// Copyright 2023 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package resultset

import "github.com/pingcap/tidb/pkg/util/chunk"

// CursorResultSet extends the `ResultSet` to provide the ability to store an iterator
type CursorResultSet interface {
	ResultSet

	StoreRowContainerReader(reader chunk.RowContainerReader)
	GetRowContainerReader() chunk.RowContainerReader
}

// WrapWithCursor wraps a ResultSet into a CursorResultSet
func WrapWithCursor(rs ResultSet) CursorResultSet {
	return &tidbCursorResultSet{
		rs, nil,
	}
}

var _ CursorResultSet = &tidbCursorResultSet{}

type tidbCursorResultSet struct {
	ResultSet

	reader chunk.RowContainerReader
}

func (tcrs *tidbCursorResultSet) StoreRowContainerReader(reader chunk.RowContainerReader) {
	tcrs.reader = reader
}

func (tcrs *tidbCursorResultSet) GetRowContainerReader() chunk.RowContainerReader {
	return tcrs.reader
}

// FetchNotifier represents notifier will be called in COM_FETCH.
type FetchNotifier interface {
	// OnFetchReturned be called when COM_FETCH returns.
	// it will be used in server-side cursor.
	OnFetchReturned()
}