    // Copyright (C) 2011  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_IMAGE_DAtASET_METADATA_CPP__
    #define DLIB_IMAGE_DAtASET_METADATA_CPP__

    #include "image_dataset_metadata.h"

    #include <fstream>
    #include <sstream>
    #include "../compress_stream.h"
    #include "../base64.h"
    #include "../xml_parser.h"
    #include "../string.h"

    // ----------------------------------------------------------------------------------------

    namespace dlib
    {
        namespace image_dataset_metadata
        {

        // ------------------------------------------------------------------------------------

            const std::string get_decoded_string();
            void create_image_metadata_stylesheet_file(const std::string& main_filename)
            {
                std::string path;
                std::string::size_type pos = main_filename.find_last_of("/\\");
                if (pos != std::string::npos)
                    path = main_filename.substr(0,pos+1);

                std::ofstream fout((path + "image_metadata_stylesheet.xsl").c_str());
                if (!fout)
                    throw dlib::error("ERROR: Unable to open image_metadata_stylesheet.xsl for writing.");

                fout << get_decoded_string();

                if (!fout)
                    throw dlib::error("ERROR: Unable to write to image_metadata_stylesheet.xsl.");
            }

            void save_image_dataset_metadata (
                const dataset& meta,
                const std::string& filename
            )
            {
                create_image_metadata_stylesheet_file(filename);

                const std::vector<image>& images = meta.images;

                std::ofstream fout(filename.c_str());
                if (!fout)
                    throw dlib::error("ERROR: Unable to open " + filename + " for writing.");

                fout << "<?xml version='1.0' encoding='ISO-8859-1'?>\n";
                fout << "<?xml-stylesheet type='text/xsl' href='image_metadata_stylesheet.xsl'?>\n";
                fout << "<dataset>\n";
                fout << "<name>" << meta.name << "</name>\n";
                fout << "<comment>" << meta.comment << "</comment>\n";
                fout << "<images>\n";
                for (unsigned long i = 0; i < images.size(); ++i)
                {
                    fout << "  <image file='" << images[i].filename << "'>\n";

                    // save all the boxes
                    for (unsigned long j = 0; j < images[i].boxes.size(); ++j)
                    {
                        const box& b = images[i].boxes[j];
                        fout << "    <box top='" << b.rect.top() << "' "
                                     << "left='" << b.rect.left() << "' "
                                    << "width='" << b.rect.width() << "' "
                                   << "height='" << b.rect.height() << "'";
                        if (b.difficult)
                            fout << " difficult='" << b.difficult << "'";
                        if (b.truncated)
                            fout << " truncated='" << b.truncated << "'";
                        if (b.occluded)
                            fout << " occluded='" << b.occluded << "'";
                        if (b.ignore)
                            fout << " ignore='" << b.ignore << "'";
                        if (b.angle != 0)
                            fout << " angle='" << b.angle << "'";

                        if (b.has_label() || b.parts.size() != 0)
                        {
                            fout << ">\n";

                            if (b.has_label())
                                fout << "      <label>" << b.label << "</label>\n";

                            // save all the parts
                            std::map<std::string,point>::const_iterator itr;
                            for (itr = b.parts.begin(); itr != b.parts.end(); ++itr)
                            {
                                fout << "      <part name='"<< itr->first << "' x='"<< itr->second.x() <<"' y='"<< itr->second.y() <<"'/>\n";
                            }

                            fout << "    </box>\n";
                        }
                        else
                        {
                            fout << "/>\n";
                        }
                    }

                    fout << "  </image>\n";

                    if (!fout)
                        throw dlib::error("ERROR: Unable to write to " + filename + ".");
                }
                fout << "</images>\n";
                fout << "</dataset>";
            }

        // ------------------------------------------------------------------------------------
        // ------------------------------------------------------------------------------------
        // ------------------------------------------------------------------------------------

            class doc_handler : public document_handler
            {
                std::vector<std::string> ts;
                image temp_image;
                box temp_box;

                dataset& meta;

            public:

                doc_handler(
                    dataset& metadata_
                ):
                    meta(metadata_)
                {}

                virtual void start_document (
                )
                {
                    meta = dataset();
                    ts.clear();
                    temp_image = image();
                    temp_box = box();
                }

                virtual void end_document (
                )
                {
                }

                virtual void start_element (
                    const unsigned long line_number,
                    const std::string& name,
                    const dlib::attribute_list& atts
                )
                {
                    try
                    {
                        if (ts.size() == 0)
                        {
                            if (name != "dataset")
                            {
                                std::ostringstream sout;
                                sout << "Invalid XML document.  Root tag must be <dataset>.  Found <" << name << "> instead.";
                                throw dlib::error(sout.str());
                            }
                            else
                            {
                                ts.push_back(name);
                                return;
                            }
                        }

                        if (name == "box")
                        {
                            if (atts.is_in_list("top")) temp_box.rect.top() = sa = atts["top"];
                            else throw dlib::error("<box> missing required attribute 'top'");

                            if (atts.is_in_list("left")) temp_box.rect.left() = sa = atts["left"];
                            else throw dlib::error("<box> missing required attribute 'left'");

                            if (atts.is_in_list("width")) temp_box.rect.right() = sa = atts["width"];
                            else throw dlib::error("<box> missing required attribute 'width'");

                            if (atts.is_in_list("height")) temp_box.rect.bottom() = sa = atts["height"];
                            else throw dlib::error("<box> missing required attribute 'height'");

                            if (atts.is_in_list("difficult")) temp_box.difficult = sa = atts["difficult"];
                            if (atts.is_in_list("truncated")) temp_box.truncated = sa = atts["truncated"];
                            if (atts.is_in_list("occluded"))  temp_box.occluded  = sa = atts["occluded"];
                            if (atts.is_in_list("ignore"))  temp_box.ignore  = sa = atts["ignore"];
                            if (atts.is_in_list("angle"))  temp_box.angle  = sa = atts["angle"];

                            temp_box.rect.bottom() += temp_box.rect.top()-1;
                            temp_box.rect.right() += temp_box.rect.left()-1;
                        }
                        else if (name == "part" && ts.back() == "box")
                        {
                            point temp;
                            if (atts.is_in_list("x")) temp.x() = sa = atts["x"];
                            else throw dlib::error("<part> missing required attribute 'x'");

                            if (atts.is_in_list("y")) temp.y() = sa = atts["y"];
                            else throw dlib::error("<part> missing required attribute 'y'");

                            if (atts.is_in_list("name"))
                            {
                                if (temp_box.parts.count(atts["name"])==0)
                                {
                                    temp_box.parts[atts["name"]] = temp;
                                }
                                else
                                {
                                    throw dlib::error("<part> with name '" + atts["name"] + "' is defined more than one time in a single box.");
                                }
                            }
                            else
                            {
                                throw dlib::error("<part> missing required attribute 'name'");
                            }
                        }
                        else if (name == "image")
                        {
                            temp_image.boxes.clear();

                            if (atts.is_in_list("file")) temp_image.filename = atts["file"];
                            else throw dlib::error("<image> missing required attribute 'file'");
                        }

                        ts.push_back(name);
                    }
                    catch (error& e)
                    {
                        throw dlib::error("Error on line " + cast_to_string(line_number) + ": " + e.what());
                    }
                }

                virtual void end_element (
                    const unsigned long ,
                    const std::string& name
                )
                {
                    ts.pop_back();
                    if (ts.size() == 0)
                        return;

                    if (name == "box" && ts.back() == "image")
                    {
                        temp_image.boxes.push_back(temp_box);
                        temp_box = box();
                    }
                    else if (name == "image" && ts.back() == "images")
                    {
                        meta.images.push_back(temp_image);
                        temp_image = image();
                    }
                }

                virtual void characters (
                    const std::string& data
                )
                {
                    if (ts.size() == 2 && ts[1] == "name")
                    {
                        meta.name = trim(data);
                    }
                    else if (ts.size() == 2 && ts[1] == "comment")
                    {
                        meta.comment = trim(data);
                    }
                    else if (ts.size() >= 2 && ts[ts.size()-1] == "label" &&
                                               ts[ts.size()-2] == "box")
                    {
                        temp_box.label = trim(data);
                    }
                }

                virtual void processing_instruction (
                    const unsigned long ,
                    const std::string& ,
                    const std::string&
                )
                {
                }
            };

        // ----------------------------------------------------------------------------------------

            class xml_error_handler : public error_handler
            {
            public:
                virtual void error (
                    const unsigned long
                ) { }

                virtual void fatal_error (
                    const unsigned long line_number
                )
                {
                    std::ostringstream sout;
                    sout << "There is a fatal error on line " << line_number << " so parsing will now halt.";
                    throw dlib::error(sout.str());
                }
            };

        // ------------------------------------------------------------------------------------

            void load_image_dataset_metadata (
                dataset& meta,
                const std::string& filename
            )
            {
                xml_error_handler eh;
                doc_handler dh(meta);

                std::ifstream fin(filename.c_str());
                if (!fin)
                    throw dlib::error("ERROR: unable to open " + filename + " for reading.");

                xml_parser parser;
                parser.add_document_handler(dh);
                parser.add_error_handler(eh);
                parser.parse(fin);
            }

        // ------------------------------------------------------------------------------------
        // ------------------------------------------------------------------------------------
        // ------------------------------------------------------------------------------------

            // This function returns the contents of the file 'images.xsl'
            const std::string get_decoded_string()
            {
                dlib::base64 base64_coder;
                dlib::compress_stream::kernel_1ea compressor;
                std::ostringstream sout;
                std::istringstream sin;

                // The base64 encoded data from the file 'image_metadata_stylesheet.xsl' we want to decode and return.
                sout << "PFWfgmWfCHr1DkV63lbjjeY2dCc2FbHDOVh0Kd7dkvaOfRYrOG24f0x77/5iMVq8FtE3UBxtGwSd";
                sout << "1ZHOHRSHgieNoeBv8ssJQ75RRxYtFKRY3OTPX5eKQoCN9jUaUnHnR4QZtEHgmKqXSs50Yrdd+2Ah";
                sout << "gNyarPZCiR6nvqNvCjtP2MP5FxleqNf8Fylatm2KdsXmrv5K87LYVN7i7JMkmZ++cTXYSOxDmxZi";
                sout << "OiCH8funXUdF9apDW547gCjz9HOQUI6dkz5dYUeFjfp6dFugpnaJyyprFLKq048Qk7+QiL4CNF/G";
                sout << "7e0VpBw8dMpiyRNi2fSQGSZGfIAUQKKT6+rPwQoRH2spdjsdXVWj4XQAqBX87nmqMnqjMhn/Vd1s";
                sout << "W5aoC0drwRGu3Xe3gn9vBL8hBkRXcJvEy6q/lb9bYnsLemhE5Zp/+nTmTBjfT9UFYLcsmgsjON9M";
                sout << "gbE5Q8tCa+WXXXsVP1ai5tLU3G1RUjctr/VtV55PKl2xKjjgb4zDldHKrKFQ23NkQR94PFHG25WM";
                sout << "a/VSFVSzLJWdeV/SK3uDq/zUdwQ1JohWp2i+0vJuTXNGCmyT3zHxqtue3HcEw7OpGIDQ+EN0nPCV";
                sout << "90Seu55zuS14zuWdRfXln3/g/hiA7Jj72Ah8Kiz3F3gwCfFbyFaMDYTbT4sda0fDkx1M9sKJ2pN8";
                sout << "3Jd7T8SU+Rk2/oDc8RuTTbFaRvulLWHfdLGPuIJpLT7FUkxGpdlIvxPypjGf0wVA8kgcYGgoKLIX";
                sout << "uUgWFEvqwDJtxvOYVApV2foeOMgfw53TRiFDqwxmaYC41gB32cGgKYuC90mmqGY1MWAD0KLl5+bF";
                sout << "GQiRmckXmDmowK5cxibnB5nTyJX1LmXaqkHFFNGPfidznTHoSqtlAF4wnCyBMuCAdgJgC0AF5gr4";
                sout << "1KNWDg042CVs3li6Nep6G9arGOkEcL7vWamNC9vvkYwOWidjDFqINBxEWGTRQCyG9RDzPX2dckEh";
                sout << "jWYwrXDOFyBNbac16Yym1ftn322+sE+RnaXq9WIoTGnrK/A1paSzdCjpfiIAAizaRnwoa6Ue9xnZ";
                sout << "HvSSQetmzyOErvK6IOWu2VwvqO3aOC28RP63JEztmiT7pF+Zl0NMHVWgW13WejABamVXvjDAlMSA";
                sout << "iBKSBqTuyC0YbuNk14G2MfQE0pg1QrAHhOi9u2KsTRN56381lxxqAhEEGvI/h+ONsveGuuDjXgcy";
                sout << "wvObjIKOawnh820yMrPBzDOx/ExSJtwqbWXBc0MGZxLXA3OgfeKsoaGB/OSB3AznJd40B1ktnmXO";
                sout << "pThos8Tl3Cs6xxFdFhob0vf3ml6WumTtNnAA";

                // Put the data into the istream sin
                sin.str(sout.str());
                sout.str("");

                // Decode the base64 text into its compressed binary form
                base64_coder.decode(sin,sout);
                sin.clear();
                sin.str(sout.str());
                sout.str("");

                // Decompress the data into its original form
                compressor.decompress(sin,sout);

                // Return the decoded and decompressed data
                return sout.str();
            }

        }
    }

    // ----------------------------------------------------------------------------------------

    #endif // DLIB_IMAGE_DAtASET_METADATA_CPP__