#include "utils/utils.h"
#include "utils/base64.h"
#include <email_parser/emailparser.h>

#include <opencv2/opencv.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/objdetect.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/videoio.hpp>

#include <utils/utils.h>
#include <check/check.h>
#include <boost/regex.hpp>
#include <boost/algorithm/string/regex.hpp>
#include <iostream>
#include <fstream>

#if __GNUC__ < 8 && __clang_major__ < 17
#	include <experimental/filesystem>
    using namespace std::experimental::filesystem;
#else
#	include <filesystem>
    using namespace std::filesystem;
#endif


EmailParser::EmailParser() {

}

std::map<std::string, std::string> EmailParser::parse(std::string &email_content) {
    //1. Search "Content-Type: image/.*" in the .eml file.
    //  1.1 If found 0, go to [2]
    //  1.2 If found 1, try decoding it, if it's not a QR code, go to [2]
    //  1.3 Loop through every found entry. If not found in any, go to [2]
    //2. Try decoding content of the e-mail
    //3. Search "t=\d{8}T\d{4,6}&s=\d{1,6}\.\d{1,2}&fn=\d{10,16}&i=\d{6}&fp=\d{10}&n=\d". Note that in some emails = and & signs could be replaced with its code in HTTP requests: %3D, %26
    // 3.1 If not found, notify the user that we could not parse the .eml file

    /* Find content-types */
    Check c;
    std::vector<std::pair<int, int>> content_types = {};
    boost::regex content_type_regex("Content-Type: image/(gif|png|jpg)");
    boost::regex part_end_regex("--.{5,48}");

    for (boost::sregex_iterator it{email_content.begin(), email_content.end(), content_type_regex}, end{}; it != end; it ++) {
        unsigned int start_position = it->position(), end_position = -1;

        for (boost::sregex_iterator it2{email_content.begin() + start_position, email_content.end(), part_end_regex}, end2{}; it2 != end2; it2++) {
            end_position = it2->position();
            break;
        }
        content_types.push_back(std::pair<int, int>(start_position, end_position));
    }

    /* iterate through found content-types and try searching qr codes, decode them and see if it's the needed data */

    for (unsigned int i = 0; i < content_types.size(); i ++) {
        boost::regex to_erase("(Content.{5,64}\\r\\n)+");
        boost::regex to_erase_two("--.{5,48}");
        std::string part = email_content.substr(content_types[i].first, content_types[i].second);
        boost::erase_regex(part, to_erase);
        boost::erase_regex(part, to_erase_two);
        part.erase(std::remove(part.begin(), part.end(), '\r'), part.end());
        part.erase(std::remove(part.begin(), part.end(), '\n'), part.end());
        std::string decoded = base64_decode(part);
        cv::Mat image;

        if (decoded.substr(1, 3) == "PNG" || decoded.substr(1, 3) == "JPG") {
            std::vector<uchar> data(decoded.begin(), decoded.end());
            image = cv::imdecode(cv::Mat(data), 1);
        } else if (decoded.substr(0, 3) == "GIF") {
            std::string gif_file_path = get_application_home_path() + "/temp.gif";

            std::ofstream gif_output(gif_file_path, std::ios::binary);
            gif_output << decoded;
            gif_output.close();
            cv::VideoCapture gif(gif_file_path, cv::CAP_FFMPEG);
            gif.read(image);
        }

        cv::QRCodeDetector qrDecoder = cv::QRCodeDetector();
        std::string decoded_qr_params = qrDecoder.detectAndDecode(image);
        boost::regex check_data_content("t=\\d+T\\d+&s=\\d+\\.\\d+&fn=\\d{16}&i=\\d{4,5}&fp=\\d{10}&n=\\d");
        if (boost::regex_match(decoded_qr_params, check_data_content)) {
            std::map<std::string, std::string> paramsMap = get_params_from_string(decoded_qr_params);

            return paramsMap;
        }
    }

    /* If the E-Mail has no QR code in it as a separate part, there's posibilly a QR code inserted using html's tag <img> with base64-encoded image. Try searching it */

    /* If there's no such case, the last chance is <img src="..."> which will have a link with needed parameters or the qr code that should be downloaded and decoded */

    /* If the code has reached this part and found nothing, it's most likely that there are no QR codes at all. */
    // return Check();
}

std::map<std::string, std::string> EmailParser::parse_file(std::string path) {
    std::ifstream ifile(path, std::ios::in | std::ios::binary);
    const unsigned int size = std::filesystem::file_size(path);
    std::string content(size, '\0');
    ifile.read(content.data(), size);
    return parse(content);
    return std::map<std::string, std::string>();
}