/*
 * 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/.
 *
 */

#include "rlc_test_common.h"
#include "srslte/common/log_filter.h"
#include "srslte/upper/rlc_um_lte.h"
#include <iostream>

#define TESTASSERT(cond)                                                                                               \
  {                                                                                                                    \
    if (!(cond)) {                                                                                                     \
      std::cout << "[" << __FUNCTION__ << "][Line " << __LINE__ << "]: FAIL at " << (#cond) << std::endl;              \
      return -1;                                                                                                       \
    }                                                                                                                  \
  }

#define MAX_NBUFS 100
#define NBUFS 5

using namespace srslte;
using namespace srsue;

// Helper class to create two pre-configured RLC instances
class rlc_um_lte_test_context1
{
public:
  rlc_um_lte_test_context1() :
    log1("RLC_UM_1"),
    log2("RLC_UM_2"),
    timers(16),
    rlc1(log1, 3, &tester, &tester, &timers),
    rlc2(log2, 3, &tester, &tester, &timers)
  {
    // setup logging
    log1->set_level(srslte::LOG_LEVEL_DEBUG);
    log2->set_level(srslte::LOG_LEVEL_DEBUG);
    log1->set_hex_limit(-1);
    log2->set_hex_limit(-1);

    // configure RLC entities
    rlc_config_t cnfg = rlc_config_t::default_rlc_um_config(10);
    if (rlc1.configure(cnfg) != true) {
      fprintf(stderr, "Couldn't configure RLC1 object\n");
    }
    if (rlc2.configure(cnfg) != true) {
      fprintf(stderr, "Couldn't configure RLC2 object\n");
    }

    tester.set_expected_sdu_len(1);
  }

  srslte::log_ref       log1, log2;
  srslte::timer_handler timers;
  rlc_um_tester         tester;
  rlc_um_lte            rlc1, rlc2;
};

int meas_obj_test()
{
  rlc_um_lte_test_context1 ctxt;

  // Push 5 SDUs into RLC1
  byte_buffer_pool*    pool = byte_buffer_pool::get_instance();
  unique_byte_buffer_t sdu_bufs[NBUFS];
  for (int i = 0; i < NBUFS; i++) {
    sdu_bufs[i]          = srslte::allocate_unique_buffer(*pool, true);
    *sdu_bufs[i]->msg    = i; // Write the index into the buffer
    sdu_bufs[i]->N_bytes = 1; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  TESTASSERT(14 == ctxt.rlc1.get_buffer_state());

  // Read 5 PDUs from RLC1 (1 byte each)
  byte_buffer_t pdu_bufs[NBUFS];
  for (int i = 0; i < NBUFS; i++) {
    int len             = ctxt.rlc1.read_pdu(pdu_bufs[i].msg, 4); // 3 bytes for header + payload
    pdu_bufs[i].N_bytes = len;
  }

  TESTASSERT(0 == ctxt.rlc1.get_buffer_state());

  // Write 5 PDUs into RLC2
  for (int i = 0; i < NBUFS; i++) {
    ctxt.rlc2.write_pdu(pdu_bufs[i].msg, pdu_bufs[i].N_bytes);
  }

  TESTASSERT(0 == ctxt.rlc2.get_buffer_state());

  TESTASSERT(NBUFS == ctxt.tester.get_num_sdus());
  for (uint32_t i = 0; i < ctxt.tester.sdus.size(); i++) {
    TESTASSERT(ctxt.tester.sdus.at(i)->N_bytes == 1);
    TESTASSERT(*(ctxt.tester.sdus[i]->msg) == i);
  }

  return 0;
}

int loss_test()
{
  rlc_um_lte_test_context1 ctxt;

  // Push 5 SDUs into RLC1
  byte_buffer_pool*    pool = byte_buffer_pool::get_instance();
  unique_byte_buffer_t sdu_bufs[NBUFS];
  for (int i = 0; i < NBUFS; i++) {
    sdu_bufs[i]          = srslte::allocate_unique_buffer(*pool, true);
    sdu_bufs[i]->msg[0]  = i; // Write the index into the buffer
    sdu_bufs[i]->N_bytes = 1; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  TESTASSERT(14 == ctxt.rlc1.get_buffer_state());

  // Read 5 PDUs from RLC1 (1 byte each)
  byte_buffer_t pdu_bufs[NBUFS];
  for (int i = 0; i < NBUFS; i++) {
    int len             = ctxt.rlc1.read_pdu(pdu_bufs[i].msg, 4); // 3 bytes for header + payload
    pdu_bufs[i].N_bytes = len;
  }

  TESTASSERT(0 == ctxt.rlc1.get_buffer_state());

  // Write 5 PDUs into RLC2 (skip SN 1)
  for (int i = 0; i < NBUFS; i++) {
    if (i != 1) {
      ctxt.rlc2.write_pdu(pdu_bufs[i].msg, pdu_bufs[i].N_bytes);
    }
  }

  // Step the reordering timer until expiry
  while (ctxt.timers.nof_running_timers() != 0) {
    ctxt.timers.step_all();
  }

  TESTASSERT(NBUFS - 1 == ctxt.tester.sdus.size());

  return 0;
}

int basic_mbsfn_test()
{
  rlc_um_lte_test_context1 ctxt;

  // configure as MCH
  ctxt.rlc1.configure(rlc_config_t::mch_config());
  ctxt.rlc2.configure(rlc_config_t::mch_config());

  // Push 5 SDUs into RLC1
  byte_buffer_pool*    pool = byte_buffer_pool::get_instance();
  unique_byte_buffer_t sdu_bufs[NBUFS * 2];
  for (int i = 0; i < NBUFS; i++) {
    sdu_bufs[i]          = srslte::allocate_unique_buffer(*pool, true);
    sdu_bufs[i]->msg[0]  = i; // Write the index into the buffer
    sdu_bufs[i]->N_bytes = 1; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  TESTASSERT(13 == ctxt.rlc1.get_buffer_state());

  // Read 5 PDUs from RLC1 (1 byte each)
  byte_buffer_t pdu_bufs[NBUFS * 2];
  for (int i = 0; i < NBUFS; i++) {
    int len             = ctxt.rlc1.read_pdu(pdu_bufs[i].msg, 3); // 2 bytes for header + payload
    pdu_bufs[i].N_bytes = len;
  }

  TESTASSERT(0 == ctxt.rlc1.get_buffer_state());

  // Write 5 PDUs into RLC2
  for (int i = 0; i < NBUFS; i++) {
    ctxt.rlc2.write_pdu(pdu_bufs[i].msg, pdu_bufs[i].N_bytes);
  }

  TESTASSERT(0 == ctxt.rlc2.get_buffer_state());

  TESTASSERT(NBUFS == ctxt.tester.sdus.size());
  for (uint32_t i = 0; i < ctxt.tester.sdus.size(); i++) {
    TESTASSERT(ctxt.tester.sdus[i]->N_bytes == 1);
    TESTASSERT(*(ctxt.tester.sdus[i]->msg) == i);
  }

  return 0;
}

// This test checks the reassembly routines when a PDU
// is lost that contains the beginning of SDU segment.
// The PDU that contains the end of this SDU _also_ contains
// a segment of another SDU.
// On reassembly of the SDUs, the missing start segment
// should be detected and the complete SDU be discarded
// Therefore, one SDU less should be received than was tx'ed.
// This test sends PDU in two batches so it's not the reordering
// timeout that detects the missing PDU but the fact more
// PDUs than rx_mod are received.
int reassmble_test()
{
  rlc_um_lte_test_context1 ctxt;

  // reconfigure them with 5bit SNs
  rlc_config_t cnfg = rlc_config_t::default_rlc_um_config(5);
  ctxt.rlc1.configure(cnfg);
  ctxt.rlc2.configure(cnfg);

  // Push SDUs into RLC1
  const int n_sdus  = 25;
  const int sdu_len = 100;

  ctxt.tester.set_expected_sdu_len(sdu_len);

  const int n_sdu_first_batch = 17;

  byte_buffer_pool*    pool = byte_buffer_pool::get_instance();
  unique_byte_buffer_t sdu_bufs[n_sdus];
  for (int i = 0; i < n_sdu_first_batch; i++) {
    sdu_bufs[i] = srslte::allocate_unique_buffer(*pool, true);
    for (int k = 0; k < sdu_len; ++k) {
      sdu_bufs[i]->msg[k] = i;
    }
    sdu_bufs[i]->N_bytes = sdu_len; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  // Read PDUs from RLC1 (use smaller grant for first PDU and large for the rest)
  const int      max_n_pdus = 100;
  int            n_pdus     = 0;
  byte_buffer_t* pdu_bufs[max_n_pdus];
  for (int i = 0; i < max_n_pdus; i++) {
    pdu_bufs[i]          = byte_buffer_pool::get_instance()->allocate();
    int len              = ctxt.rlc1.read_pdu(pdu_bufs[i]->msg, (i == 0) ? sdu_len * 3 / 4 : sdu_len * 1.25);
    pdu_bufs[i]->N_bytes = len;
    if (len) {
      n_pdus++;
    } else {
      break;
    }
  }

  printf("Generated %d PDUs in first batch\n", n_pdus);
  TESTASSERT(0 == ctxt.rlc1.get_buffer_state());

  // push second batch of SDUs
  for (int i = n_sdu_first_batch; i < n_sdus; ++i) {
    sdu_bufs[i] = srslte::allocate_unique_buffer(*pool, true);
    for (int k = 0; k < sdu_len; ++k) {
      sdu_bufs[i]->msg[k] = i;
    }
    sdu_bufs[i]->N_bytes = sdu_len; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  // Read second batch of PDUs (use large grants)
  for (int i = n_pdus; i < max_n_pdus; i++) {
    pdu_bufs[i]          = byte_buffer_pool::get_instance()->allocate();
    int len              = ctxt.rlc1.read_pdu(pdu_bufs[i]->msg, sdu_len * 1.25);
    pdu_bufs[i]->N_bytes = len;
    if (len) {
      n_pdus++;
    } else {
      // stop reading PDUs after first zero length PDU
      break;
    }
  }

  printf("Generated %d PDUs in total\n", n_pdus);

  // Write all PDUs into RLC2 except first one
  for (int i = 0; i < n_pdus; i++) {
    if (i != 0) {
      ctxt.rlc2.write_pdu(pdu_bufs[i]->msg, pdu_bufs[i]->N_bytes);
    }
  }

  // We should have received one SDU less than we tx'ed
  TESTASSERT(ctxt.tester.sdus.size() == n_sdus - 1);
  for (uint32_t i = 0; i < ctxt.tester.sdus.size(); ++i) {
    TESTASSERT(ctxt.tester.sdus[i]->N_bytes == sdu_len);
  }

  return 0;
}

// This reassmble test checks the reassembly routines when a PDU
// is lost that _only_ contains the beginning of SDU segment,
// while the next PDU contains the middle part of this SDU (and
// yet another PDU the end part).
// On reassembly of the SDUs, the missing start segment
// should be detected and the complete SDU be discarded
// Therefore, one SDU less should be received than was tx'ed.
int reassmble_test2()
{
  rlc_um_lte_test_context1 ctxt;

  // reconfigure them with 5bit SNs
  rlc_config_t cnfg = rlc_config_t::default_rlc_um_config(5);
  ctxt.rlc1.configure(cnfg);
  ctxt.rlc2.configure(cnfg);

  // Push SDUs into RLC1
  const int n_sdus  = 25;
  const int sdu_len = 100;

  ctxt.tester.set_expected_sdu_len(sdu_len);

  const int            n_sdu_first_batch = 17;
  byte_buffer_pool*    pool              = byte_buffer_pool::get_instance();
  unique_byte_buffer_t sdu_bufs[n_sdus];
  for (int i = 0; i < n_sdu_first_batch; i++) {
    sdu_bufs[i] = srslte::allocate_unique_buffer(*pool, true);
    for (int k = 0; k < sdu_len; ++k) {
      sdu_bufs[i]->msg[k] = i;
    }
    sdu_bufs[i]->N_bytes = sdu_len;
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  const int      max_n_pdus = 100;
  int            n_pdus     = 0;
  byte_buffer_t* pdu_bufs[max_n_pdus];
  for (int i = 0; i < max_n_pdus; i++) {
    pdu_bufs[i]          = byte_buffer_pool::get_instance()->allocate();
    int len              = ctxt.rlc1.read_pdu(pdu_bufs[i]->msg, (i == 0) ? sdu_len * .75 : sdu_len * .25);
    pdu_bufs[i]->N_bytes = len;
    if (len) {
      n_pdus++;
    } else {
      break;
    }
  }

  printf("Generated %d PDUs in first batch\n", n_pdus);
  TESTASSERT(0 == ctxt.rlc1.get_buffer_state());

  // push second batch of SDUs
  for (int i = n_sdu_first_batch; i < n_sdus; ++i) {
    sdu_bufs[i] = srslte::allocate_unique_buffer(*pool, true);
    for (int k = 0; k < sdu_len; ++k) {
      sdu_bufs[i]->msg[k] = i;
    }
    sdu_bufs[i]->N_bytes = sdu_len; // Give each buffer a size of 1 byte
    ctxt.rlc1.write_sdu(std::move(sdu_bufs[i]));
  }

  // Read second batch of PDUs
  for (int i = n_pdus; i < max_n_pdus; i++) {
    pdu_bufs[i]          = byte_buffer_pool::get_instance()->allocate();
    int len              = ctxt.rlc1.read_pdu(pdu_bufs[i]->msg, sdu_len * 1.25);
    pdu_bufs[i]->N_bytes = len;
    if (len) {
      n_pdus++;
    } else {
      break;
    }
  }

  printf("Generated %d PDUs in total\n", n_pdus);

  // Write all PDUs into RLC2 except first one
  for (int i = 0; i < n_pdus; i++) {
    if (i != 0) {
      ctxt.rlc2.write_pdu(pdu_bufs[i]->msg, pdu_bufs[i]->N_bytes);
    }
  }

  // We should have received one SDU less than we tx'ed
  TESTASSERT(ctxt.tester.sdus.size() == n_sdus - 1);
  for (uint32_t i = 0; i < ctxt.tester.sdus.size(); ++i) {
    TESTASSERT(ctxt.tester.sdus[i]->N_bytes == sdu_len);
  }

  return 0;
}

int main(int argc, char** argv)
{
  if (meas_obj_test()) {
    return -1;
  }
  byte_buffer_pool::get_instance()->cleanup();

  if (loss_test()) {
    return -1;
  }
  byte_buffer_pool::get_instance()->cleanup();

  if (basic_mbsfn_test()) {
    return -1;
  }
  byte_buffer_pool::get_instance()->cleanup();

  if (reassmble_test()) {
    return -1;
  }
  byte_buffer_pool::get_instance()->cleanup();

  if (reassmble_test2()) {
    return -1;
  }
  byte_buffer_pool::get_instance()->cleanup();
}