/******************************************************************************
 *
 *  Copyright (C) 2014 Google, Inc.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

#include <gtest/gtest.h>

#include "AllocationTestHarness.h"

extern "C" {
#include <stdint.h>

#include "device/include/controller.h"
#include "osi/include/allocator.h"
#include "osi/include/osi.h"
#include "hci_internals.h"
#include "packet_fragmenter.h"
#include "test_stubs.h"
}

DECLARE_TEST_MODES(
  init,
  set_data_sizes,
  no_fragmentation,
  fragmentation,
  ble_no_fragmentation,
  ble_fragmentation,
  non_acl_passthrough_fragmentation,
  no_reassembly,
  reassembly,
  non_acl_passthrough_reassembly
);

#define LOCAL_BLE_CONTROLLER_ID 1

static const char *sample_data =
  "At this point they came in sight of thirty forty windmills that there are on plain, and "
  "as soon as Don Quixote saw them he said to his squire, \"Fortune is arranging matters "
  "for us better than we could have shaped our desires ourselves, for look there, friend "
  "Sancho Panza, where thirty or more monstrous giants present themselves, all of whom I "
  "mean to engage in battle and slay, and with whose spoils we shall begin to make our "
  "fortunes; for this is righteous warfare, and it is God's good service to sweep so evil "
  "a breed from off the face of the earth.\"";

static const char *small_sample_data = "\"What giants?\" said Sancho Panza.";
static const uint16_t test_handle_start = (0x1992 & 0xCFFF) | 0x2000;
static const uint16_t test_handle_continuation = (0x1992 & 0xCFFF) | 0x1000;
static int packet_index;
static unsigned int data_size_sum;

static const packet_fragmenter_t *fragmenter;

static BT_HDR *manufacture_packet_for_fragmentation(uint16_t event, const char *data) {
  uint16_t data_length = strlen(data);
  uint16_t size = data_length;
  if (event == MSG_STACK_TO_HC_HCI_ACL) {
    size += 4; // 2 for the handle, 2 for the length;
  }

  BT_HDR *packet = (BT_HDR *)osi_malloc(size + sizeof(BT_HDR));
  packet->len = size;
  packet->offset = 0;
  packet->event = event;
  packet->layer_specific = 0;
  uint8_t *packet_data = packet->data;

  if (event == MSG_STACK_TO_HC_HCI_ACL) {
    UINT16_TO_STREAM(packet_data, test_handle_start);
    UINT16_TO_STREAM(packet_data, data_length);
  }

  memcpy(packet_data, data, data_length);
  return packet;
}

static void expect_packet_fragmented(uint16_t event, int max_acl_data_size, BT_HDR *packet, const char *expected_data, bool send_complete) {
  uint8_t *data = packet->data + packet->offset;
  int expected_data_offset;
  int length_to_check;

  if (event == MSG_STACK_TO_HC_HCI_ACL) {
    uint16_t handle;
    uint16_t length;
    STREAM_TO_UINT16(handle, data);
    STREAM_TO_UINT16(length, data);

    if (packet_index == 0)
      EXPECT_EQ(test_handle_start, handle);
    else
      EXPECT_EQ(test_handle_continuation, handle);

    int length_remaining = strlen(expected_data) - data_size_sum;
    int packet_data_length = packet->len - HCI_ACL_PREAMBLE_SIZE;
    EXPECT_EQ(packet_data_length, length);

    if (length_remaining > max_acl_data_size)
      EXPECT_EQ(max_acl_data_size, packet_data_length);

    length_to_check = packet_data_length;
    expected_data_offset = packet_index * max_acl_data_size;
    packet_index++;
  } else {
    length_to_check = strlen(expected_data);
    expected_data_offset = 0;
  }

  for (int i = 0; i < length_to_check; i++) {
    EXPECT_EQ(expected_data[expected_data_offset + i], data[i]);
    data_size_sum++;
  }

  if (event == MSG_STACK_TO_HC_HCI_ACL)
    EXPECT_TRUE(send_complete == (data_size_sum == strlen(expected_data)));

  if (send_complete)
    osi_free(packet);
}

static void manufacture_packet_and_then_reassemble(uint16_t event, uint16_t acl_size, const char *data) {
  uint16_t data_length = strlen(data);

  if (event == MSG_HC_TO_STACK_HCI_ACL) {
    uint16_t total_length = data_length + 2; // 2 for l2cap length;
    uint16_t length_sent = 0;
    uint16_t l2cap_length = data_length - 2; // l2cap length field, 2 for the pretend channel id borrowed from the data

    do {
      int length_to_send = (length_sent + (acl_size - 4) < total_length) ? (acl_size - 4) : (total_length - length_sent);
      BT_HDR *packet = (BT_HDR *)osi_malloc(length_to_send + 4 + sizeof(BT_HDR));
      packet->len = length_to_send + 4;
      packet->offset = 0;
      packet->event = event;
      packet->layer_specific = 0;

      uint8_t *packet_data = packet->data;
      if (length_sent == 0) { // first packet
        UINT16_TO_STREAM(packet_data, test_handle_start);
        UINT16_TO_STREAM(packet_data, length_to_send);
        UINT16_TO_STREAM(packet_data, l2cap_length);
        memcpy(packet_data, data, length_to_send - 2);
      } else {
        UINT16_TO_STREAM(packet_data, test_handle_continuation);
        UINT16_TO_STREAM(packet_data, length_to_send);
        memcpy(packet_data, data + length_sent - 2, length_to_send);
      }

      length_sent += length_to_send;
      fragmenter->reassemble_and_dispatch(packet);
    } while (length_sent < total_length);
  } else {
    BT_HDR *packet = (BT_HDR *)osi_malloc(data_length + sizeof(BT_HDR));
    packet->len = data_length;
    packet->offset = 0;
    packet->event = event;
    packet->layer_specific = 0;
    memcpy(packet->data, data, data_length);

    fragmenter->reassemble_and_dispatch(packet);
  }
}

static void expect_packet_reassembled(uint16_t event, BT_HDR *packet, const char *expected_data) {
  uint16_t expected_data_length = strlen(expected_data);
  uint8_t *data = packet->data + packet->offset;

  if (event == MSG_HC_TO_STACK_HCI_ACL) {
    uint16_t handle;
    uint16_t length;
    uint16_t l2cap_length;
    STREAM_TO_UINT16(handle, data);
    STREAM_TO_UINT16(length, data);
    STREAM_TO_UINT16(l2cap_length, data);

    EXPECT_EQ(test_handle_start, handle);
    EXPECT_EQ(expected_data_length + 2, length);
    EXPECT_EQ(expected_data_length - 2, l2cap_length); // -2 for the pretend channel id
  }


  for (int i = 0; i < expected_data_length; i++) {
    EXPECT_EQ(expected_data[i], data[i]);
    data_size_sum++;
  }

  osi_free(packet);
}

STUB_FUNCTION(void, fragmented_callback, (BT_HDR *packet, bool send_complete))
  DURING(no_fragmentation) AT_CALL(0) {
    expect_packet_fragmented(MSG_STACK_TO_HC_HCI_ACL, 42, packet, small_sample_data, send_complete);
    return;
  }

  DURING(fragmentation) {
    expect_packet_fragmented(MSG_STACK_TO_HC_HCI_ACL, 10, packet, sample_data, send_complete);
    return;
  }

  DURING(ble_no_fragmentation) AT_CALL(0) {
    expect_packet_fragmented(MSG_STACK_TO_HC_HCI_ACL, 42, packet, small_sample_data, send_complete);
    return;
  }

  DURING(ble_fragmentation) {
    expect_packet_fragmented(MSG_STACK_TO_HC_HCI_ACL, 10, packet, sample_data, send_complete);
    return;
  }

  DURING(non_acl_passthrough_fragmentation) AT_CALL(0) {
    expect_packet_fragmented(MSG_STACK_TO_HC_HCI_CMD, 10, packet, sample_data, send_complete);
    return;
  }

  UNEXPECTED_CALL;
}

STUB_FUNCTION(void, reassembled_callback, (BT_HDR *packet))
  DURING(no_reassembly) AT_CALL(0) {
    expect_packet_reassembled(MSG_HC_TO_STACK_HCI_ACL, packet, small_sample_data);
    return;
  }

  DURING(reassembly) AT_CALL(0) {
    expect_packet_reassembled(MSG_HC_TO_STACK_HCI_ACL, packet, sample_data);
    return;
  }

  DURING(non_acl_passthrough_reassembly) AT_CALL(0) {
    expect_packet_reassembled(MSG_HC_TO_STACK_HCI_EVT, packet, sample_data);
    return;
  }

  UNEXPECTED_CALL;
}

STUB_FUNCTION(void, transmit_finished_callback, (UNUSED_ATTR BT_HDR *packet, UNUSED_ATTR bool sent_all_fragments))
  UNEXPECTED_CALL;
}

STUB_FUNCTION(uint16_t, get_acl_data_size_classic, (void))
  DURING(no_fragmentation,
         non_acl_passthrough_fragmentation,
         no_reassembly) return 42;
  DURING(fragmentation) return 10;
  DURING(no_reassembly) return 1337;

  UNEXPECTED_CALL;
  return 0;
}

STUB_FUNCTION(uint16_t, get_acl_data_size_ble, (void))
  DURING(ble_no_fragmentation) return 42;
  DURING(ble_fragmentation) return 10;

  UNEXPECTED_CALL;
  return 0;
}

static void reset_for(TEST_MODES_T next) {
  RESET_CALL_COUNT(fragmented_callback);
  RESET_CALL_COUNT(reassembled_callback);
  RESET_CALL_COUNT(transmit_finished_callback);
  RESET_CALL_COUNT(get_acl_data_size_classic);
  RESET_CALL_COUNT(get_acl_data_size_ble);
  CURRENT_TEST_MODE = next;
}

class PacketFragmenterTest : public AllocationTestHarness {
  protected:
    virtual void SetUp() {
      AllocationTestHarness::SetUp();
      fragmenter = packet_fragmenter_get_test_interface(
        &controller,
        &allocator_malloc);

      packet_index = 0;
      data_size_sum = 0;

      callbacks.fragmented = fragmented_callback;
      callbacks.reassembled = reassembled_callback;
      callbacks.transmit_finished = transmit_finished_callback;
      controller.get_acl_data_size_classic = get_acl_data_size_classic;
      controller.get_acl_data_size_ble = get_acl_data_size_ble;

      reset_for(init);
      fragmenter->init(&callbacks);
    }

    virtual void TearDown() {
      fragmenter->cleanup();
      AllocationTestHarness::TearDown();
    }

    controller_t controller;
    packet_fragmenter_callbacks_t callbacks;
};

TEST_F(PacketFragmenterTest, test_no_fragment_necessary) {
  reset_for(no_fragmentation);
  BT_HDR *packet = manufacture_packet_for_fragmentation(MSG_STACK_TO_HC_HCI_ACL, small_sample_data);
  fragmenter->fragment_and_dispatch(packet);

  EXPECT_EQ(strlen(small_sample_data), data_size_sum);
  EXPECT_CALL_COUNT(fragmented_callback, 1);
}

TEST_F(PacketFragmenterTest, test_fragment_necessary) {
  reset_for(fragmentation);
  BT_HDR *packet = manufacture_packet_for_fragmentation(MSG_STACK_TO_HC_HCI_ACL, sample_data);
  fragmenter->fragment_and_dispatch(packet);

  EXPECT_EQ(strlen(sample_data), data_size_sum);
}

TEST_F(PacketFragmenterTest, test_ble_no_fragment_necessary) {
  reset_for(ble_no_fragmentation);
  BT_HDR *packet = manufacture_packet_for_fragmentation(MSG_STACK_TO_HC_HCI_ACL, small_sample_data);
  packet->event |= LOCAL_BLE_CONTROLLER_ID;
  fragmenter->fragment_and_dispatch(packet);

  EXPECT_EQ(strlen(small_sample_data), data_size_sum);
  EXPECT_CALL_COUNT(fragmented_callback, 1);
}

TEST_F(PacketFragmenterTest, test_ble_fragment_necessary) {
  reset_for(ble_fragmentation);
  BT_HDR *packet = manufacture_packet_for_fragmentation(MSG_STACK_TO_HC_HCI_ACL, sample_data);
  packet->event |= LOCAL_BLE_CONTROLLER_ID;
  fragmenter->fragment_and_dispatch(packet);

  EXPECT_EQ(strlen(sample_data), data_size_sum);
}

TEST_F(PacketFragmenterTest, test_non_acl_passthrough_fragmentation) {
  reset_for(non_acl_passthrough_fragmentation);
  BT_HDR *packet = manufacture_packet_for_fragmentation(MSG_STACK_TO_HC_HCI_CMD, sample_data);
  fragmenter->fragment_and_dispatch(packet);

  EXPECT_EQ(strlen(sample_data), data_size_sum);
  EXPECT_CALL_COUNT(fragmented_callback, 1);
}

TEST_F(PacketFragmenterTest, test_no_reassembly_necessary) {
  reset_for(no_reassembly);
  manufacture_packet_and_then_reassemble(MSG_HC_TO_STACK_HCI_ACL, 1337, small_sample_data);

  EXPECT_EQ(strlen(small_sample_data), data_size_sum);
  EXPECT_CALL_COUNT(reassembled_callback, 1);
}

TEST_F(PacketFragmenterTest, test_reassembly_necessary) {
  reset_for(reassembly);
  manufacture_packet_and_then_reassemble(MSG_HC_TO_STACK_HCI_ACL, 42, sample_data);

  EXPECT_EQ(strlen(sample_data), data_size_sum);
  EXPECT_CALL_COUNT(reassembled_callback, 1);
}

TEST_F(PacketFragmenterTest, test_non_acl_passthrough_reasseembly) {
  reset_for(non_acl_passthrough_reassembly);
  manufacture_packet_and_then_reassemble(MSG_HC_TO_STACK_HCI_EVT, 42, sample_data);

  EXPECT_EQ(strlen(sample_data), data_size_sum);
  EXPECT_CALL_COUNT(reassembled_callback, 1);
}