/*
 * Unit tests for data structures.
 *
 * Depends on the Boost.Test unit test framework.
 * Tested with Boost v1.74, available from https://www.boost.org/
 */

#include <algorithm>
#include <climits>
#include <memory>
#include <random>
#include <set>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

#define BOOST_TEST_MODULE datastruct
#include <boost/test/unit_test.hpp>

#include "datastruct.h"


/* **********  Test ConcatenableQueue  ********** */

BOOST_AUTO_TEST_SUITE(test_concatenable_queue)

BOOST_AUTO_TEST_CASE(test_single)
{
    using Queue = ConcatenableQueue<int, std::string, std::string>;
    Queue q("Q");
    BOOST_TEST(q.name() == std::string("Q"));

    Queue::Node n;
    q.insert(&n, 4, "a");

    BOOST_TEST(n.find() == std::string("Q"));
    BOOST_TEST(n.prio() == 4);
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == std::string("a"));

    n.set_prio(8);

    BOOST_TEST(n.prio() == 8);
    BOOST_TEST(n.find() == std::string("Q"));
    BOOST_TEST(q.min_prio() == 8);
    BOOST_TEST(q.min_elem() == std::string("a"));
}

BOOST_AUTO_TEST_CASE(test_simple)
{
    using Queue = ConcatenableQueue<int, std::string, char>;
    Queue::Node n1, n2, n3, n4, n5;

    Queue q1("A");
    q1.insert(&n1, 5, 'a');

    Queue q2("B");
    q2.insert(&n2, 6, 'b');

    Queue q3("C");
    q3.insert(&n3, 7, 'c');

    Queue q4("D");
    q4.insert(&n4, 4, 'd');

    Queue q5("E");
    q5.insert(&n5, 3, 'e');

    auto m345 = {&q3, &q4, &q5};
    Queue q345("P");
    q345.merge(m345.begin(), m345.end());

    BOOST_TEST(n1.find() == std::string("A"));
    BOOST_TEST(n2.find() == std::string("B"));
    BOOST_TEST(n3.find() == std::string("P"));
    BOOST_TEST(n4.find() == std::string("P"));
    BOOST_TEST(n5.find() == std::string("P"));
    BOOST_TEST(q345.min_prio() == 3);
    BOOST_TEST(q345.min_elem() == 'e');

    n5.set_prio(6);
    BOOST_TEST(q345.min_prio() == 4);
    BOOST_TEST(q345.min_elem() == 'd');

    auto m12 = {&q1, &q2};
    Queue q12("Q");
    q12.merge(m12.begin(), m12.end());

    BOOST_TEST(n1.find() == std::string("Q"));
    BOOST_TEST(n2.find() == std::string("Q"));
    BOOST_TEST(q12.min_prio() == 5);
    BOOST_TEST(q12.min_elem() == 'a');

    auto m12345 = {&q12, &q345};
    Queue q12345("R");
    q12345.merge(m12345.begin(), m12345.end());

    BOOST_TEST(n1.find() == std::string("R"));
    BOOST_TEST(n2.find() == std::string("R"));
    BOOST_TEST(n3.find() == std::string("R"));
    BOOST_TEST(n4.find() == std::string("R"));
    BOOST_TEST(n5.find() == std::string("R"));
    BOOST_TEST(q12345.min_prio() == 4);
    BOOST_TEST(q12345.min_elem() == 'd');

    n4.set_prio(8);

    BOOST_TEST(q12345.min_prio() == 5);
    BOOST_TEST(q12345.min_elem() == 'a');

    n3.set_prio(2);

    BOOST_TEST(q12345.min_prio() == 2);
    BOOST_TEST(q12345.min_elem() == 'c');

    q12345.split();

    BOOST_TEST(n1.find() == std::string("Q"));
    BOOST_TEST(n2.find() == std::string("Q"));
    BOOST_TEST(n3.find() == std::string("P"));
    BOOST_TEST(n4.find() == std::string("P"));
    BOOST_TEST(n5.find() == std::string("P"));
    BOOST_TEST(q12.min_prio() == 5);
    BOOST_TEST(q12.min_elem() == 'a');
    BOOST_TEST(q345.min_prio() == 2);
    BOOST_TEST(q345.min_elem() == 'c');

    q12.split();
    BOOST_TEST(n1.find() == std::string("A"));
    BOOST_TEST(n2.find() == std::string("B"));

    q345.split();
    BOOST_TEST(n3.find() == std::string("C"));
    BOOST_TEST(n4.find() == std::string("D"));
    BOOST_TEST(n5.find() == std::string("E"));
    BOOST_TEST(q3.min_prio() == 2);
    BOOST_TEST(q3.min_elem() == 'c');
}

BOOST_AUTO_TEST_CASE(test_medium)
{
    using Queue = ConcatenableQueue<int, char, char>;

    std::vector<char> queue_names(19);
    for (int i = 0; i < 14; i++) {
        queue_names[i] = 'A' + i;
    }
    queue_names[14] = 'P';
    queue_names[15] = 'Q';
    queue_names[16] = 'R';
    queue_names[17] = 'S';
    queue_names[18] = 'Z';

    std::vector<Queue> queues(queue_names.begin(), queue_names.end());
    Queue::Node nodes[14];

    int prios[14] = {3, 8, 6, 2, 9, 4, 6, 8, 1, 5, 9, 4, 7, 8};

    auto min_prio = [&prios](int begin, int end) -> int {
        int p = begin;
        int m = prios[p];
        ++p;
        while (p != end) {
            m = std::min(m, prios[p]);
            ++p;
        }
        return m;
    };

    for (int i = 0; i < 14; i++) {
        BOOST_TEST(queues[i].name() == 'A' + i);
        queues[i].insert(&nodes[i], prios[i], 'a' + i);
    }

    auto m14 = {&queues[0], &queues[1]};
    queues[14].merge(m14.begin(), m14.end());
    BOOST_TEST(queues[14].name() == 'P');
    BOOST_TEST(queues[14].min_prio() == min_prio(0, 2));

    auto m15 = {&queues[2], &queues[3], &queues[4]};
    queues[15].merge(m15.begin(), m15.end());
    BOOST_TEST(queues[15].name() == 'Q');
    BOOST_TEST(queues[15].min_prio() == min_prio(2, 5));

    auto m16 = {&queues[5], &queues[6], &queues[7], &queues[8]};
    queues[16].merge(m16.begin(), m16.end());
    BOOST_TEST(queues[16].name() == 'R');
    BOOST_TEST(queues[16].min_prio() == min_prio(5, 9));

    auto m17 = {&queues[9], &queues[10], &queues[11], &queues[12],
                &queues[13]};
    queues[17].merge(m17.begin(), m17.end());
    BOOST_TEST(queues[17].name() == 'S');
    BOOST_TEST(queues[17].min_prio() == min_prio(9, 14));

    for (int i = 0; i < 2; i++) {
        BOOST_TEST(nodes[i].find() == 'P');
    }
    for (int i = 2; i < 5; i++) {
        BOOST_TEST(nodes[i].find() == 'Q');
    }
    for (int i = 5; i < 9; i++) {
        BOOST_TEST(nodes[i].find() == 'R');
    }
    for (int i = 9; i < 14; i++) {
        BOOST_TEST(nodes[i].find() == 'S');
    }

    auto m18 = {&queues[14], &queues[15], &queues[16], &queues[17]};
    queues[18].merge(m18.begin(), m18.end());
    BOOST_TEST(queues[18].name() == 'Z');
    BOOST_TEST(queues[18].min_prio() == 1);
    BOOST_TEST(queues[18].min_elem() == 'i');

    for (int i = 0; i < 14; i++) {
        BOOST_TEST(nodes[i].find() == 'Z');
    }

    prios[8] = 5;
    nodes[8].set_prio(prios[8]);
    BOOST_TEST(queues[18].min_prio() == 2);
    BOOST_TEST(queues[18].min_elem() == 'd');

    queues[18].split();

    for (int i = 0; i < 2; i++) {
        BOOST_TEST(nodes[i].find() == 'P');
    }
    for (int i = 2; i < 5; i++) {
        BOOST_TEST(nodes[i].find() == 'Q');
    }
    for (int i = 5; i < 9; i++) {
        BOOST_TEST(nodes[i].find() == 'R');
    }
    for (int i = 9; i < 14; i++) {
        BOOST_TEST(nodes[i].find() == 'S');
    }

    BOOST_TEST(queues[14].min_prio() == min_prio(0, 2));
    BOOST_TEST(queues[15].min_prio() == min_prio(2, 5));
    BOOST_TEST(queues[16].min_prio() == min_prio(5, 9));
    BOOST_TEST(queues[17].min_prio() == min_prio(9, 14));

    for (int i = 14; i < 18; i++) {
        queues[i].split();
    }

    for (int i = 0; i < 14; i++) {
        BOOST_TEST(nodes[i].find() == 'A' + i);
        BOOST_TEST(queues[i].min_prio() == prios[i]);
        BOOST_TEST(queues[i].min_elem() == 'a' + i);
    }
}

BOOST_AUTO_TEST_CASE(test_random)
{
    using Queue = ConcatenableQueue<double, int, int>;

    constexpr int NUM_NODES = 4000;

    std::mt19937 rng(23456);
    std::uniform_real_distribution<> prio_distribution;
    std::uniform_int_distribution<> node_distribution(0, NUM_NODES - 1);

    double prios[NUM_NODES];
    Queue::Node nodes[NUM_NODES];
    std::unordered_map<int, std::unique_ptr<Queue>> queues;
    std::unordered_map<int, std::set<int>> queue_nodes;
    std::unordered_map<int, std::set<int>> queue_subs;
    std::set<int> live_queues;
    std::set<int> live_merged_queues;

    // Make trivial queues.
    for (int i = 0; i < NUM_NODES; i++) {
        int name = 10000 + i;
        prios[i] = prio_distribution(rng);
        queues[name] = std::unique_ptr<Queue>(new Queue(name));
        queues[name]->insert(&nodes[i], prios[i], i);
        queue_nodes[name].insert(i);
        live_queues.insert(name);
    }

    // Run modifications.
    for (int i = 0; i < 4000; i++) {

        // Find top-level queue of few nodes.
        for (int k = 0; k < 200; k++) {
            int t = node_distribution(rng);
            int name = nodes[t].find();
            BOOST_TEST(queue_nodes[name].count(t) == 1);
        }

        // Change priority of a few nodes.
        for (int k = 0; k < 10; k++) {
            int t = node_distribution(rng);
            int name = nodes[t].find();
            BOOST_TEST(live_queues.count(name) == 1);
            BOOST_TEST(queue_nodes[name].count(t) == 1);
            BOOST_TEST(nodes[t].prio() == prios[t]);
            double p = prio_distribution(rng);
            prios[t] = p;
            nodes[t].set_prio(p);
            for (int tt : queue_nodes[name]) {
                if (prios[tt] < p) {
                    t = tt;
                    p = prios[tt];
                }
            }
            BOOST_TEST(queues[name]->min_prio() == p);
            BOOST_TEST(queues[name]->min_elem() == t);
        }

        if (live_queues.size() > 100) {

            // Choose number of queues to merge between 2 and 100.
            int k = std::uniform_int_distribution<>(2, 100)(rng);
            k = std::uniform_int_distribution<>(2, k)(rng);

            // Choose queues to merge.
            std::vector<int> live_queue_vec(live_queues.begin(),
                                            live_queues.end());
            std::vector<int> sub_names;
            std::vector<Queue*> sub_queues;
            for (int ki = 0; ki < k; ki++) {
                int t = std::uniform_int_distribution<>(
                    0, live_queue_vec.size() - 1)(rng);
                int name = live_queue_vec[t];
                sub_names.push_back(name);
                sub_queues.push_back(queues[name].get());
                live_queue_vec[t] = live_queue_vec.back();
                live_queue_vec.pop_back();
                live_queues.erase(name);
                live_merged_queues.erase(name);
            }

            // Create new queue by merging selected queues.
            int name = 20000 + i;
            queues[name] = std::unique_ptr<Queue>(new Queue(name));
            queues[name]->merge(sub_queues.begin(), sub_queues.end());
            for (int nn : sub_names) {
                queue_nodes[name].insert(queue_nodes[nn].begin(),
                                         queue_nodes[nn].end());
            }
            queue_subs[name].insert(sub_names.begin(), sub_names.end());
            live_queues.insert(name);
            live_merged_queues.insert(name);

            // Check new queue.
            {
                double p = 2;
                int t = 0;
                for (int tt : queue_nodes[name]) {
                    if (prios[tt] < p) {
                        t = tt;
                        p = prios[tt];
                    }
                }
                BOOST_TEST(queues[name]->min_prio() == p);
                BOOST_TEST(queues[name]->min_elem() == t);
            }
        }

        if ((live_queues.size() <= 100)
                || (live_merged_queues.size() >= 100)) {

            // Choose a random queue to split.
            std::vector<int> live_queue_vec(live_merged_queues.begin(),
                                            live_merged_queues.end());
            int k = std::uniform_int_distribution<>(
                0, live_queue_vec.size() - 1)(rng);
            int name = live_queue_vec[k];

            queues[name]->split();

            for (int nn : queue_subs[name]) {
                // Check reconstructed sub-queue.
                double p = 2;
                int t = 0;
                for (int tt : queue_nodes[nn]) {
                    if (prios[tt] < p) {
                        t = tt;
                        p = prios[tt];
                    }
                }
                BOOST_TEST(queues[nn]->min_prio() == p);
                BOOST_TEST(queues[nn]->min_elem() == t);

                // Mark sub-queue as live.
                live_queues.insert(nn);
                if (queue_subs.count(nn) == 1) {
                    live_merged_queues.insert(nn);
                }
            }

            live_merged_queues.erase(name);
            live_queues.erase(name);

            queues.erase(name);
            queue_nodes.erase(name);
            queue_subs.erase(name);
        }

    }
}

BOOST_AUTO_TEST_SUITE_END()


/* **********  Test PriorityQueue  ********** */

BOOST_AUTO_TEST_SUITE(test_priority_queue)

BOOST_AUTO_TEST_CASE(test_empty)
{
    using Queue = PriorityQueue<int, std::string>;
    Queue q;
    BOOST_TEST(q.empty() == true);
}

BOOST_AUTO_TEST_CASE(test_single)
{
    using Queue = PriorityQueue<int, std::string>;
    Queue q;

    Queue::Node n1;
    BOOST_TEST(n1.valid() == false);

    q.insert(&n1, 5, "a");

    BOOST_TEST(n1.valid() == true);
    BOOST_TEST(n1.prio() == 5);
    BOOST_TEST(q.empty() == false);
    BOOST_TEST(q.min_prio() == 5);
    BOOST_TEST(q.min_elem() == std::string("a"));

    q.set_prio(&n1, 3);
    BOOST_TEST(n1.prio() == 3);
    BOOST_TEST(q.min_prio() == 3);
    BOOST_TEST(q.min_elem() == std::string("a"));

    q.remove(&n1);
    BOOST_TEST(n1.valid() == false);
    BOOST_TEST(q.empty() == true);
}

BOOST_AUTO_TEST_CASE(test_simple)
{
    using Queue = PriorityQueue<int, char>;
    Queue q;
    Queue::Node nodes[10];

    q.insert(&nodes[0], 9, 'a');
    BOOST_TEST(q.min_prio() == 9);
    BOOST_TEST(q.min_elem() == 'a');

    q.insert(&nodes[1], 4, 'b');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.insert(&nodes[2], 7, 'c');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.insert(&nodes[3], 5, 'd');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.insert(&nodes[4], 8, 'e');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.insert(&nodes[5], 6, 'f');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.insert(&nodes[6], 4, 'g');
    q.insert(&nodes[7], 5, 'h');
    q.insert(&nodes[8], 2, 'i');
    BOOST_TEST(q.min_prio() == 2);
    BOOST_TEST(q.min_elem() == 'i');

    q.insert(&nodes[9], 6, 'j');
    BOOST_TEST(q.min_prio() == 2);
    BOOST_TEST(q.min_elem() == 'i');

    q.set_prio(&nodes[2], 1);
    BOOST_TEST(q.min_prio() == 1);
    BOOST_TEST(q.min_elem() == 'c');

    q.set_prio(&nodes[4], 3);
    BOOST_TEST(q.min_prio() == 1);
    BOOST_TEST(q.min_elem() == 'c');

    q.remove(&nodes[2]);
    BOOST_TEST(q.min_prio() == 2);
    BOOST_TEST(q.min_elem() == 'i');

    q.remove(&nodes[8]);
    BOOST_TEST(q.min_prio() == 3);
    BOOST_TEST(q.min_elem() == 'e');

    q.remove(&nodes[4]);
    q.remove(&nodes[1]);
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'g');

    q.remove(&nodes[3]);
    q.remove(&nodes[9]);
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'g');

    q.remove(&nodes[6]);
    BOOST_TEST(q.min_prio() == 5);
    BOOST_TEST(q.min_elem() == 'h');

    BOOST_TEST(q.empty() == false);
    q.clear();
    BOOST_TEST(q.empty() == true);
}

BOOST_AUTO_TEST_CASE(test_increase_prio)
{
    using Queue = PriorityQueue<int, char>;

    Queue q;
    Queue::Node n1;

    q.insert(&n1, 5, 'a');
    q.set_prio(&n1, 8);
    BOOST_TEST(n1.prio() == 8);
    BOOST_TEST(q.min_prio() == 8);

    q.clear();

    Queue::Node n2, n3, n4;

    q.insert(&n1, 9, 'A');
    q.insert(&n2, 4, 'b');
    q.insert(&n3, 7, 'c');
    q.insert(&n4, 5, 'd');
    BOOST_TEST(q.min_prio() == 4);
    BOOST_TEST(q.min_elem() == 'b');

    q.set_prio(&n2, 8);
    BOOST_TEST(n2.prio() == 8);
    BOOST_TEST(q.min_elem() == 'd');
    BOOST_TEST(q.min_prio() == 5);

    q.set_prio(&n3, 10);
    BOOST_TEST(n3.prio() == 10);
    BOOST_TEST(q.min_elem() == 'd');

    q.remove(&n4);
    BOOST_TEST(q.min_elem() == 'b');

    q.remove(&n2);
    BOOST_TEST(q.min_prio() == 9);
    BOOST_TEST(q.min_elem() == 'A');

    q.remove(&n1);
    BOOST_TEST(q.min_elem() == 'c');
    BOOST_TEST(q.min_prio() == 10);

    q.remove(&n3);
    BOOST_TEST(q.empty() == true);
}

BOOST_AUTO_TEST_CASE(test_random)
{
    using Queue = PriorityQueue<int, int>;
    Queue q;

    const int num_elem = 1000;
    std::vector<std::tuple<std::unique_ptr<Queue::Node>, int, int>> elems;
    int next_data = 0;

    std::mt19937 rng(34567);

    auto check = [&q,&elems]() {
        int min_prio = q.min_prio();
        int min_data = q.min_elem();
        int best_prio = INT_MAX;
        bool found = false;
        for (const auto& v : elems) {
            int this_prio = std::get<1>(v);
            int this_data = std::get<2>(v);
            best_prio = std::min(best_prio, this_prio);
            if ((this_prio == min_prio) && (this_data == min_data)) {
                found = true;
            }
        }
        BOOST_TEST(found == true);
        BOOST_TEST(min_prio == best_prio);
    };

    for (int i = 0; i < num_elem; ++i) {
        ++next_data;
        int prio = std::uniform_int_distribution<>(0, 1000000)(rng);
        std::unique_ptr<Queue::Node> nptr(new Queue::Node);
        q.insert(nptr.get(), prio, next_data);
        elems.push_back(std::make_tuple(std::move(nptr), prio, next_data));
        check();
    }

    for (int i = 0; i < 10000; ++i) {
        int p = std::uniform_int_distribution<>(0, num_elem - 1)(rng);
        Queue::Node* node = std::get<0>(elems[p]).get();
        int prio = std::get<1>(elems[p]);
        prio = std::uniform_int_distribution<>(0, 1000000)(rng);
        q.set_prio(node, prio);
        std::get<1>(elems[p]) = prio;
        check();

        p = std::uniform_int_distribution<>(0, num_elem - 1)(rng);
        node = std::get<0>(elems[p]).get();
        q.remove(node);
        elems.erase(elems.begin() + p);
        check();

        ++next_data;
        prio = std::uniform_int_distribution<>(0, 1000000)(rng);
        std::unique_ptr<Queue::Node> nptr(new Queue::Node);
        q.insert(nptr.get(), prio, next_data);
        elems.push_back(std::make_tuple(std::move(nptr), prio, next_data));
        check();
    }

    for (int i = 0; i < num_elem; ++i) {
        int p = std::uniform_int_distribution<>(0, num_elem - 1 - i)(rng);
        Queue::Node* node = std::get<0>(elems[p]).get();
        q.remove(node);
        elems.erase(elems.begin() + p);
        if (! elems.empty()) {
            check();
        }
    }

    BOOST_TEST(q.empty() == true);
}

BOOST_AUTO_TEST_SUITE_END()