#include <stdio.h>

#include <fstream>
#include <numeric>
#include <unordered_map>

#include "examples/sudoku/percentile.h"
#include "examples/sudoku/sudoku.h"
#include "muduo/base/FileUtil.h"
#include "muduo/base/Logging.h"
#include "muduo/net/EventLoop.h"
#include "muduo/net/TcpClient.h"

using namespace muduo;
using namespace muduo::net;

typedef std::vector<string>          Input;
typedef std::shared_ptr<const Input> InputPtr;

InputPtr readInput(std::istream& in)
{
    std::shared_ptr<Input> input(new Input);
    std::string            line;
    while (getline(in, line)) {
        if (line.size() == implicit_cast<size_t>(kCells)) {
            input->push_back(line.c_str());
        }
    }
    return input;
}

class SudokuClient : noncopyable {
public:
    SudokuClient(EventLoop* loop, const InetAddress& serverAddr,
                 const InputPtr& input, const string& name, bool nodelay)
        : name_(name),
          tcpNoDelay_(nodelay),
          client_(loop, serverAddr, name_),
          input_(input),
          count_(0)
    {
        client_.setConnectionCallback(
            std::bind(&SudokuClient::onConnection, this, _1));
        client_.setMessageCallback(
            std::bind(&SudokuClient::onMessage, this, _1, _2, _3));
    }

    void connect() { client_.connect(); }

    void send(int n)
    {
        assert(n > 0);
        if (!conn_) return;

        Timestamp now(Timestamp::now());
        for (int i = 0; i < n; ++i) {
            char          buf[256];
            const string& req = (*input_)[count_ % input_->size()];
            int len = snprintf(buf, sizeof buf, "%s-%08d:%s\r\n", name_.c_str(),
                               count_, req.c_str());
            requests_.append(buf, len);
            sendTime_[count_] = now;
            ++count_;
        }

        conn_->send(&requests_);
    }

    void report(std::vector<int>* latency, int* infly)
    {
        latency->insert(latency->end(), latencies_.begin(), latencies_.end());
        latencies_.clear();
        *infly += static_cast<int>(sendTime_.size());
    }

private:
    void onConnection(const TcpConnectionPtr& conn)
    {
        if (conn->connected()) {
            LOG_INFO << name_ << " connected";
            if (tcpNoDelay_) conn->setTcpNoDelay(true);
            conn_ = conn;
        } else {
            LOG_INFO << name_ << " disconnected";
            conn_.reset();
            // FIXME: exit
        }
    }

    void onMessage(const TcpConnectionPtr& conn, Buffer* buf,
                   Timestamp recvTime)
    {
        size_t len = buf->readableBytes();
        while (len >= kCells + 2) {
            const char* crlf = buf->findCRLF();
            if (crlf) {
                string response(buf->peek(), crlf);
                buf->retrieveUntil(crlf + 2);
                len = buf->readableBytes();
                if (!verify(response, recvTime)) {
                    LOG_ERROR << "Bad response:" << response;
                    conn->shutdown();
                    break;
                }
            } else if (len > 100)  // id + ":" + kCells + "\r\n"
            {
                LOG_ERROR << "Line is too long!";
                conn->shutdown();
                break;
            } else {
                break;
            }
        }
    }

    bool verify(const string& response, Timestamp recvTime)
    {
        size_t colon = response.find(':');
        if (colon != string::npos) {
            size_t dash = response.find('-');
            if (dash != string::npos && dash < colon) {
                int id = atoi(response.c_str() + dash + 1);
                std::unordered_map<int, Timestamp>::iterator sendTime =
                    sendTime_.find(id);
                if (sendTime != sendTime_.end()) {
                    int64_t latency_us =
                        recvTime.microSecondsSinceEpoch() -
                        sendTime->second.microSecondsSinceEpoch();
                    latencies_.push_back(static_cast<int>(latency_us));
                    sendTime_.erase(sendTime);
                } else {
                    LOG_ERROR << "Unknown id " << id << " of " << name_;
                }
            }
        }
        // FIXME
        return true;
    }

    const string                       name_;
    const bool                         tcpNoDelay_;
    TcpClient                          client_;
    TcpConnectionPtr                   conn_;
    Buffer                             requests_;
    const InputPtr                     input_;
    int                                count_;
    std::unordered_map<int, Timestamp> sendTime_;
    std::vector<int>                   latencies_;
};

class SudokuLoadtest : noncopyable {
public:
    SudokuLoadtest() : count_(0), ticks_(0), sofar_(0) {}

    void runClient(const InputPtr& input, const InetAddress& serverAddr,
                   int rps, int conn, bool nodelay)
    {
        EventLoop loop;

        for (int i = 0; i < conn; ++i) {
            Fmt    f("c%04d", i + 1);
            string name(f.data(), f.length());
            clients_.emplace_back(
                new SudokuClient(&loop, serverAddr, input, name, nodelay));
            clients_.back()->connect();
        }

        loop.runEvery(1.0 / kHz, std::bind(&SudokuLoadtest::tick, this, rps));
        loop.runEvery(1.0, std::bind(&SudokuLoadtest::tock, this));
        loop.loop();
    }

private:
    void tick(int rps)
    {
        ++ticks_;
        int64_t reqs = rps * ticks_ / kHz - sofar_;
        sofar_ += reqs;

        if (reqs > 0) {
            for (const auto& client : clients_) {
                client->send(static_cast<int>(reqs));
            }
        }
    }

    void tock()
    {
        std::vector<int> latencies;
        int              infly = 0;
        for (const auto& client : clients_) {
            client->report(&latencies, &infly);
        }

        Percentile p(latencies, infly);
        LOG_INFO << p.report();
        char buf[64];
        snprintf(buf, sizeof buf, "r%04d", count_);
        p.save(latencies, buf);
        ++count_;
    }

    std::vector<std::unique_ptr<SudokuClient>> clients_;
    int                                        count_;
    int64_t                                    ticks_;
    int64_t                                    sofar_;
    static const int                           kHz = 100;
};

int main(int argc, char* argv[])
{
    int         conn = 1;
    int         rps = 100;
    bool        nodelay = false;
    InetAddress serverAddr("127.0.0.1", 9981);
    switch (argc) {
        case 6:
            nodelay = string(argv[5]) == "-n";
            // FALL THROUGH
        case 5:
            conn = atoi(argv[4]);
            // FALL THROUGH
        case 4:
            rps = atoi(argv[3]);
            // FALL THROUGH
        case 3:
            serverAddr = InetAddress(argv[2], 9981);
            // FALL THROUGH
        case 2:
            break;
        default:
            printf(
                "Usage: %s input server_ip [requests_per_second] [connections] "
                "[-n]\n",
                argv[0]);
            return 0;
    }

    std::ifstream in(argv[1]);
    if (in) {
        InputPtr input(readInput(in));
        printf("%zd requests from %s\n", input->size(), argv[1]);
        SudokuLoadtest test;
        test.runClient(input, serverAddr, rps, conn, nodelay);
    } else {
        printf("Cannot open %s\n", argv[1]);
    }
}