#include <iostream>
#include <list>
#include <cstring>
using namespace std;

class HashTable {
private:
    static const int hashGroups = 10; //количество листов, которое используем
    list<pair<int, string>> table[hashGroups]; //пара будет хранить ключ
    // List 1, Index 0, List 2, Index 1 ...

public:
    bool isEmpty() const;
    int hashFunction(int key);
    void insertItem(int key, string value);
    void removeItem(int key);
    string searchTable(int key);
    void printTable();
};

bool HashTable::isEmpty() const {
    int sum{};
    for (int i{}; i < hashGroups; i++) {
        sum += table[i].size();//Ищем размер
    }

    if (!sum) {
        return true;
    }
    return false;
}

int HashTable::hashFunction(int key) {
    return key % hashGroups; //Key: 905, in return, this function will spit on 5.
}

void HashTable::insertItem(int key, string value) {
    int hashValue = hashFunction(key);
    auto& cell = table[hashValue];
    auto bItr = begin(cell);
    bool keyExists = false;
    for (; bItr != end(cell); bItr++) {
        if (bItr->first == key) {
            keyExists = true;
            bItr->second = value;
            cout << endl << "[WARNING] Key exists. Value replaced." << endl << endl;
            break;
        }
    }

    if (!keyExists) {
        cell.emplace_back(key, value);
    }
    return;
}

void HashTable::removeItem(int key) {
    int hashValue = hashFunction(key);
    auto& cell = table[hashValue];
    auto bItr = begin(cell);
    bool keyExists = false;
    for (; bItr != end(cell); bItr++) {
        if (bItr->first == key) {
            keyExists = true;
            bItr = cell.erase(bItr);
            cout << "[INFO] Item removed." << endl;
            break;
        }
    }

    if (!keyExists) {
        cout << "[WARNING] Key is not found. Pair is not removed." << endl;
    }
    return;
}

void HashTable::printTable() {
    for (int i{}; i < hashGroups; i++) {
        if (table[i].size() == 0) continue;

        auto bItr = table[i].begin();
        for (; bItr != table[i].end(); bItr++) {
            cout << "[INFO] Key: " << bItr->first << " Value: " << bItr->second << endl;
        }
    }
    return;
}

int main() {
    HashTable HT;

    if (HT.isEmpty()) {
        cout << "Correct answer. Good job. ";
    }
    else {
        cout << "Oh, we need to check out code." << endl;
    }

    HT.insertItem(905, "Jim");
    HT.insertItem(201, "Tom");
    HT.insertItem(332, "Bob");
    HT.insertItem(124, "Sally");
    HT.insertItem(107, "Sandy");
    HT.insertItem(929, "Barb");
    HT.insertItem(928, "Rob");
    HT.insertItem(928, "Rick");

    HT.printTable();

    HT.removeItem(332);
    HT.removeItem(100);

    if (HT.isEmpty()) {
        cout << "Oh, we need to check out code." << endl;
    }
    else {
        cout << endl << "Correct answer. Good job. " << endl;
    }

    return 0;
}