#include "nng_wrap.h"

#include <string.h>

#include <random>
#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <thread>
#include <atomic>
#include <deque>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <chrono>
#include <future>
using namespace std;

#include <unistd.h>

#include <nng/nng.h>
#include <nng/protocol/reqrep0/rep.h>
#include <nng/supplemental/util/platform.h>

#include "nng/compat/nanomsg/nn.h"
#include "nng/compat/nanomsg/reqrep.h"
#include "nng/compat/nanomsg/pubsub.h"
#include "nng/compat/nanomsg/survey.h"

namespace nng_wrap {

// common function
static int client_socket(const string& url, const int protocol, int family=AF_SP){
    int sock = nn_socket(family, protocol);
    if (sock < 0) return sock;
    int rc = nn_connect(sock, url.c_str());
    if (rc < 0) {
        nn_close(sock);
        return rc;
    }
    return sock;
}

static void remove_exist(const string& url){
    if (url.find("ipc://") == 0){
        string address(url);
        address = address.substr(6);
        if (access(address.c_str(), F_OK) == 0){
            remove(address.c_str());
        }
    }
}

static int server_socket(const string& url, const int protocol, int family=AF_SP){
    int sock = nn_socket(family, protocol);
    if (sock < 0) return sock;
    remove_exist(url);
    int rc = nn_bind(sock, url.c_str());
    if (rc < 0) {
        nn_close(sock);
        return rc;
    }
    return sock;
}

static void set_socket_timeout(int sock, const int to_ms){
    nn_setsockopt(sock, NN_SOL_SOCKET, NN_SNDTIMEO, &to_ms, sizeof(to_ms));
    nn_setsockopt(sock, NN_SOL_SOCKET, NN_RCVTIMEO, &to_ms, sizeof(to_ms));
}

static int send_and_recv(int sock,
    const void* in, const int in_len,
    void** out, int *out_len)
{
    int rc = nn_send(sock, in, in_len, 0);
    if (rc != in_len) {
        nn_close(sock);
        return -1;
    }
    char *msg = NULL;
    rc = nn_recv(sock, &msg, NN_MSG, 0);
    if (rc < 0) {
        nn_close(sock);
        return rc;
    }
    nn_close(sock);
    copy_memory(out, out_len, msg, rc);
    nn_freemsg(msg);
    return 0;
}

/////////////////////////////////////////////////
// simple interface

void free_nng(void* data, const int data_len){
    if (data){
        free(data);
    }
}

void copy_memory(void** dest, int *dest_len, const void* src, const int src_len){
    char* tmp = (char*)malloc(src_len);
    memcpy(tmp, src, src_len);
    *dest = tmp;
    if(dest_len)
        *dest_len = src_len;
}

static string verbose_info{};
#ifndef PRNTVITAG
// #define TAG do{ \
//     if (verbose_info.length() > 8096) verbose_info.clear(); \
//     verbose_info=string("function [")+__FUNCTION__+string("]");}while(0)
/* #define PRNTVITAG(msg) do{ \
            if (verbose_info.length() > 8096) verbose_info.clear(); \
            verbose_info+=string("-> (") + msg + string(")"); \
        }while(0) */
#define TAG
#define PRNTVITAG(args)
#endif
void get_last_error(int* ec, void** emsg, int* emsg_len){
    *emsg = NULL;
    *emsg_len = 0;

    *ec = nn_errno();
    const char* msg = nn_strerror(*ec);
    string strMsg(msg);
    strMsg = strMsg + "{" + verbose_info + "}";
    copy_memory(emsg, emsg_len, strMsg.data(), strMsg.size());
    verbose_info.clear();
}

///////////////////////////////////////////////////////
// simple request waiting reply

static constexpr int timeout_req_rep = 5162;
int simple_request(const std::string& url,
    const void* in, const int in_len,
    void** out, int *out_len, const int to_ms){

    TAG;
    *out = NULL;
    *out_len = 0;

    // printf("------>> simple_request url %s\n", (char*)url.data);
    int sock = client_socket(url, NN_REQ);
    if (sock < 0) {
        PRNTVITAG("client_socket faild");
        return false;
    }

    int tm = to_ms < timeout_req_rep ? timeout_req_rep : to_ms;
    set_socket_timeout(sock, tm);

    auto ret = send_and_recv(sock, in, in_len, out, out_len);
    // printf("------>> simple_request out data address %p len %d\n", out->data, out->data_len);
    if (ret < 0) {
        PRNTVITAG("send_and_recv faild");
        return false;
    }
    return true;
}

///////////////////////////////////////////////////////////
// base class
#define DISABLE_COPY_AND_ASSIGN(className) className(const className&)=delete; \
                                className(className&&)=delete; \
                                className& operator=(const className&)=delete; \
                                className& operator=(className&&)=delete
class _nn{
public:
    DISABLE_COPY_AND_ASSIGN(_nn);
    _nn()=default;
    virtual ~_nn(){ if (socket_ > 0) nn_close(socket_); }
    int                         socket_{-1};
    string                      url_{};
};

///////////////////////////////////////////////
// publish
struct psmsg{
    DISABLE_COPY_AND_ASSIGN(psmsg);
    psmsg()=delete;
    psmsg(const std::string& t, std::string&& m)
    :topic_(t),msg_(std::move(m)){}
    std::string topic_{};
    std::string msg_{};
};
class _ps : public _nn{
public:
    DISABLE_COPY_AND_ASSIGN(_ps);
    _ps()=default;
    virtual ~_ps(){
        t_quit_.store(true, memory_order_relaxed);
        if (t_.joinable()) t_.join();
    }

    thread              t_;
    atomic_bool         t_quit_{false};
    deque<psmsg>        msg_{};
    mutex               mtx_msg_{};
    condition_variable  cv_msg_{};
};

static _ps pub_;
static int connect_to_center(const string& topic){
    if (pub_.socket_ > 0) return pub_.socket_;
    pub_.url_ = topic;

    TAG;
    int sock = client_socket(topic, NN_REQ);
    if (sock < 0){
        PRNTVITAG("client_socket faild");
        return -1;
    }
    set_socket_timeout(sock, timeout_req_rep);
    pub_.socket_ = sock;
    pub_.t_ = thread([]{
        while (!pub_.t_quit_.load()) {
            psmsg *msg{NULL};
            {
                unique_lock<mutex> l{pub_.mtx_msg_};
                pub_.cv_msg_.wait(l, []{
                    return !pub_.msg_.empty() || pub_.t_quit_.load();
                });
                if(pub_.t_quit_.load()) break;
                msg = &pub_.msg_.front();
                if (msg->topic_.empty()) {pub_.msg_.pop_front(); continue;}
            }
            const auto &topic = msg->topic_;
            const auto topic_size = topic.size();
            const auto &data = msg->msg_;
            const auto data_size = data.size();

            char *sndmsg = (char*)malloc(topic_size + data_size);
            memcpy(sndmsg, topic.data(), topic_size);
            memcpy(sndmsg+topic_size, data.data(), data_size);
            int rc = nn_send(pub_.socket_, sndmsg, data_size+topic_size, 0);
            free(sndmsg);
            if (rc == (int)(data_size+topic_size)){
                char* tmp{};
                rc = nn_recv(pub_.socket_, &tmp, NN_MSG, 0);
                if (rc > 0){
                    nn_freemsg(tmp);
                    printf("======>> publish topic %s data length %lu\n", topic.c_str(), data_size);
                    lock_guard<mutex> l{pub_.mtx_msg_};
                    pub_.msg_.pop_front();
                    continue;
                }else{
                    PRNTVITAG("publish req-rep thread nn_recv faild");
                }
            }else{
                PRNTVITAG("publish req-rep thread nn_send faild");
            }

        }
    });
    return sock;
}

int publish(const std::string& topic, const void* data, const int data_len){
    if (!data && data_len == 0){
        // printf("======>> publish start url %s\n", topic.c_str());
        return connect_to_center(topic);
    }
    if (pub_.socket_ < 0){
        connect_to_center(pub_.url_);
    }
    if(pub_.socket_ < 0) {
        PRNTVITAG("publish socket_ < 0");
        return -1;
    }

    // printf("======>> publish topic %s\n", topic.c_str());
    lock_guard<mutex> l{pub_.mtx_msg_};
    pub_.msg_.emplace_back(topic, string{(const char*)data, (const size_t)data_len});
    pub_.cv_msg_.notify_one();
    return pub_.msg_.size();
}

///////////////////////////////////////////////
// subscribe
class _ps_sub : public _ps{
public:
    DISABLE_COPY_AND_ASSIGN(_ps_sub);
    _ps_sub()=default;
    ~_ps_sub()=default;

    unordered_set<string>   topics_{};
    mutex                   mtx_topics_{};
    unordered_set<string>   failed_topics_{};
    mutex                   mtx_failed_topics_{};
};

static _ps_sub sub_;
int subscribe_center(const std::string& url){
    if (sub_.socket_ > 0) return 0;
    sub_.url_ = url;

    int sock = client_socket(url, NN_SUB);
    if (sock < 0){
        return -1;
    }
    // set_socket_timeout(sock, timeout_req_rep);
    sub_.socket_ = sock;
    sub_.t_ = thread([]{
        while (!sub_.t_quit_.load()) {
            char* m;
            int m_len = nn_recv(sub_.socket_, &m, NN_MSG, NN_DONTWAIT);
            if (m_len > 0){
                string topic{}, msg{};
                {
                    lock_guard<mutex> l{sub_.mtx_topics_};
                    for(auto && i : sub_.topics_){
                        auto topic_len = i.size();
                        if (m_len <= (int)topic_len) continue;
                        topic.assign(m, topic_len);
                        if (topic == i){
                            msg.assign(m+topic_len, m_len-topic_len);
                            break;
                        }
                    }
                }
                nn_freemsg(m);
                printf("======>> subscribe recv topic %s msg length %lu\n", topic.c_str(), msg.length());
                if (!msg.empty()){
                    lock_guard<mutex> l(sub_.mtx_msg_);
                    sub_.msg_.emplace_back(topic, move(msg));
                    sub_.cv_msg_.notify_all();
                }

            }else {
                {
                    lock_guard<mutex> l{sub_.mtx_failed_topics_};
                    if (!sub_.failed_topics_.empty()){
                        for(auto iter = sub_.failed_topics_.begin(); iter != sub_.failed_topics_.end();){
                            if (nn_setsockopt(sub_.socket_, NN_SUB, NN_SUB_UNSUBSCRIBE, iter->c_str(), iter->length()) >= 0){
                                iter = sub_.failed_topics_.erase(iter);
                            }else{
                                iter++;
                            }
                        }
                    }
                }
                this_thread::sleep_for(chrono::milliseconds{6});
                // printf("======>> subscribe nn_recv failed %s\n", nn_strerror(nn_errno()));
            }
        }
    });
    return 0;
}

int subscribe_topic(const std::string& topic){
    if (sub_.socket_ < 0){
        subscribe_center(sub_.url_);
    }
    if (sub_.socket_ < 0) return -1;

    auto ret = nn_setsockopt(sub_.socket_, NN_SUB, NN_SUB_SUBSCRIBE, topic.c_str(), topic.length());
    // printf("set NN_SUB_SUBSCRIBE topic %s ret %d\n", topic.c_str(), ret);
    if (ret < 0){
        lock_guard<mutex> l{sub_.mtx_failed_topics_};
        sub_.failed_topics_.insert(topic);
    }
    lock_guard<mutex> l{sub_.mtx_topics_};
    sub_.topics_.insert(topic);

    return 0;
}

int unsubscribe_topic(const std::string& topic){
    lock_guard<mutex> l(sub_.mtx_topics_);
    auto iter = sub_.topics_.find(topic);
    if (iter != sub_.topics_.end()){
        nn_setsockopt(sub_.socket_, NN_SUB, NN_SUB_UNSUBSCRIBE, topic.c_str(), topic.length());
        sub_.topics_.erase(iter);
    }

    return 0;
}

int subscribe_read(std::string* topic, std::string* msg, const int to_ms){

    int tm = to_ms > 0 ? to_ms : 30;

    unique_lock<mutex> l(sub_.mtx_msg_);
    auto status = sub_.cv_msg_.wait_for(l, chrono::milliseconds{tm}, []{
        return !sub_.msg_.empty();
    });
    if (!status){
        PRNTVITAG("subscribe_read timeout");
        return -1;
    }
    const auto& tmp = sub_.msg_.front();
    *topic = tmp.topic_;
    *msg = tmp.msg_;
    sub_.msg_.pop_front();

    return 0;
}

///////////////////////////////////////////////////////////
// survey respondent for heartbeat

class _sv : public _nn{
public:
    DISABLE_COPY_AND_ASSIGN(_sv);
    _sv()=default;
    ~_sv(){
        t_quit_.store(true, memory_order_relaxed);
        if (t_.joinable()) t_.join();
    }

    thread      t_;
    atomic_bool t_quit_{false};
    string      fixed_msg_{};
};

static _sv survey_;
int respond_survey(const std::string& url, std::string&& fixed_msg){
    survey_.url_ = url;
    survey_.fixed_msg_ = move(fixed_msg);
    survey_.t_ = thread([]{
        int& sock = survey_.socket_;
        const auto& msg = survey_.fixed_msg_;
        while (!survey_.t_quit_.load()) {
            if (sock < 0){
                sock = client_socket(survey_.url_, NN_RESPONDENT);
                if (sock > 0){
                    set_socket_timeout(sock, 126);
                }
            }
            if (sock < 0) continue;

            char* tmp{};
            int rc = nn_recv(sock, &tmp, NN_MSG, 0);
            if (rc > 0){
                nn_freemsg(tmp);
                rc = nn_send(sock, msg.data(), msg.size(), 0);
                if (rc < 0){
                    PRNTVITAG("heartbeat survey failed");
                    PRNTVITAG(nn_strerror(nn_errno()));
                }
            }
        }
    });

    return 0;
}

//////////////////////////////////////////////
// reply for request

int request2(const std::string &ipc, const void* r, const int r_len,
    void** reply, int* reply_len, const int to_ms)
{
    return simple_request(ipc, r, r_len, reply, reply_len, to_ms);
}

enum { INIT, RECV, WAIT, SEND };
struct work {
    int state{-1};
    nng_aio *aio{};
    nng_msg *msg{};
    nng_ctx  ctx;
    void(*cb_recv)(work*){};
};

class _rr : public _nn{
public:
    DISABLE_COPY_AND_ASSIGN(_rr);
    _rr()=default;
    ~_rr(){

    }

    nng_socket                                      sock_local_{0};
    nng_socket                                      sock_remote_{0};
    int                                             port_{-1};

    unordered_map<uint64_t, string>                 msg_{};
    unordered_map<uint64_t, struct work*>           works_{};
    uint64_t                                        work_index_{0};
    mutex                                           mtx_msg_{};
    condition_variable                              cv_msg_{};

};

static _rr reply_;

static void
server_cb(void *arg)
{
    struct work *work = (struct work*)arg;
    nng_msg *    msg;
    int          rv;
    uint32_t     when{0};

    switch (work->state) {
    case INIT:
        work->state = RECV;
        nng_ctx_recv(work->ctx, work->aio);
        break;
    case RECV:
        if ((rv = nng_aio_result(work->aio)) != 0) {
            break;
        }
        msg = nng_aio_get_msg(work->aio);

        work->msg   = msg;
        work->state = WAIT;
        if (work->cb_recv) work->cb_recv(work);
        // nng_sleep_aio(when, work->aio);
        break;
    case WAIT:
        // We could add more data to the message here.
        nng_aio_set_msg(work->aio, work->msg);
        work->msg   = NULL;
        work->state = SEND;
        nng_ctx_send(work->ctx, work->aio);
        break;
    case SEND:
        if ((rv = nng_aio_result(work->aio)) != 0) {
            nng_msg_free(work->msg);
            break;
        }
        work->state = RECV;
        nng_ctx_recv(work->ctx, work->aio);
        break;
    default:
        break;
    }
}

static void cb_recv_for_aio(work* w){
    nng_msg *om = w->msg;
    string msg{(const char*)nng_msg_body(om), nng_msg_len(om)};
    nng_msg_free(om);

    lock_guard<mutex> l{reply_.mtx_msg_};
    reply_.works_[reply_.work_index_] = w;
    reply_.msg_[reply_.work_index_] = msg;
    reply_.work_index_++;
    reply_.cv_msg_.notify_all();
}

static struct work *alloc_work(nng_socket sock)
{
    struct work *w;
    int          rv;

    if ((w = (struct work*)nng_alloc(sizeof(*w))) == NULL) {
        return NULL;;
    }
    w->cb_recv = cb_recv_for_aio;

    if ((rv = nng_aio_alloc(&w->aio, server_cb, w)) != 0) {
        return NULL;
    }
    if ((rv = nng_ctx_open(&w->ctx, sock)) != 0) {
        return NULL;
    }
    w->state = INIT;
    return (w);
}

static constexpr int PARALLEL = 62;
static struct work* works[PARALLEL]{};

static int create_server(nng_socket* sock, const string& url){
    TAG;
    if (sock->id > 0) return 0;

    int rv = nng_rep0_open(sock);
    if (rv < 0){
        PRNTVITAG("create_server nng_rep0_open faild");
        PRNTVITAG(url);
        return rv;
    }
    for (int i = 0; i < PARALLEL; i++) {
        works[i] = alloc_work(*sock);
    }

    remove_exist(url);
    rv = nng_listen(*sock, url.c_str(), NULL, 0);
    if (rv < 0){
        PRNTVITAG("create_server nng_listen failed");
        PRNTVITAG(url);
        return rv;
    }

    for (int i = 0; i < PARALLEL; i++) {
        server_cb(works[i]); // this starts them going (INIT state)
    }

    return 0;
}

int start_reply(const std::string& url, const int port){
    TAG;

    string ipc = "ipc:///tmp/" + url;
    if (url.find("ipc://") == 0){
        ipc = url;
    }
    reply_.url_ = ipc;
    if(create_server(&reply_.sock_local_, ipc) != 0) return -1;

    if (port > 0){
        reply_.port_ = port;
        ipc = "tcp://0.0.0.0:" + to_string(port);
        if(create_server(&reply_.sock_remote_, ipc) != 0) return -1;
    }else {
        reply_.sock_remote_.id = numeric_limits<int32_t>::max();
    }

    return 0;
}

int read_request(void** src, std::string* msg, const int to_ms){

    if (reply_.sock_local_.id == 0 || reply_.sock_remote_.id == 0) {
        if (start_reply(reply_.url_, reply_.port_) != 0)
            return -1;
    }

    int tm = to_ms > 0 ? to_ms : 30;

    uint64_t key{};
    string tmpmsg;
    {
        unique_lock<mutex> l(reply_.mtx_msg_);
        auto status = reply_.cv_msg_.wait_for(l, chrono::milliseconds{tm}, []{
            return !reply_.msg_.empty();
        });
        if (!status){
            PRNTVITAG("subscribe_read timeout");
            return -1;
        }
        const auto& iter = reply_.msg_.begin();
        key = iter->first;
        tmpmsg = iter->second;
        reply_.msg_.erase(iter);
    }
    *msg = move(tmpmsg);

    auto s = (uint64_t*)malloc(sizeof(uint64_t));
    *s = key;
    *src = s;

    return 0;
}

int send_reply(const void* src, const void* msg, const int msg_len){
    struct work* w{};
    {
        auto key = *(static_cast<uint64_t*>(const_cast<void*>(src)));

        lock_guard<mutex> l{reply_.mtx_msg_};
        auto iter = reply_.works_.find(key);
        if (iter == reply_.works_.end()) return -1;
        w = iter->second;
        reply_.works_.erase(iter);
    }

    TAG;

    nng_msg_alloc(&w->msg, 0);
    nng_msg_append(w->msg, msg, msg_len);

    nng_sleep_aio(0, w->aio);

    return 0;
}


}