/*
 * Copyright 2013-2019 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/.
 *
 */

#ifndef SRSENB_SCHEDULER_UE_H
#define SRSENB_SCHEDULER_UE_H

#include "srslte/common/log.h"
#include "srslte/interfaces/sched_interface.h"
#include <map>
#include <vector>

#include "scheduler_harq.h"
#include <deque>
#include <mutex>

namespace srsenb {

class sched_cell_params_t;
struct tti_params_t;

struct sched_dci_cce_t {
  uint32_t cce_start[4][6];
  uint32_t nof_loc[4];
};

struct sched_ue_carrier {
  const static int SCHED_MAX_HARQ_PROC = SRSLTE_FDD_NOF_HARQ;

  sched_ue_carrier(const sched_interface::ue_cfg_t& cfg_,
                   const sched_cell_params_t&       cell_cfg_,
                   uint16_t                         rnti_,
                   uint32_t                         ue_cc_idx);
  void reset();
  void set_cfg(const sched_interface::ue_cfg_t& cfg); ///< reconfigure ue carrier

  // Harq access
  void          reset_old_pending_pids(uint32_t tti_rx);
  dl_harq_proc* get_pending_dl_harq(uint32_t tti_tx_dl);
  dl_harq_proc* get_empty_dl_harq();
  int           set_ack_info(uint32_t tti_rx, uint32_t tb_idx, bool ack);
  ul_harq_proc* get_ul_harq(uint32_t tti);
  uint32_t      get_pending_ul_old_data();

  uint32_t                   get_aggr_level(uint32_t nof_bits);
  int                        alloc_tbs(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, bool is_ul, int* mcs);
  int                        alloc_tbs_dl(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, int* mcs);
  int                        alloc_tbs_ul(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, int* mcs);
  uint32_t                   get_required_prb_ul(uint32_t req_bytes);
  const sched_cell_params_t* get_cell_cfg() const { return cell_params; }
  bool                       is_active() const { return active; }
  uint32_t                   get_ue_cc_idx() const { return ue_cc_idx; }

  std::array<dl_harq_proc, SCHED_MAX_HARQ_PROC> dl_harq = {};
  std::array<ul_harq_proc, SCHED_MAX_HARQ_PROC> ul_harq = {};

  uint32_t dl_ri      = 0;
  uint32_t dl_ri_tti  = 0;
  uint32_t dl_pmi     = 0;
  uint32_t dl_pmi_tti = 0;
  uint32_t dl_cqi     = 1;
  uint32_t dl_cqi_tti = 0;
  uint32_t ul_cqi     = 1;
  uint32_t ul_cqi_tti = 0;

  int      max_mcs_dl = 28, max_mcs_ul = 28;
  uint32_t max_aggr_level = 3;
  int      fixed_mcs_ul = 0, fixed_mcs_dl = 0;

  // Allowed DCI locations per per CFI and per subframe
  std::array<std::array<sched_dci_cce_t, 10>, 3> dci_locations = {};

private:
  // config
  srslte::log*                     log_h       = nullptr;
  const sched_interface::ue_cfg_t* cfg         = nullptr;
  const sched_cell_params_t*       cell_params = nullptr;
  uint16_t                         rnti;
  uint32_t                         ue_cc_idx = 0;

  // state
  bool active = false;
};

/** This class is designed to be thread-safe because it is called from workers through scheduler thread and from
 * higher layers and mac threads.
 *
 * 1 mutex is created for every user and only access to same user variables are mutexed
 */
class sched_ue
{
public:
  /*************************************************************
   *
   * FAPI-like Interface
   *
   ************************************************************/
  sched_ue();
  void reset();
  void phy_config_enabled(uint32_t tti, bool enabled);
  void init(uint16_t rnti, const std::vector<sched_cell_params_t>& cell_list_params_);
  void set_cfg(const sched_interface::ue_cfg_t& cfg);

  void set_bearer_cfg(uint32_t lc_id, srsenb::sched_interface::ue_bearer_cfg_t* cfg);
  void rem_bearer(uint32_t lc_id);

  void dl_buffer_state(uint8_t lc_id, uint32_t tx_queue, uint32_t retx_queue);
  void ul_buffer_state(uint8_t lc_id, uint32_t bsr, bool set_value = true);
  void ul_phr(int phr);
  void mac_buffer_state(uint32_t ce_code);
  void ul_recv_len(uint32_t lcid, uint32_t len);
  void set_dl_ant_info(const sched_interface::ant_info_ded_t& dedicated);
  void set_ul_cqi(uint32_t tti, uint32_t cc_idx, uint32_t cqi, uint32_t ul_ch_code);
  void set_dl_ri(uint32_t tti, uint32_t cc_idx, uint32_t ri);
  void set_dl_pmi(uint32_t tti, uint32_t cc_idx, uint32_t ri);
  void set_dl_cqi(uint32_t tti, uint32_t cc_idx, uint32_t cqi);
  int  set_ack_info(uint32_t tti, uint32_t cc_idx, uint32_t tb_idx, bool ack);
  void set_ul_crc(uint32_t tti, uint32_t cc_idx, bool crc_res);

  /*******************************************************
   * Custom functions
   *******************************************************/

  void tpc_inc();
  void tpc_dec();

  dl_harq_proc*                    find_dl_harq(uint32_t tti_rx, uint32_t cc_idx);
  dl_harq_proc*                    get_dl_harq(uint32_t idx, uint32_t cc_idx);
  uint16_t                         get_rnti() const { return rnti; }
  std::pair<bool, uint32_t>        get_cell_index(uint32_t enb_cc_idx) const;
  const sched_interface::ue_cfg_t& get_ue_cfg() const { return cfg; }

  /*******************************************************
   * Functions used by scheduler metric objects
   *******************************************************/

  uint32_t get_required_prb_dl(uint32_t cc_idx, uint32_t req_bytes, uint32_t nof_ctrl_symbols);
  uint32_t get_required_prb_ul(uint32_t cc_idx, uint32_t req_bytes);

  uint32_t get_pending_dl_new_data();
  uint32_t get_pending_ul_new_data(uint32_t tti);
  uint32_t get_pending_ul_old_data(uint32_t cc_idx);
  uint32_t get_pending_dl_new_data_total();

  void          reset_pending_pids(uint32_t tti_rx, uint32_t cc_idx);
  dl_harq_proc* get_pending_dl_harq(uint32_t tti, uint32_t cc_idx);
  dl_harq_proc* get_empty_dl_harq(uint32_t cc_idx);
  ul_harq_proc* get_ul_harq(uint32_t tti, uint32_t cc_idx);

  /*******************************************************
   * Functions used by the scheduler carrier object
   *******************************************************/

  void finish_tti(const tti_params_t& tti_params, uint32_t enb_cc_idx);

  /*******************************************************
   * Functions used by the scheduler object
   *******************************************************/

  void set_sr();
  void unset_sr();

  void set_needs_ta_cmd(uint32_t nof_ta_cmd);

  int generate_format1(dl_harq_proc*                     h,
                       sched_interface::dl_sched_data_t* data,
                       uint32_t                          tti,
                       uint32_t                          cc_idx,
                       uint32_t                          cfi,
                       const rbgmask_t&                  user_mask);
  int generate_format2a(dl_harq_proc*                     h,
                        sched_interface::dl_sched_data_t* data,
                        uint32_t                          tti,
                        uint32_t                          cc_idx,
                        uint32_t                          cfi,
                        const rbgmask_t&                  user_mask);
  int generate_format2(dl_harq_proc*                     h,
                       sched_interface::dl_sched_data_t* data,
                       uint32_t                          tti,
                       uint32_t                          cc_idx,
                       uint32_t                          cfi,
                       const rbgmask_t&                  user_mask);
  int generate_format0(sched_interface::ul_sched_data_t* data,
                       uint32_t                          tti,
                       uint32_t                          cc_idx,
                       ul_harq_proc::ul_alloc_t          alloc,
                       bool                              needs_pdcch,
                       srslte_dci_location_t             cce_range,
                       int                               explicit_mcs = -1);

  srslte_dci_format_t get_dci_format();
  sched_dci_cce_t*    get_locations(uint32_t enb_cc_idx, uint32_t current_cfi, uint32_t sf_idx);
  sched_ue_carrier*   get_ue_carrier(uint32_t enb_cc_idx);

  bool     needs_cqi(uint32_t tti, uint32_t cc_idx, bool will_send = false);
  uint32_t get_max_retx();

  bool pucch_sr_collision(uint32_t current_tti, uint32_t n_cce);

  static int cqi_to_tbs(uint32_t  cqi,
                        uint32_t  nof_prb,
                        uint32_t  nof_re,
                        uint32_t  max_mcs,
                        uint32_t  max_Qm,
                        bool      is_ul,
                        uint32_t* mcs);

private:
  struct ue_bearer_t {
    sched_interface::ue_bearer_cfg_t cfg      = {};
    int                              buf_tx   = 0;
    int                              buf_retx = 0;
    int                              bsr      = 0;
  };

  void set_bearer_cfg_unlocked(uint32_t lc_id, const sched_interface::ue_bearer_cfg_t& cfg_);

  bool is_sr_triggered();

  uint32_t format1_count_prb(const rbgmask_t& bitmask, uint32_t cc_idx);
  int      alloc_rlc_pdu(sched_interface::dl_sched_pdu_t* mac_sdu, int rem_tbs);
  uint32_t allocate_mac_sdus(sched_interface::dl_sched_data_t* data, uint32_t total_tbs);

  static bool bearer_is_ul(ue_bearer_t* lch);
  static bool bearer_is_dl(const ue_bearer_t* lch);

  uint32_t get_pending_dl_new_data_unlocked();
  uint32_t get_pending_ul_old_data_unlocked(uint32_t cc_idx);
  uint32_t get_pending_ul_new_data_unlocked(uint32_t tti);
  uint32_t get_pending_dl_new_data_total_unlocked();
  bool     is_conres_ce_pending() const;

  bool needs_cqi_unlocked(uint32_t tti, uint32_t cc_idx, bool will_send = false);

  int generate_format2a_unlocked(dl_harq_proc*                     h,
                                 sched_interface::dl_sched_data_t* data,
                                 uint32_t                          tti,
                                 uint32_t                          cc_idx,
                                 uint32_t                          cfi,
                                 const rbgmask_t&                  user_mask);

  bool is_first_dl_tx();

  /* Args */
  sched_interface::ue_cfg_t               cfg              = {};
  srslte_cell_t                           cell             = {};
  srslte::log*                            log_h            = nullptr;
  const std::vector<sched_cell_params_t>* cell_params_list = nullptr;
  const sched_cell_params_t*              main_cc_params   = nullptr;

  std::mutex mutex;

  /* Buffer states */
  bool                                             sr      = false;
  int                                              buf_mac = 0;
  int                                              buf_ul  = 0;
  std::array<ue_bearer_t, sched_interface::MAX_LC> lch     = {};

  int      power_headroom  = 0;
  uint32_t cqi_request_tti = 0;
  uint16_t rnti            = 0;
  uint32_t max_msg3retx    = 0;

  /* User State */
  bool conres_ce_pending = true;

  int next_tpc_pusch = 0;
  int next_tpc_pucch = 0;

  bool phy_config_dedicated_enabled = false;

  sched_interface::ant_info_ded_t dl_ant_info;
  std::vector<sched_ue_carrier>   carriers; ///< map of UE CellIndex to carrier configuration

  // Control Element Command queue
  struct ce_cmd {
    int cetype = 0;

    explicit ce_cmd(int lcid) : cetype(lcid) {}
    int get_sdu_size(const sched_interface::ue_cfg_t& c) const;
    // considers both MAC CE and subheader
    int         get_req_bytes(const sched_interface::ue_cfg_t& c) const;
    std::string to_string() const;
  };
  std::deque<ce_cmd> pending_ces;
};
} // namespace srsenb

#endif // SRSENB_SCHEDULER_UE_H