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#include <private/qqmljslexer_p.h>
#include <private/qqmljsparser_p.h>
#include <private/qqmljsast_p.h>
#include <private/qv4codegen_p.h>
#include <private/qqmlpool_p.h>

#include <QtCore/QCoreApplication>
#include <QtCore/QDir>
#include <QtCore/QFile>
#include <QtCore/QFileInfo>
#include <QtCore/QSet>
#include <QtCore/QStringList>
#include <QtCore/QMetaObject>
#include <QtCore/QMetaProperty>
#include <QtCore/QVariant>
#include <QtCore/QJsonObject>
#include <QtCore/QJsonArray>
#include <QtCore/QJsonDocument>
#include <QtCore/QLibraryInfo>

#include <iostream>

QT_USE_NAMESPACE

QStringList g_qmlImportPaths;

void printUsage(const QString &appName)
{
    std::cerr << qPrintable(QString::fromLatin1(
                                 "Usage: %1 -rootPath qmldir -importPath importPath \n"
                                 "Example: %1 -rootPath qmldir -importPath importPath").arg(
                                 appName));
}

QVariantList findImportsInAst(QQmlJS::AST::UiHeaderItemList *headerItemList, const QByteArray &code, const QString &path)
{
    QVariantList imports;

    // extract uri and version from the imports (which look like "import Foo.Bar 1.2.3")
    for (QQmlJS::AST::UiHeaderItemList *headerItemIt = headerItemList; headerItemIt; headerItemIt = headerItemIt->next) {
        QVariantMap import;
        QQmlJS::AST::UiImport *importNode = QQmlJS::AST::cast<QQmlJS::AST::UiImport *>(headerItemIt->headerItem);
        if (!importNode)
            continue;
        // handle directory imports
        if (!importNode->fileName.isEmpty()) {
            QString name = importNode->fileName.toString();
            import[QStringLiteral("name")] = name;
            import[QStringLiteral("type")] = QStringLiteral("directory");
            import[QStringLiteral("path")] = path + QLatin1Char('/') + name;
        } else {
            // Walk the id chain ("Foo" -> "Bar" -> etc)
            QString  name;
            QQmlJS::AST::UiQualifiedId *uri = importNode->importUri;
            while (uri) {
                name.append(uri->name);
                name.append(QLatin1Char('.'));
                uri = uri->next;
            }
            name.chop(1); // remove trailing "."
            if (!name.isEmpty())
                import[QStringLiteral("name")] = name;
            import[QStringLiteral("type")] = QStringLiteral("module");
            import[QStringLiteral("version")] = code.mid(importNode->versionToken.offset, importNode->versionToken.length);
        }

        imports.append(import);
    }

    return imports;
}

// Scan a single qml file for import statements
QVariantList findQmlImportsInFile(const QString &qmlFilePath)
{
    QFile qmlFile(qmlFilePath);
    if (!qmlFile.open(QIODevice::ReadOnly)) {
           std::cerr << "Cannot open input file " << qPrintable(QDir::toNativeSeparators(qmlFile.fileName()))
                     << ':' << qPrintable(qmlFile.errorString()) << std::endl;
           return QVariantList();
    }
    QByteArray code = qmlFile.readAll();

    QQmlJS::Engine engine;
    QQmlJS::Lexer lexer(&engine);
    lexer.setCode(QString::fromUtf8(code), /*line = */ 1);
    QQmlJS::Parser parser(&engine);

    if (!parser.parse() || !parser.diagnosticMessages().isEmpty()) {
        // Extract errors from the parser
        foreach (const QQmlJS::DiagnosticMessage &m, parser.diagnosticMessages()) {
            std::cerr << qPrintable(QDir::toNativeSeparators(qmlFile.fileName())) << ':'
                      << m.loc.startLine << ':' << qPrintable(m.message) << std::endl;
        }
        return QVariantList();
    }

    return findImportsInAst(parser.ast()->headers, code, QFileInfo(qmlFilePath).absolutePath());
}

// Scan all qml files in directory for import statements
QVariantList findQmlImportsInDirectory(const QString &qmlDir)
{
    QVariantList ret;
    if (qmlDir.isEmpty())
        return ret;

    QStringList qmlFileNames = QDir(qmlDir).entryList(QStringList(QStringLiteral("*.qml")));
    foreach (const QString &qmlFileName, qmlFileNames) {
        QString qmlFilePath = qmlDir + QLatin1Char('/') + qmlFileName;
            QVariantList imports = findQmlImportsInFile(qmlFilePath);
            ret.append(imports);

    }
    return ret;
}

// Read the qmldir file, extract a list of plugins by
// parsing the "plugin"  and "classname" lines.
QVariantMap pluginsForModulePath(const QString &modulePath) {
    QFile qmldirFile(modulePath + QStringLiteral("/qmldir"));
    if (!qmldirFile.exists())
        return QVariantMap();

    qmldirFile.open(QIODevice::ReadOnly | QIODevice::Text);

    // a qml import may contain several plugins
    QString plugins;
    QString classnames;
    QByteArray line;
    do {
        line = qmldirFile.readLine();
        if (line.startsWith("plugin")) {
            plugins += QString::fromUtf8(line.split(' ').at(1));
            plugins += QStringLiteral(" ");
        } else if (line.startsWith("classname")) {
            classnames += QString::fromUtf8(line.split(' ').at(1));
            classnames += QStringLiteral(" ");
        }

    } while (line.length() > 0);

    QVariantMap pluginInfo;
    pluginInfo[QStringLiteral("plugins")] = plugins.simplified();
    pluginInfo[QStringLiteral("classnames")] = classnames.simplified();
    return pluginInfo;
}

// Search for a given qml import in g_qmlImportPaths.
QString resolveImportPath(const QString &uri, const QString &version)
{
    // Create path from uri (QtQuick.Controls -> QtQuick/Controls)
    QString path = uri;
    path.replace(QLatin1Char('.'), QLatin1Char('/'));
    // search for the most spesifc version first
    QString versionedName = path + QLatin1Char('.') + version;
    while (true) {
        // look in all g_qmlImportPaths
        foreach (const QString &qmlImportPath, g_qmlImportPaths) {
            QString candidatePath = QDir::cleanPath(qmlImportPath + QLatin1Char('/') + versionedName);
            if (QDir(candidatePath).exists())
                return candidatePath; // import found
        }

        // remove the last version digit; stop if there are none left
        int lastDot = versionedName.lastIndexOf(QLatin1Char('.'));
        if (lastDot == -1)
            break;
        versionedName = versionedName.mid(0, lastDot);
    }

    return QString(); // not found
}

// Find absolute file system paths and plugins for a list of modules.
QVariantList findPathsForModuleImports(const QVariantList &imports)
{
    QVariantList done;

    foreach (QVariant importVariant, imports) {
        QVariantMap import = qvariant_cast<QVariantMap>(importVariant);
        if (import[QStringLiteral("type")] == QStringLiteral("module")) {
            import[QStringLiteral("path")] = resolveImportPath(import[QStringLiteral("name")].toString(), import[QStringLiteral("version")].toString());
            QVariantMap plugininfo = pluginsForModulePath(import[QStringLiteral("path")].toString());
            QString plugins = plugininfo[QStringLiteral("plugins")].toString();
            QString classnames = plugininfo[QStringLiteral("classnames")].toString();
            if (!plugins.isEmpty()) {
                import[QStringLiteral("plugin")] = plugins;
                import[QStringLiteral("classname")] = classnames;
            }
        }
        if (!import[QStringLiteral("path")].isNull())
            done.append(import);
    }
    return done;
}

// Merge two lists of imports, discard duplicates.
QVariantList mergeImports(const QVariantList &a, const QVariantList &b)
{
    QVariantList merged = a;
    foreach (const QVariant &variant, b) {
        if (!merged.contains(variant))
            merged.append(variant);
    }
    return merged;
}

// find Qml Imports Recursively
QVariantList findQmlImportsRecursively(const QStringList &qmlDirs)
{
    QVariantList ret;

    QSet<QString> toVisit = qmlDirs.toSet();
    QSet<QString> visited;
    while (!toVisit.isEmpty()) {
        QString qmlDir = *toVisit.begin();
        toVisit.erase(toVisit.begin());
        visited.insert(qmlDir);

        QVariantList imports = findQmlImportsInDirectory(qmlDir);
        imports = findPathsForModuleImports(imports);

        // schedule recursive visit of imports
        foreach (const QVariant &importVariant, imports) {
            QVariantMap import = qvariant_cast<QVariantMap>(importVariant);
            QString path = import[QStringLiteral("path")].toString();
            if (!path.isEmpty() && !visited.contains(path)) {
                toVisit.insert(path);
            }
        }

        ret = mergeImports(ret, imports);
    }

    return ret;
}

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);
    QStringList args = app.arguments();
    const QString appName = QFileInfo(app.applicationFilePath()).baseName();
    if (args.size() < 2) {
        printUsage(appName);
        return 1;
    }

    QStringList qmlRootPaths;
    QStringList qmlImportPaths;

    int i = 1;
    while (i < args.count()) {
        const QString &arg = args.at(i);
        ++i;
        if (!arg.startsWith(QLatin1Char('-'))) {
            qmlRootPaths += arg;
        } else if (arg == QLatin1String("-rootPath")) {
            if (i >= args.count())
                std::cerr << "-rootPath requires an argument\n";

            while (i < args.count()) {
                const QString arg = args.at(i);
                if (arg.startsWith(QLatin1Char('-')))
                    break;
                ++i;
                qmlRootPaths += arg;
            }
        } else if (arg == QLatin1String("-importPath")) {
            if (i >= args.count())
                std::cerr << "-importPath requires an argument\n";

            while (i < args.count()) {
                const QString arg = args.at(i);
                if (arg.startsWith(QLatin1Char('-')))
                    break;
                ++i;
                qmlImportPaths += arg;
            }
        } else {
            std::cerr << "Invalid argument: \"" << qPrintable(arg) << "\"\n";
            return 1;
        }
    }

    g_qmlImportPaths = qmlImportPaths;

    // Find the imports!
    QVariantList imports = findQmlImportsRecursively(qmlRootPaths);

    // Convert to JSON
    QByteArray json = QJsonDocument(QJsonArray::fromVariantList(imports)).toJson();
    std::cout << json.constData() << std::endl;
    return 0;
}