// Copyright (c) 2014 Baidu, Inc.
// 
// 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.

// A client sending requests to servers(discovered by naming service) by multiple threads.

#include <gflags/gflags.h>
#include <bthread/bthread.h>
#include <butil/logging.h>
#include <butil/string_printf.h>
#include <butil/time.h>
#include <butil/macros.h>
#include <brpc/channel.h>
#include <brpc/server.h>
#include <deque>
#include "echo.pb.h"

DEFINE_int32(thread_num, 50, "Number of threads to send requests");
DEFINE_bool(use_bthread, false, "Use bthread to send requests");
DEFINE_int32(attachment_size, 0, "Carry so many byte attachment along with requests");
DEFINE_string(protocol, "baidu_std", "Protocol type. Defined in src/brpc/options.proto");
DEFINE_string(connection_type, "", "Connection type. Available values: single, pooled, short");
DEFINE_string(server, "file://server_list", "Addresses of servers");
DEFINE_string(load_balancer, "rr", "Name of load balancer");
DEFINE_int32(timeout_ms, 100, "RPC timeout in milliseconds");
DEFINE_int32(backup_timeout_ms, -1, "backup timeout in milliseconds");
DEFINE_int32(max_retry, 3, "Max retries(not including the first RPC)"); 
DEFINE_bool(dont_fail, false, "Print fatal when some call failed");
DEFINE_int32(dummy_port, -1, "Launch dummy server at this port");
DEFINE_string(http_content_type, "application/json", "Content type of http request");

std::string g_attachment;

bvar::LatencyRecorder g_latency_recorder("client");
bvar::Adder<int> g_error_count("client_error_count");
butil::static_atomic<int> g_sender_count = BUTIL_STATIC_ATOMIC_INIT(0);

static void* sender(void* arg) {
    // Normally, you should not call a Channel directly, but instead construct
    // a stub Service wrapping it. stub can be shared by all threads as well.
    example::EchoService_Stub stub(static_cast<google::protobuf::RpcChannel*>(arg));

    int log_id = 0;
    while (!brpc::IsAskedToQuit()) {
        // We will receive response synchronously, safe to put variables
        // on stack.
        example::EchoRequest request;
        example::EchoResponse response;
        brpc::Controller cntl;

        const int thread_index = g_sender_count.fetch_add(1, butil::memory_order_relaxed);
        const int input = ((thread_index & 0xFFF) << 20) | (log_id & 0xFFFFF);
        request.set_value(input);
        cntl.set_log_id(log_id ++);  // set by user
        if (FLAGS_protocol != "http" && FLAGS_protocol != "h2c") {
            // Set attachment which is wired to network directly instead of 
            // being serialized into protobuf messages.
            cntl.request_attachment().append(g_attachment);
        } else {
            cntl.http_request().set_content_type(FLAGS_http_content_type);
        }

        // Because `done'(last parameter) is NULL, this function waits until
        // the response comes back or error occurs(including timedout).
        stub.Echo(&cntl, &request, &response, NULL);
        if (!cntl.Failed()) {
            CHECK(response.value() == request.value() + 1);
            g_latency_recorder << cntl.latency_us();
        } else {
            g_error_count << 1;
            CHECK(brpc::IsAskedToQuit() || !FLAGS_dont_fail)        
                << "input=(" << thread_index << "," << (input & 0xFFFFF)        
                << ") error=" << cntl.ErrorText() << " latency=" << cntl.latency_us();
            // We can't connect to the server, sleep a while. Notice that this
            // is a specific sleeping to prevent this thread from spinning too
            // fast. You should continue the business logic in a production 
            // server rather than sleeping.
            bthread_usleep(50000);
        }
    }
    return NULL;
}

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

    // A Channel represents a communication line to a Server. Notice that 
    // Channel is thread-safe and can be shared by all threads in your program.
    brpc::Channel channel;
    
    // Initialize the channel, NULL means using default options.
    brpc::ChannelOptions options;
    options.backup_request_ms = FLAGS_backup_timeout_ms;
    options.protocol = FLAGS_protocol;
    options.connection_type = FLAGS_connection_type;
    options.timeout_ms = FLAGS_timeout_ms/*milliseconds*/;
    options.max_retry = FLAGS_max_retry;
    if (channel.Init(FLAGS_server.c_str(), FLAGS_load_balancer.c_str(), &options) != 0) {
        LOG(ERROR) << "Fail to initialize channel";
        return -1;
    }

    if (FLAGS_attachment_size > 0) {
        g_attachment.resize(FLAGS_attachment_size, 'a');
    }

    if (FLAGS_dummy_port >= 0) {
        brpc::StartDummyServerAt(FLAGS_dummy_port);
    }

    std::vector<bthread_t> tids;
    tids.resize(FLAGS_thread_num);
    if (!FLAGS_use_bthread) {
        for (int i = 0; i < FLAGS_thread_num; ++i) {
            if (pthread_create(&tids[i], NULL, sender, &channel) != 0) {
                LOG(ERROR) << "Fail to create pthread";
                return -1;
            }
        }
    } else {
        for (int i = 0; i < FLAGS_thread_num; ++i) {
            if (bthread_start_background(
                    &tids[i], NULL, sender, &channel) != 0) {
                LOG(ERROR) << "Fail to create bthread";
                return -1;
            }
        }
    }

    while (!brpc::IsAskedToQuit()) {
        sleep(1);
        LOG(INFO) << "Sending EchoRequest at qps=" << g_latency_recorder.qps(1)
                  << " latency=" << g_latency_recorder.latency(1);
    }

    LOG(INFO) << "EchoClient is going to quit";
    for (int i = 0; i < FLAGS_thread_num; ++i) {
        if (!FLAGS_use_bthread) {
            pthread_join(tids[i], NULL);
        } else {
            bthread_join(tids[i], NULL);
        }
    }

    return 0;
}
