#include <iostream>
#include <stdio.h>
#include <time.h>

using namespace std;

void encryptCaesarWithShift(char* message, char* encryptedMessage,char* shift,char* letters) {
    char newLetters[26];
    int i, j;
    int currentIndex = 1;
    newLetters[0] = shift[0];
    for (i = 1; i < 5; i++) {
        if (newLetters[0] != shift[i] && newLetters[1] != shift[i] && newLetters[2] != shift[i] && newLetters[3] != shift[i] && newLetters[4] != shift[i]) {
            newLetters[currentIndex] = shift[i];
            currentIndex++;
        }
    }
    for (i = 0; i < 26; i++) {
        if (letters[i] != shift[0] && letters[i] != shift[1] && letters[i] != shift[2] && letters[i] != shift[3] && letters[i] != shift[4]) {
            newLetters[currentIndex] = letters[i];
            currentIndex++;
        }

    }

    for (i = 0; message[i] != '\0'; ++i) {
        if (message[i] == ' ') {
            encryptedMessage[i] = ' ';
        }
        else {
            encryptedMessage[i] = newLetters[0];
            for (j = 0; message[i] != letters[j]; ++j) {
                encryptedMessage[i] = newLetters[j + 1];
            }
        }

    }
    encryptedMessage[i] = '\0';
}

void decryptCaesarWithShift(char* message, char* decryptedMessage, char* shift, char* letters) {
    //printf("SHIFT : %s", shift);


    char newLetters[26];
    int i, j;
    int currentIndex = 1;
    newLetters[0] = shift[0];
    for (i = 1; i < 5; i++) {
        if (newLetters[0] != shift[i] && newLetters[1] != shift[i] && newLetters[2] != shift[i] && newLetters[3] != shift[i] && newLetters[4] != shift[i]) {
            newLetters[currentIndex] = shift[i];
            currentIndex++;
        }

    }
    for (i = 0; i < 26; i++) {
        if (letters[i] != shift[0] && letters[i] != shift[1] && letters[i] != shift[2] && letters[i] != shift[3] && letters[i] != shift[4]) {
            newLetters[currentIndex] = letters[i];
            currentIndex++;
        }


    }
    //printf("LIBRARY : %s", newLetters);
    for (i = 0; message[i] != '\0'; ++i) {
        if (message[i] == ' ') {
            decryptedMessage[i] = ' ';
        }
        else {
            decryptedMessage[i] = letters[0];
            for (j = 0; message[i] != newLetters[j]; ++j) {
                decryptedMessage[i] = letters[j + 1];
            }
        }

    }
    decryptedMessage[i] = '\0';
    //printf("Decrypted: %s\n", decryptedMessage);

}
int main()
{
    char letters[26] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z' };
    char shift[6];
    char message[100];
    char encryptedMessage[100];
    char decryptedMessage[100];
    char a, b, c,d,e;
    int i;
    int rightWord = 0;
    printf("Enter a message to encrypt: \n");
    gets_s(message);
    do {
        printf("Enter five letters long shift \n");
        gets_s(shift);
    } while (strlen(shift) != 5);

    encryptCaesarWithShift(message, encryptedMessage, shift, letters);
    printf("%s", encryptedMessage);

    decryptCaesarWithShift(encryptedMessage, decryptedMessage, shift, letters);
    printf("Decrypted: %s", decryptedMessage);
    clock_t tStart = clock();

        for (a = 'a'; a <= 'z'; a++) {
            for (b = 'a'; b <= 'z'; b++) {
                for (c = 'a'; c <= 'z'; c++) {
                    for (d = 'a'; d <= 'z'; d++) {
                        for (e = 'a';e <= 'z'; e++) {
                            shift[0] = a;
                            shift[1] = b;
                            shift[2] = c;
                            shift[3] = d;
                            shift[4] = e;

                            decryptCaesarWithShift(encryptedMessage, decryptedMessage, shift, letters);
                            for (i = 0; message[i] != '\0'; i++) {
                                if (message[i] == decryptedMessage[i]) {
                                    rightWord = 1;
                                }
                                else {
                                    rightWord = 0;
                                    break;
                                }
                            }
                            if (rightWord == 1) {
                                printf("Znalazlem\n");
                                printf("%c%c%c%c%c\n", a, b, c, d, e);
                                printf("Decrypted message: %s\n", decryptedMessage);
                                rightWord = 0;
                            }

                        }
                    }


                }
            }
        }

    printf("Time taken: %.30fs\n", (double)(clock() - tStart) / CLOCKS_PER_SEC);
    return 0;
}