// Copyright 2016 The etcd Authors
//
// 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 v3rpc

import (
	"crypto/tls"
	"io/ioutil"
	"math"
	"os"
	"sync"

	"github.com/coreos/etcd/etcdserver"
	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"

	"github.com/grpc-ecosystem/go-grpc-prometheus"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/grpclog"
	"google.golang.org/grpc/health"
	healthpb "google.golang.org/grpc/health/grpc_health_v1"
)

const (
	grpcOverheadBytes = 512 * 1024
	maxStreams        = math.MaxUint32
	maxSendBytes      = math.MaxInt32
)

// integration tests call this multiple times, which is racey in gRPC side
var grpclogOnce sync.Once

func Server(s *etcdserver.EtcdServer, tls *tls.Config, gopts ...grpc.ServerOption) *grpc.Server {
	var opts []grpc.ServerOption
	opts = append(opts, grpc.CustomCodec(&codec{}))
	if tls != nil {
		opts = append(opts, grpc.Creds(credentials.NewTLS(tls)))
	}
	opts = append(opts, grpc.UnaryInterceptor(newUnaryInterceptor(s)))
	opts = append(opts, grpc.StreamInterceptor(newStreamInterceptor(s)))
	opts = append(opts, grpc.MaxRecvMsgSize(int(s.Cfg.MaxRequestBytes+grpcOverheadBytes)))
	opts = append(opts, grpc.MaxSendMsgSize(maxSendBytes))
	opts = append(opts, grpc.MaxConcurrentStreams(maxStreams))
	grpcServer := grpc.NewServer(append(opts, gopts...)...)

	pb.RegisterKVServer(grpcServer, NewQuotaKVServer(s))
	pb.RegisterWatchServer(grpcServer, NewWatchServer(s))
	pb.RegisterLeaseServer(grpcServer, NewQuotaLeaseServer(s))
	pb.RegisterClusterServer(grpcServer, NewClusterServer(s))
	pb.RegisterAuthServer(grpcServer, NewAuthServer(s))
	pb.RegisterMaintenanceServer(grpcServer, NewMaintenanceServer(s))

	// server should register all the services manually
	// use empty service name for all etcd services' health status,
	// see https://github.com/grpc/grpc/blob/master/doc/health-checking.md for more
	hsrv := health.NewServer()
	hsrv.SetServingStatus("", healthpb.HealthCheckResponse_SERVING)
	healthpb.RegisterHealthServer(grpcServer, hsrv)

	// set zero values for metrics registered for this grpc server
	grpc_prometheus.Register(grpcServer)

	grpclogOnce.Do(func() {
		if s.Cfg.Debug {
			grpc.EnableTracing = true
			// enable info, warning, error
			grpclog.SetLoggerV2(grpclog.NewLoggerV2(os.Stderr, os.Stderr, os.Stderr))
		} else {
			// only discard info
			grpclog.SetLoggerV2(grpclog.NewLoggerV2(ioutil.Discard, os.Stderr, os.Stderr))
		}
	})

	return grpcServer
}