#include <iostream>
#include <random>

#include "Kernel.h"
#include "MMU.h"

static int MAX_PROC = 10;
static int PAGE_N = 100;
static int PROC_CREATION_INTERVAL = 100;
static int WORKING_SET_SIZE = 15;

int main() {
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<unsigned int> page_table_distribution(500, 1000), lifetime_distribution(50, 500), access_type_distr(1, 10);

    Kernel kernel(MAX_PROC, List<PhysicalPage>(), List<PhysicalPage>());
    unsigned int elapsed_time = 0, new_proc_time = 0, new_ppn;

    for (new_ppn = 1; new_ppn <= PAGE_N; ++new_ppn) {
        kernel.free_pages.insert_head(new PhysicalPage(new_ppn));
    }

    for (int i = 0; i < kernel.RunQ.capacity(); ++i) {
        kernel.RunQ.emplace_back(i, std::vector(page_table_distribution(gen), PTE()), lifetime_distribution(gen),
                                 WORKING_SET_SIZE);
    }

    for (int i = 0; i < 10'000; ++i) {
        const int process_index = i % kernel.RunQ.size();

        if (kernel.RunQ.empty()) {
            break;
        }

        std::uniform_int_distribution<unsigned int> index_distribution;
        for (int j = 0; j < 30; ++j) {
            const AccessType access_type = access_type_distr(gen) == 1 ? WRITE : READ;

            if (access_type_distr(gen) == 1) {
                index_distribution = std::uniform_int_distribution<unsigned int>(0, kernel.RunQ.at(process_index).page_table.size() - 1);
                const unsigned int table_index = index_distribution(gen);
                MMU::access(kernel, &kernel.RunQ.at(process_index).page_table, table_index, access_type);
            }
            else {
                index_distribution = std::uniform_int_distribution<unsigned int>(0, kernel.RunQ.at(process_index).working_set.size() - 1);
                const unsigned int table_index = kernel.RunQ.at(process_index).working_set[index_distribution(gen)];
                MMU::access(kernel, &kernel.RunQ.at(process_index).page_table, table_index, access_type);
            }
        }

        ++elapsed_time;
        ++new_proc_time;

        kernel.stat_update();

        if (kernel.RunQ.at(process_index).is_finished(elapsed_time)) {
            std::cout << std::format("[kernel:remove_current_process] Cleaning up process id {}", kernel.RunQ.at(process_index).id) << std::endl;

            PhysicalPage *curr, *cached_next;
            unsigned int j;
            const unsigned int cached_len = kernel.busy_pages.get_num();
            for (curr = kernel.busy_pages.get_head(), j = 0;
                 curr && j < cached_len;
                 curr = cached_next, ++j) {
                cached_next = curr->next;
                if (curr->PT == &kernel.RunQ.at(process_index).page_table) {
                    std::cout << std::format("[kernel:remove_current_process] Found ppn #{}, freeing it", curr->PPN) << std::endl;

                    kernel.busy_pages.remove(curr);

                    curr->PT = nullptr;

                    kernel.free_pages.insert_tail(curr);
                }
            }
            kernel.RunQ.erase(kernel.RunQ.begin());

            if (new_proc_time >= PROC_CREATION_INTERVAL) {
                kernel.RunQ.emplace_back(new_ppn, std::vector(page_table_distribution(gen), PTE()), lifetime_distribution(gen), WORKING_SET_SIZE);
                ++new_ppn;
                new_proc_time = 0;
            }
        }

        {
            unsigned int busy_stat = kernel.busy_pages.get_num(), free_stat = kernel.free_pages.get_num();
            std::cout << std::format("[main:metrics] Memory usage stats: busy {}, free {}, total {}", busy_stat, free_stat, free_stat + busy_stat) << std::endl;
        }

        if (kernel.RunQ.empty()) {
            std::cout << "[main:scheduling] No processes left to execute!" << std::endl;
        }
    }

    return 0;
}