// Copyright 2025 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package common

import (
	commonEvent "github.com/pingcap/ticdc/pkg/common/event"
)

// Decoder is an abstraction for events decoder
// this interface is only for testing now
type Decoder interface {
	// AddKeyValue add the received key and values to the decoder,
	// should be called before `HasNext`
	// decoder decode the key and value into the event format.
	AddKeyValue(key, value []byte)

	// HasNext returns
	//     1. the type of the next event
	//     2. a bool if the next event is exist
	//     3. error
	HasNext() (MessageType, bool)

	// NextResolvedEvent returns the next resolved event if exists
	NextResolvedEvent() uint64

	// NextDMLEvent returns the next DML event if exists
	NextDMLEvent() *commonEvent.DMLEvent

	// NextDDLEvent returns the next DDL event if exists
	NextDDLEvent() *commonEvent.DDLEvent
}