/*
The MIT License (MIT)

Copyright (c) 2013-2015 SRS(ossrs)
Copyright (c) 2013-2015 SRS(ossrs)

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include <srs_app_bandwidth.hpp>

#include <arpa/inet.h>
#include <sstream>

using namespace std;

#include <srs_rtmp_stack.hpp>
#include <srs_rtmp_amf0.hpp>
#include <srs_app_config.hpp>
#include <srs_core_autofree.hpp>
#include <srs_kernel_utility.hpp>
#include <srs_app_utility.hpp>
#include <srs_protocol_kbps.hpp>
#include <srs_app_st.hpp>

#define _SRS_BANDWIDTH_LIMIT_INTERVAL_MS 100

// default sample duration, in ms
#define _SRS_BANDWIDTH_SAMPLE_DURATION_MS 3000

// wait for a while for flash to got all packets.
#define _SRS_BANDWIDTH_FINAL_WAIT_MS 600

SrsBandwidthSample::SrsBandwidthSample()
{
    duration_ms = _SRS_BANDWIDTH_SAMPLE_DURATION_MS;
    kbps = interval_ms = actual_duration_ms = bytes = 0;
}

SrsBandwidthSample::~SrsBandwidthSample()
{
}

void SrsBandwidthSample::calc_kbps(int _bytes, int _duration)
{
    bytes = _bytes;
    actual_duration_ms = _duration;
    
    if (actual_duration_ms <= 0) {
        return;
    }
    
    kbps = bytes * 8 / actual_duration_ms;
}

/**
* recv bandwidth helper.
*/
typedef bool (*_CheckPacketType)(SrsBandwidthPacket* pkt);
bool _bandwidth_is_final(SrsBandwidthPacket* pkt)
{
    return pkt->is_final();
}
bool _bandwidth_is_starting_play(SrsBandwidthPacket* pkt)
{
    return pkt->is_starting_play();
}
bool _bandwidth_is_stopped_play(SrsBandwidthPacket* pkt)
{
    return pkt->is_stopped_play();
}
bool _bandwidth_is_starting_publish(SrsBandwidthPacket* pkt)
{
    return pkt->is_starting_publish();
}
bool _bandwidth_is_stopped_publish(SrsBandwidthPacket* pkt)
{
    return pkt->is_stopped_publish();
}
int _srs_expect_bandwidth_packet(SrsRtmpServer* rtmp, _CheckPacketType pfn)
{
    int ret = ERROR_SUCCESS;
    
    while (true) {
        SrsCommonMessage* msg = NULL;
        SrsBandwidthPacket* pkt = NULL;
        if ((ret = rtmp->expect_message<SrsBandwidthPacket>(&msg, &pkt)) != ERROR_SUCCESS) {
            return ret;
        }
        SrsAutoFree(SrsCommonMessage, msg);
        SrsAutoFree(SrsBandwidthPacket, pkt);
        srs_info("get bwtc message success.");
        
        if (pfn(pkt)) {
            return ret;
        }
    }
    
    return ret;
}

SrsBandwidth::SrsBandwidth()
{
    _req = NULL;
    _rtmp = NULL;
}

SrsBandwidth::~SrsBandwidth()
{
}

int SrsBandwidth::bandwidth_check(SrsRtmpServer* rtmp, ISrsProtocolStatistic* io_stat, SrsRequest* req, string local_ip)
{
    int ret = ERROR_SUCCESS;
    
    _rtmp = rtmp;
    _req = req;
    
    if (!_srs_config->get_bw_check_enabled(_req->vhost)) {
        return ret;
    }

    // validate the bandwidth check key
    std::string key = "key=" + _srs_config->get_bw_check_key(_req->vhost);
    if (_req->tcUrl.find(key) == std::string::npos) {
        ret = ERROR_SYSTEM_BANDWIDTH_KEY;
        srs_error("check the vhost=%s %s failed, tcUrl=%s, ret=%d", 
            _req->vhost.c_str(), key.c_str(), _req->tcUrl.c_str(), ret);
        return ret;
    }
    
    // shared global last check time,
    // to prevent bandwidth check attack,
    // if client request check in the window(specifeid by interval),
    // directly reject the request.
    static int64_t last_check_time = 0;
    int interval_ms = _srs_config->get_bw_check_interval_ms(_req->vhost);
    
    srs_update_system_time_ms();
    int64_t time_now = srs_get_system_time_ms();
    // reject the connection in the interval window.
    if (last_check_time > 0 && time_now - last_check_time < interval_ms) {
        ret = ERROR_SYSTEM_BANDWIDTH_DENIED;
        srs_trace("reject, "
            "last_check=%"PRId64", now=%"PRId64", interval=%d",
            last_check_time, time_now, interval_ms);
            
        _rtmp->response_connect_reject(_req, "bandcheck rejected");
        return ret;
    }
    
    // accept and do bandwidth check.
    last_check_time = time_now;
    
    if ((ret = _rtmp->response_connect_app(_req, local_ip.c_str())) != ERROR_SUCCESS) {
        srs_error("response connect app failed. ret=%d", ret);
        return ret;
    }
    
    // create a limit object.
    SrsKbps kbps;
    kbps.set_io(io_stat, io_stat);

    int limit_kbps = _srs_config->get_bw_check_limit_kbps(_req->vhost);
    SrsKbpsLimit limit(&kbps, limit_kbps);
    
    return do_bandwidth_check(&limit);
}

int SrsBandwidth::do_bandwidth_check(SrsKbpsLimit* limit)
{
    int ret = ERROR_SUCCESS;

    SrsBandwidthSample play_sample;
    SrsBandwidthSample publish_sample;
    
    // timeout for a packet.
    _rtmp->set_send_timeout(play_sample.duration_ms * 1000 * 2);
    _rtmp->set_recv_timeout(publish_sample.duration_ms * 1000 * 2);

    // start test.
    srs_update_system_time_ms();
    int64_t start_time = srs_get_system_time_ms();
    
    // sample play
    srs_info("start play test.");
    
    if ((ret = play_start(&play_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth play check failed. ret=%d", ret);
        return ret;
    }
    if ((ret = play_checking(&play_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth play check failed. ret=%d", ret);
        return ret;
    }
    if ((ret = play_stop(&play_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth play check failed. ret=%d", ret);
        return ret;
    }
    
    srs_info("stop play test. kbps=%d", play_sample.kbps);
    
    // sample publish
    srs_info("start publish test.");
    
    if ((ret = publish_start(&publish_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth publish check failed. ret=%d", ret);
        return ret;
    }
    if ((ret = publish_checking(&publish_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth publish check failed. ret=%d", ret);
        return ret;
    }
    if ((ret = publish_stop(&publish_sample, limit)) != ERROR_SUCCESS) {
        srs_error("bandwidth publish check failed. ret=%d", ret);
        return ret;
    }
    
    srs_info("stop publish test. kbps=%d", publish_sample.kbps);

    // stop test.
    srs_update_system_time_ms();
    int64_t end_time = srs_get_system_time_ms();

    srs_trace("bandwidth ok. duartion=%dms(%d+%d), play=%dkbps, publish=%dkbps", 
        (int)(end_time - start_time), play_sample.actual_duration_ms, 
        publish_sample.actual_duration_ms, play_sample.kbps, 
        publish_sample.kbps);
    
    if ((ret = finial(play_sample, publish_sample, start_time, end_time)) != ERROR_SUCCESS) {
        return ret;
    }
    
    st_usleep(_SRS_BANDWIDTH_FINAL_WAIT_MS * 1000);
    srs_info("BW check finished.");

    return ret;
}

int SrsBandwidth::play_start(SrsBandwidthSample* sample, SrsKbpsLimit* limit)
{
    int ret = ERROR_SUCCESS;
    
    if (true) {
        // send start play command to client
        SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_start_play();
    
        pkt->data->set("limit_kbps", SrsAmf0Any::number(limit->limit_kbps()));
        pkt->data->set("duration_ms", SrsAmf0Any::number(sample->duration_ms));
        pkt->data->set("interval_ms", SrsAmf0Any::number(sample->interval_ms));
    
        if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
            srs_error("send bandwidth check start play message failed. ret=%d", ret);
            return ret;
        }
    }
    srs_info("BW check play begin.");

    if ((ret = _srs_expect_bandwidth_packet(_rtmp, _bandwidth_is_starting_play)) != ERROR_SUCCESS) {
        return ret;
    }
    srs_info("BW check recv play begin response.");
    
    return ret;
}

int SrsBandwidth::play_checking(SrsBandwidthSample* sample, SrsKbpsLimit* limit)
{
    int ret = ERROR_SUCCESS;

    // send play data to client
    int size = 1024; // TODO: FIXME: magic number
    char random_data[size];
    memset(random_data, 'A', size);

    int data_count = 1;
    srs_update_system_time_ms();
    int64_t starttime = srs_get_system_time_ms();
    while ((srs_get_system_time_ms() - starttime) < sample->duration_ms) {
        st_usleep(sample->interval_ms);
        
        // TODO: FIXME: use shared ptr message.
        SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_playing();

        // TODO: FIXME: magic number
        for (int i = 0; i < data_count; ++i) {
            std::stringstream seq;
            seq << i;
            std::string play_data = "SRS band check data from server's playing......";
            pkt->data->set(seq.str(), SrsAmf0Any::str(play_data.c_str()));
        }
        data_count += 2;

        if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
            srs_error("send bandwidth check play messages failed. ret=%d", ret);
            return ret;
        }
        
        limit->send_limit();
    }
    srs_update_system_time_ms();
    sample->calc_kbps(_rtmp->get_send_bytes(), srs_get_system_time_ms() - starttime);
    srs_info("BW check send play bytes over.");
    
    return ret;
}

int SrsBandwidth::play_stop(SrsBandwidthSample* sample, SrsKbpsLimit* /*limit*/)
{
    int ret = ERROR_SUCCESS;

    if (true) {
        // notify client to stop play
        SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_stop_play();
        
        pkt->data->set("duration_ms", SrsAmf0Any::number(sample->duration_ms));
        pkt->data->set("interval_ms", SrsAmf0Any::number(sample->interval_ms));
        pkt->data->set("duration_delta", SrsAmf0Any::number(sample->actual_duration_ms));
        pkt->data->set("bytes_delta", SrsAmf0Any::number(sample->bytes));

        if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
            srs_error("send bandwidth check stop play message failed. ret=%d", ret);
            return ret;
        }
    }
    srs_info("BW check stop play bytes.");

    if ((ret = _srs_expect_bandwidth_packet(_rtmp, _bandwidth_is_stopped_play)) != ERROR_SUCCESS) {
        return ret;
    }
    srs_info("BW check recv stop play response.");
    
    return ret;
}

int SrsBandwidth::publish_start(SrsBandwidthSample* sample, SrsKbpsLimit* limit)
{
    int ret = ERROR_SUCCESS;

    if (true) {
        // notify client to start publish
        SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_start_publish();
    
        pkt->data->set("limit_kbps", SrsAmf0Any::number(limit->limit_kbps()));
        pkt->data->set("duration_ms", SrsAmf0Any::number(sample->duration_ms));
        pkt->data->set("interval_ms", SrsAmf0Any::number(sample->interval_ms));
    
        if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
            srs_error("send bandwidth check start publish message failed. ret=%d", ret);
            return ret;
        }
    }
    srs_info("BW check publish begin.");

    if ((ret = _srs_expect_bandwidth_packet(_rtmp, _bandwidth_is_starting_publish)) != ERROR_SUCCESS) {
        return ret;
    }
    srs_info("BW check recv publish begin response.");
    
    return ret;
}

int SrsBandwidth::publish_checking(SrsBandwidthSample* sample, SrsKbpsLimit* limit)
{
    int ret = ERROR_SUCCESS;

    // recv publish msgs until @duration_ms ms
    srs_update_system_time_ms();
    int64_t starttime = srs_get_system_time_ms();
    while ((srs_get_system_time_ms() - starttime) < sample->duration_ms) {
        SrsCommonMessage* msg = NULL;
        SrsBandwidthPacket* pkt = NULL;
        if ((ret = _rtmp->expect_message<SrsBandwidthPacket>(&msg, &pkt)) != ERROR_SUCCESS) {
            return ret;
        }
        SrsAutoFree(SrsCommonMessage, msg);
        SrsAutoFree(SrsBandwidthPacket, pkt);
        srs_info("get publish message success.");
        
        // client requires to stop.
        if (pkt->is_stop_publish()) {
            break;
        }
        
        limit->recv_limit();
    }
    srs_update_system_time_ms();
    sample->calc_kbps(_rtmp->get_recv_bytes(), srs_get_system_time_ms() - starttime);
    srs_info("BW check recv publish data over.");
    
    return ret;
}

int SrsBandwidth::publish_stop(SrsBandwidthSample* sample, SrsKbpsLimit* /*limit*/)
{
    int ret = ERROR_SUCCESS;

    if (true) {
        // notify client to stop publish
        SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_stop_publish();
        pkt->data->set("duration_ms", SrsAmf0Any::number(sample->duration_ms));
        pkt->data->set("interval_ms", SrsAmf0Any::number(sample->interval_ms));
        pkt->data->set("duration_delta", SrsAmf0Any::number(sample->actual_duration_ms));
        pkt->data->set("bytes_delta", SrsAmf0Any::number(sample->bytes));

        if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
            srs_error("send bandwidth check stop publish message failed. ret=%d", ret);
            return ret;
        }
    }
    srs_info("BW check stop publish bytes.");

    // expect client to stop publish
    // if flash client, we never expect the client stop publish bytes, 
    // for the flash send call packet to test publish bandwidth,
    // there are many many packets in the queue.
    // we just ignore the packet and send the bandwidth test data.
    bool is_flash = (_req->swfUrl != "");
    if (!is_flash) {
        if ((ret = _srs_expect_bandwidth_packet(_rtmp, _bandwidth_is_stopped_publish)) != ERROR_SUCCESS) {
            return ret;
        }
        srs_info("BW check recv stop publish response.");
    }
    
    return ret;
}

int SrsBandwidth::finial(SrsBandwidthSample& play_sample, SrsBandwidthSample& publish_sample, int64_t start_time, int64_t& end_time)
{
    int ret = ERROR_SUCCESS;

    // send finished msg,
    // flash client will close connection when got this packet,
    // for the publish queue may contains packets.
    SrsBandwidthPacket* pkt = SrsBandwidthPacket::create_finish();
    pkt->data->set("start_time",     SrsAmf0Any::number(start_time));
    pkt->data->set("end_time",       SrsAmf0Any::number(end_time));
    pkt->data->set("play_kbps",      SrsAmf0Any::number(play_sample.kbps));
    pkt->data->set("publish_kbps",   SrsAmf0Any::number(publish_sample.kbps));
    pkt->data->set("play_bytes",     SrsAmf0Any::number(play_sample.bytes));
    pkt->data->set("publish_bytes",  SrsAmf0Any::number(publish_sample.bytes));
    pkt->data->set("play_time",      SrsAmf0Any::number(play_sample.actual_duration_ms));
    pkt->data->set("publish_time",   SrsAmf0Any::number(publish_sample.actual_duration_ms));

    if ((ret = _rtmp->send_and_free_packet(pkt, 0)) != ERROR_SUCCESS) {
        srs_error("send bandwidth check finish message failed. ret=%d", ret);
        return ret;
    }
    srs_info("send finish packet.");
    
    // we notice the result, and expect a final packet if not flash.
    // if flash client, client will disconnect when got finish packet.
    bool is_flash = (_req->swfUrl != "");
    if (!is_flash) {
        // ignore any error.
        _srs_expect_bandwidth_packet(_rtmp, _bandwidth_is_final);
        srs_info("BW check recv flash final response.");
    }
    
    srs_info("BW check finished.");

    return ret;
}

SrsKbpsLimit::SrsKbpsLimit(SrsKbps* kbps, int limit_kbps)
{
    _kbps = kbps;
    _limit_kbps = limit_kbps;
}

SrsKbpsLimit::~SrsKbpsLimit()
{
}

int SrsKbpsLimit::limit_kbps()
{
    return _limit_kbps;
}

void SrsKbpsLimit::recv_limit()
{
    _kbps->sample();
    
    while (_kbps->get_recv_kbps() > _limit_kbps) {
        _kbps->sample();
        
        st_usleep(_SRS_BANDWIDTH_LIMIT_INTERVAL_MS * 1000);
    }
}

void SrsKbpsLimit::send_limit()
{
    _kbps->sample();
    
    while (_kbps->get_send_kbps() > _limit_kbps) {
        _kbps->sample();
        
        st_usleep(_SRS_BANDWIDTH_LIMIT_INTERVAL_MS * 1000);
    }
}