// 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 datanode

import (
	"context"

	"github.com/milvus-io/milvus/internal/log"
	"github.com/milvus-io/milvus/internal/msgstream"
	"github.com/milvus-io/milvus/internal/proto/datapb"
	"github.com/milvus-io/milvus/internal/util/flowgraph"

	"go.uber.org/zap"
)

type dataSyncService struct {
	ctx          context.Context
	fg           *flowgraph.TimeTickedFlowGraph
	flushChan    <-chan *flushMsg
	replica      Replica
	idAllocator  allocatorInterface
	msFactory    msgstream.Factory
	collectionID UniqueID
}

func newDataSyncService(ctx context.Context,
	flushChan <-chan *flushMsg,
	replica Replica,
	alloc allocatorInterface,
	factory msgstream.Factory,
	vchan *datapb.VchannelInfo) *dataSyncService {

	service := &dataSyncService{
		ctx:          ctx,
		fg:           nil,
		flushChan:    flushChan,
		replica:      replica,
		idAllocator:  alloc,
		msFactory:    factory,
		collectionID: vchan.GetCollectionID(),
	}

	service.initNodes(vchan)
	return service
}

func (dsService *dataSyncService) start() {
	log.Debug("Data Sync Service Start Successfully")
	if dsService.fg != nil {
		dsService.fg.Start()
	} else {
		log.Debug("Data Sync Service flowgraph nil")
	}
}

func (dsService *dataSyncService) close() {
	if dsService.fg != nil {
		dsService.fg.Close()
	}
}

func (dsService *dataSyncService) initNodes(vchanPair *datapb.VchannelInfo) {
	// TODO: add delete pipeline support
	dsService.fg = flowgraph.NewTimeTickedFlowGraph(dsService.ctx)

	m := map[string]interface{}{
		"PulsarAddress":  Params.PulsarAddress,
		"ReceiveBufSize": 1024,
		"PulsarBufSize":  1024,
	}

	err := dsService.msFactory.SetParams(m)
	if err != nil {
		panic(err)
	}

	var dmStreamNode Node = newDmInputNode(dsService.ctx, dsService.msFactory, vchanPair.GetChannelName(), vchanPair.GetCheckPoints())
	var ddNode Node = newDDNode()
	var insertBufferNode Node = newInsertBufferNode(dsService.ctx, dsService.replica, dsService.msFactory, dsService.idAllocator, dsService.flushChan)

	dsService.fg.AddNode(dmStreamNode)
	dsService.fg.AddNode(ddNode)
	dsService.fg.AddNode(insertBufferNode)

	// ddStreamNode
	err = dsService.fg.SetEdges(dmStreamNode.Name(),
		[]string{},
		[]string{ddNode.Name()},
	)
	if err != nil {
		log.Error("set edges failed in node", zap.String("name", dmStreamNode.Name()), zap.Error(err))
		panic("set edges faild in the node")
	}

	// ddNode
	err = dsService.fg.SetEdges(ddNode.Name(),
		[]string{dmStreamNode.Name()},
		[]string{insertBufferNode.Name()},
	)
	if err != nil {
		log.Error("set edges failed in node", zap.String("name", ddNode.Name()), zap.Error(err))
		panic("set edges faild in the node")
	}

	// insertBufferNode
	err = dsService.fg.SetEdges(insertBufferNode.Name(),
		[]string{ddNode.Name()},
		[]string{},
	)
	if err != nil {
		log.Error("set edges failed in node", zap.String("name", insertBufferNode.Name()), zap.Error(err))
		panic("set edges faild in the node")
	}
}