#include <cs50.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

int shift(char c);

int pass = 0;
int d = 0;
int main(int argc, string argv[])
{
    if (argc !=2)
    {
        printf("Usage: .vigenere key\n");
        return 1;
    }

    string key = argv[1];
    //non-ints should return non-0, so string should return 0
    if (atoi(key) != 0)
    {
        printf("Usage: .vigenere key\n");
        return 1;
    }

    if (argc == 2)
    {

        //iterates through the string length of arg 2
        for (int i = 0; i < strlen(argv[1]); i++)
        {
            //if characters in arg 2 are NOT digits, then pass gets 1 point
            if (isdigit(argv[1][i]) == 0)
            {
                //printf("%c\n", argv[1][i]);
                pass++;
            }
            //otherwise the program terminates
            else
            {
                printf("%c\n", argv[1][i]);
                printf("Usage: .vigenere keyword\n");
                return 1;
            }
        }

        if (pass > 0)
        {
            string text = get_string("plaintext: ");
            printf("ciphertext: ");

            for (int i = 0; i < strlen(text); i++)
            {

                    int c = 0;
                //printf("strlenKey: %lu\n", strlen(key));
                //printf("d: %i\n", d);

                   //printf("%c\n", changed);
               if (d >= strlen(key))
                   {
                       d = 0;
                   }

                for (int j = 0; j <= 0; j++)
                   {
                        if (isalpha(text[i]) !=0 )
                        {
                            printf("%i\n", text[i]);
                            printf("%i\n", shift(key[d]));

                            char code_char = shift(key[d]) + text[i];
                            printf("%i\n", code_char);
                            if (code_char > 122)
                            {
                                code_char = (code_char) - 26;
                            }
                            printf("%i\n", code_char);
                            printf("%c", code_char);
                            c++;
                            d = c + d;
                        }

                       else
                       {
                           char code_char = text[i];
                           printf("%c", code_char);
                       }

                       //printf("key: %c\n", key[j]);
                   }


            }
             printf("\n");
        }
        //if pass is more than 0, which means all characters are digits, prints success
        if (pass == 0)
        {
            printf("Usage: .vigenere keyword\n");
            return 1;
        }

    }



    return 0;
}

int shift(char c)
{
    if (isalpha(c) != 0)
    {
       if (isupper(c) != 0)
       {
           int shift_by = c-65;
           return shift_by;
       }
        if (islower(c) != 0)
        {
            int shift_by = c-97;
            return shift_by;
        }
    }
    else
    {
        return 1;
    }
    return 0;
}