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

HearthstoneAPIHandler::HearthstoneAPIHandler()
    : m_access_token(get_valid_token()), m_header(generate_request_header()) {}

size_t HearthstoneAPIHandler::curl_callback_string_output(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((char *)t_contents, newLength);
    } catch (std::bad_alloc &e) {
        // handle memory problem
        return 0;
    }
    return newLength;
}

std::chrono::hours HearthstoneAPIHandler::get_current_time() {
    return std::chrono::duration_cast<std::chrono::hours>(
        std::chrono::utc_clock::now().time_since_epoch());
}

std::string
HearthstoneAPIHandler::extract_string_with_regex(const std::string &t_str,
                                                 const std::string t_regex) {
    std::regex regex(t_regex);
    auto it = std::sregex_iterator(t_str.begin(), t_str.end(), regex);
    std::smatch match = *it;
    return match[1].str();
}

void HearthstoneAPIHandler::write_new_token_info_to_file(
    const std::string &t_file_path) {
    std::ofstream token_file(t_file_path);
    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,
                         curl_callback_string_output);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &token_info);
        curl_easy_setopt(curl, CURLOPT_USERPWD,
                         "2b50f1123b424d5e9c21971a110fdd04:"
                         "MrMkhVMNdOeqPL4Q4XVQAsRPR14J7Yq6");
        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);
        }
    }
    std::string token =
        extract_string_with_regex(token_info, "\"access_token\":\"(\\w+)\"");
    std::chrono::hours expires_at = get_current_time() + std::chrono::hours(24);
    token_file << token << " " << expires_at.count();
}

void HearthstoneAPIHandler::refresh_token_if_needed() {
    std::string file_path =
        std::format("{}/resources/token_info.txt", SOURCE_DIR_PATH);
    std::ifstream token_file(file_path);
    std::string line;
    std::getline(token_file, line);
    if (line.empty()) {
        write_new_token_info_to_file(file_path);
    } else {
        unsigned long expire_at = std::stoull(line.substr(line.find(" ") + 1));
        if (std::chrono::duration_cast<std::chrono::hours>(
                std::chrono::utc_clock::now().time_since_epoch())
                .count() >= expire_at) {
            write_new_token_info_to_file(file_path);
        }
    }
}
std::string HearthstoneAPIHandler::get_valid_token() {
    refresh_token_if_needed();
    std::string file_path =
        std::format("{}/resources/token_info.txt", SOURCE_DIR_PATH);
    std::ifstream token_file(file_path);
    std::string line;
    std::getline(token_file, line);
    std::string token = line.substr(0, line.find(" "));
    return token;
}

std::string HearthstoneAPIHandler::generate_request_header() {
    return std::format("Authorization: Bearer {}", m_access_token);
}

const std::string
HearthstoneAPIHandler::get_url(const std::string &t_parameters) {
    return std::format("https://eu.api.blizzard.com/hearthstone/{}",
                       t_parameters);
}

const std::string HearthstoneAPIHandler::get_set_of_cards_url(
    const std::string &t_card_parameters) {
    return get_url(std::format("cards{}", t_card_parameters));
}

std::string HearthstoneAPIHandler::make_api_request(const char *t_url,
                                                    const char *t_header) {
    CURL *curl = curl_easy_init();
    std::string request_output;
    if (curl) {
        curl_easy_setopt(curl, CURLOPT_URL, t_url);
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
                         curl_callback_string_output);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &request_output);
        struct curl_slist *chunk = nullptr;
        chunk = curl_slist_append(chunk, t_header);
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
        curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }
    return request_output;
}

std::string
HearthstoneAPIHandler::make_api_request(const std::string &t_url,
                                        const std::string &t_header) {
    return make_api_request(t_url.c_str(), t_header.c_str());
}

std::string
HearthstoneAPIHandler::get_cards(const std::string &t_card_parameters) {
    return make_api_request(get_set_of_cards_url(t_card_parameters), m_header);
}