/*
 * Copyright 2013-2020 Software Radio Systems Limited
 *
 * This file is part of srsLTE.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE 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 Affero General Public License for more details.
 *
 * A copy of the GNU Affero 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/.
 *
 */

/******************************************************************************
 *  File:         pdcch.h
 *
 *  Description:  Physical downlink control channel.
 *
 *  Reference:    3GPP TS 36.211 version 10.0.0 Release 10 Sec. 6.8
 *****************************************************************************/

#ifndef SRSLTE_PDCCH_H
#define SRSLTE_PDCCH_H

#include "srslte/config.h"
#include "srslte/phy/ch_estimation/chest_dl.h"
#include "srslte/phy/common/phy_common.h"
#include "srslte/phy/fec/convcoder.h"
#include "srslte/phy/fec/crc.h"
#include "srslte/phy/fec/rm_conv.h"
#include "srslte/phy/fec/viterbi.h"
#include "srslte/phy/mimo/layermap.h"
#include "srslte/phy/mimo/precoding.h"
#include "srslte/phy/modem/demod_soft.h"
#include "srslte/phy/modem/mod.h"
#include "srslte/phy/phch/dci.h"
#include "srslte/phy/phch/regs.h"
#include "srslte/phy/scrambling/scrambling.h"

typedef enum SRSLTE_API { SEARCH_UE, SEARCH_COMMON } srslte_pdcch_search_mode_t;

/* PDCCH object */
typedef struct SRSLTE_API {
  srslte_cell_t cell;
  uint32_t      nof_regs[3];
  uint32_t      nof_cce[3];
  uint32_t      max_bits;
  uint32_t      nof_rx_antennas;
  bool          is_ue;

  srslte_regs_t* regs;

  /* buffers */
  cf_t*    ce[SRSLTE_MAX_PORTS][SRSLTE_MAX_PORTS];
  cf_t*    symbols[SRSLTE_MAX_PORTS];
  cf_t*    x[SRSLTE_MAX_PORTS];
  cf_t*    d;
  uint8_t* e;
  float    rm_f[3 * (SRSLTE_DCI_MAX_BITS + 16)];
  float*   llr;

  /* tx & rx objects */
  srslte_modem_table_t mod;
  srslte_sequence_t    seq[SRSLTE_NOF_SF_X_FRAME];
  srslte_viterbi_t     decoder;
  srslte_crc_t         crc;

} srslte_pdcch_t;

SRSLTE_API int srslte_pdcch_init_ue(srslte_pdcch_t* q, uint32_t max_prb, uint32_t nof_rx_antennas);

SRSLTE_API int srslte_pdcch_init_enb(srslte_pdcch_t* q, uint32_t max_prb);

SRSLTE_API int srslte_pdcch_set_cell(srslte_pdcch_t* q, srslte_regs_t* regs, srslte_cell_t cell);

SRSLTE_API void srslte_pdcch_set_regs(srslte_pdcch_t* q, srslte_regs_t* regs);

SRSLTE_API void srslte_pdcch_free(srslte_pdcch_t* q);

SRSLTE_API float srslte_pdcch_coderate(uint32_t nof_bits, uint32_t l);

/* Encoding function */
SRSLTE_API int srslte_pdcch_encode(srslte_pdcch_t*     q,
                                   srslte_dl_sf_cfg_t* sf,
                                   srslte_dci_msg_t*   msg,
                                   cf_t*               sf_symbols[SRSLTE_MAX_PORTS]);

/* Decoding functions: Extract the LLRs and save them in the srslte_pdcch_t object */

SRSLTE_API int srslte_pdcch_extract_llr(srslte_pdcch_t*        q,
                                        srslte_dl_sf_cfg_t*    sf,
                                        srslte_chest_dl_res_t* channel,
                                        cf_t*                  sf_symbols[SRSLTE_MAX_PORTS]);

/* Decoding functions: Try to decode a DCI message after calling srslte_pdcch_extract_llr */
SRSLTE_API int
srslte_pdcch_decode_msg(srslte_pdcch_t* q, srslte_dl_sf_cfg_t* sf, srslte_dci_cfg_t* dci_cfg, srslte_dci_msg_t* msg);

SRSLTE_API int
srslte_pdcch_dci_decode(srslte_pdcch_t* q, float* e, uint8_t* data, uint32_t E, uint32_t nof_bits, uint16_t* crc);

SRSLTE_API int
srslte_pdcch_dci_encode(srslte_pdcch_t* q, uint8_t* data, uint8_t* e, uint32_t nof_bits, uint32_t E, uint16_t rnti);

SRSLTE_API void
srslte_pdcch_dci_encode_conv(srslte_pdcch_t* q, uint8_t* data, uint32_t nof_bits, uint8_t* coded_data, uint16_t rnti);

/* Function for generation of UE-specific search space DCI locations */
SRSLTE_API uint32_t srslte_pdcch_ue_locations(srslte_pdcch_t*        q,
                                              srslte_dl_sf_cfg_t*    sf,
                                              srslte_dci_location_t* locations,
                                              uint32_t               max_locations,
                                              uint16_t               rnti);

SRSLTE_API uint32_t srslte_pdcch_ue_locations_ncce(uint32_t               nof_cce,
                                                   srslte_dci_location_t* c,
                                                   uint32_t               max_candidates,
                                                   uint32_t               sf_idx,
                                                   uint16_t               rnti);

SRSLTE_API uint32_t srslte_pdcch_ue_locations_ncce_L(uint32_t               nof_cce,
                                                     srslte_dci_location_t* c,
                                                     uint32_t               max_candidates,
                                                     uint32_t               sf_idx,
                                                     uint16_t               rnti,
                                                     int                    L);

/* Function for generation of common search space DCI locations */
SRSLTE_API uint32_t srslte_pdcch_common_locations(srslte_pdcch_t*        q,
                                                  srslte_dci_location_t* locations,
                                                  uint32_t               max_locations,
                                                  uint32_t               cfi);

SRSLTE_API uint32_t srslte_pdcch_common_locations_ncce(uint32_t               nof_cce,
                                                       srslte_dci_location_t* c,
                                                       uint32_t               max_candidates);

#endif // SRSLTE_PDCCH_H