/***************************************************************************
 *   Copyright (C) 2005 by Enrico Ros <eros.kde@email.it>                  *
 *   Copyright (C) 2006 by Albert Astals Cid <aacid@kde.org>               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#include "minibar.h"

// qt / kde includes
#include <KLocalizedString>
#include <QIcon>
#include <QToolButton>
#include <kacceleratormanager.h>
#include <kicontheme.h>
#include <klineedit.h>
#include <qapplication.h>
#include <qevent.h>
#include <qframe.h>
#include <qlabel.h>
#include <qlayout.h>
#include <qpainter.h>
#include <qpushbutton.h>
#include <qtoolbar.h>
#include <qvalidator.h>

// local includes
#include "core/document.h"
#include "core/page.h"

// [private widget] a flat qpushbutton that enlights on hover
class HoverButton : public QToolButton
{
    Q_OBJECT
public:
    HoverButton(QWidget *parent);
};

MiniBarLogic::MiniBarLogic(QObject *parent, Okular::Document *document)
    : QObject(parent)
    , m_document(document)
{
}

MiniBarLogic::~MiniBarLogic()
{
    m_document->removeObserver(this);
}

void MiniBarLogic::addMiniBar(MiniBar *miniBar)
{
    m_miniBars.insert(miniBar);
}

void MiniBarLogic::removeMiniBar(MiniBar *miniBar)
{
    m_miniBars.remove(miniBar);
}

Okular::Document *MiniBarLogic::document() const
{
    return m_document;
}

int MiniBarLogic::currentPage() const
{
    return m_document->currentPage();
}

void MiniBarLogic::notifySetup(const QVector<Okular::Page *> &pageVector, int setupFlags)
{
    // only process data when document changes
    if (!(setupFlags & Okular::DocumentObserver::DocumentChanged))
        return;

    // if document is closed or has no pages, hide widget
    const int pages = pageVector.count();
    if (pages < 1) {
        for (MiniBar *miniBar : qAsConst(m_miniBars)) {
            miniBar->setEnabled(false);
        }
        return;
    }

    bool labelsDiffer = false;
    for (const Okular::Page *page : pageVector) {
        if (!page->label().isEmpty()) {
            if (page->label().toInt() != (page->number() + 1)) {
                labelsDiffer = true;
            }
        }
    }

    const QString pagesString = QString::number(pages);

    for (MiniBar *miniBar : qAsConst(m_miniBars)) {
        // resize width of widgets
        miniBar->resizeForPage(pages);

        // update child widgets
        miniBar->m_pageLabelEdit->setPageLabels(pageVector);
        miniBar->m_pageNumberEdit->setPagesNumber(pages);
        miniBar->m_pagesButton->setText(pagesString);
        miniBar->m_prevButton->setEnabled(false);
        miniBar->m_nextButton->setEnabled(false);
        miniBar->m_pageLabelEdit->setVisible(labelsDiffer);
        miniBar->m_pageNumberLabel->setVisible(labelsDiffer);
        miniBar->m_pageNumberEdit->setVisible(!labelsDiffer);

        miniBar->adjustSize();

        miniBar->setEnabled(true);
    }
}

void MiniBarLogic::notifyCurrentPageChanged(int previousPage, int currentPage)
{
    Q_UNUSED(previousPage)

    // get current page number
    const int pages = m_document->pages();

    // if the document is opened and page is changed
    if (pages > 0) {
        const QString pageNumber = QString::number(currentPage + 1);
        const QString pageLabel = m_document->page(currentPage)->label();

        for (MiniBar *miniBar : qAsConst(m_miniBars)) {
            // update prev/next button state
            miniBar->m_prevButton->setEnabled(currentPage > 0);
            miniBar->m_nextButton->setEnabled(currentPage < (pages - 1));
            // update text on widgets
            miniBar->m_pageNumberEdit->setText(pageNumber);
            miniBar->m_pageNumberLabel->setText(pageNumber);
            miniBar->m_pageLabelEdit->setText(pageLabel);
        }
    }
}

/** MiniBar **/

MiniBar::MiniBar(QWidget *parent, MiniBarLogic *miniBarLogic)
    : QWidget(parent)
    , m_miniBarLogic(miniBarLogic)
    , m_oldToobarParent(nullptr)
{
    setObjectName(QStringLiteral("miniBar"));

    m_miniBarLogic->addMiniBar(this);

    QHBoxLayout *horLayout = new QHBoxLayout(this);

    horLayout->setContentsMargins(0, 0, 0, 0);
    horLayout->setSpacing(3);

    QSize buttonSize(KIconLoader::SizeSmallMedium, KIconLoader::SizeSmallMedium);
    // bottom: left prev_page button
    m_prevButton = new HoverButton(this);
    m_prevButton->setIcon(QIcon::fromTheme(QStringLiteral("arrow-up")));
    m_prevButton->setIconSize(buttonSize);
    horLayout->addWidget(m_prevButton);
    // bottom: left lineEdit (current page box)
    m_pageNumberEdit = new PageNumberEdit(this);
    horLayout->addWidget(m_pageNumberEdit);
    m_pageNumberEdit->installEventFilter(this);
    // bottom: left labelWidget (current page label)
    m_pageLabelEdit = new PageLabelEdit(this);
    horLayout->addWidget(m_pageLabelEdit);
    m_pageLabelEdit->installEventFilter(this);
    // bottom: left labelWidget (current page label)
    m_pageNumberLabel = new QLabel(this);
    m_pageNumberLabel->setAlignment(Qt::AlignCenter);
    horLayout->addWidget(m_pageNumberLabel);
    // bottom: central 'of' label
    horLayout->addSpacing(5);
    horLayout->addWidget(new QLabel(i18nc("Layouted like: '5 [pages] of 10'", "of"), this));
    // bottom: right button
    m_pagesButton = new HoverButton(this);
    horLayout->addWidget(m_pagesButton);
    // bottom: right next_page button
    m_nextButton = new HoverButton(this);
    m_nextButton->setIcon(QIcon::fromTheme(QStringLiteral("arrow-down")));
    m_nextButton->setIconSize(buttonSize);
    horLayout->addWidget(m_nextButton);

    QSizePolicy sp = sizePolicy();
    sp.setHorizontalPolicy(QSizePolicy::Fixed);
    sp.setVerticalPolicy(QSizePolicy::Fixed);
    setSizePolicy(sp);

    // resize width of widgets
    resizeForPage(0);

    // connect signals from child widgets to internal handlers / signals bouncers
    connect(m_pageNumberEdit, &PageNumberEdit::returnPressed, this, &MiniBar::slotChangePageFromReturn);
    connect(m_pageLabelEdit, &PageLabelEdit::pageNumberChosen, this, &MiniBar::slotChangePage);
    connect(m_pagesButton, &QAbstractButton::clicked, this, &MiniBar::gotoPage);
    connect(m_prevButton, &QAbstractButton::clicked, this, &MiniBar::prevPage);
    connect(m_nextButton, &QAbstractButton::clicked, this, &MiniBar::nextPage);

    adjustSize();

    // widget starts disabled (will be enabled after opening a document)
    setEnabled(false);
}

MiniBar::~MiniBar()
{
    m_miniBarLogic->removeMiniBar(this);
}

void MiniBar::changeEvent(QEvent *event)
{
    if (event->type() == QEvent::ParentChange) {
        QToolBar *tb = dynamic_cast<QToolBar *>(parent());
        if (tb != m_oldToobarParent) {
            if (m_oldToobarParent) {
                disconnect(m_oldToobarParent, &QToolBar::iconSizeChanged, this, &MiniBar::slotToolBarIconSizeChanged);
            }
            m_oldToobarParent = tb;
            if (tb) {
                connect(tb, &QToolBar::iconSizeChanged, this, &MiniBar::slotToolBarIconSizeChanged);
                slotToolBarIconSizeChanged();
            }
        }
    }
}

bool MiniBar::eventFilter(QObject *target, QEvent *event)
{
    if (target == m_pageNumberEdit || target == m_pageLabelEdit) {
        if (event->type() == QEvent::KeyPress) {
            QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
            int key = keyEvent->key();
            if (key == Qt::Key_PageUp || key == Qt::Key_PageDown || key == Qt::Key_Up || key == Qt::Key_Down) {
                emit forwardKeyPressEvent(keyEvent);
                return true;
            }
        }
    }
    return false;
}

void MiniBar::slotChangePageFromReturn()
{
    // get text from the lineEdit
    const QString pageNumber = m_pageNumberEdit->text();

    // convert it to page number and go to that page
    bool ok;
    int number = pageNumber.toInt(&ok) - 1;
    if (ok && number >= 0 && number < (int)m_miniBarLogic->document()->pages() && number != m_miniBarLogic->currentPage()) {
        slotChangePage(number);
    }
}

void MiniBar::slotChangePage(int pageNumber)
{
    m_miniBarLogic->document()->setViewportPage(pageNumber);
    m_pageNumberEdit->clearFocus();
    m_pageLabelEdit->clearFocus();
}

void MiniBar::slotEmitNextPage()
{
    // emit signal
    emit nextPage();
}

void MiniBar::slotEmitPrevPage()
{
    // emit signal
    emit prevPage();
}

void MiniBar::slotToolBarIconSizeChanged()
{
    const QSize buttonSize = m_oldToobarParent->iconSize();
    m_prevButton->setIconSize(buttonSize);
    m_nextButton->setIconSize(buttonSize);
}

void MiniBar::resizeForPage(int pages)
{
    const int numberWidth = 10 + fontMetrics().horizontalAdvance(QString::number(pages));
    m_pageNumberEdit->setMinimumWidth(numberWidth);
    m_pageNumberEdit->setMaximumWidth(2 * numberWidth);
    m_pageLabelEdit->setMinimumWidth(numberWidth);
    m_pageLabelEdit->setMaximumWidth(2 * numberWidth);
    m_pageNumberLabel->setMinimumWidth(numberWidth);
    m_pageNumberLabel->setMaximumWidth(2 * numberWidth);
    m_pagesButton->setMinimumWidth(numberWidth);
    m_pagesButton->setMaximumWidth(2 * numberWidth);
}

/** ProgressWidget **/

ProgressWidget::ProgressWidget(QWidget *parent, Okular::Document *document)
    : QWidget(parent)
    , m_document(document)
    , m_progressPercentage(-1)
{
    setObjectName(QStringLiteral("progress"));
    setAttribute(Qt::WA_OpaquePaintEvent, true);
    setFixedHeight(4);
    setMouseTracking(true);
}

ProgressWidget::~ProgressWidget()
{
    m_document->removeObserver(this);
}

void ProgressWidget::notifyCurrentPageChanged(int previousPage, int currentPage)
{
    Q_UNUSED(previousPage)

    // get current page number
    int pages = m_document->pages();

    // if the document is opened and page is changed
    if (pages > 0) {
        // update percentage
        const float percentage = pages < 2 ? 1.0 : (float)currentPage / (float)(pages - 1);
        setProgress(percentage);
    }
}

void ProgressWidget::setProgress(float percentage)
{
    m_progressPercentage = percentage;
    update();
}

void ProgressWidget::slotGotoNormalizedPage(float index)
{
    // figure out page number and go to that page
    int number = (int)(index * (float)m_document->pages());
    if (number >= 0 && number < (int)m_document->pages() && number != (int)m_document->currentPage())
        m_document->setViewportPage(number);
}

void ProgressWidget::mouseMoveEvent(QMouseEvent *e)
{
    if ((QApplication::mouseButtons() & Qt::LeftButton) && width() > 0)
        slotGotoNormalizedPage((float)(QApplication::isRightToLeft() ? width() - e->x() : e->x()) / (float)width());
}

void ProgressWidget::mousePressEvent(QMouseEvent *e)
{
    if (e->button() == Qt::LeftButton && width() > 0)
        slotGotoNormalizedPage((float)(QApplication::isRightToLeft() ? width() - e->x() : e->x()) / (float)width());
}

void ProgressWidget::wheelEvent(QWheelEvent *e)
{
    if (e->angleDelta().y() > 0)
        emit nextPage();
    else
        emit prevPage();
}

void ProgressWidget::paintEvent(QPaintEvent *e)
{
    QPainter p(this);

    if (m_progressPercentage < 0.0) {
        p.fillRect(rect(), palette().color(QPalette::Active, QPalette::HighlightedText));
        return;
    }

    // find out the 'fill' and the 'clear' rectangles
    int w = width(), h = height(), l = (int)((float)w * m_progressPercentage);
    QRect cRect = (QApplication::isRightToLeft() ? QRect(0, 0, w - l, h) : QRect(l, 0, w - l, h)).intersected(e->rect());
    QRect fRect = (QApplication::isRightToLeft() ? QRect(w - l, 0, l, h) : QRect(0, 0, l, h)).intersected(e->rect());

    QPalette pal = palette();
    // paint clear rect
    if (cRect.isValid())
        p.fillRect(cRect, pal.color(QPalette::Active, QPalette::HighlightedText));
    // draw a frame-like outline
    // p.setPen( palette().active().mid() );
    // p.drawRect( 0,0, w, h );
    // paint fill rect
    if (fRect.isValid())
        p.fillRect(fRect, pal.color(QPalette::Active, QPalette::Highlight));
    if (l && l != w) {
        p.setPen(pal.color(QPalette::Active, QPalette::Highlight).darker(120));
        int delta = QApplication::isRightToLeft() ? w - l : l;
        p.drawLine(delta, 0, delta, h);
    }
}

/** PageLabelEdit **/

PageLabelEdit::PageLabelEdit(MiniBar *parent)
    : PagesEdit(parent)
{
    setVisible(false);
    connect(this, &PageLabelEdit::returnPressed, this, &PageLabelEdit::pageChosen);
}

void PageLabelEdit::setText(const QString &newText)
{
    m_lastLabel = newText;
    PagesEdit::setText(newText);
}

void PageLabelEdit::setPageLabels(const QVector<Okular::Page *> &pageVector)
{
    m_labelPageMap.clear();
    completionObject()->clear();
    for (const Okular::Page *page : pageVector) {
        if (!page->label().isEmpty()) {
            m_labelPageMap.insert(page->label(), page->number());
            bool ok;
            page->label().toInt(&ok);
            if (!ok) {
                // Only add to the completion objects labels that are not numbers
                completionObject()->addItem(page->label());
            }
        }
    }
}

void PageLabelEdit::pageChosen()
{
    const QString newInput = text();
    const int pageNumber = m_labelPageMap.value(newInput, -1);
    if (pageNumber != -1) {
        emit pageNumberChosen(pageNumber);
    } else {
        setText(m_lastLabel);
    }
}

/** PageNumberEdit **/

PageNumberEdit::PageNumberEdit(MiniBar *miniBar)
    : PagesEdit(miniBar)
{
    // use an integer validator
    m_validator = new QIntValidator(1, 1, this);
    setValidator(m_validator);
}

void PageNumberEdit::setPagesNumber(int pages)
{
    m_validator->setTop(pages);
}

/** PagesEdit **/

PagesEdit::PagesEdit(MiniBar *parent)
    : KLineEdit(parent)
    , m_miniBar(parent)
    , m_eatClick(false)
{
    // customize text properties
    setAlignment(Qt::AlignCenter);

    // send a focus out event
    QFocusEvent fe(QEvent::FocusOut);
    QApplication::sendEvent(this, &fe);

    connect(qApp, &QGuiApplication::paletteChanged, this, &PagesEdit::updatePalette);
}

void PagesEdit::setText(const QString &newText)
{
    // call default handler if hasn't focus
    if (!hasFocus()) {
        KLineEdit::setText(newText);
    }
    // else preserve existing selection
    else {
        // save selection and adapt it to the new text length
        int selectionLength = selectedText().length();
        const bool allSelected = (selectionLength == text().length());
        if (allSelected) {
            KLineEdit::setText(newText);
            selectAll();
        } else {
            int newSelectionStart = newText.length() - text().length() + selectionStart();
            if (newSelectionStart < 0) {
                // the new text is shorter than the old one, and the front part, which is "cut off", is selected
                // shorten the selection accordingly
                selectionLength += newSelectionStart;
                newSelectionStart = 0;
            }
            KLineEdit::setText(newText);
            setSelection(newSelectionStart, selectionLength);
        }
    }
}

void PagesEdit::updatePalette()
{
    QPalette pal;

    if (hasFocus())
        pal.setColor(QPalette::Active, QPalette::Base, QApplication::palette().color(QPalette::Active, QPalette::Base));
    else
        pal.setColor(QPalette::Base, QApplication::palette().color(QPalette::Base).darker(102));

    setPalette(pal);
}

void PagesEdit::focusInEvent(QFocusEvent *e)
{
    // select all text
    selectAll();
    if (e->reason() == Qt::MouseFocusReason)
        m_eatClick = true;
    // change background color to the default 'edit' color
    updatePalette();
    // call default handler
    KLineEdit::focusInEvent(e);
}

void PagesEdit::focusOutEvent(QFocusEvent *e)
{
    // change background color to a dark tone
    updatePalette();
    // call default handler
    KLineEdit::focusOutEvent(e);
}

void PagesEdit::mousePressEvent(QMouseEvent *e)
{
    // if this click got the focus in, don't process the event
    if (!m_eatClick)
        KLineEdit::mousePressEvent(e);
    m_eatClick = false;
}

void PagesEdit::wheelEvent(QWheelEvent *e)
{
    if (e->angleDelta().y() > 0)
        m_miniBar->slotEmitNextPage();
    else
        m_miniBar->slotEmitPrevPage();
}

/** HoverButton **/

HoverButton::HoverButton(QWidget *parent)
    : QToolButton(parent)
{
    setAutoRaise(true);
    setFocusPolicy(Qt::NoFocus);
    setToolButtonStyle(Qt::ToolButtonIconOnly);
    KAcceleratorManager::setNoAccel(this);
}

#include "minibar.moc"

/* kate: replace-tabs on; indent-width 4; */
