//
// Cognitive radio simulator
//

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <sigprocc/sigprocc.h>
#include "cognitive_radio_test.h"

// options
#define PACKET_SIZE 1024    // packet size (number of bits)
#define NUM_TRIALS 250      // number of epochs
#define REPORT_TRIALS 10    // print report every so often

int main() {
    // bookkeeping variables and buffers
    unsigned int num_bits=PACKET_SIZE;
    char msg_in[num_bits], msg_out[num_bits];
    float I[num_bits], Q[num_bits];
    unsigned int num_symbols, num_bits_out;

    float noise_psd = -100.0f; // noise power spectral density
    float noise_power, noise_std;
    
    // quality of service metrics
    unsigned int num_bit_errors;
    float throughput_bps;

    // metadata defaults
    struct metadata_t mdt;
    metadata md = &mdt;

    md->mod_scheme = MOD_QAM;   // MOD_PSK, MOD_QAM, MOD_PAM, MOD_DPSK
    md->mod_bps = 4;            // modulation scheme [bits/s]
    md->tx_power_dBW = -3.0f;   // transmit power [dBW]
    md->symbol_rate = 250e3f;   // symbol rate [symbols/s]

    unsigned int i;
    // generate random message
    for (i=0; i<num_bits; i++)
        msg_in[i] = (char) (rand() % 2);

    printf("epoch\tutility\n");
    printf("-----\t-------\n");
    for (i=0; i<NUM_TRIALS; i++) {
        // compute internals
        noise_power = noise_psd + 20*log10f(md->symbol_rate);
        noise_std = powf(10.0f, (noise_power - md->tx_power_dBW) / 10.0f) / 2.0f;

        // execute transmitter
        execute_tx(md, msg_in, num_bits, I, Q, &num_symbols);

        // execute channel
        execute_channel(md, noise_std, I, Q, num_symbols);

        // execute receiver
        execute_rx(md, I, Q, num_symbols, msg_out, &num_bits_out);

        //
        // *** compute quality of service metrics ***
        //

        // count errors, etc.
        num_bit_errors = count_errors(msg_in, msg_out, num_bits);
        throughput_bps = ((float)(md->mod_bps)) * md->symbol_rate;

        if ( ((i+1)%REPORT_TRIALS)==0 || (i+1)==NUM_TRIALS) {
            // print results
            printf("%u\t%.2f\terrors:\t%u\t/ %u, power: %.1f dBW, Fs: %.3f kHz\n",
                    i+1, 0.0f, num_bit_errors, num_bits, md->tx_power_dBW, md->symbol_rate/1e3 );
        }

        // 
        // *** execute cognition here ***
        //

        // simple power adaptation
        if (num_bit_errors > 30) {
            md->tx_power_dBW += 0.1f;
        } else {
            md->tx_power_dBW -= 0.1f;
        }

    }

    printf("done.\n");
    return 0;
}