// SPDX-License-Identifier: GPL-3.0-or-later
// SPDX-FileCopyrightText: 2017-2019 Alejandro Sirgo Rica & Contributors

#include <QGraphicsDropShadowEffect>
#include <QPinchGesture>

#include "pinwidget.h"
#include "qguiappcurrentscreen.h"
#include "screenshotsaver.h"
#include "src/utils/confighandler.h"
#include "src/utils/globalvalues.h"

#include <QLabel>
#include <QMenu>
#include <QScreen>
#include <QShortcut>
#include <QVBoxLayout>
#include <QWheelEvent>

namespace {
constexpr int MARGIN = 7;
constexpr int BLUR_RADIUS = 2 * MARGIN;
constexpr qreal STEP = 0.03;
constexpr qreal MIN_SIZE = 100.0;
}

PinWidget::PinWidget(const QPixmap& pixmap,
                     const QRect& geometry,
                     QWidget* parent)
  : QWidget(parent)
  , m_pixmap(pixmap)
  , m_layout(new QVBoxLayout(this))
  , m_label(new QLabel())
  , m_shadowEffect(new QGraphicsDropShadowEffect(this))
{
    setWindowIcon(QIcon(GlobalValues::iconPath()));
    setWindowFlags(Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint);
    // set the bottom widget background transparent
    setAttribute(Qt::WA_TranslucentBackground);
    setAttribute(Qt::WA_DeleteOnClose);

    ConfigHandler conf;
    m_baseColor = conf.uiColor();
    m_hoverColor = conf.contrastUiColor();

    m_layout->setContentsMargins(MARGIN, MARGIN, MARGIN, MARGIN);

    m_shadowEffect->setColor(m_baseColor);
    m_shadowEffect->setBlurRadius(BLUR_RADIUS);
    m_shadowEffect->setOffset(0, 0);
    setGraphicsEffect(m_shadowEffect);

    m_label->setPixmap(m_pixmap);
    m_layout->addWidget(m_label);

    new QShortcut(QKeySequence(Qt::CTRL + Qt::Key_Q), this, SLOT(close()));
    new QShortcut(Qt::Key_Escape, this, SLOT(close()));

    qreal devicePixelRatio = 1;
#if defined(Q_OS_MACOS)
    QScreen* currentScreen = QGuiAppCurrentScreen().currentScreen();
    if (currentScreen != nullptr) {
        devicePixelRatio = currentScreen->devicePixelRatio();
    }
#endif
    const int margin =
      static_cast<int>(static_cast<double>(MARGIN) * devicePixelRatio);
    QRect adjusted_pos = geometry + QMargins(margin, margin, margin, margin);
    setGeometry(adjusted_pos);
#if defined(Q_OS_LINUX)
    setWindowFlags(Qt::X11BypassWindowManagerHint);
#endif

#if defined(Q_OS_MACOS)
    if (currentScreen != nullptr) {
        QPoint topLeft = currentScreen->geometry().topLeft();
        adjusted_pos.setX((adjusted_pos.x() - topLeft.x()) / devicePixelRatio +
                          topLeft.x());

        adjusted_pos.setY((adjusted_pos.y() - topLeft.y()) / devicePixelRatio +
                          topLeft.y());
        adjusted_pos.setWidth(adjusted_pos.size().width() / devicePixelRatio);
        adjusted_pos.setHeight(adjusted_pos.size().height() / devicePixelRatio);
        resize(0, 0);
        move(adjusted_pos.x(), adjusted_pos.y());
    }
#endif
    grabGesture(Qt::PinchGesture);

    this->setContextMenuPolicy(Qt::CustomContextMenu);

    connect(this,
            &QWidget::customContextMenuRequested,
            this,
            &PinWidget::showContextMenu);
}

bool PinWidget::scrollEvent(QWheelEvent* event)
{
    const auto phase = event->phase();
    if (phase == Qt::ScrollPhase::ScrollUpdate
#if defined(Q_OS_LINUX) || defined(Q_OS_WINDOWS)
        // Linux is getting only NoScrollPhase events.
        || phase == Qt::ScrollPhase::NoScrollPhase
#endif
    ) {
        const auto angle = event->angleDelta();
        if (angle.y() == 0) {
            return true;
        }
        m_currentStepScaleFactor = angle.y() > 0
                                     ? m_currentStepScaleFactor + STEP
                                     : m_currentStepScaleFactor - STEP;
        m_expanding = m_currentStepScaleFactor >= 1.0;
    }
#if defined(Q_OS_MACOS)
    // ScrollEnd is currently supported only on Mac OSX
    if (phase == Qt::ScrollPhase::ScrollEnd) {
#else
    else {
#endif
        m_scaleFactor *= m_currentStepScaleFactor;
        m_currentStepScaleFactor = 1.0;
        m_expanding = false;
    }

    m_sizeChanged = true;
    update();
    return true;
}

void PinWidget::enterEvent(QEvent*)
{
    m_shadowEffect->setColor(m_hoverColor);
}

void PinWidget::leaveEvent(QEvent*)
{
    m_shadowEffect->setColor(m_baseColor);
}

void PinWidget::mouseDoubleClickEvent(QMouseEvent*)
{
    update();
    close();
}

void PinWidget::mousePressEvent(QMouseEvent* e)
{
    m_dragStart = e->globalPos();
    m_offsetX = e->localPos().x() / width();
    m_offsetY = e->localPos().y() / height();
}

void PinWidget::mouseMoveEvent(QMouseEvent* e)
{
    const QPoint delta = e->globalPos() - m_dragStart;
    const int offsetW = width() * m_offsetX;
    const int offsetH = height() * m_offsetY;
    move(m_dragStart.x() + delta.x() - offsetW,
         m_dragStart.y() + delta.y() - offsetH);
}

bool PinWidget::gestureEvent(QGestureEvent* event)
{
    if (QGesture* pinch = event->gesture(Qt::PinchGesture)) {
        pinchTriggered(static_cast<QPinchGesture*>(pinch));
    }
    return true;
}

bool PinWidget::event(QEvent* event)
{
    if (event->type() == QEvent::Gesture) {
        return gestureEvent(static_cast<QGestureEvent*>(event));
    } else if (event->type() == QEvent::Wheel) {
        return scrollEvent(static_cast<QWheelEvent*>(event));
    }
    return QWidget::event(event);
}

void PinWidget::paintEvent(QPaintEvent* event)
{
    if (m_sizeChanged) {
        const auto aspectRatio =
          m_expanding ? Qt::KeepAspectRatioByExpanding : Qt::KeepAspectRatio;
        const auto transformType = ConfigHandler().antialiasingPinZoom()
                                     ? Qt::SmoothTransformation
                                     : Qt::FastTransformation;
        const qreal iw = m_pixmap.width();
        const qreal ih = m_pixmap.height();
        const qreal nw = qBound(MIN_SIZE,
                                iw * m_currentStepScaleFactor * m_scaleFactor,
                                static_cast<qreal>(maximumWidth()));
        const qreal nh = qBound(MIN_SIZE,
                                ih * m_currentStepScaleFactor * m_scaleFactor,
                                static_cast<qreal>(maximumHeight()));

        const QPixmap pix = m_pixmap.scaled(nw, nh, aspectRatio, transformType);

        m_label->setPixmap(pix);
        adjustSize();
        m_sizeChanged = false;
    }
}

void PinWidget::pinchTriggered(QPinchGesture* gesture)
{
    const QPinchGesture::ChangeFlags changeFlags = gesture->changeFlags();
    if (changeFlags & QPinchGesture::ScaleFactorChanged) {
        m_currentStepScaleFactor = gesture->totalScaleFactor();
        m_expanding = m_currentStepScaleFactor > gesture->lastScaleFactor();
    }
    if (gesture->state() == Qt::GestureFinished) {
        m_scaleFactor *= m_currentStepScaleFactor;
        m_currentStepScaleFactor = 1;
        m_expanding = false;
    }
    m_sizeChanged = true;
    update();
}

void PinWidget::showContextMenu(const QPoint& pos)
{
    QMenu contextMenu(tr("Context menu"), this);

    QAction copyToClipboardAction(tr("Copy to clipboard"), this);
    connect(&copyToClipboardAction,
            &QAction::triggered,
            this,
            &PinWidget::copyToClipboard);
    contextMenu.addAction(&copyToClipboardAction);

    QAction saveToFileAction(tr("Save to file"), this);
    connect(
      &saveToFileAction, &QAction::triggered, this, &PinWidget::saveToFile);
    contextMenu.addAction(&saveToFileAction);

    contextMenu.exec(mapToGlobal(pos));
}

void PinWidget::copyToClipboard()
{
    saveToClipboard(m_pixmap);
}
void PinWidget::saveToFile()
{
    hide();
    saveToFilesystemGUI(m_pixmap);
    show();
}