#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#include <liquid/liquid.h>

#include "layer1/rx.h"

#include "config.h"

#define RESULT_CHECK(stmt) { \
	result_t res = stmt; \
	if(res != OK) { \
		fprintf(stderr, "Error %d in %s:%d!\n", res, __FILE__, __LINE__); \
		exit(1); \
	} \
}

#define CHUNKSIZE_INPUT  8000
#define CHUNKSIZE_RF     (CHUNKSIZE_INPUT/2)
#define CHUNKSIZE_BB     (CHUNKSIZE_RF/SDR_OVERSAMPLING)

static struct {
	size_t preambles_found;
	size_t successful_decodes;
	size_t failed_decodes;
	size_t header_errors;
} m_stats;


static result_t sdr_rf_to_baseband(nco_crcf nco, firdecim_crcf  decim,
		const float complex *rf_samples, size_t nrf,
		float complex *bb_samples, size_t *nbb)
{
	if((*nbb * SDR_OVERSAMPLING) < nrf) {
		fprintf(stderr, "sdr_rf_to_baseband: result would not fit in output: %zd * %d < %zd\n", *nbb, SDR_OVERSAMPLING, nrf);
		return ERR_SIZE;
	}

	*nbb = nrf / SDR_OVERSAMPLING;

	for(size_t i = 0; i < *nbb; i++) {
		float complex tmp[SDR_OVERSAMPLING];

		assert(i*SDR_OVERSAMPLING < nrf);

		nco_crcf_mix_block_down(nco,
				(complex float*)(rf_samples + i * SDR_OVERSAMPLING),
				tmp,
				SDR_OVERSAMPLING);

		firdecim_crcf_execute(decim, tmp, bb_samples + i);
	}

	return OK;
}


void cb_rx(rx_evt_t evt, uint8_t *packet_data, size_t packet_len)
{
	switch(evt)
	{
		case RX_EVT_CHECKSUM_ERROR:
			//fprintf(stderr, "Received a message of %zu bytes, but decoding failed.\n", packet_len);
			//fprintf(stderr, "=== FAILED PAYLOAD ===\n");
			//hexdump(packet_data, packet_len);
			//fprintf(stderr, "=======================\n");
			m_stats.failed_decodes++;
			break;

		case RX_EVT_HEADER_ERROR:
			m_stats.header_errors++;
			break;

		case RX_EVT_PACKET_RECEIVED:
			//fprintf(stderr, "A message of %zu bytes was decoded successfully.\n", packet_len);
			//fprintf(stderr, "=== DECODED PAYLOAD (%4zu bytes) ===\n", packet_len);
			//hexdump(packet_data, packet_len < 64 ? packet_len : 64);
			//fprintf(stderr, "====================================\n");

			m_stats.successful_decodes++;
			break;

		case RX_EVT_PREAMBLE_FOUND:
			//fprintf(stderr, "Found preamble!\n");
			m_stats.preambles_found++;
			break;
	}
}


int main(int argc, char **argv)
{
	if(argc < 2) {
		fprintf(stderr, "Not enough arguments!\n");
		fprintf(stderr, "usage: %s <dump-file>\n\n", argv[0]);
		fprintf(stderr, "dump-file: HackRF dump in 8-bit signed interleaved I/Q format.\n");
		return 1;
	}

	layer1_rx_t rx;
	FILE *inputfile;
	int8_t rbuf[CHUNKSIZE_INPUT];

	// ** Initialize **

	firdecim_crcf decim = firdecim_crcf_create_kaiser(SDR_OVERSAMPLING, 9, 60.0f);
	nco_crcf rx_nco = nco_crcf_create(LIQUID_NCO);
	nco_crcf_set_frequency(rx_nco, 2 * 3.14159 * SDR_RX_IF_SHIFT / SDR_RX_SAMPLING_RATE);

	inputfile = fopen(argv[1], "rb");
	if(!inputfile) {
		fprintf(stderr, "Could not open input file!\n");
		return 1;
	}

	RESULT_CHECK(layer1_rx_init(&rx, cb_rx));

	// ** Process packets **

	size_t nread;
	while((nread = fread(rbuf, 1, sizeof(rbuf), inputfile)) != 0) {
		assert(nread % 2 == 0);

		// ** Receive signal **

		float complex rf_samples[CHUNKSIZE_RF];
		float complex bb_samples[CHUNKSIZE_BB];

		size_t n_rf_samples = CHUNKSIZE_RF;
		size_t n_bb_samples = CHUNKSIZE_BB;

		for(size_t iout = 0; iout < CHUNKSIZE_RF; iout++) {
			rf_samples[iout] = 0.0078125f * (rbuf[2*iout + 0] + I * rbuf[2*iout + 1]);
		}

		RESULT_CHECK(sdr_rf_to_baseband(rx_nco, decim, rf_samples, n_rf_samples, bb_samples, &n_bb_samples));

		RESULT_CHECK(layer1_rx_process(&rx, bb_samples, n_bb_samples));

		fprintf(stderr, "Receiver statistics:\n");
		fprintf(stderr, "  Preambles found:    %8zd\n", m_stats.preambles_found);
		fprintf(stderr, "  Successful decodes: %8zd (%6.2f %%)\n",
				m_stats.successful_decodes, m_stats.successful_decodes * 100.0f / m_stats.preambles_found);
		fprintf(stderr, "  Header errors:      %8zd (%6.2f %%)\n",
				m_stats.header_errors, m_stats.header_errors * 100.0f / m_stats.preambles_found);
		fprintf(stderr, "  Failed decodes:     %8zd (%6.2f %%)\n",
				m_stats.failed_decodes, m_stats.failed_decodes * 100.0f / m_stats.preambles_found);

	}

	// ** Cleanup **

	layer1_rx_shutdown(&rx);

	fprintf(stderr, "Done.\n");
}