/*
 * Unit tests for PriorityQueue data structure.
 *
 * 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 <string>
#include <tuple>
#include <vector>

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

#include "priority_queue.hpp"


BOOST_AUTO_TEST_SUITE(test_priority_queue)

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

BOOST_AUTO_TEST_CASE(test_single)
{
    using Queue = mwmatching::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 = mwmatching::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 = mwmatching::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 = mwmatching::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()