// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// 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 msgstream

import (
	"errors"

	"github.com/milvus-io/milvus/internal/proto/commonpb"
)

// UnmarshalFunc is an interface that has been implemented by each Msg
type UnmarshalFunc func(interface{}) (TsMsg, error)

// UnmarshalDispatcher is an interface contains method Unmarshal
type UnmarshalDispatcher interface {
	Unmarshal(input interface{}, msgType commonpb.MsgType) (TsMsg, error)
}

// UnmarshalDispatcherFactory is a factory to generate an object which implement interface UnmarshalDispatcher
type UnmarshalDispatcherFactory interface {
	NewUnmarshalDispatcher() *UnmarshalDispatcher
}

// ProtoUnmarshalDispatcher is Unmarshal Dispatcher which used for data of proto type
type ProtoUnmarshalDispatcher struct {
	TempMap map[commonpb.MsgType]UnmarshalFunc
}

// Unmarshal will forward unmarshal request to msg type specified unmarshal function
func (p *ProtoUnmarshalDispatcher) Unmarshal(input interface{}, msgType commonpb.MsgType) (TsMsg, error) {
	unmarshalFunc, ok := p.TempMap[msgType]
	if !ok {
		return nil, errors.New("not set unmarshalFunc for this messageType")
	}
	return unmarshalFunc(input)
}

// ProtoUDFactory is a factory to generate ProtoUnmarshalDispatcher object
type ProtoUDFactory struct{}

// NewUnmarshalDispatcher returns an new UnmarshalDispatcher
func (pudf *ProtoUDFactory) NewUnmarshalDispatcher() *ProtoUnmarshalDispatcher {
	insertMsg := InsertMsg{}
	deleteMsg := DeleteMsg{}
	searchMsg := SearchMsg{}
	searchResultMsg := SearchResultMsg{}
	retrieveMsg := RetrieveMsg{}
	retrieveResultMsg := RetrieveResultMsg{}
	timeTickMsg := TimeTickMsg{}
	createCollectionMsg := CreateCollectionMsg{}
	dropCollectionMsg := DropCollectionMsg{}
	createPartitionMsg := CreatePartitionMsg{}
	dropPartitionMsg := DropPartitionMsg{}
	queryNodeSegStatsMsg := QueryNodeStatsMsg{}
	segmentStatisticsMsg := SegmentStatisticsMsg{}
	loadBalanceSegmentsMsg := LoadBalanceSegmentsMsg{}
	dataNodeTtMsg := DataNodeTtMsg{}
	sealedSegmentsChangeInfoMsg := SealedSegmentsChangeInfoMsg{}

	p := &ProtoUnmarshalDispatcher{}
	p.TempMap = make(map[commonpb.MsgType]UnmarshalFunc)
	p.TempMap[commonpb.MsgType_Insert] = insertMsg.Unmarshal
	p.TempMap[commonpb.MsgType_Delete] = deleteMsg.Unmarshal
	p.TempMap[commonpb.MsgType_Search] = searchMsg.Unmarshal
	p.TempMap[commonpb.MsgType_SearchResult] = searchResultMsg.Unmarshal
	p.TempMap[commonpb.MsgType_Retrieve] = retrieveMsg.Unmarshal
	p.TempMap[commonpb.MsgType_RetrieveResult] = retrieveResultMsg.Unmarshal
	p.TempMap[commonpb.MsgType_TimeTick] = timeTickMsg.Unmarshal
	p.TempMap[commonpb.MsgType_QueryNodeStats] = queryNodeSegStatsMsg.Unmarshal
	p.TempMap[commonpb.MsgType_CreateCollection] = createCollectionMsg.Unmarshal
	p.TempMap[commonpb.MsgType_DropCollection] = dropCollectionMsg.Unmarshal
	p.TempMap[commonpb.MsgType_CreatePartition] = createPartitionMsg.Unmarshal
	p.TempMap[commonpb.MsgType_DropPartition] = dropPartitionMsg.Unmarshal
	p.TempMap[commonpb.MsgType_SegmentStatistics] = segmentStatisticsMsg.Unmarshal
	p.TempMap[commonpb.MsgType_LoadBalanceSegments] = loadBalanceSegmentsMsg.Unmarshal
	p.TempMap[commonpb.MsgType_DataNodeTt] = dataNodeTtMsg.Unmarshal
	p.TempMap[commonpb.MsgType_SealedSegmentsChangeInfo] = sealedSegmentsChangeInfoMsg.Unmarshal

	return p
}

// MemUnmarshalDispatcher ant its factory

//type MemUDFactory struct {
//
//}
//func (mudf *MemUDFactory) NewUnmarshalDispatcher() *UnmarshalDispatcher {
//
//}