/* This file is part of the KDE libraries
 *
 * Copyright (c) 2011 Aurélien Gâteau <agateau@kde.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */
#include "kmessagewidget.h"

#include <QEvent>
#include <QGridLayout>
#include <QHBoxLayout>
#include <QLabel>
#include <QPainter>
#include <QShowEvent>
#include <QTimeLine>
#include <QToolButton>
#include <QStyle>
#include <QAction>

void KMessageWidgetPrivate::init(KMessageWidget* q_ptr)
{
	q = q_ptr;

	q->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Fixed);

	timeLine = new QTimeLine(500, q);
	QObject::connect(timeLine, SIGNAL(valueChanged(qreal)), q, SLOT(slotTimeLineChanged(qreal)));
	QObject::connect(timeLine, SIGNAL(finished()), q, SLOT(slotTimeLineFinished()));

	content = new QFrame(q);
	content->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

	wordWrap = false;

	iconLabel = new QLabel(content);
	iconLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
	iconLabel->hide();

	textLabel = new QLabel(content);
	textLabel->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
	textLabel->setTextInteractionFlags(Qt::TextBrowserInteraction);
	QObject::connect(textLabel, SIGNAL(linkActivated(const QString&)), q, SIGNAL(linkActivated(const QString&)));
	QObject::connect(textLabel, SIGNAL(linkHovered(const QString&)), q, SIGNAL(linkHovered(const QString&)));

	QAction* closeAction = new QAction(QObject::tr("Close"), q);
	q->connect(closeAction, SIGNAL(triggered(bool)), q, SLOT(animatedHide()));

	closeButton = new QToolButton(content);
	closeButton->setAutoRaise(true);
	closeButton->setDefaultAction(closeAction);

	q->setMessageType(KMessageWidget::Information);
}

void KMessageWidgetPrivate::createLayout()
{
	delete content->layout();

	content->resize(q->size());

	qDeleteAll(buttons);
	buttons.clear();

	Q_FOREACH(QAction* action, q->actions()) {
		QToolButton* button = new QToolButton(content);
		button->setDefaultAction(action);
		button->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
		buttons.append(button);
	}

	// AutoRaise reduces visual clutter, but we don't want to turn it on if
	// there are other buttons, otherwise the close button will look different
	// from the others.
	closeButton->setAutoRaise(buttons.isEmpty());

	if (wordWrap) {
		QGridLayout* layout = new QGridLayout(content);
		// Set alignment to make sure icon does not move down if text wraps
		layout->addWidget(iconLabel, 0, 0, 1, 1, Qt::AlignHCenter | Qt::AlignTop);
		layout->addWidget(textLabel, 0, 1);

		QHBoxLayout* buttonLayout = new QHBoxLayout;
		buttonLayout->addStretch();
		Q_FOREACH(QToolButton* button, buttons) {
			// For some reason, calling show() is necessary if wordwrap is true,
			// otherwise the buttons do not show up. It is not needed if
			// wordwrap is false.
			button->show();
			buttonLayout->addWidget(button);
		}
		buttonLayout->addWidget(closeButton);
		layout->addItem(buttonLayout, 1, 0, 1, 2);
	} else {
		QHBoxLayout* layout = new QHBoxLayout(content);
		layout->addWidget(iconLabel);
		layout->addWidget(textLabel);

		Q_FOREACH(QToolButton* button, buttons) {
			layout->addWidget(button);
		}

		layout->addWidget(closeButton);
	};

	if (q->isVisible()) {
		q->setFixedHeight(content->sizeHint().height());
	}

	q->updateGeometry();
}

void KMessageWidgetPrivate::updateLayout()
{
	if (content->layout()) {
		createLayout();
	}
}

void KMessageWidgetPrivate::updateSnapShot()
{
	// Attention: updateSnapShot calls QWidget::render(), which causes the whole
	// window layouts to be activated. Calling this method from resizeEvent()
	// can lead to infinite recursion, see:
	// https://bugs.kde.org/show_bug.cgi?id=311336
	contentSnapShot = QPixmap(content->size());
	contentSnapShot.fill(Qt::transparent);
	content->render(&contentSnapShot, QPoint(), QRegion(), QWidget::DrawChildren);
}

void KMessageWidgetPrivate::slotTimeLineChanged(qreal value)
{
	q->setFixedHeight(qMin(value * 2, qreal(1.0)) * content->height());
	q->update();
}

void KMessageWidgetPrivate::slotTimeLineFinished()
{
	if (timeLine->direction() == QTimeLine::Forward) {
		// Show
		// We set the whole geometry here, because it may be wrong if a
		// KMessageWidget is shown right when the toplevel window is created.
		content->setGeometry(0, 0, q->width(), bestContentHeight());
	} else {
		// Hide
		q->hide();
	}
}

int KMessageWidgetPrivate::bestContentHeight() const
{
	int height = content->heightForWidth(q->width());

	if (height == -1) {
		height = content->sizeHint().height();
	}

	return height;
}


//---------------------------------------------------------------------
// KMessageWidget
//---------------------------------------------------------------------
KMessageWidget::KMessageWidget(QWidget* parent)
	: QFrame(parent)
	, d(new KMessageWidgetPrivate)
{
	d->init(this);
}

KMessageWidget::KMessageWidget(const QString& text, QWidget* parent)
	: QFrame(parent)
	, d(new KMessageWidgetPrivate)
{
	d->init(this);
	setText(text);
}

KMessageWidget::~KMessageWidget()
{
	delete d;
}

QString KMessageWidget::text() const
{
	return d->textLabel->text();
}

void KMessageWidget::setText(const QString& text)
{
	d->textLabel->setText(text);
	updateGeometry();
}

KMessageWidget::MessageType KMessageWidget::messageType() const
{
	return d->messageType;
}

void KMessageWidget::setMessageType(KMessageWidget::MessageType type)
{
	d->messageType = type;
	QColor bg0, bg1, bg2, border, fg;

	switch (type) {
	case Positive:
		bg1 = QColor("#72D594"); // nice green
		fg = QColor(Qt::white);
		break;

	case Information:
		bg1 = QColor("#41A8E3"); // nice blue
		fg = QColor(Qt::black);
		break;

	case Warning:
		bg1 = QColor("#72D594"); // nice yellow
		fg = QColor(Qt::black);
		break;

	case Error:
		bg1 = QColor("#E4B7B7"); // nice red.
		fg = QColor(Qt::black);
		break;
	}

	// Colors
	bg0 = bg1.lighter(110);
	bg2 = bg1.darker(110);
	border = bg2.darker(110);
	d->content->setStyleSheet(
		QString(".QFrame {"
			"background-color: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
			"    stop: 0 %1,"
			"    stop: 0.1 %2,"
			"    stop: 1.0 %3);"
			"border-radius: 5px;"
			"border: 1px solid %4;"
			"margin: %5px;"
			"}"
			".QLabel { color: %6; }"
		).arg(bg0.name())
		.arg(bg1.name())
		.arg(bg2.name())
		.arg(border.name())
		/*
		DefaultFrameWidth returns the size of the external margin + border width.
		We know our border is 1px, so we subtract this from the frame
		normal QStyle FrameWidth to get our margin
		*/

		.arg(style()->pixelMetric(QStyle::PM_DefaultFrameWidth, 0, this) -1)
		.arg(fg.name())
	);
}

QSize KMessageWidget::sizeHint() const
{
	ensurePolished();
	return d->content->sizeHint();
}

QSize KMessageWidget::minimumSizeHint() const
{
	ensurePolished();
	return d->content->minimumSizeHint();
}

bool KMessageWidget::event(QEvent* event)
{
	if (event->type() == QEvent::Polish && !d->content->layout()) {
		d->createLayout();
	}

	return QFrame::event(event);
}

void KMessageWidget::resizeEvent(QResizeEvent* event)
{
	QFrame::resizeEvent(event);

	if (d->timeLine->state() == QTimeLine::NotRunning) {
		d->content->resize(width(), d->bestContentHeight());
	}
}

int KMessageWidget::heightForWidth(int width) const
{
	ensurePolished();
	return d->content->heightForWidth(width);
}

void KMessageWidget::paintEvent(QPaintEvent* event)
{
	QFrame::paintEvent(event);

	if (d->timeLine->state() == QTimeLine::Running) {
		QPainter painter(this);
		painter.setOpacity(d->timeLine->currentValue() * d->timeLine->currentValue());
		painter.drawPixmap(0, 0, d->contentSnapShot);
	}
}

void KMessageWidget::showEvent(QShowEvent* event)
{
	// Keep this method here to avoid breaking binary compatibility:
	// QFrame::showEvent() used to be reimplemented.
	QFrame::showEvent(event);
}

bool KMessageWidget::wordWrap() const
{
	return d->wordWrap;
}

void KMessageWidget::setWordWrap(bool wordWrap)
{
	d->wordWrap = wordWrap;
	d->textLabel->setWordWrap(wordWrap);
	QSizePolicy policy = sizePolicy();
	policy.setHeightForWidth(wordWrap);
	setSizePolicy(policy);
	d->updateLayout();

	// Without this, when user does wordWrap -> !wordWrap -> wordWrap, a minimum
	// height is set, causing the widget to be too high.
	// Mostly visible in test programs.
	if (wordWrap) {
		setMinimumHeight(0);
	}
}

bool KMessageWidget::isCloseButtonVisible() const
{
	return d->closeButton->isVisible();
}

void KMessageWidget::setCloseButtonVisible(bool show)
{
	d->closeButton->setVisible(show);
	updateGeometry();
}

void KMessageWidget::addAction(QAction* action)
{
	QFrame::addAction(action);
	d->updateLayout();
}

void KMessageWidget::removeAction(QAction* action)
{
	QFrame::removeAction(action);
	d->updateLayout();
}

void KMessageWidget::animatedShow()
{
	if (isVisible()) {
		return;
	}

	QFrame::show();
	setFixedHeight(0);
	int wantedHeight = d->bestContentHeight();
	d->content->setGeometry(0, -wantedHeight, width(), wantedHeight);

	d->updateSnapShot();

	d->timeLine->setDirection(QTimeLine::Forward);

	if (d->timeLine->state() == QTimeLine::NotRunning) {
		d->timeLine->start();
	}
}

void KMessageWidget::animatedHide()
{
	if (!isVisible()) {
		return;
	}

	d->content->move(0, -d->content->height());
	d->updateSnapShot();

	d->timeLine->setDirection(QTimeLine::Backward);

	if (d->timeLine->state() == QTimeLine::NotRunning) {
		d->timeLine->start();
	}
}

QIcon KMessageWidget::icon() const
{
	return d->icon;
}

void KMessageWidget::setIcon(const QIcon& icon)
{
	d->icon = icon;

	if (d->icon.isNull()) {
		d->iconLabel->hide();
	} else {
		d->iconLabel->setPixmap(d->icon.pixmap(QSize(16,16)));
		d->iconLabel->show();
	}
}