// 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 grpcmasterservice

import (
	"context"
	"io"
	"math"
	"net"
	"strconv"
	"sync"
	"time"

	otgrpc "github.com/opentracing-contrib/go-grpc"
	"github.com/opentracing/opentracing-go"
	"go.uber.org/zap"
	"google.golang.org/grpc"

	dsc "github.com/zilliztech/milvus-distributed/internal/distributed/dataservice/client"
	isc "github.com/zilliztech/milvus-distributed/internal/distributed/indexservice/client"
	psc "github.com/zilliztech/milvus-distributed/internal/distributed/proxyservice/client"
	qsc "github.com/zilliztech/milvus-distributed/internal/distributed/queryservice/client"
	"github.com/zilliztech/milvus-distributed/internal/log"
	cms "github.com/zilliztech/milvus-distributed/internal/masterservice"
	"github.com/zilliztech/milvus-distributed/internal/msgstream"
	"github.com/zilliztech/milvus-distributed/internal/types"
	"github.com/zilliztech/milvus-distributed/internal/util/trace"

	"github.com/zilliztech/milvus-distributed/internal/proto/commonpb"
	"github.com/zilliztech/milvus-distributed/internal/proto/internalpb"
	"github.com/zilliztech/milvus-distributed/internal/proto/masterpb"
	"github.com/zilliztech/milvus-distributed/internal/proto/milvuspb"
	"github.com/zilliztech/milvus-distributed/internal/util/funcutil"
)

// grpc wrapper
type Server struct {
	masterService *cms.Core
	grpcServer    *grpc.Server
	grpcErrChan   chan error

	wg sync.WaitGroup

	ctx    context.Context
	cancel context.CancelFunc

	proxyService types.ProxyService
	dataService  types.DataService
	indexService types.IndexService
	queryService types.QueryService

	connectProxyService bool
	connectDataService  bool
	connectIndexService bool
	connectQueryService bool

	closer io.Closer
}

func NewServer(ctx context.Context, factory msgstream.Factory) (*Server, error) {

	ctx1, cancel := context.WithCancel(ctx)

	s := &Server{
		ctx:                 ctx1,
		cancel:              cancel,
		grpcErrChan:         make(chan error),
		connectDataService:  true,
		connectProxyService: true,
		connectIndexService: true,
		connectQueryService: true,
	}

	var err error
	s.masterService, err = cms.NewCore(s.ctx, factory)
	if err != nil {
		return nil, err
	}
	return s, err
}

func (s *Server) Run() error {
	if err := s.init(); err != nil {
		return err
	}

	if err := s.start(); err != nil {
		return err
	}
	return nil
}

func (s *Server) init() error {
	Params.Init()

	cms.Params.Init()
	log.Debug("grpc init done ...")

	ctx := context.Background()

	closer := trace.InitTracing("master_service")
	s.closer = closer

	log.Debug("init params done")

	err := s.startGrpc()
	if err != nil {
		return err
	}

	s.masterService.UpdateStateCode(internalpb.StateCode_Initializing)

	if s.connectProxyService {
		log.Debug("proxy service", zap.String("address", Params.ProxyServiceAddress))
		proxyService := psc.NewClient(Params.ProxyServiceAddress)
		if err := proxyService.Init(); err != nil {
			panic(err)
		}

		err := funcutil.WaitForComponentInitOrHealthy(ctx, proxyService, "ProxyService", 1000000, 200*time.Millisecond)
		if err != nil {
			panic(err)
		}

		if err = s.masterService.SetProxyService(ctx, proxyService); err != nil {
			panic(err)
		}
	}
	if s.connectDataService {
		log.Debug("data service", zap.String("address", Params.DataServiceAddress))
		dataService := dsc.NewClient(Params.DataServiceAddress)
		if err := dataService.Init(); err != nil {
			panic(err)
		}
		if err := dataService.Start(); err != nil {
			panic(err)
		}
		err := funcutil.WaitForComponentInitOrHealthy(ctx, dataService, "DataService", 1000000, 200*time.Millisecond)
		if err != nil {
			panic(err)
		}

		if err = s.masterService.SetDataService(ctx, dataService); err != nil {
			panic(err)
		}
	}
	if s.connectIndexService {
		log.Debug("index service", zap.String("address", Params.IndexServiceAddress))
		indexService := isc.NewClient(Params.IndexServiceAddress)
		if err := indexService.Init(); err != nil {
			panic(err)
		}

		if err := s.masterService.SetIndexService(indexService); err != nil {
			panic(err)

		}
	}
	if s.connectQueryService {
		queryService, err := qsc.NewClient(Params.QueryServiceAddress, 5*time.Second)
		if err != nil {
			panic(err)
		}
		if err = queryService.Init(); err != nil {
			panic(err)
		}
		if err = queryService.Start(); err != nil {
			panic(err)
		}
		if err = s.masterService.SetQueryService(queryService); err != nil {
			panic(err)
		}
	}
	if err := s.masterService.Init(); err != nil {
		return err
	}
	return nil
}

func (s *Server) startGrpc() error {
	s.wg.Add(1)
	go s.startGrpcLoop(Params.Port)
	// wait for grpc server loop start
	err := <-s.grpcErrChan
	return err
}

func (s *Server) startGrpcLoop(grpcPort int) {

	defer s.wg.Done()

	log.Debug("start grpc ", zap.Int("port", grpcPort))
	lis, err := net.Listen("tcp", ":"+strconv.Itoa(grpcPort))
	if err != nil {
		log.Error("GrpcServer:failed to listen", zap.String("error", err.Error()))
		s.grpcErrChan <- err
		return
	}

	ctx, cancel := context.WithCancel(s.ctx)
	defer cancel()

	tracer := opentracing.GlobalTracer()
	s.grpcServer = grpc.NewServer(
		grpc.MaxRecvMsgSize(math.MaxInt32),
		grpc.MaxSendMsgSize(math.MaxInt32),
		grpc.UnaryInterceptor(
			otgrpc.OpenTracingServerInterceptor(tracer)),
		grpc.StreamInterceptor(
			otgrpc.OpenTracingStreamServerInterceptor(tracer)))
	masterpb.RegisterMasterServiceServer(s.grpcServer, s)

	go funcutil.CheckGrpcReady(ctx, s.grpcErrChan)
	if err := s.grpcServer.Serve(lis); err != nil {
		s.grpcErrChan <- err
	}

}

func (s *Server) start() error {
	log.Debug("Master Core start ...")
	if err := s.masterService.Start(); err != nil {
		return err
	}
	return nil
}

func (s *Server) Stop() error {
	if s.closer != nil {
		if err := s.closer.Close(); err != nil {
			log.Error("close opentracing", zap.Error(err))
		}
	}
	if s.proxyService != nil {
		if err := s.proxyService.Stop(); err != nil {
			log.Debug("close proxyService client", zap.Error(err))
		}
	}
	if s.indexService != nil {
		if err := s.indexService.Stop(); err != nil {
			log.Debug("close indexService client", zap.Error(err))
		}
	}
	if s.dataService != nil {
		if err := s.dataService.Stop(); err != nil {
			log.Debug("close dataService client", zap.Error(err))
		}
	}
	if s.queryService != nil {
		if err := s.queryService.Stop(); err != nil {
			log.Debug("close queryService client", zap.Error(err))
		}
	}
	if s.masterService != nil {
		if err := s.masterService.Stop(); err != nil {
			log.Debug("close masterService", zap.Error(err))
		}
	}
	s.cancel()
	if s.grpcServer != nil {
		s.grpcServer.GracefulStop()
	}
	s.wg.Wait()
	return nil
}

func (s *Server) GetComponentStates(ctx context.Context, req *internalpb.GetComponentStatesRequest) (*internalpb.ComponentStates, error) {
	return s.masterService.GetComponentStates(ctx)
}

//receiver time tick from proxy service, and put it into this channel
func (s *Server) GetTimeTickChannel(ctx context.Context, req *internalpb.GetTimeTickChannelRequest) (*milvuspb.StringResponse, error) {
	return s.masterService.GetTimeTickChannel(ctx)
}

//just define a channel, not used currently
func (s *Server) GetStatisticsChannel(ctx context.Context, req *internalpb.GetStatisticsChannelRequest) (*milvuspb.StringResponse, error) {
	return s.masterService.GetStatisticsChannel(ctx)
}

//receive ddl from rpc and time tick from proxy service, and put them into this channel
func (s *Server) GetDdChannel(ctx context.Context, req *internalpb.GetDdChannelRequest) (*milvuspb.StringResponse, error) {
	return s.masterService.GetDdChannel(ctx)
}

//DDL request
func (s *Server) CreateCollection(ctx context.Context, in *milvuspb.CreateCollectionRequest) (*commonpb.Status, error) {
	return s.masterService.CreateCollection(ctx, in)
}

func (s *Server) DropCollection(ctx context.Context, in *milvuspb.DropCollectionRequest) (*commonpb.Status, error) {
	return s.masterService.DropCollection(ctx, in)
}

func (s *Server) HasCollection(ctx context.Context, in *milvuspb.HasCollectionRequest) (*milvuspb.BoolResponse, error) {
	return s.masterService.HasCollection(ctx, in)
}

func (s *Server) DescribeCollection(ctx context.Context, in *milvuspb.DescribeCollectionRequest) (*milvuspb.DescribeCollectionResponse, error) {
	return s.masterService.DescribeCollection(ctx, in)
}

func (s *Server) ShowCollections(ctx context.Context, in *milvuspb.ShowCollectionsRequest) (*milvuspb.ShowCollectionsResponse, error) {
	return s.masterService.ShowCollections(ctx, in)
}

func (s *Server) CreatePartition(ctx context.Context, in *milvuspb.CreatePartitionRequest) (*commonpb.Status, error) {
	return s.masterService.CreatePartition(ctx, in)
}

func (s *Server) DropPartition(ctx context.Context, in *milvuspb.DropPartitionRequest) (*commonpb.Status, error) {
	return s.masterService.DropPartition(ctx, in)
}

func (s *Server) HasPartition(ctx context.Context, in *milvuspb.HasPartitionRequest) (*milvuspb.BoolResponse, error) {
	return s.masterService.HasPartition(ctx, in)
}

func (s *Server) ShowPartitions(ctx context.Context, in *milvuspb.ShowPartitionsRequest) (*milvuspb.ShowPartitionsResponse, error) {
	return s.masterService.ShowPartitions(ctx, in)
}

//index builder service
func (s *Server) CreateIndex(ctx context.Context, in *milvuspb.CreateIndexRequest) (*commonpb.Status, error) {
	return s.masterService.CreateIndex(ctx, in)
}

func (s *Server) DropIndex(ctx context.Context, in *milvuspb.DropIndexRequest) (*commonpb.Status, error) {
	return s.masterService.DropIndex(ctx, in)
}

func (s *Server) DescribeIndex(ctx context.Context, in *milvuspb.DescribeIndexRequest) (*milvuspb.DescribeIndexResponse, error) {
	return s.masterService.DescribeIndex(ctx, in)
}

//global timestamp allocator
func (s *Server) AllocTimestamp(ctx context.Context, in *masterpb.AllocTimestampRequest) (*masterpb.AllocTimestampResponse, error) {
	return s.masterService.AllocTimestamp(ctx, in)
}

func (s *Server) AllocID(ctx context.Context, in *masterpb.AllocIDRequest) (*masterpb.AllocIDResponse, error) {
	return s.masterService.AllocID(ctx, in)
}

func (s *Server) DescribeSegment(ctx context.Context, in *milvuspb.DescribeSegmentRequest) (*milvuspb.DescribeSegmentResponse, error) {
	return s.masterService.DescribeSegment(ctx, in)
}

func (s *Server) ShowSegments(ctx context.Context, in *milvuspb.ShowSegmentsRequest) (*milvuspb.ShowSegmentsResponse, error) {
	return s.masterService.ShowSegments(ctx, in)
}