// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 grpcdatanode

import (
	"context"
	"fmt"
	"net"
	"strconv"
	"sync"
	"time"

	"github.com/cockroachdb/errors"

	grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
	clientv3 "go.etcd.io/etcd/client/v3"
	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
	"go.uber.org/zap"
	"google.golang.org/grpc"
	"google.golang.org/grpc/keepalive"

	"github.com/milvus-io/milvus-proto/go-api/commonpb"
	"github.com/milvus-io/milvus-proto/go-api/milvuspb"
	dn "github.com/milvus-io/milvus/internal/datanode"
	dcc "github.com/milvus-io/milvus/internal/distributed/datacoord/client"
	rcc "github.com/milvus-io/milvus/internal/distributed/rootcoord/client"
	"github.com/milvus-io/milvus/internal/log"
	"github.com/milvus-io/milvus/internal/proto/datapb"
	"github.com/milvus-io/milvus/internal/proto/internalpb"
	"github.com/milvus-io/milvus/internal/tracer"
	"github.com/milvus-io/milvus/internal/types"
	"github.com/milvus-io/milvus/internal/util/componentutil"
	"github.com/milvus-io/milvus/internal/util/dependency"
	"github.com/milvus-io/milvus/internal/util/etcd"
	"github.com/milvus-io/milvus/internal/util/funcutil"
	"github.com/milvus-io/milvus/internal/util/logutil"
	"github.com/milvus-io/milvus/internal/util/paramtable"
	"github.com/milvus-io/milvus/internal/util/retry"
)

type Server struct {
	datanode    types.DataNodeComponent
	wg          sync.WaitGroup
	grpcErrChan chan error
	grpcServer  *grpc.Server
	ctx         context.Context
	cancel      context.CancelFunc
	etcdCli     *clientv3.Client
	factory     dependency.Factory

	rootCoord types.RootCoord
	dataCoord types.DataCoord

	newRootCoordClient func(string, *clientv3.Client) (types.RootCoord, error)
	newDataCoordClient func(string, *clientv3.Client) (types.DataCoord, error)
}

// NewServer new DataNode grpc server
func NewServer(ctx context.Context, factory dependency.Factory) (*Server, error) {
	ctx1, cancel := context.WithCancel(ctx)
	var s = &Server{
		ctx:         ctx1,
		cancel:      cancel,
		factory:     factory,
		grpcErrChan: make(chan error),
		newRootCoordClient: func(etcdMetaRoot string, client *clientv3.Client) (types.RootCoord, error) {
			return rcc.NewClient(ctx1, etcdMetaRoot, client)
		},
		newDataCoordClient: func(etcdMetaRoot string, client *clientv3.Client) (types.DataCoord, error) {
			return dcc.NewClient(ctx1, etcdMetaRoot, client)
		},
	}

	s.datanode = dn.NewDataNode(s.ctx, s.factory)

	return s, nil
}

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

// startGrpcLoop starts the grep loop of datanode component.
func (s *Server) startGrpcLoop(grpcPort int) {
	defer s.wg.Done()
	Params := &paramtable.Get().DataNodeGrpcServerCfg
	var kaep = keepalive.EnforcementPolicy{
		MinTime:             5 * time.Second, // If a client pings more than once every 5 seconds, terminate the connection
		PermitWithoutStream: true,            // Allow pings even when there are no active streams
	}

	var kasp = keepalive.ServerParameters{
		Time:    60 * time.Second, // Ping the client if it is idle for 60 seconds to ensure the connection is still active
		Timeout: 10 * time.Second, // Wait 10 second for the ping ack before assuming the connection is dead
	}
	var lis net.Listener

	err := retry.Do(s.ctx, func() error {
		addr := ":" + strconv.Itoa(grpcPort)
		var err error
		lis, err = net.Listen("tcp", addr)
		return err
	}, retry.Attempts(10))

	if err != nil {
		log.Error("DataNode GrpcServer:failed to listen", zap.Error(err))
		s.grpcErrChan <- err
		return
	}

	opts := tracer.GetInterceptorOpts()
	s.grpcServer = grpc.NewServer(
		grpc.KeepaliveEnforcementPolicy(kaep),
		grpc.KeepaliveParams(kasp),
		grpc.MaxRecvMsgSize(Params.ServerMaxRecvSize.GetAsInt()),
		grpc.MaxSendMsgSize(Params.ServerMaxSendSize.GetAsInt()),
		grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
			otelgrpc.UnaryServerInterceptor(opts...),
			logutil.UnaryTraceLoggerInterceptor)),
		grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
			otelgrpc.StreamServerInterceptor(opts...),
			logutil.StreamTraceLoggerInterceptor)))
	datapb.RegisterDataNodeServer(s.grpcServer, s)

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

	go funcutil.CheckGrpcReady(ctx, s.grpcErrChan)
	if err := s.grpcServer.Serve(lis); err != nil {
		log.Warn("DataNode failed to start gRPC")
		s.grpcErrChan <- err
	}

}

func (s *Server) SetEtcdClient(client *clientv3.Client) {
	s.datanode.SetEtcdClient(client)
}

func (s *Server) SetRootCoordInterface(ms types.RootCoord) error {
	return s.datanode.SetRootCoord(ms)
}

func (s *Server) SetDataCoordInterface(ds types.DataCoord) error {
	return s.datanode.SetDataCoord(ds)
}

// Run initializes and starts Datanode's grpc service.
func (s *Server) Run() error {
	if err := s.init(); err != nil {
		// errors are propagated upstream as panic.
		return err
	}
	log.Info("DataNode gRPC services successfully initialized")
	if err := s.start(); err != nil {
		// errors are propagated upstream as panic.
		return err
	}
	log.Info("DataNode gRPC services successfully started")
	return nil
}

// Stop stops Datanode's grpc service.
func (s *Server) Stop() error {
	Params := &paramtable.Get().DataNodeGrpcServerCfg
	log.Debug("Datanode stop", zap.String("Address", Params.GetAddress()))
	s.cancel()
	if s.etcdCli != nil {
		defer s.etcdCli.Close()
	}
	if s.grpcServer != nil {
		log.Debug("Graceful stop grpc server...")
		// make graceful stop has a timeout
		stopped := make(chan struct{})
		go func() {
			s.grpcServer.GracefulStop()
			close(stopped)
		}()

		t := time.NewTimer(10 * time.Second)
		select {
		case <-t.C:
			// hard stop since grace timeout
			s.grpcServer.Stop()
		case <-stopped:
			t.Stop()
		}
	}

	err := s.datanode.Stop()
	if err != nil {
		return err
	}
	s.wg.Wait()
	return nil
}

// init initializes Datanode's grpc service.
func (s *Server) init() error {
	etcdConfig := &paramtable.Get().EtcdCfg
	Params := &paramtable.Get().DataNodeGrpcServerCfg
	ctx := context.Background()
	if !funcutil.CheckPortAvailable(Params.Port.GetAsInt()) {
		paramtable.Get().Save(Params.Port.Key, fmt.Sprintf("%d", funcutil.GetAvailablePort()))
		log.Warn("DataNode found available port during init", zap.Int("port", Params.Port.GetAsInt()))
	}

	etcdCli, err := etcd.GetEtcdClient(
		etcdConfig.UseEmbedEtcd.GetAsBool(),
		etcdConfig.EtcdUseSSL.GetAsBool(),
		etcdConfig.Endpoints.GetAsStrings(),
		etcdConfig.EtcdTLSCert.GetValue(),
		etcdConfig.EtcdTLSKey.GetValue(),
		etcdConfig.EtcdTLSCACert.GetValue(),
		etcdConfig.EtcdTLSMinVersion.GetValue())
	if err != nil {
		log.Error("failed to connect to etcd", zap.Error(err))
		return err
	}
	s.etcdCli = etcdCli
	s.SetEtcdClient(s.etcdCli)
	s.datanode.SetAddress(Params.GetAddress())
	log.Info("DataNode address", zap.String("address", Params.IP+":"+strconv.Itoa(Params.Port.GetAsInt())))

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

	// --- RootCoord Client ---
	if s.newRootCoordClient != nil {
		log.Info("initializing RootCoord client for DataNode")
		rootCoordClient, err := s.newRootCoordClient(dn.Params.EtcdCfg.MetaRootPath.GetValue(), s.etcdCli)
		if err != nil {
			log.Error("failed to create new RootCoord client", zap.Error(err))
			panic(err)
		}
		if err = rootCoordClient.Init(); err != nil {
			log.Error("failed to init RootCoord client", zap.Error(err))
			panic(err)
		}
		if err = rootCoordClient.Start(); err != nil {
			log.Error("failed to start RootCoord client", zap.Error(err))
			panic(err)
		}
		if err = componentutil.WaitForComponentHealthy(ctx, rootCoordClient, "RootCoord", 1000000, time.Millisecond*200); err != nil {
			log.Error("failed to wait for RootCoord client to be ready", zap.Error(err))
			panic(err)
		}
		log.Info("RootCoord client is ready for DataNode")
		if err = s.SetRootCoordInterface(rootCoordClient); err != nil {
			panic(err)
		}
	}

	// --- DataCoord Client ---
	if s.newDataCoordClient != nil {
		log.Debug("starting DataCoord client for DataNode")
		dataCoordClient, err := s.newDataCoordClient(dn.Params.EtcdCfg.MetaRootPath.GetValue(), s.etcdCli)
		if err != nil {
			log.Error("failed to create new DataCoord client", zap.Error(err))
			panic(err)
		}
		if err = dataCoordClient.Init(); err != nil {
			log.Error("failed to init DataCoord client", zap.Error(err))
			panic(err)
		}
		if err = dataCoordClient.Start(); err != nil {
			log.Error("failed to start DataCoord client", zap.Error(err))
			panic(err)
		}
		if err = componentutil.WaitForComponentInitOrHealthy(ctx, dataCoordClient, "DataCoord", 1000000, time.Millisecond*200); err != nil {
			log.Error("failed to wait for DataCoord client to be ready", zap.Error(err))
			panic(err)
		}
		log.Info("DataCoord client is ready for DataNode")
		if err = s.SetDataCoordInterface(dataCoordClient); err != nil {
			panic(err)
		}
	}

	s.datanode.UpdateStateCode(commonpb.StateCode_Initializing)

	if err := s.datanode.Init(); err != nil {
		log.Error("failed to init DataNode server", zap.Error(err))
		return err
	}
	log.Info("current DataNode state", zap.Any("state", s.datanode.GetStateCode()))
	return nil
}

// start starts datanode's grpc service.
func (s *Server) start() error {
	if err := s.datanode.Start(); err != nil {
		return err
	}
	err := s.datanode.Register()
	if err != nil {
		log.Debug("failed to register to Etcd", zap.Error(err))
		return err
	}
	return nil
}

// GetComponentStates gets the component states of Datanode
func (s *Server) GetComponentStates(ctx context.Context, req *milvuspb.GetComponentStatesRequest) (*milvuspb.ComponentStates, error) {
	return s.datanode.GetComponentStates(ctx)
}

// GetStatisticsChannel gets the statistics channel of Datanode.
func (s *Server) GetStatisticsChannel(ctx context.Context, req *internalpb.GetStatisticsChannelRequest) (*milvuspb.StringResponse, error) {
	return s.datanode.GetStatisticsChannel(ctx)
}

// Deprecated
func (s *Server) WatchDmChannels(ctx context.Context, req *datapb.WatchDmChannelsRequest) (*commonpb.Status, error) {
	return s.datanode.WatchDmChannels(ctx, req)
}

func (s *Server) FlushSegments(ctx context.Context, req *datapb.FlushSegmentsRequest) (*commonpb.Status, error) {
	if s.datanode.GetStateCode() != commonpb.StateCode_Healthy {
		return &commonpb.Status{
			ErrorCode: commonpb.ErrorCode_UnexpectedError,
			Reason:    "DataNode isn't healthy.",
		}, errors.New("DataNode is not ready yet")
	}
	return s.datanode.FlushSegments(ctx, req)
}

// ShowConfigurations gets specified configurations para of DataNode
func (s *Server) ShowConfigurations(ctx context.Context, req *internalpb.ShowConfigurationsRequest) (*internalpb.ShowConfigurationsResponse, error) {
	return s.datanode.ShowConfigurations(ctx, req)
}

// GetMetrics gets the metrics info of Datanode.
func (s *Server) GetMetrics(ctx context.Context, request *milvuspb.GetMetricsRequest) (*milvuspb.GetMetricsResponse, error) {
	return s.datanode.GetMetrics(ctx, request)
}

func (s *Server) Compaction(ctx context.Context, request *datapb.CompactionPlan) (*commonpb.Status, error) {
	return s.datanode.Compaction(ctx, request)
}

// GetCompactionState gets the Compaction tasks state of DataNode
func (s *Server) GetCompactionState(ctx context.Context, request *datapb.CompactionStateRequest) (*datapb.CompactionStateResponse, error) {
	return s.datanode.GetCompactionState(ctx, request)
}

func (s *Server) Import(ctx context.Context, request *datapb.ImportTaskRequest) (*commonpb.Status, error) {
	return s.datanode.Import(ctx, request)
}

func (s *Server) ResendSegmentStats(ctx context.Context, request *datapb.ResendSegmentStatsRequest) (*datapb.ResendSegmentStatsResponse, error) {
	return s.datanode.ResendSegmentStats(ctx, request)
}

func (s *Server) AddImportSegment(ctx context.Context, request *datapb.AddImportSegmentRequest) (*datapb.AddImportSegmentResponse, error) {
	return s.datanode.AddImportSegment(ctx, request)
}

func (s *Server) SyncSegments(ctx context.Context, request *datapb.SyncSegmentsRequest) (*commonpb.Status, error) {
	return s.datanode.SyncSegments(ctx, request)
}
