#include "Kernel.h"

using std::next;

Kernel::Kernel(const unsigned int RunQ_max_length, const List<PhysicalPage> &free_pages, const List<PhysicalPage> &busy_pages)
: free_pages(free_pages), busy_pages(busy_pages), swapped_page(nullptr) {
    RunQ.reserve(RunQ_max_length);
}

void Kernel::page_fault(PageTable *page_table, const unsigned int idx) {
    PhysicalPage *page = nullptr;
    if (!this->free_pages.is_empty()) {
        page = free_pages.get_head()->prev;
        free_pages.remove(page);
        busy_pages.insert_tail(page);
    } else {
        for (PhysicalPage *curr = busy_pages.get_head();; curr = curr->next) {
            if ((*curr->PT)[curr->idx].R)
                (*curr->PT)[curr->idx].R = false;
            else {
                curr->PT->entries.erase(next(curr->PT->entries.begin(), curr->idx));
                page = curr;
                busy_pages.set_head(curr->next);
                break;
            }
        }
    }

    if (page) {
        (*page_table)[idx].PPN = page->PPN;
        (*page_table)[idx].P = true;
        (*page_table)[idx].R = false;
        (*page_table)[idx].M = false;
    }
}

void Kernel::stat_update() {
    int i;
    PhysicalPage *curr;
    for (i = 0, curr = busy_pages.get_head(); i < 10; ++i, curr = curr->next) {
        if ((*curr->PT)[curr->idx].R)
            (*curr->PT)[curr->idx].R = false;
    }
}