/**
 * \file fancylineedit.cpp
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Nokia Corporation (qt-info@nokia.com)
 *
 * Full author contact details are available in file CREDITS.
 *
 */

// Code taken from the Qt Creator project and customized a little

#include <config.h>

#include "FancyLineEdit.h"

#include <QEvent>
#include <QDebug>
#include <QString>
#include <QPropertyAnimation>
#include <QApplication>
#include <QMenu>
#include <QMouseEvent>
#include <QLabel>
#include <QAbstractButton>
#include <QPainter>
#include <QStyle>
#include <QPaintEvent>
#include <QWindow>

enum { margin = 6 };

#define ICONBUTTON_HEIGHT 18
#define FADE_TIME 160


namespace lyx {
namespace frontend {

////////////////////////////////////////////////////////////////////////
//
// FancyLineEditPrivate
//
////////////////////////////////////////////////////////////////////////

class FancyLineEditPrivate : public QObject {
public:
	explicit FancyLineEditPrivate(FancyLineEdit *parent);

	bool eventFilter(QObject *obj, QEvent *event) override;

	FancyLineEdit  *m_lineEdit;
	QPixmap m_pixmap[2];
	QMenu *m_menu[2];
	bool m_menuTabFocusTrigger[2];
	IconButton *m_iconbutton[2];
	bool m_iconEnabled[2];
};


FancyLineEditPrivate::FancyLineEditPrivate(FancyLineEdit *parent)
	: QObject(parent), m_lineEdit(parent)
{
	for (int i = 0; i < 2; ++i) {
		m_menu[i] = nullptr;
		m_menuTabFocusTrigger[i] = false;
		m_iconbutton[i] = new IconButton(parent);
		m_iconbutton[i]->installEventFilter(this);
		m_iconbutton[i]->hide();
		m_iconbutton[i]->setAutoHide(false);
		m_iconEnabled[i] = false;
	}
}


bool FancyLineEditPrivate::eventFilter(QObject *obj, QEvent *event)
{
	int buttonIndex = -1;
	for (int i = 0; i < 2; ++i) {
		if (obj == m_iconbutton[i]) {
			buttonIndex = i;
			break;
		}
	}
	if (buttonIndex == -1)
		return QObject::eventFilter(obj, event);
	switch (event->type()) {
	case QEvent::FocusIn:
		if (m_menuTabFocusTrigger[buttonIndex] && m_menu[buttonIndex]) {
			m_lineEdit->setFocus();
			m_menu[buttonIndex]->exec(m_iconbutton[buttonIndex]->mapToGlobal(
							  m_iconbutton[buttonIndex]->rect().center()));
			return true;
		}
	default:
		break;
	}
	return QObject::eventFilter(obj, event);
}


////////////////////////////////////////////////////////////////////////
//
// FancyLineEdit
//
////////////////////////////////////////////////////////////////////////

FancyLineEdit::FancyLineEdit(QWidget *parent) :
    QLineEdit(parent),
    m_d(new FancyLineEditPrivate(this))
{
	ensurePolished();
	updateMargins();

	connect(this, SIGNAL(textChanged(QString)),
		this, SLOT(checkButtons(QString)));
	connect(m_d->m_iconbutton[Left], SIGNAL(clicked()),
		this, SLOT(iconClicked()));
	connect(m_d->m_iconbutton[Right], SIGNAL(clicked()),
		this, SLOT(iconClicked()));
}


void FancyLineEdit::checkButtons(const QString &text)
{
	if (m_oldText.isEmpty() || text.isEmpty()) {
		for (int i = 0; i < 2; ++i) {
			if (m_d->m_iconbutton[i]->hasAutoHide())
				m_d->m_iconbutton[i]->animateShow(!text.isEmpty());
		}
		m_oldText = text;
	}
}


void FancyLineEdit::setClearButton(bool visible)
{
	// QLineEdit::setClearButtonEnabled() has been implemented in Qt 5.2.
	// This is now the minimum required version
	setClearButtonEnabled(visible);
}


void FancyLineEdit::setButtonVisible(Side side, bool visible)
{
	m_d->m_iconbutton[side]->setVisible(visible);
	m_d->m_iconEnabled[side] = visible;
	updateMargins();
}


bool FancyLineEdit::isButtonVisible(Side side) const
{
	return m_d->m_iconEnabled[side];
}


void FancyLineEdit::iconClicked()
{
	IconButton *button = qobject_cast<IconButton *>(sender());
	int index = -1;
	for (int i = 0; i < 2; ++i)
		if (m_d->m_iconbutton[i] == button)
			index = i;
	if (index == -1)
		return;
	if (m_d->m_menu[index]) {
		m_d->m_menu[index]->exec(QCursor::pos());
	} else {
		buttonClicked((Side)index);
		if (index == Left)
			leftButtonClicked();
		else if (index == Right)
			rightButtonClicked();
	}
}


void FancyLineEdit::updateMargins()
{
	bool leftToRight = (layoutDirection() == Qt::LeftToRight);
	Side realLeft = (leftToRight ? Left : Right);
	Side realRight = (leftToRight ? Right : Left);

	qreal dpr = 1.0;
	// Consider device/pixel ratio (HiDPI)
	dpr = devicePixelRatio();
	int leftMargin = (m_d->m_iconbutton[realLeft]->pixmap().width() / dpr ) + 8;
	int rightMargin = (m_d->m_iconbutton[realRight]->pixmap().width() / dpr) + 8;
	// Note KDE does not reserve space for the highlight color
	if (style()->inherits("OxygenStyle")) {
		leftMargin = qMax(24, leftMargin);
		rightMargin = qMax(24, rightMargin);
	}

	QMargins margins((m_d->m_iconEnabled[realLeft] ? leftMargin : 0), 0,
			 (m_d->m_iconEnabled[realRight] ? rightMargin : 0), 0);

	setTextMargins(margins);
}


void FancyLineEdit::updateButtonPositions()
{
	QRect contentRect = rect();
	for (int i = 0; i < 2; ++i) {
		Side iconpos = (Side)i;
		if (layoutDirection() == Qt::RightToLeft)
			iconpos = (iconpos == Left ? Right : Left);

		if (iconpos == FancyLineEdit::Right) {
			const int iconoffset = textMargins().right() + 4;
			m_d->m_iconbutton[i]->setGeometry(
						contentRect.adjusted(width() - iconoffset,
								     0, 0, 0));
		} else {
			const int iconoffset = textMargins().left() + 4;
			m_d->m_iconbutton[i]->setGeometry(
						contentRect.adjusted(0, 0,
								     -width() + iconoffset, 0));
		}
	}
}


void FancyLineEdit::resizeEvent(QResizeEvent *)
{
	updateButtonPositions();
}


void FancyLineEdit::keyPressEvent(QKeyEvent * e)
{
	if (e->type() == QEvent::KeyPress && e->key() == Qt::Key_Down)
		Q_EMIT downPressed();
	else
		QLineEdit::keyPressEvent(e);
}


void FancyLineEdit::setButtonPixmap(Side side, const QPixmap &buttonPixmap)
{
	m_d->m_iconbutton[side]->setPixmap(buttonPixmap);
	updateMargins();
	updateButtonPositions();
	update();
}


QPixmap FancyLineEdit::buttonPixmap(Side side) const
{
	return m_d->m_pixmap[side];
}


void FancyLineEdit::setButtonMenu(Side side, QMenu *buttonMenu)
{
	m_d->m_menu[side] = buttonMenu;
	m_d->m_iconbutton[side]->setIconOpacity(1.0);
}

QMenu *FancyLineEdit::buttonMenu(Side side) const
{
	return  m_d->m_menu[side];
}


bool FancyLineEdit::hasMenuTabFocusTrigger(Side side) const
{
	return m_d->m_menuTabFocusTrigger[side];
}


void FancyLineEdit::setMenuTabFocusTrigger(Side side, bool v)
{
	if (m_d->m_menuTabFocusTrigger[side] == v)
		return;

	m_d->m_menuTabFocusTrigger[side] = v;
	m_d->m_iconbutton[side]->setFocusPolicy(v ? Qt::TabFocus : Qt::NoFocus);
}


bool FancyLineEdit::hasAutoHideButton(Side side) const
{
	return m_d->m_iconbutton[side]->hasAutoHide();
}


void FancyLineEdit::setAutoHideButton(Side side, bool h)
{
	m_d->m_iconbutton[side]->setAutoHide(h);
	if (h)
		m_d->m_iconbutton[side]->setIconOpacity(text().isEmpty() ?  0.0 : 1.0);
	else
		m_d->m_iconbutton[side]->setIconOpacity(1.0);
}


void FancyLineEdit::setButtonToolTip(Side side, const QString &tip)
{
	m_d->m_iconbutton[side]->setToolTip(tip);
}


void FancyLineEdit::setButtonFocusPolicy(Side side, Qt::FocusPolicy policy)
{
	m_d->m_iconbutton[side]->setFocusPolicy(policy);
}


////////////////////////////////////////////////////////////////////////
//
// IconButton - helper class to represent a clickable icon
//
////////////////////////////////////////////////////////////////////////

IconButton::IconButton(QWidget *parent)
	: QAbstractButton(parent), m_iconOpacity(0.0), m_autoHide(false)
{
	setCursor(Qt::ArrowCursor);
	setFocusPolicy(Qt::NoFocus);
}


void IconButton::paintEvent(QPaintEvent *)
{
	// Consider device/pixel ratio (HiDPI)
	QWindow * window = this->window()->windowHandle();
	qreal const dpr = window->devicePixelRatio();
	QRect pixmapRect(QPoint(), m_pixmap.size() / dpr);
	pixmapRect.moveCenter(rect().center());
	QPixmap pm = m_pixmap;

	QPainter painter(this);
	if (m_autoHide)
		painter.setOpacity(m_iconOpacity);

	painter.drawPixmap(pixmapRect, pm);
}


void IconButton::animateShow(bool visible)
{
	if (visible) {
		QPropertyAnimation *animation =
			new QPropertyAnimation(this, "iconOpacity");
		animation->setDuration(FADE_TIME);
		animation->setEndValue(1.0);
		animation->start(QAbstractAnimation::DeleteWhenStopped);
	} else {
		QPropertyAnimation *animation =
			new QPropertyAnimation(this, "iconOpacity");
		animation->setDuration(FADE_TIME);
		animation->setEndValue(0.0);
		animation->start(QAbstractAnimation::DeleteWhenStopped);
	}
}

} // namespace frontend

} // namespace lyx

#include "moc_FancyLineEdit.cpp"
