// Licensed to the Apache Software Foundation (ASF) 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.

// A server to receive EchoRequest and send back EchoResponse.

#include <gflags/gflags.h>
#include <butil/logging.h>
#include <brpc/server.h>
#include <json2pb/pb_to_json.h>
#include "echo.pb.h"

DEFINE_bool(echo_attachment, true, "Echo attachment as well");
DEFINE_int32(port, 8000, "TCP Port of this server");
DEFINE_string(listen_addr, "", "Server listen address, may be IPV4/IPV6/UDS."
            " If this is set, the flag port will be ignored");
DEFINE_int32(idle_timeout_s, -1, "Connection will be closed if there is no "
             "read/write operations during the last `idle_timeout_s'");
DEFINE_bool(enable_checksum, false, "Enable checksum or not");

// Your implementation of example::EchoService
// Notice that implementing brpc::Describable grants the ability to put
// additional information in /status.
namespace example {
class EchoServiceImpl : public EchoService {
public:
    EchoServiceImpl() {}
    virtual ~EchoServiceImpl() {}
    virtual void Echo(google::protobuf::RpcController* cntl_base,
                      const EchoRequest* request,
                      EchoResponse* response,
                      google::protobuf::Closure* done) {
        // This object helps you to call done->Run() in RAII style. If you need
        // to process the request asynchronously, pass done_guard.release().
        brpc::ClosureGuard done_guard(done);

        brpc::Controller* cntl =
            static_cast<brpc::Controller*>(cntl_base);

        // optional: set a callback function which is called after response is sent
        // and before cntl/req/res is destructed.
        cntl->set_after_rpc_resp_fn(std::bind(&EchoServiceImpl::CallAfterRpc,
            std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));

        // The purpose of following logs is to help you to understand
        // how clients interact with servers more intuitively. You should 
        // remove these logs in performance-sensitive servers.
        LOG(INFO) << "Received request[log_id=" << cntl->log_id() 
                  << "] from " << cntl->remote_side() 
                  << " to " << cntl->local_side()
                  << ": " << request->message()
                  << " (attached=" << cntl->request_attachment() << ")";

        // Fill response.
        response->set_message(request->message());

        // You can compress the response by setting Controller, but be aware
        // that compression may be costly, evaluate before turning on.
        // cntl->set_response_compress_type(brpc::COMPRESS_TYPE_GZIP);

        if (FLAGS_echo_attachment) {
            // Set attachment which is wired to network directly instead of
            // being serialized into protobuf messages.
            cntl->response_attachment().append(cntl->request_attachment());
        }

        // Use checksum, only support CRC32C now.
        if (FLAGS_enable_checksum) {
            cntl->set_response_checksum_type(brpc::CHECKSUM_TYPE_CRC32C);
        }
    }

    // optional
    static void CallAfterRpc(brpc::Controller* cntl,
                        const google::protobuf::Message* req,
                        const google::protobuf::Message* res) {
        // at this time res is already sent to client, but cntl/req/res is not destructed
        std::string req_str;
        std::string res_str;
        json2pb::ProtoMessageToJson(*req, &req_str, NULL);
        json2pb::ProtoMessageToJson(*res, &res_str, NULL);
        LOG(INFO) << "req:" << req_str
                    << " res:" << res_str;
    }
};
}  // namespace example

int main(int argc, char* argv[]) {
    // Parse gflags. We recommend you to use gflags as well.
    GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);

    // Generally you only need one Server.
    brpc::Server server;

    // Instance of your service.
    example::EchoServiceImpl echo_service_impl;

    // Add the service into server. Notice the second parameter, because the
    // service is put on stack, we don't want server to delete it, otherwise
    // use brpc::SERVER_OWNS_SERVICE.
    if (server.AddService(&echo_service_impl, 
                          brpc::SERVER_DOESNT_OWN_SERVICE) != 0) {
        LOG(ERROR) << "Fail to add service";
        return -1;
    }

    butil::EndPoint point;
    if (!FLAGS_listen_addr.empty()) {
        if (butil::str2endpoint(FLAGS_listen_addr.c_str(), &point) < 0) {
            LOG(ERROR) << "Invalid listen address:" << FLAGS_listen_addr;
            return -1;
        }
    } else {
        point = butil::EndPoint(butil::IP_ANY, FLAGS_port);
    }
    // Start the server.
    brpc::ServerOptions options;
    options.idle_timeout_sec = FLAGS_idle_timeout_s;
    if (server.Start(point, &options) != 0) {
        LOG(ERROR) << "Fail to start EchoServer";
        return -1;
    }

    // Wait until Ctrl-C is pressed, then Stop() and Join() the server.
    server.RunUntilAskedToQuit();
    return 0;
}