_unsigned] = { :name => "bigint" } # meh
        types[:inet] = { :name=> "inet" }
        types
      end

      def myisam_table
        return { :id => false, :force => true, :options => ""}
      end

      def innodb_table
        return { :id => false, :force => true, :options => ""}
      end

      def innodb_option
        return ""
      end
 
      def change_engine (table_name, engine)
      end

      def add_fulltext_index (table_name, column)
        execute "CREATE INDEX #{table_name}_#{column}_idx on #{table_name} (#{column})"
      end

      def alter_column_nwr_enum (table_name, column)
        response = select_one("select count(*) as count from pg_type where typname = 'nwr_enum'")
        if response['count'] == "0" #yep, as a string
          execute "create type nwr_enum as ENUM ('Node', 'Way', 'Relation')"
        end
        execute	"alter table #{table_name} drop #{column}"
        execute "alter table #{table_name} add #{column} nwr_enum"
      end

      def alter_primary_key(table_name, new_columns)
        execute "alter table #{table_name} drop constraint #{table_name}_pkey; alter table #{table_name} add primary key (#{new_columns.join(',')})"
      end

      def interval_constant(interval)
        "'#{interval}'::interval"
      end

      def add_index(table_name, column_name, options = {})
        column_names = Array(column_name)
        index_name   = index_name(table_name, :column => column_names)

        if Hash === options # legacy support, since this param was a string
          index_type = options[:unique] ? "UNIQUE" : ""
          index_name = options[:name] || index_name
          index_method = options[:method] || "BTREE"
        else
          index_type = options
        end
        quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ")
        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} USING #{index_method} (#{quoted_column_names})"
      end
    end
  end
end