// Decode.cpp : This file contains the 'main' function. Program execution begins and ends there.

#include <iostream>
using namespace std;

string encrypt(const string& s, int n) {
    string new_string = "";

    for (int i = 0; i < s.length(); i++)
    {
        if (s[i] == ' ')
        {
            new_string += ' ';
            continue;
        }

        int how_far_away = s[i] - 'a';
        int new_character = (how_far_away + n) % 25;
        new_string += 'a' + new_character;
    }

    return new_string;

}

string remove_first_word(const string& s) {
    string new_string = "";

    for (int i = 0; i < s.length(); i++)
    {

        if (s[i] == ' ')
        {
            for (int j = i + 1; j < s.length(); j++) {
                // Start one position to the right of the space
                new_string += s[j];
            }

            return new_string;
        }
    }

    return new_string; //returns empty if there is only one word in the string
}

string first_word(const string& s) {
    string new_string = "";

    for (int i = 0; i < s.length(); i++)
    {
        if (s[i] != ' ')
        {
            new_string += s[i];
        }

        else
        {
            return new_string;
        }
    }

    return new_string; //Returns if this is the last word in the string
}

bool check_word(string s, const string& key)
{
    if (s.length() != key.length()) //First check the if the lengths of the strings even match
    {
        return false;
    }

    for (int i = 0; i < s.length(); i++) //Then check each character
    {
        if (s[i] != key[i])
        {
            return false;
        }
    }

    return true;
}

string decode(const string& code, const string& key)
{
    for (int i = 0; i < 26; i++)
    {
        string decoded_string = encrypt(code, i);
        string dummy_string = decoded_string; // We need a copy string that we can remove words from
        string decoded_word = first_word(dummy_string);

        while (!check_word(decoded_word, key) && (decoded_word.length() > 0)) //Remove_first_word keeps getting rid of the first word so if it isn't the right key, it will return a null string-- so must account for that
        {
            dummy_string = remove_first_word(dummy_string);
            decoded_word = first_word(dummy_string);
        }

        if (check_word(decoded_word, key))
        {
            return decoded_string;
        }
    }
}

int main()
{
    string s = "YoonA eats";
    string x = "YoonA";
    string y = remove_first_word(s);
    string z = first_word(s);
    cout << y << endl;
    cout << z << endl;

    string encoded = "ojdl jt tnbsu jg if dbo tpmwf uijt";
    cout << encoded << endl;
    string decoded = decode(encoded, "smart");
    cout << encoded << endl;
    cout << decoded << endl;  // prints "nick is smart if he can solve this"

}