#include <iostream>



using namespace std;

int transferLetter(const char*, int const, char const);

int* encoding(char const*, char const*);

char* decoding(int const*, int, char const*);

char* createRule(const char*);

void createRuleTest();

void encodingTests();

void decodingTests();

bool equals(const char*, const char*);

bool equals(const int*, const int*, int);



int main()

{
    createRuleTest();

    encodingTests();

    decodingTests();

    system("pause");

}
int getlength(const char* source)
{
    if (source == nullptr)
    {
        throw std::invalid_argument("String cannot be null!");
    }

    int length = 0;
    while (source[length])
    {
        length++;
    }
    return length;
}
bool isAlphabet(char symbol)
{
    return 'A' <= symbol && symbol <= 'Z' || 'a' <= symbol && symbol <= 'z';
}
bool isLower(char symbol)
{
    return 'a' <= symbol && symbol <= 'z';
}
char toUpper(char symbol)
{
    if (isAlphabet(symbol) && isLower(symbol))
    {
        return symbol - 32;
    }
    return symbol;
}
char* createRule(const char* source)
{
    for (int i = 0; i < getlength(source); i++)
        for (int j = getlength(source) - 1; j >= 0; j--)
        {
            swap(source[j], source[i]);
        }

    return nullptr;

}
int* encoding(const char* source, const char* rule)

{
    int* code = new int[getlength(source)+1];

    int transfer = 1;

    for(int i = 0; i < (getlength(source) + 1); i++)
        for (int j = 0; j < (getlength(rule) + 1); j++)
        {
             if (isAlphabet(source[i]))
             {
                code[i] = transferLetter(rule, getlength(rule), toUpper(source[i])) + 1;
             }
             else
             {
                 code[i] = source[i];
             }
        }
    return nullptr;
}
char* decoding(const int* source, int size, const char* rule)
{

    // TODO decoding logic here

    return nullptr;

}
int transferLetter(const char* array, int const size, char const value)
{
    for (int i = 0; i < size; i++)
    {
        if (array[i] == value)
        {
            return i;
        }
    }
}


bool equals(const char* lhs, const char* rhs)
{
    int i = 0;

    while (lhs[i])
    {
        if (lhs[i] != rhs[i])
        {
            return false;
        }
        i++;
    }
    return true;
}

bool equals(const int* lhs, const int* rhs, int size)

{
    for (int i = 0; i < size; i++)
    {
        if (lhs[i] != rhs[i])
        {
            return false;
        }
    }
    return true;
}



void createRuleTest()

{

    const char* source = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    const char* actual = createRule(source);

    const char* expected = "ZYXWVUTSRQPONMLKJIHGFEDCBA";

    cout << "Test for creation rule " << (equals(actual, expected) ? "Passed." : "Failed.") << endl;

}



void encodingTests()

{

    const char* source = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";



    const char* rule = createRule(source);



    int* encode = encoding("Learn C++!", rule);



    cout << "Test for encoding " << (equals(encode, new int[10]{ 15, 22, 26, 9, 13, 32, 24, 43, 43, 33 }, 10) ? "Passed." : "Failed.") << endl;



    encode = encoding("Cogito, ergo sum! (Descartes)", rule);



    cout << "Test for encoding " << (equals(encode, new int[29]{ 24, 12, 20, 18, 7, 12, 44, 32, 22, 9, 20, 12, 32, 8, 6, 14, 33, 32, 40, 23, 22, 8, 24, 26, 9, 7, 22, 8, 41 }, 29) ? "Passed." : "Failed.") << endl;



}



void decodingTests()

{

    const char* source = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";



    const char* rule = createRule(source);



    char* decode = decoding(new int[10]{ 15, 22, 26, 9, 13, 32, 24, 43, 43, 33 }, 10, rule);



    cout << "Test for decoding " << (equals(decode, "Learn C++!") ? "Passed." : "Failed.") << endl;



    decode = decoding(new int[29]{ 24, 12, 20, 18, 7, 12, 44, 32, 22, 9, 20, 12, 32, 8, 6, 14, 33, 32, 40, 23, 22, 8, 24, 26, 9, 7, 22, 8, 41 },29, rule);



    cout << "Test for decoding " << (equals(decode, "Cogito, ergo sum! (Descartes)") ? "Passed." : "Failed.") << endl;

}