//
// Copyright 2010-2012 Ettus Research LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/safe_main.hpp>
#include <uhd/utils/static.hpp>
#include <uhd/usrp/multi_usrp.hpp>
#include <uhd/exception.hpp>
#include <boost/thread/thread.hpp>
#include <boost/program_options.hpp>
#include <boost/math/special_functions/round.hpp>
#include <boost/foreach.hpp>
#include <boost/format.hpp>
#include <iostream>
#include <fstream>
#include <complex>
#include <csignal>
#include <cmath>

namespace po = boost::program_options;

/***********************************************************************
 * Signal handlers
 **********************************************************************/
static bool stop_signal_called = false;
void sig_int_handler(int){stop_signal_called = true;}

/***********************************************************************
 * Waveform generators
 **********************************************************************/
static const size_t wave_table_len = 8192;

class wave_table_class{
public:
    wave_table_class(const std::string &wave_type, const float ampl):
        _wave_table(wave_table_len)
    {
        //compute real wave table with 1.0 amplitude
        std::vector<double> real_wave_table(wave_table_len);
        if (wave_type == "CONST"){
            for (size_t i = 0; i < wave_table_len; i++)
                real_wave_table[i] = 1.0;
        }
        else if (wave_type == "SQUARE"){
            for (size_t i = 0; i < wave_table_len; i++)
                real_wave_table[i] = (i < wave_table_len/2)? 0.0 : 1.0;
        }
        else if (wave_type == "RAMP"){
            for (size_t i = 0; i < wave_table_len; i++)
                real_wave_table[i] = 2.0*i/(wave_table_len-1) - 1.0;
        }
        else if (wave_type == "SINE"){
            static const double tau = 2*std::acos(-1.0);
            for (size_t i = 0; i < wave_table_len; i++)
                real_wave_table[i] = std::sin((tau*i)/wave_table_len);
        }
        else throw std::runtime_error("unknown waveform type: " + wave_type);

        //compute i and q pairs with 90% offset and scale to amplitude
        for (size_t i = 0; i < wave_table_len; i++){
            const size_t q = (i+(3*wave_table_len)/4)%wave_table_len;
            _wave_table[i] = std::complex<float>(ampl*real_wave_table[i], ampl*real_wave_table[q]);
        }
    }

    inline std::complex<float> operator()(const size_t index) const{
        return _wave_table[index % wave_table_len];
    }

private:
    std::vector<std::complex<float> > _wave_table;
};

/***********************************************************************
 * transmit_worker function
 * A function to be used as a boost::thread_group thread for transmitting
 **********************************************************************/
void transmit_worker(
    std::vector<std::complex<float> > buff,
    wave_table_class wave_table,
    uhd::tx_streamer::sptr tx_streamer,
    uhd::tx_metadata_t metadata,
    size_t step,
    size_t index,
    int num_channels
){
    std::vector<std::complex<float> *> buffs(num_channels, &buff.front());

    //send data until the signal handler gets called
    while(not stop_signal_called){
        //fill the buffer with the waveform
        for (size_t n = 0; n < buff.size(); n++){
            buff[n] = wave_table(index += step);
        }

        //send the entire contents of the buffer
        tx_streamer->send(buffs, buff.size(), metadata);

        metadata.start_of_burst = false;
        metadata.has_time_spec = false;
    }

    //send a mini EOB packet
    metadata.end_of_burst = true;
    tx_streamer->send("", 0, metadata);
}


/***********************************************************************
 * recv_to_file function
 **********************************************************************/
template<typename samp_type> void recv_to_file(
    uhd::usrp::multi_usrp::sptr usrp,
    const std::string &cpu_format,
    const std::string &wire_format,
    const std::string &file,
    size_t samps_per_buff,
    int num_requested_samples,
    float settling_time
){
    int num_total_samps = 0;
    //create a receive streamer
    uhd::stream_args_t stream_args(cpu_format,wire_format);
    uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);

    uhd::rx_metadata_t md;
    std::vector<samp_type> buff(samps_per_buff);
    std::ofstream outfile(file.c_str(), std::ofstream::binary);
    bool overflow_message = true;
    float timeout = settling_time + 0.1; //expected settling time + padding for first recv

    //setup streaming
    uhd::stream_cmd_t stream_cmd((num_requested_samples == 0)?
        uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS:
        uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE
    );
    stream_cmd.num_samps = num_requested_samples;
    stream_cmd.stream_now = false;
    stream_cmd.time_spec = uhd::time_spec_t(settling_time);
    usrp->issue_stream_cmd(stream_cmd);

    while(not stop_signal_called and (num_requested_samples != num_total_samps or num_requested_samples == 0)){
        size_t num_rx_samps = rx_stream->recv(&buff.front(), buff.size(), md, timeout);
        timeout = 0.1; //small timeout for subsequent recv

        if (md.error_code == uhd::rx_metadata_t::ERROR_CODE_TIMEOUT) {
            std::cout << boost::format("Timeout while streaming") << std::endl;
            break;
        }
        if (md.error_code == uhd::rx_metadata_t::ERROR_CODE_OVERFLOW){
            if (overflow_message){
                overflow_message = false;
                std::cerr << boost::format(
                    "Got an overflow indication. Please consider the following:\n"
                    "  Your write medium must sustain a rate of %fMB/s.\n"
                    "  Dropped samples will not be written to the file.\n"
                    "  Please modify this example for your purposes.\n"
                    "  This message will not appear again.\n"
                ) % (usrp->get_rx_rate()*sizeof(samp_type)/1e6);
            }
            continue;
        }
        if (md.error_code != uhd::rx_metadata_t::ERROR_CODE_NONE){
            throw std::runtime_error(str(boost::format(
                "Unexpected error code 0x%x"
            ) % md.error_code));
        }

        num_total_samps += num_rx_samps;

        outfile.write((const char*)&buff.front(), num_rx_samps*sizeof(samp_type));
    }

    outfile.close();
}


/***********************************************************************
 * Main function
 **********************************************************************/
int UHD_SAFE_MAIN(int argc, char *argv[]){
    uhd::set_thread_priority_safe();

    //transmit variables to be set by po
    std::string tx_args, wave_type, tx_ant, tx_subdev, ref, otw;
    double tx_rate, tx_freq, tx_gain, wave_freq, tx_bw;
    float ampl;

    //receive variables to be set by po
    std::string rx_args, file, type, rx_ant, rx_subdev;
    size_t total_num_samps, spb;
    double rx_rate, rx_freq, rx_gain, rx_bw;
    float settling;

    //setup the program options
    po::options_description desc("Allowed options");
    desc.add_options()
        ("help", "help message")
        ("tx-args", po::value<std::string>(&tx_args)->default_value(""), "uhd transmit device address args")
        ("rx-args", po::value<std::string>(&rx_args)->default_value(""), "uhd receive device address args")
        ("file", po::value<std::string>(&file)->default_value("usrp_samples.dat"), "name of the file to write binary samples to")
        ("type", po::value<std::string>(&type)->default_value("short"), "sample type in file: double, float, or short")
        ("nsamps", po::value<size_t>(&total_num_samps)->default_value(0), "total number of samples to receive")
        ("settling", po::value<float>(&settling)->default_value(float(0.2)), "settling time (seconds) before receiving")
        ("spb", po::value<size_t>(&spb)->default_value(0), "samples per buffer, 0 for default")
        ("tx-rate", po::value<double>(&tx_rate), "rate of transmit outgoing samples")
        ("rx-rate", po::value<double>(&rx_rate), "rate of receive incoming samples")
        ("tx-freq", po::value<double>(&tx_freq), "transmit RF center frequency in Hz")
        ("rx-freq", po::value<double>(&rx_freq), "receive RF center frequency in Hz")
        ("ampl", po::value<float>(&ampl)->default_value(float(0.3)), "amplitude of the waveform [0 to 0.7]")
        ("tx-gain", po::value<double>(&tx_gain), "gain for the transmit RF chain")
        ("rx-gain", po::value<double>(&rx_gain), "gain for the receive RF chain")
        ("tx-ant", po::value<std::string>(&tx_ant), "daughterboard transmit antenna selection")
        ("rx-ant", po::value<std::string>(&rx_ant), "daughterboard receive antenna selection")
        ("tx-subdev", po::value<std::string>(&tx_subdev), "daughterboard transmit subdevice specification")
        ("rx-subdev", po::value<std::string>(&rx_subdev), "daughterboard receive subdevice specification")
        ("tx-bw", po::value<double>(&tx_bw), "daughterboard transmit IF filter bandwidth in Hz")
        ("rx-bw", po::value<double>(&rx_bw), "daughterboard receive IF filter bandwidth in Hz")
        ("wave-type", po::value<std::string>(&wave_type)->default_value("CONST"), "waveform type (CONST, SQUARE, RAMP, SINE)")
        ("wave-freq", po::value<double>(&wave_freq)->default_value(0), "waveform frequency in Hz")
        ("ref", po::value<std::string>(&ref)->default_value("internal"), "clock reference (internal, external, mimo)")
        ("otw", po::value<std::string>(&otw)->default_value("sc16"), "specify the over-the-wire sample mode")
    ;
    po::variables_map vm;
    po::store(po::parse_command_line(argc, argv, desc), vm);
    po::notify(vm);

    //print the help message
    if (vm.count("help")){
        std::cout << boost::format("UHD TXRX Loopback to File %s") % desc << std::endl;
        return ~0;
    }

    //create a usrp device
    std::cout << std::endl;
    std::cout << boost::format("Creating the transmit usrp device with: %s...") % tx_args << std::endl;
    uhd::usrp::multi_usrp::sptr tx_usrp = uhd::usrp::multi_usrp::make(tx_args);
    std::cout << std::endl;
    std::cout << boost::format("Creating the receive usrp device with: %s...") % rx_args << std::endl;
    uhd::usrp::multi_usrp::sptr rx_usrp = uhd::usrp::multi_usrp::make(rx_args);

    //Lock mboard clocks
    tx_usrp->set_clock_source(ref);
    rx_usrp->set_clock_source(ref);

    //always select the subdevice first, the channel mapping affects the other settings
    if (vm.count("tx-subdev")) tx_usrp->set_tx_subdev_spec(tx_subdev);
    if (vm.count("rx-subdev")) rx_usrp->set_rx_subdev_spec(rx_subdev);

    std::cout << boost::format("Using Device: %s") % tx_usrp->get_pp_string() << std::endl;
    std::cout << boost::format("Using Device: %s") % rx_usrp->get_pp_string() << std::endl;

    //set the transmit sample rate
    if (not vm.count("tx-rate")){
        std::cerr << "Please specify the transmit sample rate with --tx-rate" << std::endl;
        return ~0;
    }
    std::cout << boost::format("Setting TX Rate: %f Msps...") % (tx_rate/1e6) << std::endl;
    tx_usrp->set_tx_rate(tx_rate);
    std::cout << boost::format("Actual TX Rate: %f Msps...") % (tx_usrp->get_tx_rate()/1e6) << std::endl << std::endl;

    //set the receive sample rate
    if (not vm.count("rx-rate")){
        std::cerr << "Please specify the sample rate with --rx-rate" << std::endl;
        return ~0;
    }
    std::cout << boost::format("Setting RX Rate: %f Msps...") % (rx_rate/1e6) << std::endl;
    rx_usrp->set_rx_rate(rx_rate);
    std::cout << boost::format("Actual RX Rate: %f Msps...") % (rx_usrp->get_rx_rate()/1e6) << std::endl << std::endl;

    //set the transmit center frequency
    if (not vm.count("tx-freq")){
        std::cerr << "Please specify the transmit center frequency with --tx-freq" << std::endl;
        return ~0;
    }

    for(size_t chan = 0; chan < tx_usrp->get_tx_num_channels(); chan++) {
        std::cout << boost::format("Setting TX Freq: %f MHz...") % (tx_freq/1e6) << std::endl;
        tx_usrp->set_tx_freq(tx_freq, chan);
        std::cout << boost::format("Actual TX Freq: %f MHz...") % (tx_usrp->get_tx_freq(chan)/1e6) << std::endl << std::endl;

        //set the rf gain
        if (vm.count("tx-gain")){
            std::cout << boost::format("Setting TX Gain: %f dB...") % tx_gain << std::endl;
            tx_usrp->set_tx_gain(tx_gain, chan);
            std::cout << boost::format("Actual TX Gain: %f dB...") % tx_usrp->get_tx_gain(chan) << std::endl << std::endl;
        }

        //set the IF filter bandwidth
        if (vm.count("tx-bw")){
            std::cout << boost::format("Setting TX Bandwidth: %f MHz...") % tx_bw << std::endl;
            tx_usrp->set_tx_bandwidth(tx_bw, chan);
            std::cout << boost::format("Actual TX Bandwidth: %f MHz...") % tx_usrp->get_tx_bandwidth(chan) << std::endl << std::endl;
        }

        //set the antenna
        if (vm.count("tx-ant")) tx_usrp->set_tx_antenna(tx_ant, chan);
    }

    //set the receive center frequency
    if (not vm.count("rx-freq")){
        std::cerr << "Please specify the center frequency with --rx-freq" << std::endl;
        return ~0;
    }
    std::cout << boost::format("Setting RX Freq: %f MHz...") % (rx_freq/1e6) << std::endl;
    rx_usrp->set_rx_freq(rx_freq);
    std::cout << boost::format("Actual RX Freq: %f MHz...") % (rx_usrp->get_rx_freq()/1e6) << std::endl << std::endl;

    //set the receive rf gain
    if (vm.count("rx_gain")){
        std::cout << boost::format("Setting RX Gain: %f dB...") % rx_gain << std::endl;
        rx_usrp->set_rx_gain(rx_gain);
        std::cout << boost::format("Actual RX Gain: %f dB...") % rx_usrp->get_rx_gain() << std::endl << std::endl;
    }

    //set the receive IF filter bandwidth
    if (vm.count("rx_bw")){
        std::cout << boost::format("Setting RX Bandwidth: %f MHz...") % rx_bw << std::endl;
        rx_usrp->set_rx_bandwidth(rx_bw);
        std::cout << boost::format("Actual RX Bandwidth: %f MHz...") % rx_usrp->get_rx_bandwidth() << std::endl << std::endl;
    }

    //set the receive antenna
    if (vm.count("ant")) rx_usrp->set_rx_antenna(rx_ant);

    //for the const wave, set the wave freq for small samples per period
    if (wave_freq == 0 and wave_type == "CONST"){
        wave_freq = tx_usrp->get_tx_rate()/2;
    }

    //error when the waveform is not possible to generate
    if (std::abs(wave_freq) > tx_usrp->get_tx_rate()/2){
        throw std::runtime_error("wave freq out of Nyquist zone");
    }
    if (tx_usrp->get_tx_rate()/std::abs(wave_freq) > wave_table_len/2){
        throw std::runtime_error("wave freq too small for table");
    }

    //pre-compute the waveform values
    const wave_table_class wave_table(wave_type, ampl);
    const size_t step = boost::math::iround(wave_freq/tx_usrp->get_tx_rate() * wave_table_len);
    size_t index = 0;

    //create a transmit streamer
    //linearly map channels (index0 = channel0, index1 = channel1, ...)
    uhd::stream_args_t stream_args("fc32", otw);
    for (size_t chan = 0; chan < tx_usrp->get_tx_num_channels(); chan++)
        stream_args.channels.push_back(chan); //linear mapping
    uhd::tx_streamer::sptr tx_stream = tx_usrp->get_tx_stream(stream_args);

    //allocate a buffer which we re-use for each channel
    if (spb == 0) spb = tx_stream->get_max_num_samps()*10;
    std::vector<std::complex<float> > buff(spb);
    int num_channels = tx_usrp->get_tx_num_channels();

    //setup the metadata flags
    uhd::tx_metadata_t md;
    md.start_of_burst = true;
    md.end_of_burst   = false;
    md.has_time_spec  = true;
    md.time_spec = uhd::time_spec_t(0.1); //give us 0.1 seconds to fill the tx buffers

    //Check Ref and LO Lock detect
    std::vector<std::string> tx_sensor_names, rx_sensor_names;
    tx_sensor_names = tx_usrp->get_tx_sensor_names(0);
    if (std::find(tx_sensor_names.begin(), tx_sensor_names.end(), "lo_locked") != tx_sensor_names.end()) {
        uhd::sensor_value_t lo_locked = tx_usrp->get_tx_sensor("lo_locked",0);
        std::cout << boost::format("Checking TX: %s ...") % lo_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(lo_locked.to_bool());
    }
    rx_sensor_names = rx_usrp->get_rx_sensor_names(0);
    if (std::find(rx_sensor_names.begin(), rx_sensor_names.end(), "lo_locked") != rx_sensor_names.end()) {
        uhd::sensor_value_t lo_locked = rx_usrp->get_rx_sensor("lo_locked",0);
        std::cout << boost::format("Checking RX: %s ...") % lo_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(lo_locked.to_bool());
    }

    tx_sensor_names = tx_usrp->get_mboard_sensor_names(0);
    if ((ref == "mimo") and (std::find(tx_sensor_names.begin(), tx_sensor_names.end(), "mimo_locked") != tx_sensor_names.end())) {
        uhd::sensor_value_t mimo_locked = tx_usrp->get_mboard_sensor("mimo_locked",0);
        std::cout << boost::format("Checking TX: %s ...") % mimo_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(mimo_locked.to_bool());
    }
    if ((ref == "external") and (std::find(tx_sensor_names.begin(), tx_sensor_names.end(), "ref_locked") != tx_sensor_names.end())) {
        uhd::sensor_value_t ref_locked = tx_usrp->get_mboard_sensor("ref_locked",0);
        std::cout << boost::format("Checking TX: %s ...") % ref_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(ref_locked.to_bool());
    }

    rx_sensor_names = rx_usrp->get_mboard_sensor_names(0);
    if ((ref == "mimo") and (std::find(rx_sensor_names.begin(), rx_sensor_names.end(), "mimo_locked") != rx_sensor_names.end())) {
        uhd::sensor_value_t mimo_locked = rx_usrp->get_mboard_sensor("mimo_locked",0);
        std::cout << boost::format("Checking RX: %s ...") % mimo_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(mimo_locked.to_bool());
    }
    if ((ref == "external") and (std::find(rx_sensor_names.begin(), rx_sensor_names.end(), "ref_locked") != rx_sensor_names.end())) {
        uhd::sensor_value_t ref_locked = rx_usrp->get_mboard_sensor("ref_locked",0);
        std::cout << boost::format("Checking RX: %s ...") % ref_locked.to_pp_string() << std::endl;
        UHD_ASSERT_THROW(ref_locked.to_bool());
    }

    if (total_num_samps == 0){
        std::signal(SIGINT, &sig_int_handler);
        std::cout << "Press Ctrl + C to stop streaming..." << std::endl;
    }

    //reset usrp time to prepare for transmit/receive
    std::cout << boost::format("Setting device timestamp to 0...") << std::endl;
    tx_usrp->set_time_now(uhd::time_spec_t(0.0));

    //start transmit worker thread
    boost::thread_group transmit_thread;
    transmit_thread.create_thread(boost::bind(&transmit_worker, buff, wave_table, tx_stream, md, step, index, num_channels));

    //recv to file
    if (type == "double") recv_to_file<std::complex<double> >(rx_usrp, "fc64", otw, file, spb, total_num_samps, settling);
    else if (type == "float") recv_to_file<std::complex<float> >(rx_usrp, "fc32", otw, file, spb, total_num_samps, settling);
    else if (type == "short") recv_to_file<std::complex<short> >(rx_usrp, "sc16", otw, file, spb, total_num_samps, settling);
    else {
        //clean up transmit worker
        stop_signal_called = true;
        transmit_thread.join_all();
        throw std::runtime_error("Unknown type " + type);
    }

    //clean up transmit worker
    stop_signal_called = true;
    transmit_thread.join_all();

    //finished
    std::cout << std::endl << "Done!" << std::endl << std::endl;
    return 0;
}