#include <iostream>
#include <fstream>
#include <list>

int main() {
    std::fstream jpg_in;
    jpg_in.open("/Users/dongl/code/Binarization/WechatIMG7.jpg", std::ios::in);
    if (!jpg_in.is_open()) {
        perror("jpg 打开失败");
    }

    // 校验是否是jpg文件
    char file_header[2] = {0};
    // ARM 小端字节序 jpg标识头是0xffd8  所以小端0xd8ff
    uint16_t jpg_header = 0xd8ff;
    // 读取标识头 n-1 个字读  3-1=2
    jpg_in.get(file_header, 3);
    if (memcmp(file_header, &jpg_header, 2) == 0) {
        printf("FFD8  是jpg\n");
    }

    std::list<std::string> application_segments;
    std::list<std::string> dqt_segments;
    std::list<std::string> frame_segments;
    std::list<std::string> huffman_segments;
    std::list<std::string> scan_segments;
    std::string segments_buf = "";
    char key_marker = 0xFF;       // 关键头
    char head_marker = 0xD8;      // 文件头
    char app_marker = 0xE0;       // app段
    char dqt_marker = 0xDB;       // 定义量化头
    char frame_marker = 0xC0;     // 帧段
    char huffman_marker = 0xC4;   // huffman表
    char scan_marker = 0xDA;      // 扫描段
    char foot_marker = 0xD9;      // 文件尾
    //RSTn (Restart Marker)：0xFFD0 至 0xFFD7，表示重启标记，用于在解码过程中进行数据恢复。
    //APPn (Application Segment n)：0xFFE1 至 0xFFEF，表示其他应用段，可以用于存储各种应用程序或设备的相关信息。

    char buf[1024] = {0};
    jpg_in.get(buf, sizeof(buf));
    char FFE0[2];
    uint16_t tmp1;
    memcpy(&FFE0, &buf, 2);
    memcpy(&tmp1, &FFE0, 2);

    while (jpg_in.get(buf, sizeof(buf))) {
        // 读取取出来的文件缓存
        for (const auto &item: buf) {
            // 查看是不是新的段
            if (item == key_marker && segments_buf != "") {
                // 添加段
                // 添加应用段
                if (segments_buf[1] == app_marker)
                    application_segments.push_back(segments_buf);
                // 定义量化表
                else if(segments_buf[1] == dqt_marker)
                    dqt_segments.push_back(segments_buf);
                // 添加帧段
                if (segments_buf[1] == frame_marker)
                    frame_segments.push_back(segments_buf);
                // huffman段
                if (segments_buf[1] == huffman_marker)
                    huffman_segments.push_back(segments_buf);
                // 添加扫描段
                else if(segments_buf[1] == scan_marker)
                    scan_segments.push_back(segments_buf);

                // 文件尾
                else if(segments_buf[1] == foot_marker) {
                    segments_buf = "";
                    break;
                }
                segments_buf = "";
            }
            // 添加到段缓存
            segments_buf.push_back(item);
        }
    }

    std::fstream segments_out;
    segments_out.open("/Users/dongl/code/Binarization/jpg_segments_out.txt",
                      std::ios::out | std::ios::ate);
    if (!segments_out.is_open()) {
        perror("jpg_segments_out 打开失败");
    }

    segments_out << "application_segments:\n";
    for (const auto &segments: application_segments) {
        segments_out << segments;
        segments_out << "\n";
    }

    segments_out << "dqt_segments:\n";
    for (const auto &segments: dqt_segments) {
        segments_out << segments;
        segments_out << "\n";
    }

    segments_out << "frame_segments:\n";
    for (const auto &segments: frame_segments) {
        uint16_t tmp;
        uint16_t frame_size;
        memcpy(&tmp, segments.c_str()+2, 2);
        memcpy(&frame_size, &tmp, 2);
        segments_out << "frame_size: " << frame_size << "\n";
    }

    segments_out << "huffman_segments:\n";
    for (const auto &segments: huffman_segments) {
        segments_out << segments;
        segments_out << "\n";
    }

    segments_out << "scan_segments:\n";
    for (const auto &segments: scan_segments) {
        segments_out << segments;
        segments_out << "\n";
    }

    segments_out.close();
    jpg_in.close();
    return 0;
}