#include <fstream>
#include <iostream>
#include <queue>
#include <stack>
#include <string>
#include <unordered_set>

const string ALPHABET = "abcdefghijklmnopqrstuvwxyz";

const char *const FORMAT_UNDERSCORE = "\033[4m";
const char *const END_FORMATTING = "\033[0m";
const char *const DICTIONARY_PATH = "./dictionary.txt";

std::string input(const char *message) {
    if (message != nullptr)
        std::cout << message;

    std::cout << FORMAT_UNDERSCORE;
    std::flush(std::cout);

    std::string ret;
    std::getline(std::cin, ret);
    std::cout << END_FORMATTING;
    return ret;
}

std::string fileRead(const std::string &filePath) {
    std::ifstream file(filePath, std::ios::binary);
    if (!file.is_open())
        throw std::runtime_error("File couldn't be found");

    std::string content;
    const int BUF_LENGTH = 1024;
    char buf[BUF_LENGTH];
    while (file.read(buf, BUF_LENGTH))
        content.append(buf, file.gcount());
    content.append(buf, file.gcount());

    if (!file.eof() && file.fail())
        throw std::runtime_error("Error: Failed to read the file '" + filePath +
                                 "'");

    return content;
}

std::unordered_set<std::string> readDictionary() {
    std::string fileContent = fileRead(DICTIONARY_PATH);
    std::unordered_set<std::string> set;
    size_t last = 0, idx;
    while ((idx = fileContent.find('\n', last)) != std::string::npos) {
        std::string sub = fileContent.substr(last, idx - last);
        set.insert(sub);
        last = idx + 1;
    }

    set.insert(fileContent.substr(last));
    return set;
}

int main() {
    std::cout << "Welcome to TDDD86 Word Chain.\n"
              << "If you give me two English words, I will transform the\n"
              << "first into the second by changing one letter at a time.\n\n"
              <<"Please type two words: ";
    std::flush(std::cout);

    std::unordered_set<std::string> dictionary = readDictionary();
    std::string userInput = input(nullptr);
    size_t wordSep = userInput.find(' ');
    std::string wordOne = userInput.substr(0, wordSep);
    std::string wordTwo = userInput.substr(wordSep + 1);
    std::cout << "Chain from " << wordTwo << " to " << wordOne << std::endl;

    std::cout << "Have a nice day!" << std::endl;
    return 0;
}