/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2014 The libLTE Developers. See the
 * COPYRIGHT file at the top-level directory of this distribution.
 *
 * \section LICENSE
 *
 * This file is part of the libLTE library.
 *
 * libLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * libLTE 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 Lesser General Public License for more details.
 *
 * A copy of the GNU Lesser General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */


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

#include "lte/common/base.h"
#include "lte/mimo/layermap.h"



int layermap_single(cf_t *d, cf_t *x, int nof_symbols) {
	memcpy(x, d, sizeof(cf_t) * nof_symbols);
	return nof_symbols;
}

int layermap_diversity(cf_t *d, cf_t *x[MAX_LAYERS], int nof_layers, int nof_symbols) {
	int i, j;
	for (i=0;i<nof_symbols/nof_layers;i++) {
		for (j=0;j<nof_layers;j++) {
			x[j][i] = d[nof_layers*i+j];
		}
	}
	return i;
}

int layermap_multiplex(cf_t *d[MAX_CODEWORDS], cf_t *x[MAX_LAYERS], int nof_cw, int nof_layers,
		int nof_symbols[MAX_CODEWORDS]) {
	if (nof_cw == 1) {
		return layermap_diversity(d[0], x, nof_layers, nof_symbols[0]);
	} else {
		int n[2];
		n[0] = nof_layers / nof_cw;
		n[1] = nof_layers - n[0];
		if (nof_symbols[0] / n[0] == nof_symbols[1] / n[1]) {

			layermap_diversity(d[0], x, 		n[0], nof_symbols[0]);
			layermap_diversity(d[1], &x[n[0]], n[1], nof_symbols[1]);
			return nof_symbols[0] / n[0];

		} else {
			fprintf(stderr, "Number of symbols in codewords 0 and 1 is not consistent (%d, %d)\n",
					nof_symbols[0], nof_symbols[1]);
			return -1;
		}
	}
	return 0;
}

/* Layer mapping generates the vector of layer-mapped symbols "x" based on the vector of data symbols "d"
 * Based on 36.211 6.3.3
 * Returns the number of symbols per layer (M_symb^layer in the specs)
 */
int layermap_type(cf_t *d[MAX_CODEWORDS], cf_t *x[MAX_LAYERS], int nof_cw, int nof_layers,
		int nof_symbols[MAX_CODEWORDS], mimo_type_t type) {

	if (nof_cw > MAX_CODEWORDS) {
		fprintf(stderr, "Maximum number of codewords is %d (nof_cw=%d)\n", MAX_CODEWORDS, nof_cw);
		return -1;
	}
	if (nof_layers > MAX_LAYERS) {
		fprintf(stderr, "Maximum number of layers is %d (nof_layers=%d)\n", MAX_LAYERS, nof_layers);
		return -1;
	}
	if (nof_layers < nof_cw) {
		fprintf(stderr, "Number of codewords must be lower or equal than number of layers\n");
		return -1;
	}

	switch(type) {
	case SINGLE_ANTENNA:
		if (nof_cw == 1 && nof_layers == 1) {
			return layermap_single(x[0], d[0], nof_symbols[0]);
		} else {
			fprintf(stderr, "Number of codewords and layers must be 1 for transmission on single antenna ports\n");
			return -1;
		}
		break;
	case TX_DIVERSITY:
		if (nof_cw == 1) {
			if (nof_layers == 2 || nof_layers == 4) {
				return layermap_diversity(d[0], x, nof_layers, nof_symbols[0]);
			} else {
				fprintf(stderr, "Number of layers must be 2 or 4 for transmit diversity\n");
				return -1;
			}
		} else {
			fprintf(stderr, "Number of codewords must be 1 for transmit diversity\n");
			return -1;
		}
		break;
	case SPATIAL_MULTIPLEX:
		return layermap_multiplex(d, x, nof_cw, nof_layers, nof_symbols);
		break;
	}
	return 0;
}









int layerdemap_single(cf_t *x, cf_t *d, int nof_symbols) {
	memcpy(d, x, sizeof(cf_t) * nof_symbols);
	return nof_symbols;
}
int layerdemap_diversity(cf_t *x[MAX_LAYERS], cf_t *d, int nof_layers, int nof_layer_symbols) {
	int i, j;
	for (i=0;i<nof_layer_symbols;i++) {
		for (j=0;j<nof_layers;j++) {
			d[nof_layers*i+j] = x[j][i];
		}
	}
	return nof_layer_symbols * nof_layers;
}

int layerdemap_multiplex(cf_t *x[MAX_LAYERS], cf_t *d[MAX_CODEWORDS], int nof_layers, int nof_cw,
		int nof_layer_symbols, int nof_symbols[MAX_CODEWORDS]) {
	if (nof_cw == 1) {
		return layerdemap_diversity(x, d[0], nof_layers, nof_layer_symbols);
	} else {
		int n[2];
		n[0] = nof_layers / nof_cw;
		n[1] = nof_layers - n[0];
		nof_symbols[0] = n[0] * nof_layer_symbols;
		nof_symbols[1] = n[1] * nof_layer_symbols;

		nof_symbols[0] = layerdemap_diversity(x, 	   d[0], n[0], nof_layer_symbols);
		nof_symbols[1] = layerdemap_diversity(&x[n[0]], d[1], n[1], nof_layer_symbols);
	}
	return 0;
}

/* Generates the vector of data symbols "d" based on the vector of layer-mapped symbols "x"
 * Based on 36.211 6.3.3
 * Returns 0 on ok and saves the number of symbols per codeword (M_symb^(q) in the specs) in
 * nof_symbols. Returns -1 on error
 */
int layerdemap_type(cf_t *x[MAX_LAYERS], cf_t *d[MAX_CODEWORDS], int nof_layers, int nof_cw,
		int nof_layer_symbols, int nof_symbols[MAX_CODEWORDS], mimo_type_t type) {

	if (nof_cw > MAX_CODEWORDS) {
		fprintf(stderr, "Maximum number of codewords is %d (nof_cw=%d)\n", MAX_CODEWORDS, nof_cw);
		return -1;
	}
	if (nof_layers > MAX_LAYERS) {
		fprintf(stderr, "Maximum number of layers is %d (nof_layers=%d)\n", MAX_LAYERS, nof_layers);
		return -1;
	}
	if (nof_layers < nof_cw) {
		fprintf(stderr, "Number of codewords must be lower or equal than number of layers\n");
		return -1;
	}

	switch(type) {
	case SINGLE_ANTENNA:
		if (nof_cw == 1 && nof_layers == 1) {
			nof_symbols[0] = layerdemap_single(x[0], d[0], nof_layer_symbols);
			nof_symbols[1] = 0;
		} else {
			fprintf(stderr, "Number of codewords and layers must be 1 for transmission on single antenna ports\n");
			return -1;
		}
		break;
	case TX_DIVERSITY:
		if (nof_cw == 1) {
			if (nof_layers == 2 || nof_layers == 4) {
				nof_symbols[0] = layerdemap_diversity(x, d[0], nof_layers, nof_layer_symbols);
				nof_symbols[1] = 0;
			} else {
				fprintf(stderr, "Number of layers must be 2 or 4 for transmit diversity\n");
				return -1;
			}
		} else {
			fprintf(stderr, "Number of codewords must be 1 for transmit diversity\n");
			return -1;
		}
		break;
	case SPATIAL_MULTIPLEX:
		return layerdemap_multiplex(x, d, nof_layers, nof_cw, nof_layer_symbols, nof_symbols);
		break;
	}
	return 0;
}