/***************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2013 BlackBerry Limited. All rights reserved.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Controls 2 module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** accordance with the commercial license agreement provided with the
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** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
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** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
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** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
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** rights. These rights are described in The Qt Company LGPL Exception
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** $QT_END_LICENSE$
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****************************************************************************/

#include "qquickstyleselector_p.h"
#include "qquickstyleselector_p_p.h"
#include "qquickstyle.h"

#include <QtCore/qdir.h>
#include <QtCore/qfile.h>
#include <QtCore/qfileinfo.h>
#include <QtCore/qsysinfo.h>
#include <QtCore/qlocale.h>

#include <QtGui/private/qguiapplication_p.h>

QT_BEGIN_NAMESPACE

static bool isLocalScheme(const QString &scheme)
{
    bool local = scheme == QLatin1String("qrc");
#ifdef Q_OS_ANDROID
    local |= scheme == QLatin1String("assets");
#endif
    return local;
}

// similar, but not identical to QSysInfo::osType
static QStringList platformSelectors()
{
    static QStringList selectors;
    if (!selectors.isEmpty())
        return selectors;

#if defined(Q_OS_WIN)
    // can't fall back to QSysInfo because we need both "winphone" and "winrt" for the Windows Phone case
    selectors << QStringLiteral("windows");
    selectors << QSysInfo::kernelType();  // "wince" and "winnt"
#  if defined(Q_OS_WINRT)
    selectors << QStringLiteral("winrt");
#    if defined(Q_OS_WINPHONE)
    selectors << QStringLiteral("winphone");
#    endif
#  endif
#elif defined(Q_OS_UNIX)
    selectors << QStringLiteral("unix");
#  if !defined(Q_OS_ANDROID) && !defined(Q_OS_BLACKBERRY)
    // we don't want "linux" for Android or "qnx" for Blackberry here
    selectors << QSysInfo::kernelType();
#     ifdef Q_OS_MAC
    selectors << QStringLiteral("mac"); // compatibility, since kernelType() is "darwin"
#     endif
#  endif
    QString productName = QSysInfo::productType();
    if (productName != QLatin1String("unknown"))
        selectors << productName; // "opensuse", "fedora", "osx", "ios", "blackberry", "android"
#endif
    return selectors;
}

static QStringList allSelectors(bool includeStyle)
{
    QStringList selectors = platformSelectors();
    selectors += QLocale().name();
    if (includeStyle) {
        QString style = QQuickStyle::name();
        if (!style.isEmpty())
            selectors.prepend(style);
    }
    return selectors;
}

static QString selectionHelper(const QString &path, const QString &fileName, const QStringList &selectors)
{
    /* selectionHelper does a depth-first search of possible selected files. Because there is strict
       selector ordering in the API, we can stop checking as soon as we find the file in a directory
       which does not contain any other valid selector directories.
    */
    Q_ASSERT(path.isEmpty() || path.endsWith(QLatin1Char('/')));

    for (const QString &s : selectors) {
        QString prospectiveBase = path + s + QLatin1Char('/');
        QStringList remainingSelectors = selectors;
        remainingSelectors.removeAll(s);
        if (!QDir(prospectiveBase).exists())
            continue;
        QString prospectiveFile = selectionHelper(prospectiveBase, fileName, remainingSelectors);
        if (!prospectiveFile.isEmpty())
            return prospectiveFile;
    }

    // If we reach here there were no successful files found at a lower level in this branch, so we
    // should check this level as a potential result.
    const QString result = path + fileName;
    if (!QFileInfo::exists(result))
        return QString();
    return result;
}

QString QQuickStyleSelectorPrivate::select(const QString &filePath) const
{
    QFileInfo fi(filePath);
    // If file doesn't exist, don't select
    if (!fi.exists())
        return filePath;

    const QString path = fi.path();
    const QString ret = selectionHelper(path.isEmpty() ? QString() : path + QLatin1Char('/'),
                                        fi.fileName(), allSelectors(true));

    if (!ret.isEmpty())
        return ret;
    return filePath;
}

QQuickStyleSelector::QQuickStyleSelector() : d_ptr(new QQuickStyleSelectorPrivate)
{
}

QQuickStyleSelector::~QQuickStyleSelector()
{
}

QUrl QQuickStyleSelector::baseUrl() const
{
    Q_D(const QQuickStyleSelector);
    return d->baseUrl;
}

void QQuickStyleSelector::setBaseUrl(const QUrl &url)
{
    Q_D(QQuickStyleSelector);
    d->baseUrl = url;
}

QString QQuickStyleSelector::select(const QString &fileName) const
{
    Q_D(const QQuickStyleSelector);
    const QString overridePath = QQuickStyle::path();
    if (!overridePath.isEmpty()) {
        const QString stylePath = overridePath + QQuickStyle::name() + QLatin1Char('/');
        if (QFile::exists(stylePath + fileName)) {
            // the style name is included to the path, so exclude it from the selectors.
            // the rest of the selectors (os, locale) are still valid, though.
            const QString selectedPath = selectionHelper(stylePath, fileName, allSelectors(false));
            if (selectedPath.startsWith(QLatin1Char(':')))
                return QLatin1String("qrc") + selectedPath;
            return QUrl::fromLocalFile(selectedPath).toString();
        }
    }

    QUrl url(d->baseUrl.toString() + QLatin1Char('/') + fileName);
    if (isLocalScheme(url.scheme())) {
        QString equivalentPath = QLatin1Char(':') + url.path();
        QString selectedPath = d->select(equivalentPath);
        url.setPath(selectedPath.remove(0, 1));
    } else if (url.isLocalFile()) {
        url = QUrl::fromLocalFile(d->select(url.toLocalFile()));
    }
    return url.toString();
}

QT_END_NAMESPACE