package internal

import (
	"fmt"
	"log"
	"net"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/keepalive"

	clusterservice "github.com/envoyproxy/go-control-plane/envoy/service/cluster/v3"
	discoverygrpc "github.com/envoyproxy/go-control-plane/envoy/service/discovery/v3"
	endpointservice "github.com/envoyproxy/go-control-plane/envoy/service/endpoint/v3"
	listenerservice "github.com/envoyproxy/go-control-plane/envoy/service/listener/v3"
	routeservice "github.com/envoyproxy/go-control-plane/envoy/service/route/v3"
	runtimeservice "github.com/envoyproxy/go-control-plane/envoy/service/runtime/v3"
	secretservice "github.com/envoyproxy/go-control-plane/envoy/service/secret/v3"

	"github.com/envoyproxy/go-control-plane/pkg/server/v3"
)

const (
	grpcKeepaliveTime    = 30 * time.Second
	grpcKeepaliveTimeout = 5 * time.Second
	grpcKeepaliveMinTime = 30 * time.Second
	grpcMaxConcurrent    = 1000000
)

// RunServer starts the xDS management server on the given port.
func RunServer(srv server.Server, port uint) {
	var grpcOptions []grpc.ServerOption
	grpcOptions = append(grpcOptions,
		grpc.MaxConcurrentStreams(grpcMaxConcurrent),
		grpc.KeepaliveParams(keepalive.ServerParameters{
			Time:    grpcKeepaliveTime,
			Timeout: grpcKeepaliveTimeout,
		}),
		grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
			MinTime:             grpcKeepaliveMinTime,
			PermitWithoutStream: true,
		}),
	)

	grpcServer := grpc.NewServer(grpcOptions...)

	// Register all xDS services
	discoverygrpc.RegisterAggregatedDiscoveryServiceServer(grpcServer, srv)
	endpointservice.RegisterEndpointDiscoveryServiceServer(grpcServer, srv)
	clusterservice.RegisterClusterDiscoveryServiceServer(grpcServer, srv)
	routeservice.RegisterRouteDiscoveryServiceServer(grpcServer, srv)
	listenerservice.RegisterListenerDiscoveryServiceServer(grpcServer, srv)
	secretservice.RegisterSecretDiscoveryServiceServer(grpcServer, srv)
	runtimeservice.RegisterRuntimeDiscoveryServiceServer(grpcServer, srv)

	addr := fmt.Sprintf(":%d", port)
	lis, err := net.Listen("tcp", addr)
	if err != nil {
		log.Fatalf("failed to listen on %s: %v", addr, err)
	}

	log.Printf("management server listening on %s\n", addr)
	if err := grpcServer.Serve(lis); err != nil {
		log.Fatalf("gRPC server failed: %v", err)
	}
}