/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

#ifdef RUN_SELF_TESTS

#include "ns3/test.h"

#include "ns3/simulator.h"

#include "dcf-manager.h"

namespace ns3 {

class DcfManagerTest;

class DcfStateTest : public DcfState 

{

public:

  DcfStateTest (DcfManagerTest *test, uint32_t i);

  void QueueTx (uint64_t txTime, uint64_t expectedGrantTime);

private:

  friend class DcfManagerTest;

  virtual void DoNotifyAccessGranted (void);

  virtual void DoNotifyInternalCollision (void);

  virtual void DoNotifyCollision (void);

  typedef std::pair<uint64_t,uint64_t> ExpectedGrant;

  typedef std::list<ExpectedGrant> ExpectedGrants;

  struct ExpectedCollision {

    uint64_t at;

    uint32_t nSlots;

  };

  typedef std::list<struct ExpectedCollision> ExpectedCollisions;

  ExpectedCollisions m_expectedInternalCollision;

  ExpectedCollisions m_expectedCollision;

  ExpectedGrants m_expectedGrants;

  DcfManagerTest *m_test;

  uint32_t m_i;

};

class DcfManagerTest : public Test

{

public:

  DcfManagerTest ();

  virtual bool RunTests (void);

  void NotifyAccessGranted (uint32_t i);

  void NotifyInternalCollision (uint32_t i);

  void NotifyCollision (uint32_t i);

private:

  void StartTest (uint64_t slotTime, uint64_t sifs, uint64_t eifsNoDifsNoSifs);

  void AddDcfState (uint32_t aifsn);

  void EndTest (void);

  void ExpectInternalCollision (uint64_t time, uint32_t from, uint32_t nSlots);

  void ExpectCollision (uint64_t time, uint32_t from, uint32_t nSlots);

  void AddRxOkEvt (uint64_t at, uint64_t duration);

  void AddRxErrorEvt (uint64_t at, uint64_t duration);

  void AddNavReset (uint64_t at, uint64_t duration);

  void AddNavStart (uint64_t at, uint64_t duration);

  void AddAccessRequest (uint64_t at, uint64_t txTime, 

                         uint64_t expectedGrantTime, uint32_t from);

  void DoAccessRequest (uint64_t txTime, uint64_t expectedGrantTime, DcfStateTest *state);

  typedef std::vector<DcfStateTest *> DcfStates;

  DcfManager *m_dcfManager;

  DcfStates m_dcfStates;

  bool m_result;

};

DcfStateTest::DcfStateTest (DcfManagerTest *test, uint32_t i) 

  : m_test (test), m_i(i)

{}

void 

DcfStateTest::QueueTx (uint64_t txTime, uint64_t expectedGrantTime)

{

  m_expectedGrants.push_back (std::make_pair (txTime, expectedGrantTime));

}

void 

DcfStateTest::DoNotifyAccessGranted (void)

{

  m_test->NotifyAccessGranted (m_i);

}

void

DcfStateTest::DoNotifyInternalCollision (void)

{

  m_test->NotifyInternalCollision (m_i);

}

void 

DcfStateTest::DoNotifyCollision (void)

{

  m_test->NotifyCollision (m_i);

}

DcfManagerTest::DcfManagerTest ()

  : Test ("DcfManager")

{}

void 

DcfManagerTest::NotifyAccessGranted (uint32_t i)

{

  DcfStateTest *state = m_dcfStates[i];

  bool result = true;

  NS_TEST_ASSERT (!state->m_expectedGrants.empty ());

  std::pair<uint64_t, uint64_t> expected = state->m_expectedGrants.front ();

  state->m_expectedGrants.pop_front ();

  NS_TEST_ASSERT_EQUAL (Simulator::Now (), MicroSeconds (expected.second));

  m_dcfManager->NotifyTxStartNow (MicroSeconds (expected.first));

  if (!result)

    {

      m_result = result;

    }

}

void 

DcfManagerTest::NotifyInternalCollision (uint32_t i)

{

  DcfStateTest *state = m_dcfStates[i];

  bool result = true;

  NS_TEST_ASSERT (!state->m_expectedInternalCollision.empty ());

  struct DcfStateTest::ExpectedCollision expected = state->m_expectedInternalCollision.front ();

  state->m_expectedInternalCollision.pop_front ();

  NS_TEST_ASSERT_EQUAL (Simulator::Now (), MicroSeconds (expected.at));

  state->StartBackoffNow (expected.nSlots);

  if (!result)

    {

      m_result = result;

    }

}

void 

DcfManagerTest::NotifyCollision (uint32_t i)

{

  DcfStateTest *state = m_dcfStates[i];

  bool result = true;

  NS_TEST_ASSERT (!state->m_expectedCollision.empty ());

  struct DcfStateTest::ExpectedCollision expected = state->m_expectedCollision.front ();

  state->m_expectedCollision.pop_front ();

  NS_TEST_ASSERT_EQUAL (Simulator::Now (), MicroSeconds (expected.at));

  state->StartBackoffNow (expected.nSlots);

  if (!result)

    {

      m_result = result;

    }

}

void 

DcfManagerTest::ExpectInternalCollision (uint64_t time, uint32_t nSlots, uint32_t from)

{

  DcfStateTest *state = m_dcfStates[from];

  struct DcfStateTest::ExpectedCollision col;

  col.at = time;

  col.nSlots = nSlots;

  state->m_expectedInternalCollision.push_back (col);

}

void 

DcfManagerTest::ExpectCollision (uint64_t time, uint32_t nSlots, uint32_t from)

{

  DcfStateTest *state = m_dcfStates[from];

  struct DcfStateTest::ExpectedCollision col;

  col.at = time;

  col.nSlots = nSlots;

  state->m_expectedCollision.push_back (col);

}

void

DcfManagerTest::StartTest (uint64_t slotTime, uint64_t sifs, uint64_t eifsNoDifsNoSifs)

{

  m_dcfManager = new DcfManager ();

  m_dcfManager->SetSlot (MicroSeconds (slotTime));

  m_dcfManager->SetSifs (MicroSeconds (sifs));

  m_dcfManager->SetEifsNoDifs (MicroSeconds (eifsNoDifsNoSifs+sifs));

}

void

DcfManagerTest::AddDcfState (uint32_t aifsn)

{

  DcfStateTest *state = new DcfStateTest (this, m_dcfStates.size ());

  state->SetAifsn (aifsn);

  m_dcfStates.push_back (state);

  m_dcfManager->Add (state);

}

void

DcfManagerTest::EndTest (void)

{

  bool result = true;

  Simulator::Run ();

  Simulator::Destroy ();

  for (DcfStates::const_iterator i = m_dcfStates.begin (); i != m_dcfStates.end (); i++)

    {

      DcfStateTest *state = *i;

      NS_TEST_ASSERT (state->m_expectedGrants.empty ());

      NS_TEST_ASSERT (state->m_expectedInternalCollision.empty ());

      NS_TEST_ASSERT (state->m_expectedCollision.empty ());

      delete state;

    }

  m_dcfStates.clear ();

  delete m_dcfManager;

  if (!result)

    {

      m_result = result;

    }

}

void 

DcfManagerTest::AddRxOkEvt (uint64_t at, uint64_t duration)

{

  Simulator::Schedule (MicroSeconds (at) - Now (), 

                       &DcfManager::NotifyRxStartNow, m_dcfManager, 

                       MicroSeconds (duration));

  Simulator::Schedule (MicroSeconds (at+duration) - Now (), 

                       &DcfManager::NotifyRxEndOkNow, m_dcfManager);

}

void 

DcfManagerTest::AddRxErrorEvt (uint64_t at, uint64_t duration)

{

  Simulator::Schedule (MicroSeconds (at) - Now (), 

                       &DcfManager::NotifyRxStartNow, m_dcfManager, 

                       MicroSeconds (duration));

  Simulator::Schedule (MicroSeconds (at+duration) - Now (), 

                       &DcfManager::NotifyRxEndErrorNow, m_dcfManager);

}

void 

DcfManagerTest::AddNavReset (uint64_t at, uint64_t duration)

{

  Simulator::Schedule (MicroSeconds (at) - Now (), 

                       &DcfManager::NotifyNavResetNow, m_dcfManager, 

                       MicroSeconds (duration));

}

void 

DcfManagerTest::AddNavStart (uint64_t at, uint64_t duration)

{

  Simulator::Schedule (MicroSeconds (at) - Now (), 

                       &DcfManager::NotifyNavStartNow, m_dcfManager, 

                       MicroSeconds (duration));

}

void 

DcfManagerTest::AddAccessRequest (uint64_t at, uint64_t txTime, 

                                  uint64_t expectedGrantTime, uint32_t from)

{

  Simulator::Schedule (MicroSeconds (at) - Now (), 

                       &DcfManagerTest::DoAccessRequest, this,

                       txTime, expectedGrantTime, m_dcfStates[from]);

}

void

DcfManagerTest::DoAccessRequest (uint64_t txTime, uint64_t expectedGrantTime, DcfStateTest *state)

{

  state->QueueTx (txTime, expectedGrantTime);

  m_dcfManager->RequestAccess (state);

}

bool 

DcfManagerTest::RunTests (void)

{

  m_result = true;

  //  0      3       4    5      8       9  10   12

  //  | sifs | aifsn | tx | sifs | aifsn |   | tx | 

  //

  StartTest (1, 3, 10);

  AddDcfState (1);

  AddAccessRequest (1, 1, 4, 0);

  AddAccessRequest (10, 2, 10, 0);

  EndTest ();

  // The test below mainly intends to test the case where the medium

  // becomes busy in the middle of a backoff slot: the backoff counter

  // must not be decremented for this backoff slot. This is the case

  // below for the backoff slot starting at time 78us.

  //

  //  20          60     66      70        74        78  80    100     106      110      114      118   120

  //   |    rx     | sifs | aifsn | bslot0  | bslot1  |   | rx   | sifs  |  aifsn | bslot2 | bslot3 | tx  |

  //        |

  //       30 request access. backoff slots: 4

  StartTest (4, 6 , 10);

  AddDcfState (1);

  AddRxOkEvt (20, 40);

  AddRxOkEvt (80, 20);

  AddAccessRequest (30, 2, 118, 0);

  ExpectCollision (30, 4, 0); // backoff: 4 slots

  EndTest ();

  // Test the case where the backoff slots is zero.

  //

  //  20          60     66      70   72

  //   |    rx     | sifs | aifsn | tx | 

  //        |

  //       30 request access. backoff slots: 0

  StartTest (4, 6 , 10);

  AddDcfState (1);

  AddRxOkEvt (20, 40);

  AddAccessRequest (30, 2, 70, 0);

  ExpectCollision (30, 0, 0); // backoff: 0 slots

  EndTest ();

  // The test below is subject to some discussion because I am 

  // not sure I understand the intent of the spec here.

  // i.e., what happens if you make a request to get access

  // to the medium during the difs idle time after a busy period ?

  // do you need to start a backoff ? Or do you need to wait until

  // the end of difs and access the medium ?

  // Here, we wait until the end of difs and access the medium.

  //

  //  20    60     66      70   72

  //   | rx  | sifs | aifsn | tx |

  //           |

  //          62 request access.

  //

  StartTest (4, 6 , 10);

  AddDcfState (1);

  AddRxOkEvt (20, 40);

  AddAccessRequest (62, 2, 70, 0);

  EndTest ();

  // Test an EIFS

  // 

  //  20          60     66           76      80       84       88       92       96   98

  //   |    rx     | sifs | acktxttime | aifsn | bslot0 | bslot1 | bslot2 | bslot3 | tx |

  //        |      | <---------eifs----------->|

  //       30 request access. backoff slots: 4

  StartTest (4, 6, 10);

  AddDcfState (1);

  AddRxErrorEvt (20, 40);

  AddAccessRequest (30, 2, 96, 0);

  ExpectCollision (30, 4, 0); // backoff: 4 slots  

  EndTest ();

  // Test an EIFS which is interupted by a successfull transmission.

  // 

  //  20          60      66  69     75     81      85       89       93       97      101  103

  //   |    rx     | sifs  |   |  rx  | sifs | aifsn | bslot0 | bslot1 | bslot2 | bslot3 | tx |

  //        |      | <--eifs-->|

  //       30 request access. backoff slots: 4

  StartTest (4, 6, 10);

  AddDcfState (1);

  AddRxErrorEvt (20, 40);

  AddAccessRequest (30, 2, 101, 0);

  ExpectCollision (30, 4, 0); // backoff: 4 slots  

  AddRxOkEvt (69, 6);

  EndTest ();

  // Test two DCFs which suffer an internal collision. the first DCF has a higher

  // priority than the second DCF.

  //

  //      20          60      66      70       74       78    88

  // DCF0  |    rx     | sifs  | aifsn | bslot0 | bslot1 | tx  |

  // DCF1  |    rx     | sifs  | aifsn | aifsn  | aifsn  |     | sifs | aifsn | aifsn | aifsn | bslot |  tx  |

  //                                                                 94      98     102     106     110    112

  StartTest (4, 6, 10);

  AddDcfState (1); // high priority DCF

  AddDcfState (3); // low priority DCF

  AddRxOkEvt (20, 40);

  AddAccessRequest (30, 10, 78, 0);

  ExpectCollision (30, 2, 0); // backoff: 2 slot

  AddAccessRequest (40, 2, 110, 1);

  ExpectCollision (40, 0, 1); // backoff: 0 slot

  ExpectInternalCollision (78, 1, 1); // backoff: 1 slot

  EndTest ();

  //

  // test simple NAV count. This scenario modelizes a simple DATA+ACK handshake

  // where the data rate used for the ACK is higher than expected by the DATA source

  // so, the data exchange completes before the end of nav.

  // 

  StartTest (4, 6, 10);

  AddDcfState (1);

  AddRxOkEvt (20, 40);

  AddNavStart (60, 15);

  AddRxOkEvt (66, 5);

  AddNavStart (71, 0);

  AddAccessRequest (30, 10, 93, 0);

  ExpectCollision (30, 2, 0); // backoff: 2 slot

  EndTest ();

  //

  // test more complex NAV handling by a CF-poll. This scenario modelizes a 

  // simple DATA+ACK handshake interrupted by a CF-poll which resets the

  // NAV counter.

  // 

  StartTest (4, 6, 10);

  AddDcfState (1);

  AddRxOkEvt (20, 40);

  AddNavStart (60, 15);

  AddRxOkEvt (66, 5);

  AddNavReset (71, 2);

  AddAccessRequest (30, 10, 91, 0);

  ExpectCollision (30, 2, 0); // backoff: 2 slot

  EndTest ();

  StartTest (4, 6, 10);

  AddDcfState (2);

  AddRxOkEvt (20, 40);

  AddAccessRequest (80, 10, 80, 0);

  EndTest ();

  StartTest (4, 6, 10);

  AddDcfState (2);

  AddRxOkEvt (20, 40);

  AddRxOkEvt (78, 8);

  AddAccessRequest (30, 50, 108, 0);

  ExpectCollision (30, 3, 0); // backoff: 3 slots

  EndTest ();

  return m_result;

}

static DcfManagerTest g_dcf_manager_test;

} // namespace ns3

#endif /* RUN_SELF_TESTS */