/*******************************************************************************

  Eurecom OpenAirInterface
  Copyright(c) 1999 - 2011 Eurecom

  This program is free software; you can redistribute it and/or modify it
  under the terms and conditions of the GNU General Public License,
  version 2, as published by the Free Software Foundation.

  This program is distributed in the hope it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  more details.

  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

  The full GNU General Public License is included in this distribution in
  the file called "COPYING".

  Contact Information
  Openair Admin: openair_admin@eurecom.fr
  Openair Tech : openair_tech@eurecom.fr
  Forums       : http://forums.eurecom.fsr/openairinterface
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 *******************************************************************************/

/*! \file openair2/LAYER2/MAC/ra_procedures.c
 * \brief Routines for UE MAC-layer Random-access procedures (36.321) V8.6 2009-03
 * \author R. Knopp
 * \date 2011
 * \version 0.1
 * \company Eurecom
 * \email: knopp@eurecom.fr
 * \note
 * \warning
 */

#include "extern.h"
#include "defs.h"
#include "PHY_INTERFACE/defs.h"
#include "PHY_INTERFACE/extern.h"
#include "COMMON/mac_rrc_primitives.h"
#include "RRC/LITE/extern.h"
#include "RRC/L2_INTERFACE/openair_rrc_L2_interface.h"
#include "UTIL/LOG/log.h"
#include "UTIL/OPT/opt.h"
#include "OCG.h"
#include "OCG_extern.h"
#ifdef PHY_EMUL
#include "SIMULATION/simulation_defs.h"
#endif

extern inline unsigned int taus(void);

int8_t get_DELTA_PREAMBLE(module_id_t module_idP) {

  uint8_t prachConfigIndex = UE_mac_inst[module_idP].radioResourceConfigCommon->prach_Config.prach_ConfigInfo.prach_ConfigIndex;
  uint8_t preambleformat;

  if (UE_mac_inst[module_idP].tdd_Config) { // TDD
      if (prachConfigIndex < 20)
        preambleformat = 0;
      else if (prachConfigIndex < 30)
        preambleformat = 1;
      else if (prachConfigIndex < 40)
        preambleformat = 2;
      else if (prachConfigIndex < 48)
        preambleformat = 3;
      else
        preambleformat = 4;
  }
  else { // FDD
      preambleformat = prachConfigIndex>>2;
  }
  switch (preambleformat) {
  case 0:
  case 1:
    return(0);
  case 2:
  case 3:
    return(-3);
  case 4:
    return(8);
  default:
    LOG_E(MAC,"[UE %d] ue_procedures.c: FATAL, Illegal preambleformat %d, prachConfigIndex %d\n",
        module_idP,
        preambleformat,prachConfigIndex);
    mac_xface->macphy_exit("");
    return(0);
  }

}

/// This routine implements Section 5.1.2 (Random Access Resource Selection) from 36.321
void get_prach_resources(module_id_t module_idP,
    uint8_t eNB_index,
    uint8_t t_id,
    uint8_t first_Msg3,
    RACH_ConfigDedicated_t *rach_ConfigDedicated) {

  uint8_t Msg3_size = UE_mac_inst[module_idP].RA_Msg3_size;
  PRACH_RESOURCES_t *prach_resources = &UE_mac_inst[module_idP].RA_prach_resources;
  RACH_ConfigCommon_t *rach_ConfigCommon = NULL;
  uint8_t noGroupB = 0;
  uint8_t f_id = 0,num_prach=0;

  if (UE_mac_inst[module_idP].radioResourceConfigCommon)
    rach_ConfigCommon = &UE_mac_inst[module_idP].radioResourceConfigCommon->rach_ConfigCommon;
  else {
      LOG_E(MAC,"[UE %d] FATAL  radioResourceConfigCommon is NULL !!!\n",module_idP);
      mac_xface->macphy_exit("");
  }

  if (rach_ConfigDedicated) {   // This is for network controlled Mobility, later
      if (rach_ConfigDedicated->ra_PRACH_MaskIndex != 0) {
          prach_resources->ra_PreambleIndex = rach_ConfigDedicated->ra_PreambleIndex;
          prach_resources->ra_RACH_MaskIndex = rach_ConfigDedicated->ra_PRACH_MaskIndex;
          return;
      }
  }

  if (!rach_ConfigCommon->preambleInfo.preamblesGroupAConfig) {
      noGroupB = 1;

  }
  else {
      if (rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA ==
          rach_ConfigCommon->preambleInfo.numberOfRA_Preambles)
        noGroupB = 1;
  }

  if (first_Msg3 == 1) {
      if (noGroupB == 1) {
          // use Group A procedure
          UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  = (taus())&0x3f;
          UE_mac_inst[module_idP].RA_prach_resources.ra_RACH_MaskIndex = 0;
          UE_mac_inst[module_idP].RA_usedGroupA = 1;
      }
      else if ((Msg3_size < rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->messageSizeGroupA) ||
          (mac_xface->get_PL(module_idP,eNB_index) > UE_mac_inst[module_idP].RA_maxPL)) {
          // use Group A procedure
          UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  = (taus())%rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA;
          UE_mac_inst[module_idP].RA_prach_resources.ra_RACH_MaskIndex = 0;
          UE_mac_inst[module_idP].RA_usedGroupA = 1;
      }
      else {  // use Group B
          UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  =
              rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA +
              (taus())%(rach_ConfigCommon->preambleInfo.numberOfRA_Preambles -
                  rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA);
          UE_mac_inst[module_idP].RA_prach_resources.ra_RACH_MaskIndex = 0;
          UE_mac_inst[module_idP].RA_usedGroupA = 0;
      }
      UE_mac_inst[module_idP].RA_prach_resources.ra_PREAMBLE_RECEIVED_TARGET_POWER = get_Po_NOMINAL_PUSCH(module_idP);
  }
  else {  // Msg3 is being retransmitted
      if (UE_mac_inst[module_idP].RA_usedGroupA == 1) {
          if (rach_ConfigCommon->preambleInfo.preamblesGroupAConfig)
            UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  = (taus())%rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA;
          else
            UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  = (taus())&0x3f;
          UE_mac_inst[module_idP].RA_prach_resources.ra_RACH_MaskIndex = 0;
      }
      else {
          UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex  =
              rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA +
              (taus())%(rach_ConfigCommon->preambleInfo.numberOfRA_Preambles -
                  rach_ConfigCommon->preambleInfo.preamblesGroupAConfig->sizeOfRA_PreamblesGroupA);
          UE_mac_inst[module_idP].RA_prach_resources.ra_RACH_MaskIndex = 0;
      }
  }
  // choose random PRACH resource in TDD
  if (UE_mac_inst[module_idP].tdd_Config) {
      num_prach = mac_xface->get_num_prach_tdd(mac_xface->lte_frame_parms);
      if ((num_prach>0) && (num_prach<6))
        UE_mac_inst[module_idP].RA_prach_resources.ra_TDD_map_index = (taus()%num_prach);
      f_id = mac_xface->get_fid_prach_tdd(mac_xface->lte_frame_parms,
          UE_mac_inst[module_idP].RA_prach_resources.ra_TDD_map_index);
  }

  // choose RA-RNTI
  UE_mac_inst[module_idP].RA_prach_resources.ra_RNTI = 1 + t_id + 10*f_id;
}

void Msg1_tx(module_id_t module_idP,frame_t frameP, uint8_t eNB_id) {

  // start contention resolution timer
  UE_mac_inst[module_idP].RA_attempt_number++;
#if defined(USER_MODE) && defined(OAI_EMU)
  if (oai_emulation.info.opt_enabled) {
      trace_pdu(0, NULL, 0, module_idP, 3, UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex,
          UE_mac_inst[module_idP].subframe, 0, UE_mac_inst[module_idP].RA_attempt_number);
      LOG_D(OPT,"[UE %d][RAPROC] TX MSG1 Frame %d trace pdu for rnti %x  with size %d\n",
          module_idP, frameP, 1, UE_mac_inst[module_idP].RA_Msg3_size);
  }
#endif
}


void Msg3_tx(module_id_t module_idP,frame_t frameP, uint8_t eNB_id) {

  // start contention resolution timer
  LOG_I(MAC,"[UE %d][RAPROC] Frame %d : Msg3_tx: Setting contention resolution timer\n",module_idP,frameP);
  UE_mac_inst[module_idP].RA_contention_resolution_cnt = 0;
  UE_mac_inst[module_idP].RA_contention_resolution_timer_active = 1;

#if defined(USER_MODE) && defined(OAI_EMU)
  if (oai_emulation.info.opt_enabled) { // msg3
      trace_pdu(0, &UE_mac_inst[module_idP].CCCH_pdu.payload[0], UE_mac_inst[module_idP].RA_Msg3_size,
          module_idP, 3, UE_mac_inst[module_idP].crnti, UE_mac_inst[module_idP].subframe, 0, 0);
      LOG_D(OPT,"[UE %d][RAPROC] MSG3 Frame %d trace pdu Preamble %d   with size %d\n",
          module_idP, frameP, UE_mac_inst[module_idP].crnti /*UE_mac_inst[module_idP].RA_prach_resources.ra_PreambleIndex*/, UE_mac_inst[module_idP].RA_Msg3_size);
  }
#endif
}


PRACH_RESOURCES_t *ue_get_rach(module_id_t module_idP,frame_t frameP, uint8_t eNB_indexP,sub_frame_t subframeP){


  uint8_t                        Size=0;
  UE_MODE_t                 UE_mode = mac_xface->get_ue_mode(module_idP,eNB_indexP);
  uint8_t                        lcid = CCCH;
  uint16_t                       Size16;
  struct RACH_ConfigCommon *rach_ConfigCommon = (struct RACH_ConfigCommon *)NULL;
  int32_t                       frame_diff=0;
  mac_rlc_status_resp_t     rlc_status;
  uint8_t                        dcch_header_len=0;
  uint16_t                       sdu_lengths[8];
  uint8_t                        ulsch_buff[MAX_ULSCH_PAYLOAD_BYTES];

  if (UE_mode == PRACH) {
      if (UE_mac_inst[module_idP].radioResourceConfigCommon)
        rach_ConfigCommon = &UE_mac_inst[module_idP].radioResourceConfigCommon->rach_ConfigCommon;
      else {
          return(NULL);
      }
      if (Is_rrc_registered == 1) {

          if (UE_mac_inst[module_idP].RA_active == 0) {
              // check if RRC is ready to initiate the RA procedure
              Size = mac_rrc_data_req(module_idP,
                  frameP,
                  CCCH,1,
                  &UE_mac_inst[module_idP].CCCH_pdu.payload[sizeof(SCH_SUBHEADER_SHORT)+1],0,
                  eNB_indexP,
                  0);
              Size16 = (uint16_t)Size;

              //	LOG_D(MAC,"[UE %d] Frame %d: Requested RRCConnectionRequest, got %d bytes\n",module_idP,frameP,Size);
              LOG_D(RRC, "[MSC_MSG][FRAME %05d][RRC_UE][MOD %02d][][--- MAC_DATA_REQ (RRCConnectionRequest eNB %d) --->][MAC_UE][MOD %02d][]\n",
                  frameP, module_idP, eNB_indexP, module_idP);
              LOG_D(MAC,"[UE %d] Frame %d: Requested RRCConnectionRequest, got %d bytes\n",module_idP,frameP,Size);

              if (Size>0) {

                  UE_mac_inst[module_idP].RA_active                        = 1;
                  UE_mac_inst[module_idP].RA_PREAMBLE_TRANSMISSION_COUNTER = 1;
                  UE_mac_inst[module_idP].RA_Msg3_size                     = Size+sizeof(SCH_SUBHEADER_SHORT)+sizeof(SCH_SUBHEADER_SHORT);
                  UE_mac_inst[module_idP].RA_prachMaskIndex                = 0;
                  UE_mac_inst[module_idP].RA_prach_resources.Msg3          = UE_mac_inst[module_idP].CCCH_pdu.payload;
                  UE_mac_inst[module_idP].RA_backoff_cnt                   = 0;  // add the backoff condition here if we have it from a previous RA reponse which failed (i.e. backoff indicator)
                  if (rach_ConfigCommon) {
                      UE_mac_inst[module_idP].RA_window_cnt                    = 2+ rach_ConfigCommon->ra_SupervisionInfo.ra_ResponseWindowSize;
                      if (UE_mac_inst[module_idP].RA_window_cnt == 9)
                        UE_mac_inst[module_idP].RA_window_cnt = 10;  // Note: 9 subframe window doesn't exist, after 8 is 10!
                  }
                  else {
                      LOG_D(MAC,"[UE %d] FATAL Frame %d: rach_ConfigCommon is NULL !!!\n",module_idP,frameP);
                      mac_xface->macphy_exit("");
                  }
                  UE_mac_inst[module_idP].RA_tx_frame         = frameP;
                  UE_mac_inst[module_idP].RA_tx_subframe      = subframeP;
                  UE_mac_inst[module_idP].RA_backoff_frame    = frameP;
                  UE_mac_inst[module_idP].RA_backoff_subframe = subframeP;
                  // Fill in preamble and PRACH resource
                  get_prach_resources(module_idP,eNB_indexP,subframeP,1,NULL);

                  generate_ulsch_header((uint8_t*)&UE_mac_inst[module_idP].CCCH_pdu.payload[0],  // mac header
                      1,      // num sdus
                      0,            // short pading
                      &Size16,  // sdu length
                      &lcid,    // sdu lcid
                      NULL,  // power headroom
                      NULL,  // crnti
                      NULL,  // truncated bsr
                      NULL, // short bsr
                      NULL, // long_bsr
                      1); //post_padding

                  return(&UE_mac_inst[module_idP].RA_prach_resources);
              }
              else if (UE_mac_inst[module_idP].scheduling_info.BSR_bytes[DCCH] > 0) {
                  // This is for triggering a transmission on DCCH using PRACH (during handover, or sending SR for example)
                  dcch_header_len = 2 + 2;  /// SHORT Subheader + C-RNTI control element
                  rlc_status = mac_rlc_status_ind(0, module_idP,frameP,ENB_FLAG_NO,MBMS_FLAG_NO,
                      DCCH,
                      6);
                  if (UE_mac_inst[module_idP].crnti_before_ho)
                    LOG_D(MAC,"[UE %d] Frame %d : UL-DCCH -> ULSCH, HO RRCConnectionReconfigurationComplete (%x, %x), RRC message has %d bytes to send throug PRACH (mac header len %d)\n",
                        module_idP,frameP, UE_mac_inst[module_idP].crnti,UE_mac_inst[module_idP].crnti_before_ho, rlc_status.bytes_in_buffer,dcch_header_len);
                  else
                    LOG_D(MAC,"[UE %d] Frame %d : UL-DCCH -> ULSCH, RRC message has %d bytes to send through PRACH(mac header len %d)\n",
                        module_idP,frameP, rlc_status.bytes_in_buffer,dcch_header_len);

                  sdu_lengths[0] = mac_rlc_data_req(eNB_indexP, module_idP,frameP,ENB_FLAG_NO, MBMS_FLAG_NO,
                      DCCH,
                      (char *)&ulsch_buff[0]);

                  LOG_D(MAC,"[UE %d] TX Got %d bytes for DCCH\n",module_idP,sdu_lengths[0]);
                  update_bsr(module_idP, frameP, DCCH,UE_mac_inst[module_idP].scheduling_info.LCGID[DCCH]);
                  //header_len +=2;
                  UE_mac_inst[module_idP].RA_active                        = 1;
                  UE_mac_inst[module_idP].RA_PREAMBLE_TRANSMISSION_COUNTER = 1;
                  UE_mac_inst[module_idP].RA_Msg3_size                     = Size+dcch_header_len;
                  UE_mac_inst[module_idP].RA_prachMaskIndex                = 0;
                  UE_mac_inst[module_idP].RA_prach_resources.Msg3          = ulsch_buff;
                  UE_mac_inst[module_idP].RA_backoff_cnt                   = 0;  // add the backoff condition here if we have it from a previous RA reponse which failed (i.e. backoff indicator)
                  if (rach_ConfigCommon) {
                      UE_mac_inst[module_idP].RA_window_cnt                    = 2+ rach_ConfigCommon->ra_SupervisionInfo.ra_ResponseWindowSize;
                      if (UE_mac_inst[module_idP].RA_window_cnt == 9)
                        UE_mac_inst[module_idP].RA_window_cnt = 10;  // Note: 9 subframe window doesn't exist, after 8 is 10!
                  }
                  else {
                      LOG_D(MAC,"[UE %d] FATAL Frame %d: rach_ConfigCommon is NULL !!!\n",module_idP,frameP);
                      mac_xface->macphy_exit("");
                  }
                  UE_mac_inst[module_idP].RA_tx_frame         = frameP;
                  UE_mac_inst[module_idP].RA_tx_subframe      = subframeP;
                  UE_mac_inst[module_idP].RA_backoff_frame    = frameP;
                  UE_mac_inst[module_idP].RA_backoff_subframe = subframeP;
                  // Fill in preamble and PRACH resource
                  get_prach_resources(module_idP,eNB_indexP,subframeP,1,NULL);
                  generate_ulsch_header((uint8_t*)ulsch_buff,  // mac header
                      1,      // num sdus
                      0,            // short pading
                      &Size16,  // sdu length
                      &lcid,    // sdu lcid
                      NULL,  // power headroom
                      &UE_mac_inst[module_idP].crnti,  // crnti
                      NULL,  // truncated bsr
                      NULL, // short bsr
                      NULL, // long_bsr
                      0); //post_padding

                  return(&UE_mac_inst[module_idP].RA_prach_resources);
              }
          }
          else {  // RACH is active
              LOG_D(MAC,"[MAC][UE %d][RAPROC] frameP %d, subframe %d: RA Active, window cnt %d (RA_tx_frame %d, RA_tx_subframe %d)\n",module_idP,
                  frameP,subframeP,UE_mac_inst[module_idP].RA_window_cnt,
                  UE_mac_inst[module_idP].RA_tx_frame,UE_mac_inst[module_idP].RA_tx_subframe);
              // compute backoff parameters
              if (UE_mac_inst[module_idP].RA_backoff_cnt>0) {
                  frame_diff = (sframe_t)frameP - UE_mac_inst[module_idP].RA_backoff_frame;
                  if (frame_diff < 0)
                    frame_diff = -frame_diff;
                  UE_mac_inst[module_idP].RA_backoff_cnt -= ((10*frame_diff) + (subframeP-UE_mac_inst[module_idP].RA_backoff_subframe));

                  UE_mac_inst[module_idP].RA_backoff_frame    = frameP;
                  UE_mac_inst[module_idP].RA_backoff_subframe = subframeP;
              }
              // compute RA window parameters
              if (UE_mac_inst[module_idP].RA_window_cnt>0) {
                  frame_diff = (frame_t)frameP - UE_mac_inst[module_idP].RA_tx_frame;
                  if (frame_diff < 0)
                    frame_diff = -frame_diff;
                  UE_mac_inst[module_idP].RA_window_cnt -= ((10*frame_diff) + (subframeP-UE_mac_inst[module_idP].RA_tx_subframe));
                  LOG_D(MAC,"[MAC][UE %d][RAPROC] frameP %d, subframe %d: RA Active, adjusted window cnt %d\n",module_idP,
                      frameP,subframeP,UE_mac_inst[module_idP].RA_window_cnt);
              }
              if ((UE_mac_inst[module_idP].RA_window_cnt<=0) &&
                  (UE_mac_inst[module_idP].RA_backoff_cnt<=0)) {

                  UE_mac_inst[module_idP].RA_tx_frame    = frameP;
                  UE_mac_inst[module_idP].RA_tx_subframe = subframeP;
                  UE_mac_inst[module_idP].RA_PREAMBLE_TRANSMISSION_COUNTER++;
                  UE_mac_inst[module_idP].RA_prach_resources.ra_PREAMBLE_RECEIVED_TARGET_POWER += (rach_ConfigCommon->powerRampingParameters.powerRampingStep<<1);  // 2dB increments in ASN.1 definition
                  if (UE_mac_inst[module_idP].RA_PREAMBLE_TRANSMISSION_COUNTER == rach_ConfigCommon->ra_SupervisionInfo.preambleTransMax) {
                      LOG_D(MAC,"[UE %d] Frame %d: Maximum number of RACH attempts (%d)\n",module_idP,frameP,rach_ConfigCommon->ra_SupervisionInfo.preambleTransMax);
                      // send message to RRC
                      UE_mac_inst[module_idP].RA_PREAMBLE_TRANSMISSION_COUNTER=1;
                      UE_mac_inst[module_idP].RA_prach_resources.ra_PREAMBLE_RECEIVED_TARGET_POWER = get_Po_NOMINAL_PUSCH(module_idP);
                  }
                  UE_mac_inst[module_idP].RA_window_cnt                    = 2+ rach_ConfigCommon->ra_SupervisionInfo.ra_ResponseWindowSize;
                  UE_mac_inst[module_idP].RA_backoff_cnt                   = 0;

                  // Fill in preamble and PRACH resource
                  get_prach_resources(module_idP,eNB_indexP,subframeP,0,NULL);
                  return(&UE_mac_inst[module_idP].RA_prach_resources);
              }
          }
      }
  }
  else if (UE_mode == PUSCH) {
      LOG_D(MAC,"[UE %d] FATAL: Should not have checked for RACH in PUSCH yet ...",module_idP);
      mac_xface->macphy_exit("");
  }
  return(NULL);
}