#include <tins/config.h>
#include <gtest/gtest.h>

#ifdef TINS_HAVE_TCPIP

#include <iostream>
#include <algorithm>
#include <string>
#include <limits>
#include <cassert>
#include <tins/tcp_ip/stream_follower.h>
#include <tins/tcp.h>
#include <tins/ip.h>
#include <tins/ip_address.h>
#include <tins/ipv6_address.h>
#include <tins/exceptions.h>
#include <tins/ethernetII.h>
#include <tins/rawpdu.h>
#include <tins/packet.h>
#include <tins/config.h>
#ifdef TINS_HAVE_ACK_TRACKER
    #include <tins/tcp_ip/ack_tracker.h>
#endif // TINS_HAVE_ACK_TRACKER

using namespace std;
using namespace std::chrono;
using namespace Tins;
using namespace Tins::TCPIP;

class FlowTest : public testing::Test {
public:
    struct order_element {
        order_element(size_t payload_index, uint32_t payload_size) 
        : payload_index(payload_index),payload_size(payload_size) {

        }

        size_t payload_index;
        uint32_t payload_size;
    };

    static const size_t num_packets = 20;
    static EthernetII packets[], overlapped_packets1[], 
                      overlapped_packets2[], overlapped_packets3[],
                      overlapped_packets4[], overlapped_packets5[];
    static const string payload;
    typedef vector<order_element> ordering_info_type;
    
    void cumulative_flow_data_handler(Flow& flow);
    void on_new_stream(Stream& stream);
    void cumulative_stream_client_data_handler(Stream& stream);
    void cumulative_stream_server_data_handler(Stream& stream);
    void out_of_order_handler(Flow& session, uint32_t seq, Flow::payload_type payload);
    void run_test(uint32_t initial_seq, const ordering_info_type& chunks, 
                  const string& payload);
    void run_test(uint32_t initial_seq, const ordering_info_type& chunks);
    void run_tests(const ordering_info_type& chunks, const string& payload);
    void run_tests(const ordering_info_type& chunks);
    ordering_info_type split_payload(const string& payload, uint32_t chunk_size);
    string merge_chunks(const vector<Flow::payload_type>& chunks);
    vector<EthernetII> chunks_to_packets(uint32_t initial_seq,
                                         const ordering_info_type& chunks, 
                                         const string& payload);
    vector<EthernetII> three_way_handshake(uint32_t client_seq, uint32_t server_seq,
                                           IPv4Address client_addr, uint16_t client_port,
                                           IPv4Address server_addr, uint16_t server_port);
    void set_endpoints(vector<EthernetII>& packets, IPv4Address src_addr,
                       uint16_t src_port, IPv4Address dst_addr,
                       uint16_t dst_port);
    
    vector<Flow::payload_type> flow_payload_chunks;
    vector<pair<uint32_t, Flow::payload_type> > flow_out_of_order_chunks;
    vector<Flow::payload_type> stream_client_payload_chunks;
    vector<Flow::payload_type> stream_server_payload_chunks;
};

const string FlowTest::payload = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
                                 "Sed at aliquam arcu. Sed at iaculis magna. Nam ut dolor "
                                 "eget velit mattis posuere ut non dui. Aliquam faucibus "
                                 "erat pretium ligula tincidunt eget tristique justo placerat. "
                                 "Phasellus turpis tellus, ornare ultricies egestas vitae, "
                                 "mollis sed neque. Sed et libero in nunc pharetra auctor ut "
                                 "a eros. Mauris quis faucibus nibh. \nLorem ipsum dolor sit "
                                 "amet, consectetur adipiscing elit. Sed at aliquam arcu. "
                                 "Sed at iaculis magna. Nam ut dolor eget velit mattis "
                                 "posuere ut non dui. Aliquam faucibus erat pretium ligula "
                                 "tincidunt eget tristique justo placerat. Phasellus turpis "
                                 "tellus, ornare ultricies egestas vitae, mollis sed neque. "
                                 "Sed et libero in nunc pharetra auctor ut a eros. Mauris "
                                 "quis faucibus nibh. \n\n\nCurabitur sem erat, bibendum "
                                 "quis condimentum ut, imperdiet at est. Duis sagittis rhoncus "
                                 "felis at ultricies. In libero urna, dignissim eu elementum "
                                 "quis, consectetur a neque. Praesent leo sem, cursus sed lobortis "
                                 "sit amet, ornare ac augue. Mauris tristique semper ipsum at "
                                 "consequat. Sed fringilla dolor ut lacus sagittis quis ultricies "
                                 "leo vulputate. Maecenas dignissim imperdiet justo. Cras libero "
                                 "odio, vehicula et adipiscing quis, luctus vel ante. \nAliquam "
                                 "imperdiet est quis nunc malesuada eget convallis tellus "
                                 "ullamcorper. Vivamus ullamcorper eros sit amet odio sollicitudin "
                                 "rutrum. Donec pellentesque faucibus nulla, ut fringilla risus "
                                 "aliquam eget. Sed et ante mi. Morbi a turpis et tellus dapibus "
                                 "iaculis. Etiam faucibus tellus sed metus consequat rutrum. "
                                 "Fusce sit amet nulla massa, tempus vulputate sem. Cras tincidunt "
                                 "quam in libero rutrum interdum. Aliquam quam sapien, facilisis "
                                 "at vestibulum et, venenatis id mauris. Morbi rutrum gravida "
                                 "ultricies. \nAenean et justo ut libero euismod sollicitudin. "
                                 "Nullam enim dui, iaculis vitae bibendum et, commodo in tellus. "
                                 "Nullam eget purus mi, a ullamcorper lorem. Suspendisse potenti. "
                                 "Duis ac justo ut leo euismod gravida sit amet at lectus. Lorem "
                                 "ipsum dolor sit amet, consectetur adipiscing elit. Maecenas sed "
                                 "arcu vitae nisi sollicitudin gravida. Nulla facilisis nibh turpis. "
                                 "Maecenas quis imperdiet arcu. Sed sit amet nulla urna, at "
                                 "vestibulum mauris. Suspendisse quis elit dui. Class aptent taciti "
                                 "sociosqu ad litora torquent per conubia nostra, per inceptos "
                                 "himenaeos. \n";

void FlowTest::cumulative_flow_data_handler(Flow& flow) {
    flow_payload_chunks.push_back(flow.payload());
    flow.payload().clear();
}

void FlowTest::on_new_stream(Stream& stream) {
    using std::placeholders::_1;
    stream.client_data_callback(bind(&FlowTest::cumulative_stream_client_data_handler,
                                     this, _1));
    stream.server_data_callback(bind(&FlowTest::cumulative_stream_server_data_handler,
                                     this, _1));
}

void FlowTest::cumulative_stream_client_data_handler(Stream& stream) {
    stream_client_payload_chunks.push_back(stream.client_flow().payload());
}

void FlowTest::cumulative_stream_server_data_handler(Stream& stream) {
    stream_server_payload_chunks.push_back(stream.server_flow().payload());
}

void FlowTest::out_of_order_handler(Flow& /*session*/, uint32_t seq, Flow::payload_type payload) {
    flow_out_of_order_chunks.push_back(make_pair(seq, move(payload)));
}

void FlowTest::run_test(uint32_t initial_seq, const ordering_info_type& chunks, 
                        const string& payload) {
    using std::placeholders::_1;
    flow_payload_chunks.clear();

    Flow flow(IPv4Address("1.2.3.4"), 22, initial_seq);
    flow.data_callback(bind(&FlowTest::cumulative_flow_data_handler, this, _1));
    vector<EthernetII> packets = chunks_to_packets(initial_seq, chunks, payload);
    for (size_t i = 0; i < packets.size(); ++i) {
        flow.process_packet(packets[i]);
    }
    string flow_payload = merge_chunks(flow_payload_chunks);
    EXPECT_EQ(payload, string(flow_payload.begin(), flow_payload.end()));
    EXPECT_EQ(0U, flow.total_buffered_bytes());
    EXPECT_TRUE(flow.buffered_payload().empty());
}

void FlowTest::run_test(uint32_t initial_seq, const ordering_info_type& chunks) {
    run_test(initial_seq, chunks, payload);
}

void FlowTest::run_tests(const ordering_info_type& chunks, const string& payload) {
    run_test(0, chunks, payload);
    run_test(20, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() / 2, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() - 2, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() - 5, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() - 10, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() - 34, chunks, payload);
    run_test(numeric_limits<uint32_t>::max() - 31, chunks, payload);
}

void FlowTest::run_tests(const ordering_info_type& chunks) {
    run_tests(chunks, payload);
}

FlowTest::ordering_info_type FlowTest::split_payload(const string& payload,
                                                     uint32_t chunk_size) {
    ordering_info_type output;
    uint32_t chunk_count = payload.size() / chunk_size;
    for (uint32_t i = 0; i < chunk_count; ++i) {
        output.push_back(order_element(i * chunk_size, chunk_size));
    }
    if (chunk_count * chunk_size < payload.size()) {
        uint32_t index = chunk_count * chunk_size;
        output.push_back(order_element(index, payload.size() - index));
    }
    return output;
}

string FlowTest::merge_chunks(const vector<Flow::payload_type>& chunks) {
    string output;
    for (size_t i = 0; i < chunks.size(); ++i) {
        Flow::payload_type this_chunk = chunks[i];
        output += string(this_chunk.begin(), this_chunk.end());
    }
    return output;
}

vector<EthernetII> FlowTest::chunks_to_packets(uint32_t initial_seq,
                                               const ordering_info_type& chunks, 
                                               const string& payload) {
    vector<EthernetII> output;
    for (size_t i = 0; i < chunks.size(); ++i) {
        const order_element& element = chunks[i];
        assert(element.payload_index + element.payload_size <= payload.size());
        TCP tcp;
        RawPDU raw(payload.begin() + element.payload_index, 
                   payload.begin() + element.payload_index + element.payload_size);
        tcp.seq(initial_seq + element.payload_index);
        output.push_back(EthernetII() / IP() / tcp / raw);
    }
    return output;
}

vector<EthernetII> FlowTest::three_way_handshake(uint32_t client_seq, uint32_t server_seq,
                                                 IPv4Address client_addr, uint16_t client_port,
                                                 IPv4Address server_addr, uint16_t server_port) {
    vector<EthernetII> output;
    output.push_back(EthernetII() / IP(server_addr, client_addr) / TCP(server_port, client_port));
    output.push_back(EthernetII() / IP(client_addr, server_addr) / TCP(client_port, server_port));
    output.push_back(EthernetII() / IP(server_addr, client_addr) / TCP(server_port, client_port));
    output[0].rfind_pdu<TCP>().flags(TCP::SYN);
    output[0].rfind_pdu<TCP>().seq(client_seq);
    output[1].rfind_pdu<TCP>().flags(TCP::SYN | TCP::ACK);
    output[1].rfind_pdu<TCP>().seq(server_seq);
    output[1].rfind_pdu<TCP>().ack_seq(client_seq + 1);
    output[2].rfind_pdu<TCP>().flags(TCP::ACK);
    output[2].rfind_pdu<TCP>().seq(client_seq + 1);
    output[2].rfind_pdu<TCP>().ack_seq(server_seq + 1);
    return output;
}

void FlowTest::set_endpoints(vector<EthernetII>& packets, IPv4Address src_addr,
                             uint16_t src_port, IPv4Address dst_addr,
                             uint16_t dst_port) {
    for (size_t i = 0; i < packets.size(); ++i) {
        packets[i].rfind_pdu<IP>().src_addr(src_addr);
        packets[i].rfind_pdu<IP>().dst_addr(dst_addr);
        packets[i].rfind_pdu<TCP>().sport(src_port);
        packets[i].rfind_pdu<TCP>().dport(dst_port);
    }
}

TEST_F(FlowTest, ReassembleStreamPlain) {
    ordering_info_type chunks = split_payload(payload, 5);
    run_tests(chunks);
}

TEST_F(FlowTest, ReassembleStreamReordering) {
    ordering_info_type chunks = split_payload(payload, 5);
    // e.g. input [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    // after this it's [2, 1, 0, 3, 6, 5, 4, 7, 10, 9, 8]
    for (size_t i = 0; i < chunks.size(); i += 4) {
        if (i + 2 < chunks.size()) {
            swap(chunks[i], chunks[i + 2]);
        }
    }
    run_tests(chunks);
}

TEST_F(FlowTest, ReassembleStreamReversed) {
    ordering_info_type chunks = split_payload(payload, 5);
    reverse(chunks.begin(), chunks.end());
    run_tests(chunks);
}

TEST_F(FlowTest, Overlapping) {
    string payload = "Hello world. This is a payload";
    ordering_info_type chunks;
    // "Hello "
    chunks.push_back(order_element(0, 6));
    // "ello Wo"
    chunks.push_back(order_element(1, 7));
    // "lo World"
    chunks.push_back(order_element(3, 8));
    chunks.push_back(order_element(10, payload.size() - 10));
    chunks.push_back(order_element(9, 1));
    run_tests(chunks, payload);

    reverse(chunks.begin(), chunks.end());
    run_tests(chunks, payload);

    swap(chunks[2], chunks[4]);
    run_tests(chunks, payload);
}

TEST_F(FlowTest, IgnoreDataPackets) {
    using std::placeholders::_1;

    ordering_info_type chunks = split_payload(payload, 5);
    Flow flow(IPv4Address("1.2.3.4"), 22, 0);
    flow.data_callback(bind(&FlowTest::cumulative_flow_data_handler, this, _1));
    flow.ignore_data_packets();
    vector<EthernetII> packets = chunks_to_packets(0, chunks, payload);
    for (size_t i = 0; i < packets.size(); ++i) {
        flow.process_packet(packets[i]);
    }
    EXPECT_TRUE(flow_payload_chunks.empty());
}

TEST_F(FlowTest, OutOfOrderCallback) {
    using namespace std::placeholders;

    ordering_info_type chunks = split_payload(payload, 5);
    Flow flow(IPv4Address("1.2.3.4"), 22, 0);
    flow.out_of_order_callback(bind(&FlowTest::out_of_order_handler, this, _1, _2, _3));
    vector<EthernetII> packets = chunks_to_packets(0, chunks, payload);
    reverse(packets.begin(), packets.end());
    // Copy, as Flow::process_packet takes ownership of the payload
    vector<EthernetII> original_packets = packets;
    for (size_t i = 0; i < packets.size(); ++i) {
        flow.process_packet(packets[i]);
    }
    // All elements should be out of order except the first
    // one (last one in reverse order)
    ASSERT_EQ(original_packets.size() - 1, flow_out_of_order_chunks.size());
    for (size_t i = 0; i < original_packets.size() - 1; ++i) {
        // Compare sequence number
        EXPECT_EQ(
            original_packets[i].rfind_pdu<TCP>().seq(),
            flow_out_of_order_chunks[i].first
        );
        // Compare payload
        EXPECT_EQ(
            original_packets[i].rfind_pdu<RawPDU>().payload(),
            flow_out_of_order_chunks[i].second
        );
    }
}

// Stream follower tests

TEST_F(FlowTest, StreamFollower_ThreeWayHandshake) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    packets[0].src_addr("00:01:02:03:04:05");
    packets[0].dst_addr("05:04:03:02:01:00");
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));

    Stream::timestamp_type ts(10000);
    Stream::timestamp_type create_time = ts;
    for (size_t i = 0; i < packets.size(); ++i) {
        if (i != 0) {
            ts += milliseconds(100);
        }
        Packet packet(packets[i], duration_cast<microseconds>(ts));
        follower.process_packet(packet);
    }
    Stream& stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                          IPv4Address("4.3.2.1"), 25);
    EXPECT_EQ(Flow::ESTABLISHED, stream.client_flow().state());
    EXPECT_EQ(Flow::SYN_SENT, stream.server_flow().state());
    EXPECT_EQ(30U, stream.client_flow().sequence_number());
    EXPECT_EQ(61U, stream.server_flow().sequence_number());
    EXPECT_EQ(IPv4Address("4.3.2.1"), stream.client_flow().dst_addr_v4());
    EXPECT_EQ(25, stream.client_flow().dport());
    EXPECT_EQ(IPv4Address("1.2.3.4"), stream.server_flow().dst_addr_v4());
    EXPECT_EQ(22, stream.server_flow().dport());
    EXPECT_EQ(IPv4Address("1.2.3.4"), stream.client_addr_v4());
    EXPECT_EQ(IPv4Address("4.3.2.1"), stream.server_addr_v4());
    EXPECT_EQ(HWAddress<6>("00:01:02:03:04:05"), stream.client_hw_addr());
    EXPECT_EQ(HWAddress<6>("05:04:03:02:01:00"), stream.server_hw_addr());
    EXPECT_EQ(22, stream.client_port());
    EXPECT_EQ(25, stream.server_port());
    EXPECT_EQ(create_time, stream.create_time());
    EXPECT_EQ(ts, stream.last_seen());

    IP server_packet = IP("1.2.3.4", "4.3.2.1") / TCP(22, 25);
    server_packet.rfind_pdu<TCP>().flags(TCP::ACK);
    follower.process_packet(server_packet);

    EXPECT_EQ(Flow::ESTABLISHED, stream.server_flow().state());
    EXPECT_EQ(61U, stream.server_flow().sequence_number());
    EXPECT_FALSE(stream.is_partial_stream());
}

TEST_F(FlowTest, StreamFollower_TCPOptions) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    // Client's mss is 1220
    packets[0].rfind_pdu<TCP>().mss(1220);
    // Server's mss is 1460
    packets[1].rfind_pdu<TCP>().mss(1460);
    // Server supports SACK
    packets[1].rfind_pdu<TCP>().sack_permitted();
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    Stream& stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                          IPv4Address("4.3.2.1"), 25);
    EXPECT_EQ(1220, stream.client_flow().mss());
    EXPECT_EQ(1460, stream.server_flow().mss());
    EXPECT_FALSE(stream.client_flow().sack_permitted());
    EXPECT_TRUE(stream.server_flow().sack_permitted());
}

TEST_F(FlowTest, StreamFollower_CleanupWorks) {
    using std::placeholders::_1;

    bool timed_out = false;
    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    follower.stream_termination_callback([&](Stream&, StreamFollower::TerminationReason reason) {
        timed_out = (reason == StreamFollower::TIMEOUT);
    });
    packets[2].rfind_pdu<IP>().src_addr("6.6.6.6");
    auto base_time = duration_cast<Stream::timestamp_type>(system_clock::now().time_since_epoch());
    Packet packet1(packets[0], base_time);   
    Packet packet2(packets[1], base_time + seconds(50));   
    Packet packet3(packets[2], base_time + minutes(10));   
    follower.process_packet(packet1);
    Stream& stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                          IPv4Address("4.3.2.1"), 25);
    EXPECT_EQ(base_time, stream.create_time());
    follower.process_packet(packet2);
    follower.process_packet(packet3);
    // At this point, it should be cleaned up
    EXPECT_THROW(
        follower.find_stream(IPv4Address("1.2.3.4"), 22, IPv4Address("4.3.2.1"), 25), 
        stream_not_found
    );
    EXPECT_TRUE(timed_out);
}

TEST_F(FlowTest, StreamFollower_RSTClosesStream) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    Stream stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                         IPv4Address("4.3.2.1"), 25);

    IP server_packet = IP("1.2.3.4", "4.3.2.1") / TCP(22, 25);
    server_packet.rfind_pdu<TCP>().flags(TCP::RST);
    stream.process_packet(server_packet);

    EXPECT_EQ(Flow::RST_SENT, stream.server_flow().state());
    EXPECT_TRUE(stream.is_finished());
}

TEST_F(FlowTest, StreamFollower_FINClosesStream) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    Stream stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                         IPv4Address("4.3.2.1"), 25);

    IP server_packet = IP("1.2.3.4", "4.3.2.1") / TCP(22, 25);
    server_packet.rfind_pdu<TCP>().flags(TCP::FIN | TCP::ACK);
    stream.process_packet(server_packet);

    EXPECT_EQ(Flow::FIN_SENT, stream.server_flow().state());
    EXPECT_FALSE(stream.is_finished());

    IP client_packet = IP("4.3.2.1", "1.2.3.4") / TCP(25, 22);
    client_packet.rfind_pdu<TCP>().flags(TCP::FIN | TCP::ACK);
    stream.process_packet(client_packet);

    EXPECT_EQ(Flow::FIN_SENT, stream.client_flow().state());
    EXPECT_TRUE(stream.is_finished());
}

TEST_F(FlowTest, StreamFollower_StreamIsRemovedWhenFinished) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    IP server_packet = IP("1.2.3.4", "4.3.2.1") / TCP(22, 25);
    server_packet.rfind_pdu<TCP>().flags(TCP::RST);
    follower.process_packet(server_packet);

    // We shouldn't be able to find it
    EXPECT_THROW(
        follower.find_stream(IPv4Address("1.2.3.4"), 22, IPv4Address("4.3.2.1"), 25), 
        stream_not_found
    );
}

TEST_F(FlowTest, StreamFollower_FollowStream) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    ordering_info_type chunks = split_payload(payload, 5);
    vector<EthernetII> chunk_packets = chunks_to_packets(30 /*initial_seq*/, chunks, payload);
    set_endpoints(chunk_packets, "1.2.3.4", 22, "4.3.2.1", 25);
    packets.insert(packets.end(), chunk_packets.begin(), chunk_packets.end());
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    EXPECT_EQ(chunk_packets.size(), stream_client_payload_chunks.size());
    EXPECT_EQ(payload, merge_chunks(stream_client_payload_chunks));
}

TEST_F(FlowTest, StreamFollower_AttachToStreams) {
    using std::placeholders::_1;

    ordering_info_type chunks = split_payload(payload, 5);
    vector<EthernetII> packets = chunks_to_packets(30 /*initial_seq*/, chunks, payload);
    set_endpoints(packets, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.follow_partial_streams(true);
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    EXPECT_EQ(packets.size(), stream_client_payload_chunks.size());
    EXPECT_EQ(payload, merge_chunks(stream_client_payload_chunks));

    Stream& stream = follower.find_stream(IPv4Address("1.2.3.4"), 22, IPv4Address("4.3.2.1"), 25);
    EXPECT_TRUE(stream.is_partial_stream());
}

TEST_F(FlowTest, StreamFollower_AttachToStreams_PacketsInBothDirections) {
    using std::placeholders::_1;

    ordering_info_type client_chunks = split_payload(payload, 5);
    ordering_info_type server_chunks = split_payload(payload, 5);
    vector<EthernetII> client_packets = chunks_to_packets(30 /*initial_seq*/, client_chunks,
                                                          payload);
    vector<EthernetII> server_packets = chunks_to_packets(42 /*initial_seq*/, server_chunks,
                                                          payload);
    // Let's say the first packet acks the range before the first server packet
    client_packets[0].rfind_pdu<TCP>().ack_seq(42);
    set_endpoints(client_packets, "1.2.3.4", 22, "4.3.2.1", 25);
    set_endpoints(server_packets, "4.3.2.1", 25, "1.2.3.4", 22);
    StreamFollower follower;
    follower.follow_partial_streams(true);
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < client_packets.size(); ++i) {
        follower.process_packet(client_packets[i]);
    }
    for (size_t i = 0; i < server_packets.size(); ++i) {
        follower.process_packet(server_packets[i]);
    }
    EXPECT_EQ(client_packets.size(), stream_client_payload_chunks.size());
    EXPECT_EQ(server_packets.size(), stream_server_payload_chunks.size());
    EXPECT_EQ(payload, merge_chunks(stream_client_payload_chunks));
    EXPECT_EQ(payload, merge_chunks(stream_server_payload_chunks));
}

TEST_F(FlowTest, StreamFollower_AttachToStreams_SecondPacketLost) {
    using std::placeholders::_1;

    ordering_info_type chunks = split_payload(payload, 5);
    vector<EthernetII> packets = chunks_to_packets(30 /*initial_seq*/, chunks, payload);
    string trimmed_payload = payload;
    // Erase the second packet
    packets.erase(packets.begin() + 1);
    // Erase the 5-10th bytes
    trimmed_payload.erase(5, 5);

    set_endpoints(packets, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.follow_partial_streams(true);
    follower.new_stream_callback([&](Stream& stream) {
        on_new_stream(stream);
        stream.client_out_of_order_callback([](Stream& stream, uint32_t seq,
                                               const Stream::payload_type&) {
            stream.client_flow().advance_sequence(seq);
        });
    });
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    EXPECT_EQ(packets.size(), stream_client_payload_chunks.size());
    EXPECT_EQ(trimmed_payload, merge_chunks(stream_client_payload_chunks));
}

TEST_F(FlowTest, StreamFollower_AttachToStreams_RecoveryMode) {
    using std::placeholders::_1;

    ordering_info_type chunks = split_payload(payload, 5);
    vector<EthernetII> packets = chunks_to_packets(30 /*initial_seq*/, chunks, payload);
    string trimmed_payload = payload;
    // Erase the 15-20th and 5-10th bytes
    trimmed_payload.erase(15, 5);
    trimmed_payload.erase(5, 5);
    // Erase the second packet
    packets.erase(packets.begin() + 3);
    packets.erase(packets.begin() + 1);

    set_endpoints(packets, "1.2.3.4", 22, "4.3.2.1", 25);
    StreamFollower follower;
    follower.follow_partial_streams(true);
    follower.new_stream_callback([&](Stream& stream) {
        on_new_stream(stream);
        stream.enable_recovery_mode(20 /*recovery window size*/);
    });
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    EXPECT_EQ(packets.size(), stream_client_payload_chunks.size());
    EXPECT_EQ(trimmed_payload, merge_chunks(stream_client_payload_chunks));
    EXPECT_EQ(trimmed_payload, merge_chunks(stream_client_payload_chunks));
}

#ifdef TINS_HAVE_ACK_TRACKER

using namespace boost;
using namespace boost::icl;

class AckTrackerTest : public testing::Test {
public:
    typedef AckedRange::interval_type interval_type;
private:

};

vector<uint32_t> make_sack() {
    return vector<uint32_t>();
}

template <typename... SackEdges>
vector<uint32_t> make_sack(pair<uint32_t, uint32_t> head, SackEdges&&... tail) {
    vector<uint32_t> output = make_sack(tail...);
    output.push_back(head.first);
    output.push_back(head.second);
    return output;
}

TCP make_tcp_ack(uint32_t ack_number) {
    TCP output;
    output.ack_seq(ack_number);
    return output;
}

template <typename... SackEdges>
TCP make_tcp_ack(uint32_t ack_number, SackEdges&&... rest) {
    TCP output = make_tcp_ack(ack_number);
    vector<uint32_t> sack = make_sack(rest...);
    output.sack(sack);
    return output;
}

// This section compares ranges using 
//
// EXPECT_TRUE(r1 == r2)
//
// Since otherwise gtest fails to compile when trying to print an interval
// to a std::ostream
TEST_F(AckTrackerTest, AckedRange_1) {
    AckedRange range(0, 100);
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(interval_type::closed(0, 100) == range.next());
    EXPECT_FALSE(range.has_next());
}

TEST_F(AckTrackerTest, AckedRange_2) {
    AckedRange range(2, 3);
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(interval_type::closed(2, 3) == range.next());
    EXPECT_FALSE(range.has_next());
}

TEST_F(AckTrackerTest, AckedRange_3) {
    AckedRange range(0, 0);
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(interval_type::right_open(0, 1) == range.next());
    EXPECT_FALSE(range.has_next());
}

TEST_F(AckTrackerTest, AckedRange_4) {
    uint32_t maximum = numeric_limits<uint32_t>::max();
    AckedRange range(maximum, maximum);
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(interval_type::left_open(maximum - 1, maximum) == range.next());
    EXPECT_FALSE(range.has_next());
}

TEST_F(AckTrackerTest, AckedRange_WrapAround) {
    uint32_t first = numeric_limits<uint32_t>::max() - 5;
    AckedRange range(first, 100);
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(
        interval_type::closed(first, numeric_limits<uint32_t>::max()) ==
        range.next()
    );
    EXPECT_TRUE(range.has_next());
    EXPECT_TRUE(interval_type::closed(0, 100) == range.next());
    EXPECT_FALSE(range.has_next());
}

TEST_F(AckTrackerTest, AckingTcp1) {
    AckTracker tracker(0, false);
    EXPECT_EQ(0U, tracker.ack_number());
    tracker.process_packet(make_tcp_ack(100));
    EXPECT_EQ(100U, tracker.ack_number());
    EXPECT_TRUE(tracker.is_segment_acked(0, 10));
    EXPECT_TRUE(tracker.is_segment_acked(50, 10));
    EXPECT_TRUE(tracker.is_segment_acked(99, 1));
    EXPECT_FALSE(tracker.is_segment_acked(90, 20));
    EXPECT_FALSE(tracker.is_segment_acked(99, 2));
    tracker.process_packet(make_tcp_ack(50));
    EXPECT_EQ(100U, tracker.ack_number());
    tracker.process_packet(make_tcp_ack(150));
    EXPECT_EQ(150U, tracker.ack_number());
    tracker.process_packet(make_tcp_ack(200));
    EXPECT_EQ(200U, tracker.ack_number());
}

TEST_F(AckTrackerTest, AckingTcp2) {
    uint32_t maximum = numeric_limits<uint32_t>::max();
    AckTracker tracker(maximum - 10, false);
    EXPECT_EQ(maximum - 10, tracker.ack_number());   
    tracker.process_packet(make_tcp_ack(maximum - 3));
    EXPECT_EQ(maximum - 3, tracker.ack_number());   
    tracker.process_packet(make_tcp_ack(maximum));
    EXPECT_EQ(maximum, tracker.ack_number());   
    tracker.process_packet(make_tcp_ack(5));
    EXPECT_EQ(5U, tracker.ack_number());   
}

TEST_F(AckTrackerTest, AckingTcp3) {
    uint32_t maximum = numeric_limits<uint32_t>::max();
    AckTracker tracker(maximum - 10, false);
    tracker.process_packet(make_tcp_ack(5));
    EXPECT_EQ(5U, tracker.ack_number());   
}

TEST_F(AckTrackerTest, AckingTcp_Sack1) {
    AckTracker tracker(0, true);
    tracker.process_packet(make_tcp_ack(0, make_pair(2, 5), make_pair(9, 11)));
    EXPECT_EQ(3U + 2U, tracker.acked_intervals().size());
    EXPECT_TRUE(tracker.is_segment_acked(2, 3));
    EXPECT_TRUE(tracker.is_segment_acked(9, 2));
    EXPECT_FALSE(tracker.is_segment_acked(2, 9));

    tracker.process_packet(make_tcp_ack(9));
    EXPECT_EQ(1UL, tracker.acked_intervals().size());

    tracker.process_packet(make_tcp_ack(15));
    EXPECT_EQ(0UL, tracker.acked_intervals().size());
}

TEST_F(AckTrackerTest, AckingTcp_Sack2) {
    uint32_t maximum = numeric_limits<uint32_t>::max();
    AckTracker tracker(maximum - 10, true);
    tracker.process_packet(make_tcp_ack(
        maximum - 10,
        make_pair(maximum - 3, maximum),
        make_pair(0, 10)
    ));
    EXPECT_EQ(3U + 10U, tracker.acked_intervals().size());
    EXPECT_TRUE(tracker.is_segment_acked(maximum - 12, 2));
    EXPECT_TRUE(tracker.is_segment_acked(maximum - 2, 1));
    EXPECT_TRUE(tracker.is_segment_acked(2, 3));
    EXPECT_FALSE(tracker.is_segment_acked(maximum - 10, 10));
    EXPECT_EQ(maximum - 10, tracker.ack_number());

    tracker.process_packet(make_tcp_ack(maximum - 2));
    EXPECT_EQ(1U + 10U, tracker.acked_intervals().size());
    EXPECT_EQ(maximum - 2, tracker.ack_number());

    tracker.process_packet(make_tcp_ack(5));
    EXPECT_EQ(4U, tracker.acked_intervals().size());
    EXPECT_EQ(5U, tracker.ack_number());

    tracker.process_packet(make_tcp_ack(15));
    EXPECT_EQ(0U, tracker.acked_intervals().size());
    EXPECT_EQ(15U, tracker.ack_number());
}

TEST_F(AckTrackerTest, AckingTcp_Sack3) {
    uint32_t maximum = numeric_limits<uint32_t>::max();
    AckTracker tracker(maximum - 10, true);
    tracker.process_packet(make_tcp_ack(
        maximum - 10,
        make_pair(maximum - 3, 5)
    ));
    EXPECT_EQ(9U, tracker.acked_intervals().size());
    EXPECT_EQ(maximum - 10, tracker.ack_number());

    tracker.process_packet(make_tcp_ack(maximum));
    EXPECT_EQ(5U, tracker.acked_intervals().size());
    EXPECT_EQ(maximum, tracker.ack_number());
}

TEST_F(AckTrackerTest, AckingTcp_SackOutOfOrder1) {
    AckTracker tracker(0, true);
    tracker.process_packet(make_tcp_ack(10));
    tracker.process_packet(make_tcp_ack(0, make_pair(9, 12)));
    EXPECT_EQ(0U, tracker.acked_intervals().size());
    EXPECT_EQ(11U, tracker.ack_number());
}

TEST_F(AckTrackerTest, AckingTcp_SackOutOfOrder2) {
    AckTracker tracker(0, true);
    tracker.process_packet(make_tcp_ack(10));
    tracker.process_packet(make_tcp_ack(0, make_pair(10, 12)));
    EXPECT_EQ(0U, tracker.acked_intervals().size());
    EXPECT_EQ(11U, tracker.ack_number());
}

TEST_F(FlowTest, AckNumbersAreCorrect) {
    using std::placeholders::_1;

    vector<EthernetII> packets = three_way_handshake(29, 60, "1.2.3.4", 22, "4.3.2.1", 25);
    // Server's ACK number is 9898
    packets[1].rfind_pdu<TCP>().ack_seq(9898);
    // Client's ACK number is 1717
    packets[2].rfind_pdu<TCP>().ack_seq(1717);
    StreamFollower follower;
    follower.new_stream_callback(bind(&FlowTest::on_new_stream, this, _1));
    for (size_t i = 0; i < packets.size(); ++i) {
        follower.process_packet(packets[i]);
    }
    Stream& stream = follower.find_stream(IPv4Address("1.2.3.4"), 22,
                                          IPv4Address("4.3.2.1"), 25);
    EXPECT_EQ(1717U, stream.client_flow().ack_tracker().ack_number());
    EXPECT_EQ(9898U, stream.server_flow().ack_tracker().ack_number());
}

#endif // TINS_HAVE_ACK_TRACKER

#else

TEST(Foo, Dummy) {

}

#endif // TINS_HAVE_TCPIP