syntax = "proto3";
package GrpcLibrary;

service GrpcService{
    rpc SayHello(HelloRequest) returns (HelloReply) {}
}

message HelloRequest{
    string name = 1;
}

message HelloReply{
    string message = 1;
}

// GrpcServer.cpp
#include <iostream>
#include <memory>
#include <string>

#include <grpcpp/grpcpp.h>

#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "HelloWorld.grpc.pb.h"
#endif

using grpc::Server;
using grpc::ServerBuilder;
using grpc::ServerContext;
using grpc::Status;
using GrpcLibrary::HelloRequest;
using GrpcLibrary::HelloReply;
using GrpcLibrary::GrpcService;

// Logic and data behind the server's behavior.
class GreeterServiceImpl final : public GrpcService::Service {
    Status SayHello(ServerContext* context, const HelloRequest* request, HelloReply* reply) override
    {
        std::string prefix("A Hello World demo, echo client request name: ");
        reply->set_message(prefix + request->name());
        return Status::OK;
    }
};

void RunServer() {
    std::string server_address("0.0.0.0:50051");
    GreeterServiceImpl service;

    ServerBuilder builder;
    // Listen on the given address without any authentication mechanism.
    builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
    // Register "service" as the instance through which we'll communicate with
    // clients. In this case it corresponds to an *synchronous* service.
    builder.RegisterService(&service);
    // Finally assemble the server.
    std::unique_ptr<Server> server(builder.BuildAndStart());
    std::cout << "Server listening on " << server_address << std::endl;

    // Wait for the server to shutdown. Note that some other thread must be
    // responsible for shutting down the server for this call to ever return.
    server->Wait();
}

int main(int argc, char** argv) {
    RunServer();

    return 0;
}

// GrpcClient.cpp
#include <iostream>
#include <memory>
#include <string>

#include <grpcpp/grpcpp.h>

#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "helloworld.grpc.pb.h"
#endif

using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using GrpcLibrary::HelloRequest;
using GrpcLibrary::HelloReply;
using GrpcLibrary::GrpcService;

class GreeterClient {
public:
    GreeterClient(std::shared_ptr<Channel> channel)
        : stub_(GrpcService::NewStub(channel)) {}


    std::string SayHello(const std::string& user) {
        // Data we are sending to the server.
        HelloRequest request;
        request.set_name(user);

        // Container for the data we expect from the server.
        HelloReply reply;

        // Context for the client. It could be used to convey extra information to
        // the server and/or tweak certain RPC behaviors.
        ClientContext context;

        // The actual RPC.
        Status status = stub_->SayHello(&context, request, &reply);

        // Act upon its status.
        if (status.ok()) {
            return reply.message();
        }
        else {
            std::cout << status.error_code() << ": " << status.error_message()
                << std::endl;
            return "RPC failed";
        }
    }

private:
    std::unique_ptr<GrpcService::Stub> stub_;
};

int main(int argc, char** argv) {

    GreeterClient greeter(grpc::CreateChannel(
        "localhost:50051", grpc::InsecureChannelCredentials()));
    std::string user("world");
    std::string reply = greeter.SayHello(user);
    std::cout << "Greeter received: " << reply << std::endl;
    system("pause");
    return 0;
}