/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2017 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of srsLTE.
 *
 * srsUE 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.
 *
 * srsUE 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 RRC_H
#define RRC_H

#include <map>
#include <queue>
#include "srslte/common/buffer_pool.h"
#include "srslte/common/common.h"
#include "srslte/common/block_queue.h"
#include "srslte/common/threads.h"
#include "srslte/common/timeout.h"
#include "srslte/common/log.h"
#include "srslte/interfaces/enb_interfaces.h"
#include "upper/common_enb.h"
#include "rrc_metrics.h"

namespace srsenb {

typedef struct {
  uint32_t                      period;   
  LIBLTE_RRC_DSR_TRANS_MAX_ENUM dsr_max; 
  uint32_t                      nof_prb; 
  uint32_t                      sf_mapping[80]; 
  uint32_t                      nof_subframes; 
} rrc_cfg_sr_t; 
  
typedef enum {
  RRC_CFG_CQI_MODE_PERIODIC = 0,
  RRC_CFG_CQI_MODE_APERIODIC,
  RRC_CFG_CQI_MODE_N_ITEMS
} rrc_cfg_cqi_mode_t;

static const char rrc_cfg_cqi_mode_text[RRC_CFG_CQI_MODE_N_ITEMS][20] = {"periodic", "aperiodic"};

typedef struct {
  uint32_t           sf_mapping[80]; 
  uint32_t           nof_subframes; 
  uint32_t           nof_prb; 
  uint32_t           period; 
  bool               simultaneousAckCQI;
  rrc_cfg_cqi_mode_t mode; 
} rrc_cfg_cqi_t; 

typedef struct {
  bool configured; 
  LIBLTE_RRC_UL_SPECIFIC_PARAMETERS_STRUCT lc_cfg; 
  LIBLTE_RRC_PDCP_CONFIG_STRUCT            pdcp_cfg; 
  LIBLTE_RRC_RLC_CONFIG_STRUCT             rlc_cfg; 
} rrc_cfg_qci_t;

#define MAX_NOF_QCI 10
  
typedef struct {
  LIBLTE_RRC_SYS_INFO_BLOCK_TYPE_STRUCT    sibs[LIBLTE_RRC_MAX_SIB];  
  LIBLTE_RRC_MAC_MAIN_CONFIG_STRUCT        mac_cnfg; 
  LIBLTE_RRC_PUSCH_CONFIG_DEDICATED_STRUCT pusch_cfg;   
  rrc_cfg_sr_t                             sr_cfg; 
  rrc_cfg_cqi_t                            cqi_cfg; 
  rrc_cfg_qci_t                            qci_cfg[MAX_NOF_QCI]; 
  srslte_cell_t cell; 
  uint32_t inactivity_timeout_ms; 
}rrc_cfg_t; 

static const char rrc_state_text[RRC_STATE_N_ITEMS][100] = {"IDLE",
                                                            "WAIT FOR CON SETUP COMPLETE",
                                                            "WAIT FOR SECURITY MODE COMPLETE",
                                                            "WAIT FOR UE CAPABILITIY INFORMATION",
                                                            "WAIT FOR CON RECONF COMPLETE",
                                                            "RRC CONNECTED"
                                                            "RELEASE REQUEST"};

class rrc : public rrc_interface_pdcp, 
            public rrc_interface_mac, 
            public rrc_interface_rlc,
            public rrc_interface_s1ap,
            public thread
{
public:
  
  rrc() : act_monitor(this), cnotifier(NULL) {}
  
  void init(rrc_cfg_t *cfg,
            phy_interface_rrc *phy, 
            mac_interface_rrc *mac, 
            rlc_interface_rrc *rlc, 
            pdcp_interface_rrc *pdcp,
            s1ap_interface_rrc *s1ap,
            gtpu_interface_rrc *gtpu,
            srslte::log *log_rrc);
  
  void stop(); 
  void get_metrics(rrc_metrics_t &m);
  
  // rrc_interface_mac
  void rl_failure(uint16_t rnti);  
  void add_user(uint16_t rnti); 
  void upd_user(uint16_t new_rnti, uint16_t old_rnti);
  void set_activity_user(uint16_t rnti);
  bool is_paging_opportunity(uint32_t tti, uint32_t *payload_len); 
  
  // rrc_interface_rlc
  void read_pdu_bcch_dlsch(uint32_t sib_idx, uint8_t *payload);
  void read_pdu_pcch(uint8_t *payload, uint32_t buffer_size); 
  void max_retx_attempted(uint16_t rnti);
  
  // rrc_interface_s1ap
  void write_dl_info(uint16_t rnti, srslte::byte_buffer_t *sdu);
  void release_complete(uint16_t rnti);
  bool setup_ue_ctxt(uint16_t rnti, LIBLTE_S1AP_MESSAGE_INITIALCONTEXTSETUPREQUEST_STRUCT *msg);
  bool setup_ue_erabs(uint16_t rnti, LIBLTE_S1AP_MESSAGE_E_RABSETUPREQUEST_STRUCT *msg);
  bool release_erabs(uint32_t rnti);
  void add_paging_id(uint32_t ueid, LIBLTE_S1AP_UEPAGINGID_STRUCT UEPagingID);
  
  // rrc_interface_pdcp
  void write_pdu(uint16_t rnti, uint32_t lcid, srslte::byte_buffer_t *pdu);
  
  void parse_sibs(); 
  uint32_t get_nof_users();

  // Notifier for user connect 
  class connect_notifier {
  public:
    virtual void user_connected(uint16_t rnti) = 0; 
  }; 
  void set_connect_notifer(connect_notifier *cnotifier); 
  
  class activity_monitor : public thread
  {
  public:
    activity_monitor(rrc* parent_); 
    void stop(); 
  private:
    rrc* parent;
    bool running;
    void run_thread(); 
  };
  
  class ue
  {
  public: 
    ue(); 
    bool is_connected();
    bool is_idle(); 
    bool is_timeout();
    void set_activity();
    
    rrc_state_t get_state();
    
    void send_connection_setup(bool is_setup = true);
    void send_connection_reest(); 
    void send_connection_release();
    void send_connection_reest_rej(); 
    void send_connection_reconf(srslte::byte_buffer_t *sdu);
    void send_connection_reconf_new_bearer(LIBLTE_S1AP_E_RABTOBESETUPLISTBEARERSUREQ_STRUCT *e);
    void send_connection_reconf_upd(srslte::byte_buffer_t *pdu); 
    void send_security_mode_command();
    void send_ue_cap_enquiry();
    void parse_ul_dcch(uint32_t lcid, srslte::byte_buffer_t* pdu);

    void handle_rrc_con_req(LIBLTE_RRC_CONNECTION_REQUEST_STRUCT *msg);
    void handle_rrc_con_reest_req(LIBLTE_RRC_CONNECTION_REESTABLISHMENT_REQUEST_STRUCT *msg); 
    void handle_rrc_con_setup_complete(LIBLTE_RRC_CONNECTION_SETUP_COMPLETE_STRUCT *msg, srslte::byte_buffer_t *pdu);
    void handle_security_mode_complete(LIBLTE_RRC_SECURITY_MODE_COMPLETE_STRUCT *msg);
    void handle_security_mode_failure(LIBLTE_RRC_SECURITY_MODE_FAILURE_STRUCT *msg);
    void handle_ue_cap_info(LIBLTE_RRC_UE_CAPABILITY_INFORMATION_STRUCT *msg);
    
    void set_bitrates(LIBLTE_S1AP_UEAGGREGATEMAXIMUMBITRATE_STRUCT *rates);
    void set_security_capabilities(LIBLTE_S1AP_UESECURITYCAPABILITIES_STRUCT *caps);
    void set_security_key(uint8_t* key, uint32_t length);

    bool setup_erabs(LIBLTE_S1AP_E_RABTOBESETUPLISTCTXTSUREQ_STRUCT *e);
    bool setup_erabs(LIBLTE_S1AP_E_RABTOBESETUPLISTBEARERSUREQ_STRUCT *e);
    void setup_erab(uint8_t id, LIBLTE_S1AP_E_RABLEVELQOSPARAMETERS_STRUCT *qos,
                    LIBLTE_S1AP_TRANSPORTLAYERADDRESS_STRUCT *addr, uint32_t teid_out,
                    LIBLTE_S1AP_NAS_PDU_STRUCT *nas_pdu);
    bool release_erabs();

    void notify_s1ap_ue_ctxt_setup_complete();
    void notify_s1ap_ue_erab_setup_response(LIBLTE_S1AP_E_RABTOBESETUPLISTBEARERSUREQ_STRUCT *e);

    int sr_allocate(uint32_t period, uint32_t *I_sr, uint32_t *N_pucch_sr); 
    void sr_get(uint32_t *I_sr, uint32_t *N_pucch_sr); 
    int sr_free();

    int cqi_allocate(uint32_t period, uint32_t *pmi_idx, uint32_t *n_pucch); 
    void cqi_get(uint32_t *pmi_idx, uint32_t *n_pucch); 
    int cqi_free(); 
    
    void send_dl_ccch(LIBLTE_RRC_DL_CCCH_MSG_STRUCT *dl_ccch_msg);
    void send_dl_dcch(LIBLTE_RRC_DL_DCCH_MSG_STRUCT *dl_dcch_msg, srslte::byte_buffer_t *pdu = NULL);
    
    uint16_t rnti; 
    rrc *parent; 
    
    bool connect_notified; 
    
  private:
    
    struct timeval t_last_activity; 

    // S-TMSI for this UE
    bool      has_tmsi;
    uint32_t  m_tmsi;
    uint8_t   mmec;

    uint8_t     transaction_id;
    rrc_state_t state;
    
    std::map<uint32_t, LIBLTE_RRC_SRB_TO_ADD_MOD_STRUCT>  srbs;
    std::map<uint32_t, LIBLTE_RRC_DRB_TO_ADD_MOD_STRUCT>  drbs;
    
    uint8_t               k_enb[32];      // Provided by MME
    uint8_t               k_rrc_enc[32];
    uint8_t               k_rrc_int[32];
    uint8_t               k_up_enc[32];
    uint8_t               k_up_int[32];   // Not used: only for relay nodes (3GPP 33.401 Annex A.7)

    srslte::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
    srslte::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;

    LIBLTE_S1AP_UEAGGREGATEMAXIMUMBITRATE_STRUCT  bitrates;
    LIBLTE_S1AP_UESECURITYCAPABILITIES_STRUCT     security_capabilities;
    LIBLTE_RRC_UE_EUTRA_CAPABILITY_STRUCT         eutra_capabilities;

    typedef struct {
      uint8_t                                     id;
      LIBLTE_S1AP_E_RABLEVELQOSPARAMETERS_STRUCT  qos_params;
      LIBLTE_S1AP_TRANSPORTLAYERADDRESS_STRUCT    address;
      uint32_t                                    teid_out;
      uint32_t                                    teid_in;
    }erab_t;
    std::map<uint8_t, erab_t> erabs;
    int sr_sched_sf_idx;
    int sr_sched_prb_idx;
    bool sr_allocated;
    uint32_t sr_N_pucch;
    uint32_t sr_I;
    uint32_t cqi_pucch; 
    uint32_t cqi_idx; 
    bool cqi_allocated; 
    int cqi_sched_sf_idx; 
    bool cqi_sched_prb_idx; 
    int get_drbid_config(LIBLTE_RRC_DRB_TO_ADD_MOD_STRUCT *drb, int drbid);
  }; 
  
  
private: 
      
  std::map<uint16_t,ue> users;
  
  std::map<uint32_t, LIBLTE_S1AP_UEPAGINGID_STRUCT > pending_paging; 

  activity_monitor act_monitor; 
  
  LIBLTE_BYTE_MSG_STRUCT sib_buffer[LIBLTE_RRC_MAX_SIB];

  // user connect notifier 
  connect_notifier *cnotifier; 

  void rem_user(uint16_t rnti); 
  uint32_t generate_sibs();
  void config_mac(); 
  void parse_ul_dcch(uint16_t rnti, uint32_t lcid, srslte::byte_buffer_t *pdu);
  void parse_ul_ccch(uint16_t rnti, srslte::byte_buffer_t *pdu);
  void configure_security(uint16_t rnti,
                          uint32_t lcid,
                          uint8_t *k_rrc_enc,
                          uint8_t *k_rrc_int,
                          uint8_t *k_up_enc,
                          uint8_t *k_up_int,
                          srslte::CIPHERING_ALGORITHM_ID_ENUM cipher_algo,
                          srslte::INTEGRITY_ALGORITHM_ID_ENUM integ_algo);

  srslte::byte_buffer_pool  *pool;
  srslte::bit_buffer_t  bit_buf;
  srslte::bit_buffer_t  bit_buf_paging;
  srslte::byte_buffer_t erab_info;
    
  phy_interface_rrc    *phy;
  mac_interface_rrc    *mac;
  rlc_interface_rrc    *rlc;
  pdcp_interface_rrc   *pdcp;
  gtpu_interface_rrc   *gtpu;
  s1ap_interface_rrc   *s1ap;
  srslte::log          *rrc_log;

  typedef struct{
    uint16_t                rnti;
    uint32_t                lcid;
    srslte::byte_buffer_t*  pdu;
  }rrc_pdu;

  const static uint32_t LCID_REM_USER = 0xffff0001; 
  
  bool                  running;
  static const int      RRC_THREAD_PRIO = 7;
  srslte::block_queue<rrc_pdu> rx_pdu_queue;

  typedef struct {
    uint32_t nof_users[100][80]; 
  } sr_sched_t;
    
  sr_sched_t sr_sched; 
  sr_sched_t cqi_sched; 
  
  rrc_cfg_t cfg; 
  uint32_t nof_si_messages;
  LIBLTE_RRC_SYS_INFO_BLOCK_TYPE_2_STRUCT sib2; 

  void run_thread();
  void rem_user_thread(uint16_t rnti);
  pthread_mutex_t user_mutex;
  
  pthread_mutex_t paging_mutex; 
};

} // namespace srsenb

#endif // RRC_H