/******************************************************************************
 * This program compares recursion to iteration in computing palindromes.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

#undef NDEBUG

#include "Utils.hpp"
#include <clocale>
#include <codecvt>
#include <iostream>
#include <regex>
#include <string>
#include <vector>

std::locale utf8loc(std::locale(), new std::codecvt_utf8<wchar_t>);
using namespace Utils;
using namespace std;

static const vector<wstring> TEST_CASES = {L"Hannah", L"Able was I ere I saw Elba", L"A man, a plan, a canal – Panama", L"T. Eliot, top bard, notes putrid tang emanating, is sad; I'd assign it a name: gnat dirt upset on drab pot toilet.", L"This is not a palindrome!"};

bool palindrome_recursive0(wstring s) noexcept {
    int const S_LEN = s.length();
    if (S_LEN < 2) {
        return true;
    }
    if ((int)(s[0]) != (int)(s[S_LEN - 1])) {
        return false;
    }
    return palindrome_recursive0(s.substr(1, (S_LEN - 1) - 1));
}

bool palindrome_recursive(wstring s) noexcept {
    wstring s0 = std::regex_replace(s, wregex(L"\\W+"), L"");
    s0 = Utils::tolower(s0);
    return palindrome_recursive0(s0);
}

bool palindrome_iterative(wstring s) noexcept {
    wstring s0 = std::regex_replace(s, wregex(L"\\W+"), L"");
    s0 = Utils::tolower(s0);
    int const S_LEN = s0.length();
    for (int x = 0; x <= (S_LEN - 1) / 2; ++x) {
        if ((int)(s0[x]) != (int)(s0[S_LEN - 1 - x])) {
            return false;
        }
    }
    return true;
}

int main(int argc, char **argv) {
    setlocale(LC_ALL, "en_US.UTF-8");
    wcout.imbue(utf8loc);
    wcin.imbue(utf8loc);

    for (auto s : TEST_CASES) {
        wcout << L"Test Case: " << s << endl;
        bool result = palindrome_recursive(s);
        wcout << L"palindromeRecursive: " << (result ? L"Yes" : L"No") << endl;
        result = palindrome_iterative(s);
        wcout << L"palindromeIterative: " << (result ? L"Yes" : L"No") << endl;
    }
    return 0;
}