/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2020 Winlin
 *
 * 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_rtsp_stack.hpp>

#if !defined(SRS_EXPORT_LIBRTMP)

#include <stdlib.h>
#include <map>
using namespace std;

#include <srs_protocol_io.hpp>
#include <srs_kernel_stream.hpp>
#include <srs_kernel_error.hpp>
#include <srs_kernel_log.hpp>
#include <srs_kernel_consts.hpp>
#include <srs_core_autofree.hpp>
#include <srs_kernel_utility.hpp>
#include <srs_kernel_buffer.hpp>
#include <srs_kernel_codec.hpp>

#define SRS_RTSP_BUFFER 4096

// get the status text of code.
string srs_generate_rtsp_status_text(int status)
{
    static std::map<int, std::string> _status_map;
    if (_status_map.empty()) {
        _status_map[SRS_CONSTS_RTSP_Continue] = SRS_CONSTS_RTSP_Continue_str;
        _status_map[SRS_CONSTS_RTSP_OK] = SRS_CONSTS_RTSP_OK_str;
        _status_map[SRS_CONSTS_RTSP_Created] = SRS_CONSTS_RTSP_Created_str;
        _status_map[SRS_CONSTS_RTSP_LowOnStorageSpace] = SRS_CONSTS_RTSP_LowOnStorageSpace_str;
        _status_map[SRS_CONSTS_RTSP_MultipleChoices] = SRS_CONSTS_RTSP_MultipleChoices_str;
        _status_map[SRS_CONSTS_RTSP_MovedPermanently] = SRS_CONSTS_RTSP_MovedPermanently_str;
        _status_map[SRS_CONSTS_RTSP_MovedTemporarily] = SRS_CONSTS_RTSP_MovedTemporarily_str;
        _status_map[SRS_CONSTS_RTSP_SeeOther] = SRS_CONSTS_RTSP_SeeOther_str;
        _status_map[SRS_CONSTS_RTSP_NotModified] = SRS_CONSTS_RTSP_NotModified_str;
        _status_map[SRS_CONSTS_RTSP_UseProxy] = SRS_CONSTS_RTSP_UseProxy_str;
        _status_map[SRS_CONSTS_RTSP_BadRequest] = SRS_CONSTS_RTSP_BadRequest_str;
        _status_map[SRS_CONSTS_RTSP_Unauthorized] = SRS_CONSTS_RTSP_Unauthorized_str;
        _status_map[SRS_CONSTS_RTSP_PaymentRequired] = SRS_CONSTS_RTSP_PaymentRequired_str;
        _status_map[SRS_CONSTS_RTSP_Forbidden] = SRS_CONSTS_RTSP_Forbidden_str;
        _status_map[SRS_CONSTS_RTSP_NotFound] = SRS_CONSTS_RTSP_NotFound_str;
        _status_map[SRS_CONSTS_RTSP_MethodNotAllowed] = SRS_CONSTS_RTSP_MethodNotAllowed_str;
        _status_map[SRS_CONSTS_RTSP_NotAcceptable] = SRS_CONSTS_RTSP_NotAcceptable_str;
        _status_map[SRS_CONSTS_RTSP_ProxyAuthenticationRequired] = SRS_CONSTS_RTSP_ProxyAuthenticationRequired_str;
        _status_map[SRS_CONSTS_RTSP_RequestTimeout] = SRS_CONSTS_RTSP_RequestTimeout_str;
        _status_map[SRS_CONSTS_RTSP_Gone] = SRS_CONSTS_RTSP_Gone_str;
        _status_map[SRS_CONSTS_RTSP_LengthRequired] = SRS_CONSTS_RTSP_LengthRequired_str;
        _status_map[SRS_CONSTS_RTSP_PreconditionFailed] = SRS_CONSTS_RTSP_PreconditionFailed_str;
        _status_map[SRS_CONSTS_RTSP_RequestEntityTooLarge] = SRS_CONSTS_RTSP_RequestEntityTooLarge_str;
        _status_map[SRS_CONSTS_RTSP_RequestURITooLarge] = SRS_CONSTS_RTSP_RequestURITooLarge_str;
        _status_map[SRS_CONSTS_RTSP_UnsupportedMediaType] = SRS_CONSTS_RTSP_UnsupportedMediaType_str;
        _status_map[SRS_CONSTS_RTSP_ParameterNotUnderstood] = SRS_CONSTS_RTSP_ParameterNotUnderstood_str;
        _status_map[SRS_CONSTS_RTSP_ConferenceNotFound] = SRS_CONSTS_RTSP_ConferenceNotFound_str;
        _status_map[SRS_CONSTS_RTSP_NotEnoughBandwidth] = SRS_CONSTS_RTSP_NotEnoughBandwidth_str;
        _status_map[SRS_CONSTS_RTSP_SessionNotFound] = SRS_CONSTS_RTSP_SessionNotFound_str;
        _status_map[SRS_CONSTS_RTSP_MethodNotValidInThisState] = SRS_CONSTS_RTSP_MethodNotValidInThisState_str;
        _status_map[SRS_CONSTS_RTSP_HeaderFieldNotValidForResource] = SRS_CONSTS_RTSP_HeaderFieldNotValidForResource_str;
        _status_map[SRS_CONSTS_RTSP_InvalidRange] = SRS_CONSTS_RTSP_InvalidRange_str;
        _status_map[SRS_CONSTS_RTSP_ParameterIsReadOnly] = SRS_CONSTS_RTSP_ParameterIsReadOnly_str;
        _status_map[SRS_CONSTS_RTSP_AggregateOperationNotAllowed] = SRS_CONSTS_RTSP_AggregateOperationNotAllowed_str;
        _status_map[SRS_CONSTS_RTSP_OnlyAggregateOperationAllowed] = SRS_CONSTS_RTSP_OnlyAggregateOperationAllowed_str;
        _status_map[SRS_CONSTS_RTSP_UnsupportedTransport] = SRS_CONSTS_RTSP_UnsupportedTransport_str;
        _status_map[SRS_CONSTS_RTSP_DestinationUnreachable] = SRS_CONSTS_RTSP_DestinationUnreachable_str;
        _status_map[SRS_CONSTS_RTSP_InternalServerError] = SRS_CONSTS_RTSP_InternalServerError_str;
        _status_map[SRS_CONSTS_RTSP_NotImplemented] = SRS_CONSTS_RTSP_NotImplemented_str;
        _status_map[SRS_CONSTS_RTSP_BadGateway] = SRS_CONSTS_RTSP_BadGateway_str;
        _status_map[SRS_CONSTS_RTSP_ServiceUnavailable] = SRS_CONSTS_RTSP_ServiceUnavailable_str;
        _status_map[SRS_CONSTS_RTSP_GatewayTimeout] = SRS_CONSTS_RTSP_GatewayTimeout_str;
        _status_map[SRS_CONSTS_RTSP_RTSPVersionNotSupported] = SRS_CONSTS_RTSP_RTSPVersionNotSupported_str;
        _status_map[SRS_CONSTS_RTSP_OptionNotSupported] = SRS_CONSTS_RTSP_OptionNotSupported_str;
    }
    
    std::string status_text;
    if (_status_map.find(status) == _status_map.end()) {
        status_text = "Status Unknown";
    } else {
        status_text = _status_map[status];
    }
    
    return status_text;
}

std::string srs_generate_rtsp_method_str(SrsRtspMethod method)
{
    switch (method) {
        case SrsRtspMethodDescribe: return SRS_METHOD_DESCRIBE;
        case SrsRtspMethodAnnounce: return SRS_METHOD_ANNOUNCE;
        case SrsRtspMethodGetParameter: return SRS_METHOD_GET_PARAMETER;
        case SrsRtspMethodOptions: return SRS_METHOD_OPTIONS;
        case SrsRtspMethodPause: return SRS_METHOD_PAUSE;
        case SrsRtspMethodPlay: return SRS_METHOD_PLAY;
        case SrsRtspMethodRecord: return SRS_METHOD_RECORD;
        case SrsRtspMethodRedirect: return SRS_METHOD_REDIRECT;
        case SrsRtspMethodSetup: return SRS_METHOD_SETUP;
        case SrsRtspMethodSetParameter: return SRS_METHOD_SET_PARAMETER;
        case SrsRtspMethodTeardown: return SRS_METHOD_TEARDOWN;
        default: return "Unknown";
    }
}

SrsRtpPacket::SrsRtpPacket()
{
    version = 2;
    padding = 0;
    extension = 0;
    csrc_count = 0;
    marker = 1;
    
    payload_type = 0;
    sequence_number = 0;
    timestamp = 0;
    ssrc = 0;
    
    payload = new SrsSimpleStream();
    audio = new SrsAudioFrame();
    chunked = false;
    completed = false;
}

SrsRtpPacket::~SrsRtpPacket()
{
    srs_freep(payload);
    srs_freep(audio);
}

void SrsRtpPacket::copy(SrsRtpPacket* src)
{
    version = src->version;
    padding = src->padding;
    extension = src->extension;
    csrc_count = src->csrc_count;
    marker = src->marker;
    payload_type = src->payload_type;
    sequence_number = src->sequence_number;
    timestamp = src->timestamp;
    ssrc = src->ssrc;
    
    chunked = src->chunked;
    completed = src->completed;

    srs_freep(audio);
    audio = new SrsAudioFrame();
}

void SrsRtpPacket::reap(SrsRtpPacket* src)
{
    copy(src);
    
    srs_freep(payload);
    payload = src->payload;
    src->payload = NULL;
    
    srs_freep(audio);
    audio = src->audio;
    src->audio = NULL;
}

srs_error_t SrsRtpPacket::decode(SrsBuffer* stream)
{
    srs_error_t err = srs_success;
    
    // 12bytes header
    if (!stream->require(12)) {
        return srs_error_new(ERROR_RTP_HEADER_CORRUPT, "requires 12 only %d bytes", stream->left());
    }
    
    int8_t vv = stream->read_1bytes();
    version = (vv >> 6) & 0x03;
    padding = (vv >> 5) & 0x01;
    extension = (vv >> 4) & 0x01;
    csrc_count = vv & 0x0f;
    
    int8_t mv = stream->read_1bytes();
    marker = (mv >> 7) & 0x01;
    payload_type = mv & 0x7f;
    
    sequence_number = stream->read_2bytes();
    timestamp = stream->read_4bytes();
    ssrc = stream->read_4bytes();
    
    // TODO: FIXME: check sequence number.
    
    // video codec.
    if (payload_type == 96) {
        return decode_96(stream);
    } else if (payload_type == 97) {
        return decode_97(stream);
    }
    
    return err;
}

srs_error_t SrsRtpPacket::decode_97(SrsBuffer* stream)
{
    srs_error_t err = srs_success;
    
    // atleast 2bytes content.
    if (!stream->require(2)) {
        return srs_error_new(ERROR_RTP_TYPE97_CORRUPT, "requires 2 only %d bytes", stream->left());
    }
    
    int8_t hasv = stream->read_1bytes();
    int8_t lasv = stream->read_1bytes();
    uint16_t au_size = ((hasv << 5) & 0xE0) | ((lasv >> 3) & 0x1f);
    
    if (!stream->require(au_size)) {
        return srs_error_new(ERROR_RTP_TYPE97_CORRUPT, "requires %d only %d bytes", au_size, stream->left());
    }
    
    int required_size = 0;
    
    // append left bytes to payload.
    payload->append(stream->data() + stream->pos() + au_size, stream->size() - stream->pos() - au_size);
    char* p = payload->bytes();
    
    for (int i = 0; i < au_size; i += 2) {
        hasv = stream->read_1bytes();
        lasv = stream->read_1bytes();
        
        uint16_t sample_size = ((hasv << 5) & 0xE0) | ((lasv >> 3) & 0x1f);
        // TODO: FIXME: finger out how to parse the size of sample.
        if (sample_size < 0x100 && stream->require(required_size + sample_size + 0x100)) {
            sample_size = sample_size | 0x100;
        }
        
        char* sample = p + required_size;
        required_size += sample_size;
        
        if (!stream->require(required_size)) {
            return srs_error_new(ERROR_RTP_TYPE97_CORRUPT, "requires %d only %d bytes", required_size, stream->left());
        }
        
        if ((err = audio->add_sample(sample, sample_size)) != srs_success) {
            srs_freep(err);
            return srs_error_wrap(err, "add sample");
        }
    }
    
    // parsed ok.
    completed = true;
    
    return err;
}

srs_error_t SrsRtpPacket::decode_96(SrsBuffer* stream)
{
    srs_error_t err = srs_success;
    
    // atleast 2bytes content.
    if (!stream->require(2)) {
        return srs_error_new(ERROR_RTP_TYPE96_CORRUPT, "requires 2 only %d bytes", stream->left());
    }
    
    // frame type
    // 0... .... reserverd
    // .11. .... NALU[0]&0x60
    // ...1 11.. FU indicator
    // .... ..00 reserverd
    int8_t ftv = stream->read_1bytes();
    int8_t nalu_0x60 = ftv & 0x60;
    int8_t fu_indicator = ftv & 0x1c;
    
    // nri, whatever
    // 10.. .... first chunk.
    // 00.. .... continous chunk.
    // 01.. .... last chunk.
    // ...1 1111 NALU[0]&0x1f
    int8_t nriv = stream->read_1bytes();
    bool first_chunk = (nriv & 0xC0) == 0x80;
    bool last_chunk = (nriv & 0xC0) == 0x40;
    bool contious_chunk = (nriv & 0xC0) == 0x00;
    int8_t nalu_0x1f = nriv & 0x1f;
    
    // chunked, generate the first byte NALU.
    if (fu_indicator == 0x1c && (first_chunk || last_chunk || contious_chunk)) {
        chunked = true;
        completed = last_chunk;
        
        // generate and append the first byte NALU.
        if (first_chunk) {
            int8_t nalu_byte0 = nalu_0x60 | nalu_0x1f;
            payload->append((char*)&nalu_byte0, 1);
        }
        
        payload->append(stream->data() + stream->pos(), stream->size() - stream->pos());
        return err;
    }
    
    // no chunked, append to payload.
    stream->skip(-2);
    payload->append(stream->data() + stream->pos(), stream->size() - stream->pos());
    completed = true;
    
    return err;
}

SrsRtspSdp::SrsRtspSdp()
{
    state = SrsRtspSdpStateOthers;
}

SrsRtspSdp::~SrsRtspSdp()
{
}

srs_error_t SrsRtspSdp::parse(string token)
{
    srs_error_t err = srs_success;
    
    if (token.empty()) {
        // ignore empty token
        return err;
    }
    
    size_t pos = string::npos;
    
    char* start = (char*)token.data();
    char* end = start + (int)token.length();
    char* p = start;
    
    // key, first 2bytes.
    // v=0
    // o=- 0 0 IN IP4 127.0.0.1
    // s=No Name
    // c=IN IP4 192.168.43.23
    // t=0 0
    // a=tool:libavformat 53.9.0
    // m=video 0 RTP/AVP 96
    // b=AS:850
    // a=rtpmap:96 H264/90000
    // a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z2QAKKzRwFAFu/8ALQAiEAAAAwAQAAADAwjxgxHg,aOmrLIs=
    // a=control:streamid=0
    // m=audio 0 RTP/AVP 97
    // b=AS:49
    // a=rtpmap:97 MPEG4-GENERIC/44100/2
    // a=fmtp:97 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=139056E5A0
    // a=control:streamid=1
    char key = p[0];
    p += 2;
    
    // left bytes as attr string.
    std::string attr_str;
    if (end - p) {
        attr_str.append(p, end - p);
    }
    
    // parse the attributes from left bytes.
    std::vector<std::string> attrs;
    while (p < end) {
        // parse an attribute, split by SP.
        char* pa = p;
        for (; p < end && p[0] != SRS_RTSP_SP; p++) {
        }
        std::string attr;
        if (p > pa) {
            attr.append(pa, p - pa);
            attrs.push_back(attr);
        }
        p++;
    }
    
    // parse the first attr as desc, update the first elem for desc.
    // for example, the value can be "tool", "AS", "rtpmap", "fmtp", "control"
    std::string desc_key;
    if (attrs.size() > 0) {
        std::string attr = attrs.at(0);
        if ((pos = attr.find(":")) != string::npos) {
            desc_key = attr.substr(0, pos);
            attr = attr.substr(pos + 1);
            attr_str = attr_str.substr(pos + 1);
            attrs[0] = attr;
        } else {
            desc_key = attr;
        }
    }
    
    // interpret the attribute according by key.
    switch (key) {
        case 'v': version = attr_str; break;
        case 'o':
            owner_username = (attrs.size() > 0)? attrs[0]:"";
            owner_session_id = (attrs.size() > 1)? attrs[1]:"";
            owner_session_version = (attrs.size() > 2)? attrs[2]:"";
            owner_network_type = (attrs.size() > 3)? attrs[3]:"";
            owner_address_type = (attrs.size() > 4)? attrs[4]:"";
            owner_address = (attrs.size() > 5)? attrs[5]:"";
            break;
        case 's': session_name = attr_str; break;
        case 'c':
            connection_network_type = (attrs.size() > 0)? attrs[0]:"";
            connection_address_type = (attrs.size() > 0)? attrs[0]:"";
            connection_address = (attrs.size() > 0)? attrs[0]:"";
            break;
        case 'a':
            if (desc_key == "tool") {
                tool = attr_str;
            } else if (desc_key == "rtpmap") {
                if (state == SrsRtspSdpStateVideo) {
                    video_codec = (attrs.size() > 1)? attrs[1]:"";
                    if ((pos = video_codec.find("/")) != string::npos) {
                        video_sample_rate = video_codec.substr(pos + 1);
                        video_codec = video_codec.substr(0, pos);
                    }
                } else if (state == SrsRtspSdpStateAudio) {
                    audio_codec = (attrs.size() > 1)? attrs[1]:"";
                    if ((pos = audio_codec.find("/")) != string::npos) {
                        audio_sample_rate = audio_codec.substr(pos + 1);
                        audio_codec = audio_codec.substr(0, pos);
                    }
                    if ((pos = audio_sample_rate.find("/")) != string::npos) {
                        audio_channel = audio_sample_rate.substr(pos + 1);
                        audio_sample_rate = audio_sample_rate.substr(0, pos);
                    }
                }
            } else if (desc_key == "fmtp") {
                for (int i = 1; i < (int)attrs.size(); i++) {
                    std::string attr = attrs.at(i);
                    if ((err = parse_fmtp_attribute(attr)) != srs_success) {
                        return srs_error_wrap(err, "parse fmtp attr=%s", attr.c_str());
                    }
                }
            } else if (desc_key == "control") {
                for (int i = 0; i < (int)attrs.size(); i++) {
                    std::string attr = attrs.at(i);
                    if ((err = parse_control_attribute(attr)) != srs_success) {
                        return srs_error_wrap(err, "parse control attr=%s", attr.c_str());
                    }
                }
            }
            break;
        case 'm':
            if (desc_key == "video") {
                state = SrsRtspSdpStateVideo;
                video_port = (attrs.size() > 1)? attrs[1]:"";
                video_protocol = (attrs.size() > 2)? attrs[2]:"";
                video_transport_format = (attrs.size() > 3)? attrs[3]:"";
            } else if (desc_key == "audio") {
                state = SrsRtspSdpStateAudio;
                audio_port = (attrs.size() > 1)? attrs[1]:"";
                audio_protocol = (attrs.size() > 2)? attrs[2]:"";
                audio_transport_format = (attrs.size() > 3)? attrs[3]:"";
            }
            break;
        case 'b':
            if (desc_key == "AS") {
                if (state == SrsRtspSdpStateVideo) {
                    video_bandwidth_kbps = (attrs.size() > 0)? attrs[0]:"";
                } else if (state == SrsRtspSdpStateAudio) {
                    audio_bandwidth_kbps = (attrs.size() > 0)? attrs[0]:"";
                }
            }
            break;
        case 't':
        default: break;
    }
    
    return err;
}

srs_error_t SrsRtspSdp::parse_fmtp_attribute(string attr)
{
    srs_error_t err = srs_success;
    
    size_t pos = string::npos;
    std::string token = attr;
    
    while (!token.empty()) {
        std::string item = token;
        if ((pos = item.find(";")) != string::npos) {
            item = token.substr(0, pos);
            token = token.substr(pos + 1);
        } else {
            token = "";
        }
        
        std::string item_key = item, item_value;
        if ((pos = item.find("=")) != string::npos) {
            item_key = item.substr(0, pos);
            item_value = item.substr(pos + 1);
        }
        
        if (state == SrsRtspSdpStateVideo) {
            if (item_key == "packetization-mode") {
                video_packetization_mode = item_value;
            } else if (item_key == "sprop-parameter-sets") {
                video_sps = item_value;
                if ((pos = video_sps.find(",")) != string::npos) {
                    video_pps = video_sps.substr(pos + 1);
                    video_sps = video_sps.substr(0, pos);
                }
                // decode the sps/pps by base64
                video_sps = base64_decode(video_sps);
                video_pps = base64_decode(video_pps);
            }
        } else if (state == SrsRtspSdpStateAudio) {
            if (item_key == "profile-level-id") {
                audio_profile_level_id = item_value;
            } else if (item_key == "mode") {
                audio_mode = item_value;
            } else if (item_key == "sizelength") {
                audio_size_length = item_value;
            } else if (item_key == "indexlength") {
                audio_index_length = item_value;
            } else if (item_key == "indexdeltalength") {
                audio_index_delta_length = item_value;
            } else if (item_key == "config") {
                if (item_value.length() <= 0) {
                    return srs_error_new(ERROR_RTSP_AUDIO_CONFIG, "audio config");
                }
                
                char* tmp_sh = new char[item_value.length()];
                SrsAutoFreeA(char, tmp_sh);
                
                int nb_tmp_sh = srs_hex_to_data((uint8_t*)tmp_sh, item_value.c_str(), item_value.length());
                if (nb_tmp_sh <= 0) {
                    return srs_error_new(ERROR_RTSP_AUDIO_CONFIG, "audio config");
                }
                
                audio_sh.append(tmp_sh, nb_tmp_sh);
            }
        }
    }
    
    return err;
}

srs_error_t SrsRtspSdp::parse_control_attribute(string attr)
{
    srs_error_t err = srs_success;
    
    size_t pos = string::npos;
    std::string token = attr;
    
    while (!token.empty()) {
        std::string item = token;
        if ((pos = item.find(";")) != string::npos) {
            item = token.substr(0, pos);
            token = token.substr(pos + 1);
        } else {
            token = "";
        }
        
        std::string item_key = item, item_value;
        if ((pos = item.find("=")) != string::npos) {
            item_key = item.substr(0, pos);
            item_value = item.substr(pos + 1);
        }
        
        if (state == SrsRtspSdpStateVideo) {
            if (item_key == "streamid") {
                video_stream_id = item_value;
            }
        } else if (state == SrsRtspSdpStateAudio) {
            if (item_key == "streamid") {
                audio_stream_id = item_value;
            }
        }
    }
    
    return err;
}

string SrsRtspSdp::base64_decode(string cipher)
{
    if (cipher.empty()) {
        return "";
    }
    
    string plaintext;
    srs_error_t err = srs_av_base64_decode(cipher, plaintext);
    srs_freep(err);
    
    return plaintext;
}

SrsRtspTransport::SrsRtspTransport()
{
    client_port_min = 0;
    client_port_max = 0;
}

SrsRtspTransport::~SrsRtspTransport()
{
}

srs_error_t SrsRtspTransport::parse(string attr)
{
    srs_error_t err = srs_success;
    
    size_t pos = string::npos;
    std::string token = attr;
    
    while (!token.empty()) {
        std::string item = token;
        if ((pos = item.find(";")) != string::npos) {
            item = token.substr(0, pos);
            token = token.substr(pos + 1);
        } else {
            token = "";
        }
        
        std::string item_key = item, item_value;
        if ((pos = item.find("=")) != string::npos) {
            item_key = item.substr(0, pos);
            item_value = item.substr(pos + 1);
        }
        
        if (transport.empty()) {
            transport = item_key;
            if ((pos = transport.find("/")) != string::npos) {
                profile = transport.substr(pos + 1);
                transport = transport.substr(0, pos);
            }
            if ((pos = profile.find("/")) != string::npos) {
                lower_transport = profile.substr(pos + 1);
                profile = profile.substr(0, pos);
            }
        }
        
        if (item_key == "unicast" || item_key == "multicast") {
            cast_type = item_key;
        } else if (item_key == "mode") {
            mode = item_value;
        } else if (item_key == "client_port") {
            std::string sport = item_value;
            std::string eport = item_value;
            if ((pos = eport.find("-")) != string::npos) {
                sport = eport.substr(0, pos);
                eport = eport.substr(pos + 1);
            }
            client_port_min = ::atoi(sport.c_str());
            client_port_max = ::atoi(eport.c_str());
        }
    }
    
    return err;
}

SrsRtspRequest::SrsRtspRequest()
{
    seq = 0;
    content_length = 0;
    stream_id = 0;
    sdp = NULL;
    transport = NULL;
}

SrsRtspRequest::~SrsRtspRequest()
{
    srs_freep(sdp);
    srs_freep(transport);
}

bool SrsRtspRequest::is_options()
{
    return method == SRS_METHOD_OPTIONS;
}

bool SrsRtspRequest::is_announce()
{
    return method == SRS_METHOD_ANNOUNCE;
}

bool SrsRtspRequest::is_setup()
{
    return method == SRS_METHOD_SETUP;
}

bool SrsRtspRequest::is_record()
{
    return method == SRS_METHOD_RECORD;
}

SrsRtspResponse::SrsRtspResponse(int cseq)
{
    seq = cseq;
    status = SRS_CONSTS_RTSP_OK;
}

SrsRtspResponse::~SrsRtspResponse()
{
}

srs_error_t SrsRtspResponse::encode(stringstream& ss)
{
    srs_error_t err = srs_success;
    
    // status line
    ss << SRS_RTSP_VERSION << SRS_RTSP_SP
    << status << SRS_RTSP_SP
    << srs_generate_rtsp_status_text(status) << SRS_RTSP_CRLF;
    
    // cseq
    ss << SRS_RTSP_TOKEN_CSEQ << ":" << SRS_RTSP_SP << seq << SRS_RTSP_CRLF;
    
    // others.
    ss << "Cache-Control: no-store" << SRS_RTSP_CRLF
    << "Pragma: no-cache" << SRS_RTSP_CRLF
    << "Server: " << RTMP_SIG_SRS_SERVER << SRS_RTSP_CRLF;
    
    // session if specified.
    if (!session.empty()) {
        ss << SRS_RTSP_TOKEN_SESSION << ":" << session << SRS_RTSP_CRLF;
    }
    
    if ((err = encode_header(ss)) != srs_success) {
        return srs_error_wrap(err, "encode header");
    };
    
    // header EOF.
    ss << SRS_RTSP_CRLF;
    
    return err;
}

srs_error_t SrsRtspResponse::encode_header(std::stringstream& ss)
{
    return srs_success;
}

SrsRtspOptionsResponse::SrsRtspOptionsResponse(int cseq) : SrsRtspResponse(cseq)
{
    methods = (SrsRtspMethod)(SrsRtspMethodDescribe | SrsRtspMethodOptions
        | SrsRtspMethodPause | SrsRtspMethodPlay | SrsRtspMethodSetup | SrsRtspMethodTeardown
        | SrsRtspMethodAnnounce | SrsRtspMethodRecord);
}

SrsRtspOptionsResponse::~SrsRtspOptionsResponse()
{
}

srs_error_t SrsRtspOptionsResponse::encode_header(stringstream& ss)
{
    SrsRtspMethod rtsp_methods[] = {
        SrsRtspMethodDescribe,
        SrsRtspMethodAnnounce,
        SrsRtspMethodGetParameter,
        SrsRtspMethodOptions,
        SrsRtspMethodPause,
        SrsRtspMethodPlay,
        SrsRtspMethodRecord,
        SrsRtspMethodRedirect,
        SrsRtspMethodSetup,
        SrsRtspMethodSetParameter,
        SrsRtspMethodTeardown,
    };
    
    ss << SRS_RTSP_TOKEN_PUBLIC << ":" << SRS_RTSP_SP;
    
    bool appended = false;
    int nb_methods = (int)(sizeof(rtsp_methods) / sizeof(SrsRtspMethod));
    for (int i = 0; i < nb_methods; i++) {
        SrsRtspMethod method = rtsp_methods[i];
        if (((int)methods & (int)method) != (int)method) {
            continue;
        }
        
        if (appended) {
            ss << ", ";
        }
        ss << srs_generate_rtsp_method_str(method);
        appended = true;
    }
    ss << SRS_RTSP_CRLF;
    
    return srs_success;
}

SrsRtspSetupResponse::SrsRtspSetupResponse(int seq) : SrsRtspResponse(seq)
{
    local_port_min = 0;
    local_port_max = 0;
}

SrsRtspSetupResponse::~SrsRtspSetupResponse()
{
}

srs_error_t SrsRtspSetupResponse::encode_header(stringstream& ss)
{
    ss << SRS_RTSP_TOKEN_SESSION << ":" << SRS_RTSP_SP << session << SRS_RTSP_CRLF;
    ss << SRS_RTSP_TOKEN_TRANSPORT << ":" << SRS_RTSP_SP
    << "RTP/AVP;unicast;client_port=" << client_port_min << "-" << client_port_max << ";"
    << "server_port=" << local_port_min << "-" << local_port_max
    << SRS_RTSP_CRLF;
    return srs_success;
}

SrsRtspStack::SrsRtspStack(ISrsProtocolReadWriter* s)
{
    buf = new SrsSimpleStream();
    skt = s;
}

SrsRtspStack::~SrsRtspStack()
{
    srs_freep(buf);
}

srs_error_t SrsRtspStack::recv_message(SrsRtspRequest** preq)
{
    srs_error_t err = srs_success;
    
    SrsRtspRequest* req = new SrsRtspRequest();
    if ((err = do_recv_message(req)) != srs_success) {
        srs_freep(req);
        return srs_error_wrap(err, "recv message");
    }
    
    *preq = req;
    
    return err;
}

srs_error_t SrsRtspStack::send_message(SrsRtspResponse* res)
{
    srs_error_t err = srs_success;
    
    std::stringstream ss;
    // encode the message to string.
    res->encode(ss);
    
    std::string str = ss.str();
    srs_assert(!str.empty());
    
    if ((err = skt->write((char*)str.c_str(), (int)str.length(), NULL)) != srs_success) {
        return srs_error_wrap(err, "write message");
    }
    
    return err;
}

srs_error_t SrsRtspStack::do_recv_message(SrsRtspRequest* req)
{
    srs_error_t err = srs_success;
    
    // parse request line.
    if ((err = recv_token_normal(req->method)) != srs_success) {
        return srs_error_wrap(err, "method");
    }
    
    if ((err = recv_token_normal(req->uri)) != srs_success) {
        return srs_error_wrap(err, "uri");
    }
    
    if ((err = recv_token_eof(req->version)) != srs_success) {
        return srs_error_wrap(err, "version");
    }
    
    // parse headers.
    for (;;) {
        // parse the header name
        std::string token;
        if ((err = recv_token_normal(token)) != srs_success) {
            if (srs_error_code(err) == ERROR_RTSP_REQUEST_HEADER_EOF) {
                srs_error_reset(err);
                break;
            }
            return srs_error_wrap(err, "recv token");
        }
        
        // parse the header value according by header name
        if (token == SRS_RTSP_TOKEN_CSEQ) {
            std::string seq;
            if ((err = recv_token_eof(seq)) != srs_success) {
                return srs_error_wrap(err, "seq");
            }
            req->seq = ::atoll(seq.c_str());
        } else if (token == SRS_RTSP_TOKEN_CONTENT_TYPE) {
            std::string ct;
            if ((err = recv_token_eof(ct)) != srs_success) {
                return srs_error_wrap(err, "ct");
            }
            req->content_type = ct;
        } else if (token == SRS_RTSP_TOKEN_CONTENT_LENGTH) {
            std::string cl;
            if ((err = recv_token_eof(cl)) != srs_success) {
                return srs_error_wrap(err, "cl");
            }
            req->content_length = ::atoll(cl.c_str());
        } else if (token == SRS_RTSP_TOKEN_TRANSPORT) {
            std::string transport;
            if ((err = recv_token_eof(transport)) != srs_success) {
                return srs_error_wrap(err, "transport");
            }
            if (!req->transport) {
                req->transport = new SrsRtspTransport();
            }
            if ((err = req->transport->parse(transport)) != srs_success) {
                return srs_error_wrap(err, "parse transport=%s", transport.c_str());
            }
        } else if (token == SRS_RTSP_TOKEN_SESSION) {
            if ((err = recv_token_eof(req->session)) != srs_success) {
                return srs_error_wrap(err, "session");
            }
        } else {
            // unknown header name, parse util EOF.
            SrsRtspTokenState state = SrsRtspTokenStateNormal;
            while (state == SrsRtspTokenStateNormal) {
                std::string value;
                if ((err = recv_token(value, state)) != srs_success) {
                    return srs_error_wrap(err, "state");
                }
                srs_trace("rtsp: ignore header %s=%s", token.c_str(), value.c_str());
            }
        }
    }
    
    // for setup, parse the stream id from uri.
    if (req->is_setup()) {
        size_t pos = string::npos;
        std::string stream_id = srs_path_basename(req->uri);
        if ((pos = stream_id.find("=")) != string::npos) {
            stream_id = stream_id.substr(pos + 1);
        }
        req->stream_id = ::atoi(stream_id.c_str());
        srs_info("rtsp: setup stream id=%d", req->stream_id);
    }
    
    // parse rdp body.
    long consumed = 0;
    while (consumed < req->content_length) {
        if (!req->sdp) {
            req->sdp = new SrsRtspSdp();
        }
        
        int nb_token = 0;
        std::string token;
        if ((err = recv_token_util_eof(token, &nb_token)) != srs_success) {
            return srs_error_wrap(err, "recv token");
        }
        consumed += nb_token;
        
        if ((err = req->sdp->parse(token)) != srs_success) {
            return srs_error_wrap(err, "parse token");
        }
    }
    
    return err;
}

srs_error_t SrsRtspStack::recv_token_normal(std::string& token)
{
    srs_error_t err = srs_success;
    
    SrsRtspTokenState state;
    
    if ((err = recv_token(token, state)) != srs_success) {
        if (srs_error_code(err) == ERROR_RTSP_REQUEST_HEADER_EOF) {
            return srs_error_wrap(err, "EOF");
        }
        return srs_error_wrap(err, "recv token");
    }
    
    if (state != SrsRtspTokenStateNormal) {
        return srs_error_new(ERROR_RTSP_TOKEN_NOT_NORMAL, "invalid state=%d", state);
    }
    
    return err;
}

srs_error_t SrsRtspStack::recv_token_eof(std::string& token)
{
    srs_error_t err = srs_success;
    
    SrsRtspTokenState state;
    
    if ((err = recv_token(token, state)) != srs_success) {
        if (srs_error_code(err) == ERROR_RTSP_REQUEST_HEADER_EOF) {
            return srs_error_wrap(err, "EOF");
        }
        return srs_error_wrap(err, "recv token");
    }
    
    if (state != SrsRtspTokenStateEOF) {
        return srs_error_new(ERROR_RTSP_TOKEN_NOT_NORMAL, "invalid state=%d", state);
    }
    
    return err;
}

srs_error_t SrsRtspStack::recv_token_util_eof(std::string& token, int* pconsumed)
{
    srs_error_t err = srs_success;
    
    SrsRtspTokenState state;
    
    // use 0x00 as ignore the normal token flag.
    if ((err = recv_token(token, state, 0x00, pconsumed)) != srs_success) {
        if (srs_error_code(err) == ERROR_RTSP_REQUEST_HEADER_EOF) {
            return srs_error_wrap(err, "EOF");
        }
        return srs_error_wrap(err, "recv token");
    }
    
    if (state != SrsRtspTokenStateEOF) {
        return srs_error_new(ERROR_RTSP_TOKEN_NOT_NORMAL, "invalid state=%d", state);
    }
    
    return err;
}

srs_error_t SrsRtspStack::recv_token(std::string& token, SrsRtspTokenState& state, char normal_ch, int* pconsumed)
{
    srs_error_t err = srs_success;
    
    // whatever, default to error state.
    state = SrsRtspTokenStateError;
    
    // when buffer is empty, append bytes first.
    bool append_bytes = buf->length() == 0;
    
    // parse util token.
    for (;;) {
        // append bytes if required.
        if (append_bytes) {
            append_bytes = false;
            
            char buffer[SRS_RTSP_BUFFER];
            ssize_t nb_read = 0;
            if ((err = skt->read(buffer, SRS_RTSP_BUFFER, &nb_read)) != srs_success) {
                return srs_error_wrap(err, "recv data");
            }
            
            buf->append(buffer, (int)nb_read);
        }
        
        // parse one by one.
        char* start = buf->bytes();
        char* end = start + buf->length();
        char* p = start;
        
        // find util SP/CR/LF, max 2 EOF, to finger out the EOF of message.
        for (; p < end && p[0] != normal_ch && p[0] != SRS_RTSP_CR && p[0] != SRS_RTSP_LF; p++) {
        }
        
        // matched.
        if (p < end) {
            // finger out the state.
            if (p[0] == normal_ch) {
                state = SrsRtspTokenStateNormal;
            } else {
                state = SrsRtspTokenStateEOF;
            }
            
            // got the token.
            int nb_token = (int)(p - start);
            // trim last ':' character.
            if (nb_token && p[-1] == ':') {
                nb_token--;
            }
            if (nb_token) {
                token.append(start, nb_token);
            } else {
                err = srs_error_new(ERROR_RTSP_REQUEST_HEADER_EOF, "EOF");
            }
            
            // ignore SP/CR/LF
            for (int i = 0; i < 2 && p < end && (p[0] == normal_ch || p[0] == SRS_RTSP_CR || p[0] == SRS_RTSP_LF); p++, i++) {
            }
            
            // consume the token bytes.
            srs_assert(p - start);
            buf->erase((int)(p - start));
            if (pconsumed) {
                *pconsumed = (int)(p - start);
            }
            break;
        }
        
        // append more and parse again.
        append_bytes = true;
    }
    
    return err;
}

#endif