/***************************************************************************
 *   Copyright (c) 2022 FreeCAD Project Association                        *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  is distributed in the hope that it will be useful,      *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file LICENSE.html. If not,   *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/

#include "PreCompiled.h"

#ifndef _PreComp_
#include <boost/core/ignore_unused.hpp>
#include <memory>
#include <sstream>
#endif

#include "Metadata.h"

#include <xercesc/framework/LocalFileFormatTarget.hpp>
#include <xercesc/sax/HandlerBase.hpp>

#include "App/Application.h"
#include "App/Expression.h"
#include "Base/XMLTools.h"

/*
*** From GCC: ***
In the GNU C Library, "major" and "minor" are defined
by <sys/sysmacros.h>. For historical compatibility, it is
currently defined by <sys/types.h> as well, but we plan to
remove this soon. To use "major", include <sys/sysmacros.h>
directly. If you did not intend to use a system-defined macro
"major", you should undefine it after including <sys/types.h>.
*/
#ifdef major
#undef major
#endif
#ifdef minor
#undef minor
#endif

using namespace App;
namespace fs = boost::filesystem;
XERCES_CPP_NAMESPACE_USE

namespace MetadataInternal
{
class XMLErrorHandler: public HandlerBase
{
    void warning(const SAXParseException &toCatch) override
    {
        // Don't deal with warnings at all
        boost::ignore_unused(toCatch);
    }

    void error(const SAXParseException &toCatch) override
    {
        std::stringstream message;
        message << "Error at file \"" << StrX(toCatch.getSystemId()) << "\", line "
                << toCatch.getLineNumber() << ", column " << toCatch.getColumnNumber()
                << "\n   Message: " << StrX(toCatch.getMessage()) << std::endl;
        throw Base::XMLBaseException(message.str());
    }

    void fatalError(const SAXParseException &toCatch) override
    {
        std::stringstream message;
        message << "Fatal error at file \"" << StrX(toCatch.getSystemId()) << "\", line "
                << toCatch.getLineNumber() << ", column " << toCatch.getColumnNumber()
                << "\n   Message: " << StrX(toCatch.getMessage()) << std::endl;
        throw Base::XMLBaseException(message.str());
    }
};
}// namespace MetadataInternal

Metadata::Metadata(const fs::path &metadataFile)
{
    // Any exception thrown by the XML code propagates out and prevents object creation
    XMLPlatformUtils::Initialize();

    _parser = std::make_shared<XercesDOMParser>();
    _parser->setValidationScheme(XercesDOMParser::Val_Never);
    _parser->setDoNamespaces(true);

    auto errHandler = std::make_unique<MetadataInternal::XMLErrorHandler>();
    _parser->setErrorHandler(errHandler.get());

#if defined(FC_OS_WIN32)
    _parser->parse(reinterpret_cast<const XMLCh *>(metadataFile.wstring().c_str()));
#else
    _parser->parse(metadataFile.string().c_str());
#endif

    auto doc = _parser->getDocument();
    _dom = doc->getDocumentElement();

    auto rootTagName = StrXUTF8(_dom->getTagName()).str;
    if (rootTagName != "package")
        throw Base::XMLBaseException(
            "Malformed package.xml document: Root <package> group not found");

    auto formatVersion = XMLString::parseInt(_dom->getAttribute(XUTF8Str("format").unicodeForm()));
    switch (formatVersion) {
        case 1: parseVersion1(_dom); break;
        default:
            throw Base::XMLBaseException(
                "package.xml format version is not supported by this version of FreeCAD");
    }
}

Metadata::Metadata() : _dom(nullptr) {}

Metadata::Metadata(const DOMNode *domNode, int format) : _dom(nullptr)
{
    auto element = dynamic_cast<const DOMElement *>(domNode);
    if (element) {
        switch (format) {
            case 1: parseVersion1(element); break;
            default:
                throw Base::XMLBaseException(
                    "package.xml format version is not supported by this version of FreeCAD");
        }
    }
}

Metadata::~Metadata() = default;

std::string Metadata::name() const { return _name; }

Meta::Version Metadata::version() const { return _version; }

std::string App::Metadata::date() const { return _date; }

std::string Metadata::description() const { return _description; }

std::vector<Meta::Contact> Metadata::maintainer() const { return _maintainer; }

std::vector<Meta::License> Metadata::license() const { return _license; }

std::vector<Meta::Url> Metadata::url() const { return _url; }

std::vector<Meta::Contact> Metadata::author() const { return _author; }

std::vector<Meta::Dependency> Metadata::depend() const { return _depend; }

std::vector<Meta::Dependency> Metadata::conflict() const { return _conflict; }

std::vector<Meta::Dependency> Metadata::replace() const { return _replace; }

std::vector<std::string> Metadata::tag() const { return _tag; }

fs::path Metadata::icon() const { return _icon; }

std::string Metadata::classname() const { return _classname; }

boost::filesystem::path Metadata::subdirectory() const { return _subdirectory; }

std::vector<fs::path> Metadata::file() const { return _file; }

Meta::Version Metadata::freecadmin() const { return _freecadmin; }

Meta::Version Metadata::freecadmax() const { return _freecadmax; }

Meta::Version Metadata::pythonmin() const { return _pythonmin; }

std::multimap<std::string, Metadata> Metadata::content() const { return _content; }

std::vector<Meta::GenericMetadata> Metadata::operator[](const std::string &tag) const
{
    std::vector<Meta::GenericMetadata> returnValue;
    auto range = _genericMetadata.equal_range(tag);
    for (auto item = range.first; item != range.second; ++item) returnValue.push_back(item->second);
    return returnValue;
}

XERCES_CPP_NAMESPACE::DOMElement *Metadata::dom() const { return _dom; }

void Metadata::setName(const std::string &name)
{
    std::string invalidCharacters = "/\\?%*:|\"<>";// Should cover all OSes
    if (_name.find_first_of(invalidCharacters) != std::string::npos)
        throw Base::RuntimeError("Name cannot contain any of: " + invalidCharacters);

    _name = name;
}

void Metadata::setVersion(const Meta::Version &version) { _version = version; }

void App::Metadata::setDate(const std::string &date) { _date = date; }

void Metadata::setDescription(const std::string &description) { _description = description; }

void Metadata::addMaintainer(const Meta::Contact &maintainer) { _maintainer.push_back(maintainer); }

void Metadata::addLicense(const Meta::License &license) { _license.push_back(license); }

void Metadata::addUrl(const Meta::Url &url) { _url.push_back(url); }

void Metadata::addAuthor(const Meta::Contact &author) { _author.push_back(author); }

void Metadata::addDepend(const Meta::Dependency &dep) { _depend.push_back(dep); }

void Metadata::addConflict(const Meta::Dependency &dep) { _conflict.push_back(dep); }

void Metadata::addReplace(const Meta::Dependency &dep) { _replace.push_back(dep); }

void Metadata::addTag(const std::string &tag) { _tag.push_back(tag); }

void Metadata::setIcon(const fs::path &path) { _icon = path; }

void Metadata::setClassname(const std::string &name) { _classname = name; }

void Metadata::setSubdirectory(const boost::filesystem::path &path) { _subdirectory = path; }

void Metadata::addFile(const fs::path &path) { _file.push_back(path); }

void Metadata::addContentItem(const std::string &tag, const Metadata &item)
{
    _content.insert(std::make_pair(tag, item));
}

void Metadata::setFreeCADMin(const Meta::Version &version) { _freecadmin = version; }

void Metadata::setPythonMin(const Meta::Version &version) { _pythonmin = version; }

void Metadata::setFreeCADMax(const Meta::Version &version) { _freecadmax = version; }

void Metadata::addGenericMetadata(const std::string &tag,
                                  const Meta::GenericMetadata &genericMetadata)
{
    _genericMetadata.insert(std::make_pair(tag, genericMetadata));
}

void Metadata::removeContentItem(const std::string &tag, const std::string &itemName)
{
    auto tagRange = _content.equal_range(tag);
    auto foundItem =
        std::find_if(tagRange.first, tagRange.second, [&itemName](const auto &check) -> bool {
            return itemName == check.second.name();
        });
    if (foundItem != tagRange.second) _content.erase(foundItem);
}

void Metadata::removeMaintainer(const Meta::Contact &maintainer)
{
    auto new_end = std::remove(_maintainer.begin(), _maintainer.end(), maintainer);
    _maintainer.erase(new_end, _maintainer.end());
}

void Metadata::removeLicense(const Meta::License &license)
{
    auto new_end = std::remove(_license.begin(), _license.end(), license);
    _license.erase(new_end, _license.end());
}

void Metadata::removeUrl(const Meta::Url &url)
{
    auto new_end = std::remove(_url.begin(), _url.end(), url);
    _url.erase(new_end, _url.end());
}

void Metadata::removeAuthor(const Meta::Contact &author)
{
    auto new_end = std::remove(_author.begin(), _author.end(), author);
    _author.erase(new_end, _author.end());
}

void Metadata::removeDepend(const Meta::Dependency &dep)
{
    bool found = false;
    for (const auto &check : _depend) {
        if (dep == check) found = true;
    }
    if (!found) throw Base::RuntimeError("No match found for dependency to remove");
    auto new_end = std::remove(_depend.begin(), _depend.end(), dep);
    _depend.erase(new_end, _depend.end());
}

void Metadata::removeConflict(const Meta::Dependency &dep)
{
    auto new_end = std::remove(_conflict.begin(), _conflict.end(), dep);
    _conflict.erase(new_end, _conflict.end());
}

void Metadata::removeReplace(const Meta::Dependency &dep)
{
    auto new_end = std::remove(_replace.begin(), _replace.end(), dep);
    _replace.erase(new_end, _replace.end());
}

void Metadata::removeTag(const std::string &tag)
{
    auto new_end = std::remove(_tag.begin(), _tag.end(), tag);
    _tag.erase(new_end, _tag.end());
}

void Metadata::removeFile(const boost::filesystem::path &path)
{
    auto new_end = std::remove(_file.begin(), _file.end(), path);
    _file.erase(new_end, _file.end());
}


void Metadata::clearContent() { _content.clear(); }

void Metadata::clearMaintainer() { _maintainer.clear(); }

void Metadata::clearLicense() { _license.clear(); }

void Metadata::clearUrl() { _url.clear(); }

void Metadata::clearAuthor() { _author.clear(); }

void Metadata::clearDepend() { _depend.clear(); }

void Metadata::clearConflict() { _conflict.clear(); }

void Metadata::clearReplace() { _replace.clear(); }

void Metadata::clearTag() { _tag.clear(); }

void Metadata::clearFile() { _file.clear(); }


DOMElement *appendSimpleXMLNode(DOMElement *baseNode, const std::string &nodeName,
                                const std::string &nodeContents)
{
    // For convenience (and brevity of final output) don't create nodes that don't have contents
    if (nodeContents.empty())
        return nullptr;

    auto doc = baseNode->getOwnerDocument();
    DOMElement *namedElement = doc->createElement(XUTF8Str(nodeName.c_str()).unicodeForm());
    baseNode->appendChild(namedElement);
    DOMText *namedNode = doc->createTextNode(XUTF8Str(nodeContents.c_str()).unicodeForm());
    namedElement->appendChild(namedNode);
    return namedElement;
}

void addAttribute(DOMElement *node, const std::string &key, const std::string &value)
{
    if (value.empty())
        return;

    node->setAttribute(XUTF8Str(key.c_str()).unicodeForm(), XUTF8Str(value.c_str()).unicodeForm());
}

void addAttribute(DOMElement *node, const std::string &key, bool value)
{
    if (value)
        node->setAttribute(XUTF8Str(key.c_str()).unicodeForm(), XUTF8Str("True").unicodeForm());
    else
        node->setAttribute(XUTF8Str(key.c_str()).unicodeForm(), XUTF8Str("False").unicodeForm());
}

void addAttribute(DOMElement *node, const std::string &key, Meta::DependencyType value)
{
    // Someday we should be able to change this to use reflection, but it's not yet
    // available (using C++17)
    std::string stringified("automatic");
    switch (value) {
        case Meta::DependencyType::automatic: stringified = "automatic"; break;
        case Meta::DependencyType::internal: stringified = "internal"; break;
        case Meta::DependencyType::addon: stringified = "addon"; break;
        case Meta::DependencyType::python: stringified = "python"; break;
    }
    node->setAttribute(XUTF8Str(key.c_str()).unicodeForm(),
                       XUTF8Str(stringified.c_str()).unicodeForm());
}

void addDependencyNode(DOMElement *root, const std::string &name, const Meta::Dependency &depend)
{
    auto element = appendSimpleXMLNode(root, name, depend.package);
    if (element) {
        addAttribute(element, "version_lt", depend.version_lt);
        addAttribute(element, "version_lte", depend.version_lte);
        addAttribute(element, "version_eq", depend.version_eq);
        addAttribute(element, "version_gte", depend.version_gte);
        addAttribute(element, "version_gt", depend.version_gt);
        addAttribute(element, "condition", depend.condition);
        addAttribute(element, "optional", depend.optional);
        addAttribute(element, "type", depend.dependencyType);
    }
}

void Metadata::write(const fs::path &file) const
{
    DOMImplementation *impl =
        DOMImplementationRegistry::getDOMImplementation(XUTF8Str("Core LS").unicodeForm());

    DOMDocument *doc = impl->createDocument(nullptr, XUTF8Str("package").unicodeForm(), nullptr);
    DOMElement *root = doc->getDocumentElement();
    root->setAttribute(XUTF8Str("format").unicodeForm(), XUTF8Str("1").unicodeForm());
    root->setAttribute(XUTF8Str("xmlns").unicodeForm(),
                       XUTF8Str("https://wiki.freecad.org/Package_Metadata").unicodeForm());

    appendToElement(root);

    DOMLSSerializer *theSerializer = ((DOMImplementationLS *)impl)->createLSSerializer();
    DOMConfiguration *config = theSerializer->getDomConfig();
    if (config->canSetParameter(XMLUni::fgDOMWRTFormatPrettyPrint, true))
        config->setParameter(XMLUni::fgDOMWRTFormatPrettyPrint, true);

    // set feature if the serializer supports the feature/mode
    if (config->canSetParameter(XMLUni::fgDOMWRTSplitCdataSections, true))
        config->setParameter(XMLUni::fgDOMWRTSplitCdataSections, true);

    if (config->canSetParameter(XMLUni::fgDOMWRTDiscardDefaultContent, true))
        config->setParameter(XMLUni::fgDOMWRTDiscardDefaultContent, true);

    try {
        XMLFormatTarget *myFormTarget = new LocalFileFormatTarget(file.string().c_str());
        DOMLSOutput *theOutput = ((DOMImplementationLS *)impl)->createLSOutput();

        theOutput->setByteStream(myFormTarget);
        theSerializer->write(doc, theOutput);

        theOutput->release();
        theSerializer->release();
        delete myFormTarget;
    }
    catch (const XMLException &toCatch) {
        char *message = XMLString::transcode(toCatch.getMessage());
        std::string what = message;
        XMLString::release(&message);
        throw Base::XMLBaseException(what);
    }
    catch (const DOMException &toCatch) {
        char *message = XMLString::transcode(toCatch.getMessage());
        std::string what = message;
        XMLString::release(&message);
        throw Base::XMLBaseException(what);
    }

    doc->release();
}

bool Metadata::satisfies(const Meta::Dependency &dep)
{
    if (dep.package != _name)
        return false;

    // The "condition" attribute allows an expression to enable or disable this dependency check: it must contain a valid
    // FreeCAD Expression. If it evaluates to false, this dependency is bypassed (e.g. this function returns false).
    if (!dep.condition.empty()) {
        auto injectedString = dep.condition;
        std::map<std::string, std::string> replacements;
        std::map<std::string, std::string> &config = App::Application::Config();
        replacements.insert(std::make_pair("$BuildVersionMajor", config["BuildVersionMajor"]));
        replacements.insert(std::make_pair("$BuildVersionMinor", config["BuildVersionMinor"]));
        replacements.insert(std::make_pair("$BuildVersionMinor", config["BuildVersionPoint"]));
        replacements.insert(std::make_pair("$BuildRevision", config["BuildRevision"]));
        for (const auto &replacement : replacements) {
            auto pos = injectedString.find(replacement.first);
            while (pos != std::string::npos) {
                injectedString.replace(pos, replacement.first.length(), replacement.second);
                pos = injectedString.find(replacement.first);
            }
        }
        auto parsedExpression = App::Expression::parse(nullptr, dep.condition);
        auto result = parsedExpression->eval();
        if (!boost::any_cast<bool>(result->getValueAsAny()))
            return false;
    }

    if (!dep.version_eq.empty())
        return _version == Meta::Version(dep.version_eq);

    // Any of the others might be specified in pairs, so only return the "false" case

    if (!dep.version_lt.empty())
        if (!(_version < Meta::Version(dep.version_lt)))
            return false;

    if (!dep.version_lte.empty())
        if (!(_version <= Meta::Version(dep.version_lt)))
            return false;

    if (!dep.version_gt.empty())
        if (!(_version > Meta::Version(dep.version_lt)))
            return false;

    if (!dep.version_gte.empty())
        if (!(_version >= Meta::Version(dep.version_lt)))
            return false;

    return true;
}

bool Metadata::supportsCurrentFreeCAD() const
{
    static auto fcVersion = Meta::Version();
    if (fcVersion == Meta::Version()) {
        std::map<std::string, std::string> &config = App::Application::Config();
        std::stringstream ss;
        ss << config["BuildVersionMajor"]
            << "." << config["BuildVersionMinor"]
            << "." << config["BuildVersionPoint"]
            << "." << (config["BuildRevision"].empty() ? "0" : config["BuildRevision"]);
        fcVersion = Meta::Version(ss.str());
    }

    if (_freecadmin != Meta::Version() && _freecadmin > fcVersion)
        return false;
    else if (_freecadmax != Meta::Version() && _freecadmax < fcVersion)
        return false;
    return true;
}

void Metadata::appendToElement(DOMElement *root) const
{
    appendSimpleXMLNode(root, "name", _name);
    appendSimpleXMLNode(root, "description", _description);
    if (_version != Meta::Version())
        // Only append version if it's not 0.0.0
        appendSimpleXMLNode(root, "version", _version.str());

    if (!_date.empty()) appendSimpleXMLNode(root, "date", _date);

    for (const auto &maintainer : _maintainer) {
        auto element = appendSimpleXMLNode(root, "maintainer", maintainer.name);
        if (element) addAttribute(element, "email", maintainer.email);
    }

    for (const auto &license : _license) {
        auto element = appendSimpleXMLNode(root, "license", license.name);
        if (element) addAttribute(element, "file", license.file.string());
    }

    if (_freecadmin != Meta::Version()) appendSimpleXMLNode(root, "freecadmin", _freecadmin.str());

    if (_freecadmax != Meta::Version()) appendSimpleXMLNode(root, "freecadmax", _freecadmax.str());

    if (_pythonmin != Meta::Version()) appendSimpleXMLNode(root, "pythonmin", _pythonmin.str());

    for (const auto &url : _url) {
        auto element = appendSimpleXMLNode(root, "url", url.location);
        if (element) {
            std::string typeAsString("website");
            switch (url.type) {
                case Meta::UrlType::website: typeAsString = "website"; break;
                case Meta::UrlType::repository: typeAsString = "repository"; break;
                case Meta::UrlType::bugtracker: typeAsString = "bugtracker"; break;
                case Meta::UrlType::readme: typeAsString = "readme"; break;
                case Meta::UrlType::documentation: typeAsString = "documentation"; break;
                case Meta::UrlType::discussion: typeAsString = "discussion"; break;
            }
            addAttribute(element, "type", typeAsString);
            if (url.type == Meta::UrlType::repository) {
                addAttribute(element, "branch", url.branch);
            }
        }
    }

    for (const auto &author : _author) {
        auto element = appendSimpleXMLNode(root, "author", author.name);
        if (element) addAttribute(element, "email", author.email);
    }

    for (const auto &depend : _depend) addDependencyNode(root, "depend", depend);

    for (const auto &conflict : _conflict) addDependencyNode(root, "conflict", conflict);

    for (const auto &replace : _replace) addDependencyNode(root, "replace", replace);

    for (const auto &tag : _tag) appendSimpleXMLNode(root, "tag", tag);

    appendSimpleXMLNode(root, "icon", _icon.string());

    appendSimpleXMLNode(root, "classname", _classname);

    appendSimpleXMLNode(root, "subdirectory", _subdirectory.string());

    for (const auto &file : _file) appendSimpleXMLNode(root, "file", file.string());

    for (const auto &md : _genericMetadata) {
        auto element = appendSimpleXMLNode(root, md.first, md.second.contents);
        for (const auto &attr : md.second.attributes)
            addAttribute(element, attr.first, attr.second);
    }

    if (!_content.empty()) {
        auto doc = root->getOwnerDocument();
        DOMElement *contentRootElement = doc->createElement(XUTF8Str("content").unicodeForm());
        root->appendChild(contentRootElement);
        for (const auto &content : _content) {
            DOMElement *contentElement =
                doc->createElement(XUTF8Str(content.first.c_str()).unicodeForm());
            contentRootElement->appendChild(contentElement);
            content.second.appendToElement(contentElement);
        }
    }
}


void Metadata::parseVersion1(const DOMNode *startNode)
{
    auto children = startNode->getChildNodes();

    for (XMLSize_t i = 0; i < children->getLength(); ++i) {
        auto child = children->item(i);
        auto element = dynamic_cast<const DOMElement *>(child);
        if (!element) continue;

        auto tag = element->getNodeName();
        auto tagString = StrXUTF8(tag).str;

        if (tagString == "name") _name = StrXUTF8(element->getTextContent()).str;
        else if (tagString == "version")
            _version = Meta::Version(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "date")
            _date = StrXUTF8(element->getTextContent()).str;
        else if (tagString == "description")
            _description = StrXUTF8(element->getTextContent()).str;
        else if (tagString == "maintainer")
            _maintainer.emplace_back(element);
        else if (tagString == "license")
            _license.emplace_back(element);
        else if (tagString == "freecadmin")
            _freecadmin = Meta::Version(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "freecadmax")
            _freecadmax = Meta::Version(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "pythonmin")
            _pythonmin = Meta::Version(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "url")
            _url.emplace_back(element);
        else if (tagString == "author")
            _author.emplace_back(element);
        else if (tagString == "depend")
            _depend.emplace_back(element);
        else if (tagString == "conflict")
            _conflict.emplace_back(element);
        else if (tagString == "replace")
            _replace.emplace_back(element);
        else if (tagString == "tag")
            _tag.emplace_back(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "file")
            _file.emplace_back(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "classname")
            _classname = StrXUTF8(element->getTextContent()).str;
        else if (tagString == "subdirectory")
            _subdirectory = StrXUTF8(element->getTextContent()).str;
        else if (tagString == "icon")
            _icon = fs::path(StrXUTF8(element->getTextContent()).str);
        else if (tagString == "content")
            parseContentNodeVersion1(element);// Recursive call
        else {
            // If none of this node's children have children of their own, it is a simple element and we
            // can handle it as a GenericMetadata object
            auto children = element->getChildNodes();
            bool hasGrandchildren = false;
            for (XMLSize_t i = 0; i < children->getLength() && !hasGrandchildren; ++i)
                if (children->item(i)->getChildNodes()->getLength() > 0) hasGrandchildren = true;
            if (!hasGrandchildren)
                _genericMetadata.insert(std::make_pair(tagString, Meta::GenericMetadata(element)));
        }
    }
}

void Metadata::parseContentNodeVersion1(const DOMElement *contentNode)
{
    auto children = contentNode->getChildNodes();
    for (XMLSize_t i = 0; i < children->getLength(); ++i) {
        auto child = dynamic_cast<const DOMElement *>(children->item(i));
        if (child) {
            auto tag = StrXUTF8(child->getTagName()).str;
            _content.insert(std::make_pair(tag, Metadata(child, 1)));
        }
    }
}

Meta::Contact::Contact(const std::string &name, const std::string &email) : name(name), email(email)
{
    // This has to be provided manually since we have another constructor
}

Meta::Contact::Contact(const XERCES_CPP_NAMESPACE::DOMElement *e)
{
    auto emailAttribute = e->getAttribute(XUTF8Str("email").unicodeForm());
    name = StrXUTF8(e->getTextContent()).str;
    email = StrXUTF8(emailAttribute).str;
}

bool App::Meta::Contact::operator==(const Contact &rhs) const
{
    return name == rhs.name && email == rhs.email;
}

Meta::License::License(const std::string &name, fs::path file) : name(name), file(file)
{
    // This has to be provided manually since we have another constructor
}

Meta::License::License(const XERCES_CPP_NAMESPACE::DOMElement *e)
{
    auto fileAttribute = e->getAttribute(XUTF8Str("file").unicodeForm());
    if (XMLString::stringLen(fileAttribute) > 0) { file = fs::path(StrXUTF8(fileAttribute).str); }
    name = StrXUTF8(e->getTextContent()).str;
}

bool App::Meta::License::operator==(const License &rhs) const
{
    return name == rhs.name && file == rhs.file;
}

App::Meta::Url::Url() : location(""), type(App::Meta::UrlType::website) {}

Meta::Url::Url(const std::string &location, UrlType type) : location(location), type(type)
{
    // This has to be provided manually since we have another constructor
}

Meta::Url::Url(const XERCES_CPP_NAMESPACE::DOMElement *e)
{
    auto typeAttribute = StrXUTF8(e->getAttribute(XUTF8Str("type").unicodeForm())).str;
    if (typeAttribute.empty() || typeAttribute == "website") type = UrlType::website;
    else if (typeAttribute == "bugtracker")
        type = UrlType::bugtracker;
    else if (typeAttribute == "repository")
        type = UrlType::repository;
    else if (typeAttribute == "readme")
        type = UrlType::readme;
    else if (typeAttribute == "documentation")
        type = UrlType::documentation;
    else if (typeAttribute == "discussion")
        type = UrlType::discussion;
    else
        type = UrlType::website;

    if (type == UrlType::repository)
        branch = StrXUTF8(e->getAttribute(XUTF8Str("branch").unicodeForm())).str;

    location = StrXUTF8(e->getTextContent()).str;
}

bool App::Meta::Url::operator==(const Url &rhs) const
{
    if (type == UrlType::repository && branch != rhs.branch)
        return false;
    return type == rhs.type && location == rhs.location;
}

App::Meta::Dependency::Dependency()
    : optional(false), dependencyType(App::Meta::DependencyType::automatic)
{}

App::Meta::Dependency::Dependency(const std::string &pkg)
    : package(pkg), optional(false), dependencyType(App::Meta::DependencyType::automatic)
{}

Meta::Dependency::Dependency(const XERCES_CPP_NAMESPACE::DOMElement *e)
{
    version_lt = StrXUTF8(e->getAttribute(XUTF8Str("version_lt").unicodeForm())).str;
    version_lte = StrXUTF8(e->getAttribute(XUTF8Str("version_lte").unicodeForm())).str;
    version_eq = StrXUTF8(e->getAttribute(XUTF8Str("version_eq").unicodeForm())).str;
    version_gte = StrXUTF8(e->getAttribute(XUTF8Str("version_gte").unicodeForm())).str;
    version_gt = StrXUTF8(e->getAttribute(XUTF8Str("version_gt").unicodeForm())).str;
    condition = StrXUTF8(e->getAttribute(XUTF8Str("condition").unicodeForm())).str;
    std::string opt_string = StrXUTF8(e->getAttribute(XUTF8Str("optional").unicodeForm())).str;
    if (opt_string == "true"
        || opt_string == "True")// Support Python capitalization in this one case...
        optional = true;
    else
        optional = false;
    std::string type_string = StrXUTF8(e->getAttribute(XUTF8Str("type").unicodeForm())).str;
    if (type_string == "automatic" || type_string == "")
        dependencyType = Meta::DependencyType::automatic;
    else if (type_string == "addon")
        dependencyType = Meta::DependencyType::addon;
    else if (type_string == "internal")
        dependencyType = Meta::DependencyType::internal;
    else if (type_string == "python")
        dependencyType = Meta::DependencyType::python;
    else {
        auto message = std::string("Invalid dependency type \"") + type_string + "\"";
        throw Base::XMLBaseException(message);
    }

    package = StrXUTF8(e->getTextContent()).str;
}

bool App::Meta::Dependency::operator==(const Dependency &rhs) const
{
    return package == rhs.package && version_lt == rhs.version_lt && version_lte == rhs.version_lte
        && version_eq == rhs.version_eq && version_gte == rhs.version_gte
        && version_gt == rhs.version_gt && condition == rhs.condition && optional == rhs.optional
        && dependencyType == rhs.dependencyType;
}

Meta::Version::Version() : major(0), minor(0), patch(0) {}

Meta::Version::Version(int major, int minor, int patch, const std::string &suffix)
    : major(major), minor(minor), patch(patch), suffix(suffix)
{}

Meta::Version::Version(const std::string &versionString) : minor(0), patch(0)
{
    std::istringstream stream(versionString);
    char separator;
    stream >> major;
    if (stream) stream >> separator;
    if (stream) stream >> minor;
    if (stream) stream >> separator;
    if (stream) stream >> patch;
    if (stream) stream >> suffix;
}

std::string Meta::Version::str() const
{
    if (*this == Meta::Version())
        return "";
    std::ostringstream stream;
    stream << major << "." << minor << "." << patch << suffix;
    return stream.str();
}

bool Meta::Version::operator<(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        < std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

bool Meta::Version::operator>(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        > std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

bool Meta::Version::operator<=(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        <= std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

bool Meta::Version::operator>=(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        >= std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

bool Meta::Version::operator==(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        == std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

bool Meta::Version::operator!=(const Version &rhs) const
{
    return std::tie(major, minor, patch, suffix)
        != std::tie(rhs.major, rhs.minor, rhs.patch, rhs.suffix);
}

Meta::GenericMetadata::GenericMetadata(const XERCES_CPP_NAMESPACE::DOMElement *e)
{
    contents = StrXUTF8(e->getTextContent()).str;
    for (XMLSize_t i = 0; i < e->getAttributes()->getLength(); ++i) {
        auto a = e->getAttributes()->item(i);
        attributes.insert(
            std::make_pair(StrXUTF8(a->getNodeName()).str, StrXUTF8(a->getTextContent()).str));
    }
}

App::Meta::GenericMetadata::GenericMetadata(const std::string &contents) : contents(contents) {}