main.cpp

#include <iostream>
#include <chrono>
#include "rsakey.h"
#include "bigint.h"
#include "rsaengine.h"
#include "message.h"
using namespace std;

int main() {

    // pointeri la obiectele active
    RSAKey* currentKey = nullptr;
    RSAEngine* engine = nullptr;
    Message* msg = nullptr;

    int choice;


   cout<< RSAKey::modInv(12,5)<<endl;

    
    do {
        cout << "\n=== RSA Cryptosystem ===" << endl;
        cout << "1. Generate RSA key" << endl;
        cout << "2. Display key" << endl;
        cout << "3. Change owner" << endl;
        cout << "4. Enter message" << endl;
        cout << "5. Encrypt message" << endl;
        cout << "6. Decrypt message" << endl;
        cout << "7. Display message" << endl;
        cout << "8. Benchmark" << endl;
        cout << "9. Toggle hex/decimal" << endl;
        cout << "10. Exit" << endl;
        cout << "Choice: ";
        cin >> choice;

        switch (choice) {

        // GENERARE CHEIE
        // citesc p si q in hex (sunt numere prime), plus un owner name
        // din p si q se face: n = p*q, phi = (p-1)*(q-1), d = modInv(e, phi)
        // engine-ul e legat de cheie, il recreez si pe el
        case 1: {
        if (currentKey != nullptr) {
            char answer;
            cout << "A key already exists for " << currentKey->getOwner() << ". Overwrite? (y/n): ";
            cin >> answer;
            if (answer != 'y') break;
            delete engine;
            delete currentKey;
        }

        cout << "Select key size:" << endl;
        cout << "1. Small  (p=101, q=103)" << endl;
        cout << "2. Medium (p=257, q=263)" << endl;
        cout << "3. Large  (p=1009, q=1013)" << endl;
        cout << "Choice: ";
        
        int keyChoice;
        cin >> keyChoice;

        BigInt p, q;
        switch (keyChoice) {

            //realmente vorbind tind sa mentionez ca alegerea acestor p si q este una oribila pentru ca sunt ft close
            //ele fiind close pot fi sparte instant folosind factorizarea fermat ( care incepe sa itereze de la a = sqrt n)
            //alegerea acestora este in scop pur demonstrativ pentru functionalitatea aplcaitiei    
            case 1:
             p = BigInt(101); q = BigInt(103); break;
            case 2:
            
            p = BigInt(257); q = BigInt(263); break;
            case 3:
             p = BigInt(1009); q = BigInt(1013); break;

            default: cout << "Invalid choice." << endl; break;
        }

        string owner;
        cout << "Owner: ";
        cin >> owner;

        currentKey = new RSAKey(p, q, owner.c_str());
        currentKey->generatePrivateKey();
        engine = new RSAEngine(currentKey);

        cout << "Key generated successfully!" << endl;
        cout << *currentKey;
        break;
}

        // AFISARE CHEIE
        // operator<< pe RSAKey — afiseaza owner, n, e, d, bitSize
        case 2: {
            if (!currentKey) { cout << "No key exists. Generate one first." << endl; break; }
            cout << *currentKey;
            break;
        }

        // SCHIMBA OWNER
        // operator>> pe RSAKey — citeste un nou owner name
        case 3: {
            if (!currentKey) { cout << "No key exists. Generate one first." << endl; break; }
            cin >> *currentKey;
            cout << "Owner changed to: " << currentKey->getOwner() << endl;
            break;
        }

        // INTRODU MESAJ
        // creez un obiect Message din textul introdus
        // getline ca sa pot citi si spatii, cin.ignore() ca sa consum \n-ul ramas de la cin >> choice
        case 4: {
            if (msg != nullptr) {
                char answer;
                cout << "A message already exists: \"" << msg->getText() << "\". Overwrite? (y/n): ";
                cin >> answer;
                if (answer != 'y') break;
                delete msg;
            }

            string input;
            cout << "Message: ";
            cin.ignore();
            getline(cin, input);

            msg = new Message(input.c_str());
            cout << "Message saved." << endl;
            break;
        }

        // CRIPTARE
        // toBlocks() transforma fiecare caracter in BigInt: 'H' -> BigInt(72), 'e' -> BigInt(101), etc imi ia codif ascii
        // apoi fiecare bloc se cripteaza: bloc = bloc^e mod n (prin engine->encrypt care apeleaza modpow)
        // rezultatul e un numar mare pe fiecare pozitie — textul original nu mai e vizibil (il cripteaza, that s the point)
        case 5: {
            if (!currentKey) { cout << "No key exists. Generate one first." << endl; break; }
            if (!msg) { cout << "No message exists. Enter one first." << endl; break; }
            if (msg->getIsEncrypted()) { cout << "Message is already encrypted." << endl; break; }
            // aici zice ca e deja criptata, probabil la proiecte viitoare o sa modific pentru double encrypt cu AES
            //sau o voi lasa doar flag de criptare RSA 

            msg->toBlocks(); // "Hello" -> [72, 101, 108, 108, 111] de ex

            BigInt* blocks = msg->getBlocks(); // pointer la array-ul intern
            for (int i = 0; i < msg->getBlockCount(); i++) {
                blocks[i] = engine->encrypt(blocks[i]); // blocks[i] = blocks[i]^e mod n
            }
            msg->setEncrypted(true);

            cout << "Message encrypted! (" << msg->getBlockCount() << " blocks)" << endl;
            break;
        }

        // DECRIPTARE
        // operatia inversa: fiecare bloc se decripteaza: bloc = bloc^d mod n
        // fromBlocks() reconstruieste textul din blocurile decriptate: BigInt(72) -> 'H', etc
        case 6: {
            if (!currentKey) { cout << "No key exists. Generate one first." << endl; break; }
            if (!msg) { cout << "No message exists. Enter one first." << endl; break; }
            if (!msg->getIsEncrypted()) { cout << "Message is not encrypted." << endl; break; }

            BigInt* blocks = msg->getBlocks();
            for (int i = 0; i < msg->getBlockCount(); i++) {
                blocks[i] = engine->decrypt(blocks[i]); // blocks[i] = blocks[i]^d mod n
            }
            msg->fromBlocks(); // [72, 101, 108, 108, 111] -> "Hello"

            cout << "Decrypted message: " << msg->getText() << endl;
            break;
        }

        // AFISARE MESAJ
        // operator<< pe Message — daca e criptat, afiseaza blocurile ca numere mari
        // daca nu e criptat, afiseaza textul normal
        case 7: {
            if (!msg) { cout << "No message exists." << endl; break; }
            cout << *msg << endl;
            break;
        }

        // BENCHMARK
        // operator>> pe RSAEngine — citeste nr de iteratii, ruleaza modpow de atatea ori
        // afiseaza media geometrica a timpilor (prin operator<< intern)
        case 8: {
            if (!engine) { cout << "No key/engine exists." << endl; break; }
            cin >> *engine;
            break;
        }

        // TOGGLE HEX/DEC
        // schimba modul de afisare pentru TOATE BigInt-urile (e static)
        // hex: afiseaza in baza 16 (ex: 1A2B)
        // dec: afiseaza in baza 10 (ex: 6699)
        case 9: {
            if (BigInt::getHexmode()) {
                BigInt::setDec();
                cout << "Display mode: decimal" << endl;
            } else {
                BigInt::setHex();
                cout << "Display mode: hexadecimal" << endl;
            }
            break;
        }

        case 10:
            cout << "Exiting." << endl;
            break;

        default:
            cout << "Invalid option." << endl;
            break;
        }

    } while (choice != 10);

    // cleanup — eliberez tot ce am alocat cu new
    delete currentKey;
    delete engine;
    delete msg;

    return 0;
}