#ifndef _2Q_CACHE_H_
#define _2Q_CACHE_H_
#include <iostream>
#include <unordered_map>
#include <list>


class TwoCache {
private:
    //2 LRU caches

    size_t cpct_q1;
    std::unordered_map<int, std::list<int>::iterator> umap1;
    std::list <int> q1;                                                 //fast queue - the most popular pages

    size_t cpct_q2;
    std::unordered_map<int, std::list<int>::iterator> umap2;
    std::list <int> q2;                                                 //slow queue - if page asked at the first time put it to q2, if itasked from q2 it put it to q1,

public:
    TwoCache(size_t q1sz, size_t q2sz): cpct_q1(q1sz), cpct_q2(q2sz) {} //ctor

    void put_page(int id) {
        if (umap1.find(id) != umap1.end()) {                            //page is in fast queue in the end, nothing to do (fast case)
            std::cout<<"fast case\n";

            return;
        } else if (umap2.find(id) != umap2.end()) {
            q2.erase(umap2[id]);                                        //if page is in slow put it in fast
            if (q1.size() < cpct_q1) {
                q1.push_front(id);
                umap1[id] = q1.begin();
            } else {
                int lru_page = q1.back();                               //if fast is overflow - delete
                q1.pop_back();
                umap1.erase(lru_page);
                q1.push_front(id);
                umap1[id] = q1.begin();
            }

            return;
        } else if (q2.size() < cpct_q2) {                               //if not in cache put it in slow
            q2.push_front(id);
            umap2[id] = q2.begin();

            return;
        } else {                                                        //if slow is overflow - pop
            int lru_page = q2.back();
            q2.pop_back();
            umap2.erase(lru_page);  
            q2.push_front(id);
            umap2[id] = q2.begin();

            return;
        }
    }

    void info() {
        std::cout << "q1 (the most usable): ";
        for (auto i = q1.begin(); i != q1.end(); i++) {
            std::cout << *i << " ";
        }
        std::cout << "\nq2 (Less usable): ";
        for (auto i = q2.begin(); i != q2.end(); i++) {
            std::cout << *i << " ";
        }
    }
};

#endif