/*
 * This file is part of the KDE project
 * SPDX-FileCopyrightText: 2014 Arjen Hiemstra <ahiemstra@heimr.nl>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "Theme.h"

#include <QApplication>
#include <QColor>
#include <QDebug>
#include <QDir>
#include <QFile>
#include <QFont>
#include <QFontDatabase>
#include <QQmlComponent>
#include <QStandardPaths>
#include <QStringList>
#include <QUrl>
#include <QWidget>

#include <KIconLoader>

#include "QmlGlobalEngine.h"

#ifdef Q_OS_WIN
#include <windows.h>
#endif

class Theme::Private
{
public:
    Private()
        : inheritedTheme(nullptr)
        , iconPath("icons/")
        , imagePath("images/")
        , fontPath("fonts/")
        , fontsAdded(false)
        , lineCountLandscape(40)
        , lineCountPortrait(70)
    {
    }

    void rebuildFontCache();

    QString id;
    QString name;
    QString inherits;
    Theme *inheritedTheme;

    QVariantMap colors;
    QVariantMap sizes;
    QVariantMap fonts;

    QString basePath;
    QString iconPath;
    QString imagePath;
    QString fontPath;

    QHash<QString, QColor> colorCache;
    QHash<QString, QFont> fontMap;

    bool fontsAdded;
    QList<int> addedFonts;
    int lineCountLandscape;
    int lineCountPortrait;
};

Theme::Theme(QObject *parent)
    : QObject(parent)
    , d(new Private)
{
    qApp->installEventFilter(this);
}

Theme::~Theme()
{
    QFontDatabase db;
    Q_FOREACH (int id, d->addedFonts) {
        db.removeApplicationFont(id);
    }

    delete d;
}

QString Theme::id() const
{
    return d->id;
}

void Theme::setId(const QString &newValue)
{
    if (newValue != d->id) {
        d->id = newValue;
        const QString qmlFileSubPath = QStringLiteral("calligragemini/themes/") + d->id + QStringLiteral("/theme.qml");
        const QString qmlFileFullPath = QStandardPaths::locate(QStandardPaths::GenericDataLocation, qmlFileSubPath);
        d->basePath = QFileInfo(qmlFileFullPath).dir().absolutePath();
        emit idChanged();
    }
}

QString Theme::name() const
{
    return d->name;
}

void Theme::setName(const QString &newValue)
{
    if (newValue != d->name) {
        d->name = newValue;
        emit nameChanged();
    }
}

QString Theme::inherits() const
{
    return d->inherits;
}

void Theme::setInherits(const QString &newValue)
{
    if (newValue != d->inherits) {
        if (d->inheritedTheme) {
            delete d->inheritedTheme;
            d->inheritedTheme = nullptr;
        }
        d->inherits = newValue;

        if (!d->inherits.isEmpty()) {
            d->inheritedTheme = Theme::load(d->inherits, this);
            connect(d->inheritedTheme, &Theme::fontCacheRebuilt, this, &Theme::fontCacheRebuilt);
        }

        emit inheritsChanged();
    }
}

QVariantMap Theme::colors() const
{
    return d->colors;
}

void Theme::setColors(const QVariantMap &newValue)
{
    if (newValue != d->colors) {
        d->colors = newValue;
        emit colorsChanged();
    }
}

QColor Theme::color(const QString &name)
{
    if (d->colorCache.contains(name))
        return d->colorCache.value(name);

    QStringList parts = name.split('/');
    QColor result;

    if (!parts.isEmpty()) {
        QVariantMap map = d->colors;
        QString current = parts.takeFirst();

        while (map.contains(current)) {
            QVariant value = map.value(current);
            if (value.type() == QVariant::Map) {
                if (parts.isEmpty())
                    break;

                map = value.toMap();
                current = parts.takeFirst();
            } else {
                result = value.value<QColor>();
                map = QVariantMap();
            }
        }
    }

    if (!result.isValid() && d->inheritedTheme) {
        result = d->inheritedTheme->color(name);
    }

    if (!result.isValid()) {
        qWarning() << "Unable to find color" << name;
    } else {
        d->colorCache.insert(name, result);
    }

    return result;
}

QVariantMap Theme::sizes() const
{
    return d->sizes;
}

void Theme::setSizes(const QVariantMap &newValue)
{
    if (newValue != d->sizes) {
        d->sizes = newValue;
        emit sizesChanged();
    }
}

float Theme::size(const QString &name)
{
    Q_UNUSED(name);
    return 0.f;
}

QVariantMap Theme::fonts() const
{
    return d->fonts;
}

void Theme::setFonts(const QVariantMap &newValue)
{
    if (newValue != d->fonts) {
        d->fonts = newValue;

        d->fontMap.clear();

        emit fontsChanged();
    }
}

QFont Theme::font(const QString &name)
{
    if (!d->fontsAdded) {
        QDir fontDir(d->basePath + '/' + d->fontPath);
        QStringList entries = fontDir.entryList(QDir::Files);
        QFontDatabase db;
        Q_FOREACH (const QString &entry, entries) {
            d->addedFonts.append(db.addApplicationFont(fontDir.absoluteFilePath(entry)));
        }
        d->fontsAdded = true;
    }

    if (d->fontMap.isEmpty()) {
        d->rebuildFontCache();
    }

    if (d->fontMap.contains(name))
        return d->fontMap.value(name);

    if (d->inheritedTheme)
        return d->inheritedTheme->font(name);

    qWarning() << "Unable to find font" << name;
    return QFont();
}

QString Theme::fontPath() const
{
    return d->fontPath;
}

void Theme::setFontPath(const QString &newValue)
{
    if (newValue != d->fontPath) {
        if (!d->addedFonts.isEmpty()) {
            QFontDatabase db;
            Q_FOREACH (int id, d->addedFonts) {
                db.removeApplicationFont(id);
            }
            d->addedFonts.clear();
        }

        d->fontPath = newValue;
        d->fontsAdded = false;

        emit fontPathChanged();
    }
}

QString Theme::iconPath() const
{
    return d->iconPath;
}

void Theme::setIconPath(const QString &newValue)
{
    if (newValue != d->iconPath) {
        d->iconPath = newValue;
        emit iconPathChanged();
    }
}

QUrl Theme::icon(const QString &name, bool useSystemFallback)
{
    QString url = QString("%1/%2/%3.svg").arg(d->basePath, d->iconPath, name);
    if (!QFile::exists(url)) {
        if (d->inheritedTheme) {
            return d->inheritedTheme->icon(name);
        } else {
            if (useSystemFallback) {
                url = KIconLoader::global()->iconPath(name, -128);
                qWarning() << "Attempting to use a system fallback icon" << url;
            } else {
                qWarning() << "Unable to find icon" << url;
            }
        }
    }

    return QUrl::fromLocalFile(url);
}

QIcon Theme::iconActual(const QString &name)
{
    return QIcon(icon(name).toLocalFile());
}

QString Theme::imagePath() const
{
    return d->imagePath;
}

void Theme::setImagePath(const QString &newValue)
{
    if (newValue != d->imagePath) {
        d->imagePath = newValue;
        emit imagePathChanged();
    }
}

QUrl Theme::image(const QString &name)
{
    QString url = QString("%1/%2/%3").arg(d->basePath, d->imagePath, name);
    if (!QFile::exists(url)) {
        if (d->inheritedTheme) {
            return d->inheritedTheme->image(name);
        } else {
            qWarning() << "Unable to find image" << url;
        }
    }

    return QUrl::fromLocalFile(url);
}

Theme *Theme::load(const QString &id, QObject *parent)
{
    QString qml;

    // Ugly hacky stuff for making things work on Windows
#ifdef Q_OS_WIN
    QDir appdir(qApp->applicationDirPath());

    // Corrects for mismatched case errors in path (qtdeclarative fails to load)
    wchar_t buffer[1024];
    QString absolute = appdir.absolutePath();
    DWORD rv = ::GetShortPathName((wchar_t *)absolute.utf16(), buffer, 1024);
    rv = ::GetLongPathName(buffer, buffer, 1024);
    QString correctedPath((QChar *)buffer);
    appdir.setPath(correctedPath);

    // for now, the app in bin/ and we still use the env.bat script
    appdir.cdUp();
    qml = QString("%1/bin/data/calligragemini/themes/%2/theme.qml").arg(appdir.canonicalPath(), id);
#else
    const QString qmlFileSubPath = QStringLiteral("calligragemini/themes/") + id + QStringLiteral("/theme.qml");
    qml = QStandardPaths::locate(QStandardPaths::GenericDataLocation, qmlFileSubPath);
#endif

    QQmlComponent themeComponent(QmlGlobalEngine::instance()->engine(), parent);
    themeComponent.loadUrl(QUrl::fromLocalFile(qml));

    if (themeComponent.isError()) {
        qWarning() << themeComponent.errorString();
        return nullptr;
    }

    Theme *theme = qobject_cast<Theme *>(themeComponent.create());
    if (!theme) {
        qWarning() << "Failed to create theme instance!";
        return nullptr;
    }

    return theme;
}

bool Theme::eventFilter(QObject *target, QEvent *event)
{
    if (target == qApp->activeWindow() && target->inherits("QMainWindow") && event->type() == QEvent::Resize) {
        d->rebuildFontCache();
        emit fontCacheRebuilt();
    }

    return QObject::eventFilter(target, event);
}

int Theme::adjustedPixel(const int &pixel) const
{
    if (!qApp->activeWindow())
        return 0;

    // If we are in portrait mode, we still assume 1080p for font size purposes
    int width = qApp->activeWindow()->height() > qApp->activeWindow()->width() ? qApp->activeWindow()->height() : qApp->activeWindow()->width();
    // The pixel size is based on a 1080p screen, and it is accepted that the window size
    // will vary slightly on there, depending on whether or not we are full screened (so
    // we accept up to 10 pixels less width)
    float sizeAdjustment = 1;
    if (width > 1920 || width < 1910)
        sizeAdjustment = width / 1920.f;
    return pixel * sizeAdjustment;
}

void Theme::Private::rebuildFontCache()
{
    fontMap.clear();
    QFontDatabase db;
    for (QVariantMap::ConstIterator itr = fonts.constBegin(); itr != fonts.constEnd(); ++itr) {
        QVariantMap map = itr->toMap();
        if (map.isEmpty())
            continue;

        QFont font = db.font(map.value("family").toString(), map.value("style", "Regular").toString(), 10);

        if (font.isCopyOf(qApp->font()))
            qWarning() << "Could not find font" << map.value("family") << "with style" << map.value("style", "Regular");

        if (map.contains("pixelSize")) {
            // If we are in portrait mode, we still assume 1080p for font size purposes
            int width = qApp->activeWindow()->height() > qApp->activeWindow()->width() ? qApp->activeWindow()->height() : qApp->activeWindow()->width();
            // The pixel size is based on a 1080p screen, and it is accepted that the window size
            // will vary slightly on there, depending on whether or not we are full screened (so
            // we accept up to 10 pixels less width)
            float sizeAdjustment = 1;
            if (width > 1920 || width < 1910)
                sizeAdjustment = width / 1920.f;
            font.setPixelSize(map.value("pixelSize").toInt() * sizeAdjustment);
        } else {
            float lineCount = qApp->activeWindow()->height() > qApp->activeWindow()->width() ? lineCountPortrait : lineCountLandscape;
            float lineHeight = qApp->activeWindow()->height() / lineCount;
            font.setPixelSize(lineHeight * map.value("size", 1).toFloat());
        }

        fontMap.insert(itr.key(), font);
    }
}