#include "token.hpp"
#include <chrono>
#include <curl/curl.h>
#include <format>
#include <fstream>
#include <iostream>
#include <regex>

Token::Token(const std::string &iTokenFilePath, const std::string &iUsername, const std::string &iPassword)
    : mFilePath{iTokenFilePath}, mUsername{iUsername}, mPassword{iPassword}, mToken{getValidToken()} {}

std::string Token::toString() const { return mToken; }

std::string Token::getValidToken() const {
    refreshToken();
    std::ifstream token_file(mFilePath);
    std::string line;
    std::getline(token_file, line);
    std::string token = line.substr(0, line.find(" "));
    return token;
}

void Token::refreshToken() const {
    std::ifstream token_file{mFilePath};
    std::string line;
    std::getline(token_file, line);
    if (line.empty()) {
        writeNewTokenToFile();
    } else {
        long expire_at = std::stoull(line.substr(line.find(" ") + 1));
        if (std::chrono::duration_cast<std::chrono::seconds>(std::chrono::utc_clock::now().time_since_epoch())
                .count() >= expire_at) {
            writeNewTokenToFile();
        }
    }
}

void Token::writeNewTokenToFile() const {
    std::string aToken{getValidTokenWithApi()};
    if (not aToken.empty()) {
        writeTokenToFile(aToken);
    }
}

void Token::writeTokenToFile(const std::string &iToken) const {
    std::ofstream token_file{mFilePath};
    std::chrono::seconds expires_at = getCurrentTime() + std::chrono::hours(24);
    token_file << iToken << " " << expires_at.count() << '\n';
}

std::string Token::getValidTokenWithApi() const {
    CURL *curl = curl_easy_init();
    std::string token_info;
    if (curl) {
        curl_easy_setopt(curl, CURLOPT_URL, "https://oauth.battle.net/token");
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curlCallbackStringOutput);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &token_info);
        curl_easy_setopt(curl, CURLOPT_USERPWD, std::format("{}:{}", mUsername, mPassword).data());
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "grant_type=client_credentials");
        CURLcode result_code;
        result_code = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
        if (result_code != CURLE_OK) {
            std::cerr << "ERROR: token request failed" << std::endl;
            std::exit(EXIT_FAILURE);
        }
    }

    return extractFirstMatchRegex(token_info, "\"access_token\":\"(\\w+)\"");
}

std::chrono::seconds Token::getCurrentTime() const {
    return std::chrono::duration_cast<std::chrono::seconds>(std::chrono::utc_clock::now().time_since_epoch());
}

std::string Token::extractFirstMatchRegex(const std::string &iText, const std::string &iRegex) const {
    std::regex regex(iRegex);
    auto aMatchBegin = std::sregex_iterator(iText.begin(), iText.end(), regex);
    auto aMatchEnd = std::sregex_iterator();
    if (std::distance(aMatchBegin, aMatchEnd) > 0) {
        std::smatch match = *aMatchBegin;
        return match[1].str();
    }
    return "";
}

size_t Token::curlCallbackStringOutput(void *t_contents, size_t t_size, size_t t_nmemb, std::string *t_s) {
    size_t newLength = t_size * t_nmemb;
    try {
        t_s->append(static_cast<char *>(t_contents), newLength);
    } catch (std::bad_alloc &e) {
        // handle memory problem
        return 0;
    }
    return newLength;
}