/* This file is part of the KDE libraries
   Copyright (C) 2000 David Faure <faure@kde.org>, Alexander Neundorf <neundorf@kde.org>
             (C) 2000, 2002 Carsten Pfeiffer <pfeiffer@kde.org>
             (C) 2010 Sebastian Trueg <trueg@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include "keditlistwidget.h"

#include <QStringList>
#include <QKeyEvent>
#include <QLabel>
#include <QLayout>
#include <QLineEdit>
#include <QListView>
#include <QPushButton>
#include <QApplication>
#include <QComboBox>
#include <QStringListModel>

class KEditListWidgetPrivate
{
public:
    KEditListWidgetPrivate(KEditListWidget *parent)
        : lineEdit(nullptr),
          editingWidget(nullptr),
          q(parent)
    {
    }
    QListView *listView = nullptr;
    QPushButton *servUpButton = nullptr;
    QPushButton *servDownButton = nullptr;
    QPushButton *servNewButton = nullptr;
    QPushButton *servRemoveButton = nullptr;
    QLineEdit *lineEdit = nullptr;
    QWidget *editingWidget = nullptr;
    QVBoxLayout *mainLayout = nullptr;
    QVBoxLayout *btnsLayout = nullptr;
    QStringListModel *model = nullptr;

    bool checkAtEntering;
    KEditListWidget::Buttons buttons;

    void init(bool check = false, KEditListWidget::Buttons buttons = KEditListWidget::All,
              QWidget *representationWidget = nullptr);
    void setEditor(QLineEdit *lineEdit, QWidget *representationWidget = nullptr);
    void updateButtonState();
    QModelIndex selectedIndex();

private:
    KEditListWidget *q;
};

void KEditListWidgetPrivate::init(bool check, KEditListWidget::Buttons newButtons,
                                  QWidget *representationWidget)
{
    checkAtEntering = check;

    servNewButton = servRemoveButton = servUpButton = servDownButton = nullptr;
    q->setSizePolicy(QSizePolicy(QSizePolicy::MinimumExpanding,
                                 QSizePolicy::Preferred));

    mainLayout = new QVBoxLayout(q);
    mainLayout->setMargin(0);

    QHBoxLayout *subLayout = new QHBoxLayout;
    btnsLayout = new QVBoxLayout;
    btnsLayout->addStretch();

    model = new QStringListModel();
    listView = new QListView(q);
    listView->setModel(model);

    subLayout->addWidget(listView);
    subLayout->addLayout(btnsLayout);

    mainLayout->insertLayout(1, subLayout);

    setEditor(lineEdit, representationWidget);

    buttons = KEditListWidget::Buttons();
    q->setButtons(newButtons);

    q->connect(listView->selectionModel(), &QItemSelectionModel::selectionChanged,
               q, &KEditListWidget::slotSelectionChanged);
}

void KEditListWidgetPrivate::setEditor(QLineEdit *newLineEdit, QWidget *representationWidget)
{
    if (editingWidget != lineEdit &&
            editingWidget != representationWidget) {
        delete editingWidget;
    }
    if (lineEdit != newLineEdit) {
        delete lineEdit;
    }
    lineEdit = newLineEdit ? newLineEdit : new QLineEdit(q);
    editingWidget = representationWidget ?
                    representationWidget : lineEdit;

    if (representationWidget) {
        representationWidget->setParent(q);
    }

    mainLayout->insertWidget(0, editingWidget);

    lineEdit->installEventFilter(q);

    q->connect(lineEdit, &QLineEdit::textChanged, q, &KEditListWidget::typedSomething);
    q->connect(lineEdit, &QLineEdit::returnPressed, q, &KEditListWidget::addItem);

    // maybe supplied lineedit has some text already
    q->typedSomething(lineEdit->text());

    // fix tab ordering
    q->setTabOrder(editingWidget, listView);
    QWidget *w = listView;
    if (servNewButton) {
        q->setTabOrder(w, servNewButton);
        w = servNewButton;
    }
    if (servRemoveButton) {
        q->setTabOrder(w, servRemoveButton);
        w = servRemoveButton;
    }
    if (servUpButton) {
        q->setTabOrder(w, servUpButton);
        w = servUpButton;
    }
    if (servDownButton) {
        q->setTabOrder(w, servDownButton);
        w = servDownButton;
    }
}

void KEditListWidgetPrivate::updateButtonState()
{
    const bool hasSelectedItem = selectedIndex().isValid();

    // TODO: merge with enableMoveButtons()
    QPushButton * const buttons[3] = { servUpButton, servDownButton, servRemoveButton };

    for (QPushButton *button : buttons) {
        if (button) {
            // keep focus in widget
            if (!hasSelectedItem && button->hasFocus()) {
                lineEdit->setFocus(Qt::OtherFocusReason);
            }
            button->setEnabled(hasSelectedItem);
        }
    }
}

QModelIndex KEditListWidgetPrivate::selectedIndex()
{
    QItemSelectionModel *selection = listView->selectionModel();
    const QModelIndexList selectedIndexes = selection->selectedIndexes();
    if (!selectedIndexes.isEmpty() && selectedIndexes[0].isValid()) {
        return selectedIndexes[0];
    } else {
        return QModelIndex();
    }
}

class Q_DECL_HIDDEN KEditListWidget::CustomEditorPrivate
{
public:
    CustomEditorPrivate(KEditListWidget::CustomEditor *q):
        q(q),
        representationWidget(nullptr),
        lineEdit(nullptr) {}

    KEditListWidget::CustomEditor *q;
    QWidget *representationWidget;
    QLineEdit *lineEdit;
};

KEditListWidget::CustomEditor::CustomEditor()
    : d(new CustomEditorPrivate(this))
{
}

KEditListWidget::CustomEditor::CustomEditor(QWidget *repWidget, QLineEdit *edit)
    : d(new CustomEditorPrivate(this))
{
    d->representationWidget = repWidget;
    d->lineEdit = edit;
}

KEditListWidget::CustomEditor::CustomEditor(QComboBox *combo)
    : d(new CustomEditorPrivate(this))
{
    d->representationWidget = combo;
    d->lineEdit = qobject_cast<QLineEdit *>(combo->lineEdit());
    Q_ASSERT(d->lineEdit);
}

KEditListWidget::CustomEditor::~CustomEditor()
{
    delete d;
}

void KEditListWidget::CustomEditor::setRepresentationWidget(QWidget *repWidget)
{
    d->representationWidget = repWidget;
}

void KEditListWidget::CustomEditor::setLineEdit(QLineEdit *edit)
{
    d->lineEdit = edit;
}

QWidget *KEditListWidget::CustomEditor::representationWidget() const
{
    return d->representationWidget;
}

QLineEdit *KEditListWidget::CustomEditor::lineEdit() const
{
    return d->lineEdit;
}

KEditListWidget::KEditListWidget(QWidget *parent)
    : QWidget(parent), d(new KEditListWidgetPrivate(this))
{
    d->init();
}

KEditListWidget::KEditListWidget(const CustomEditor &custom,
                                 QWidget *parent,
                                 bool checkAtEntering,
                                 Buttons buttons)
    : QWidget(parent), d(new KEditListWidgetPrivate(this))
{
    d->lineEdit = custom.lineEdit();
    d->init(checkAtEntering, buttons, custom.representationWidget());
}

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

void KEditListWidget::setCustomEditor(const CustomEditor &editor)
{
    d->setEditor(editor.lineEdit(), editor.representationWidget());
}

QListView *KEditListWidget::listView() const
{
    return d->listView;
}

QLineEdit *KEditListWidget::lineEdit() const
{
    return d->lineEdit;
}

QPushButton *KEditListWidget::addButton() const
{
    return d->servNewButton;
}

QPushButton *KEditListWidget::removeButton() const
{
    return d->servRemoveButton;
}

QPushButton *KEditListWidget::upButton() const
{
    return d->servUpButton;
}

QPushButton *KEditListWidget::downButton() const
{
    return d->servDownButton;
}

int KEditListWidget::count() const
{
    return int(d->model->rowCount());
}

void KEditListWidget::setButtons(Buttons buttons)
{
    if (d->buttons == buttons) {
        return;
    }

    if ((buttons & Add) && !d->servNewButton) {
        d->servNewButton = new QPushButton(QIcon::fromTheme(QStringLiteral("list-add")), tr("&Add"), this);
        d->servNewButton->setEnabled(false);
        d->servNewButton->show();
        connect(d->servNewButton, &QAbstractButton::clicked, this, &KEditListWidget::addItem);

        d->btnsLayout->insertWidget(0, d->servNewButton);
    } else if ((buttons & Add) == 0 && d->servNewButton) {
        delete d->servNewButton;
        d->servNewButton = nullptr;
    }

    if ((buttons & Remove) && !d->servRemoveButton) {
        d->servRemoveButton = new QPushButton(QIcon::fromTheme(QStringLiteral("list-remove")), tr("&Remove"), this);
        d->servRemoveButton->setEnabled(false);
        d->servRemoveButton->show();
        connect(d->servRemoveButton, &QAbstractButton::clicked, this, &KEditListWidget::removeItem);

        d->btnsLayout->insertWidget(1, d->servRemoveButton);
    } else if ((buttons & Remove) == 0 && d->servRemoveButton) {
        delete d->servRemoveButton;
        d->servRemoveButton = nullptr;
    }

    if ((buttons & UpDown) && !d->servUpButton) {
        d->servUpButton = new QPushButton(QIcon::fromTheme(QStringLiteral("arrow-up")), tr("Move &Up"), this);
        d->servUpButton->setEnabled(false);
        d->servUpButton->show();
        connect(d->servUpButton, &QAbstractButton::clicked, this, &KEditListWidget::moveItemUp);

        d->servDownButton = new QPushButton(QIcon::fromTheme(QStringLiteral("arrow-down")), tr("Move &Down"), this);
        d->servDownButton->setEnabled(false);
        d->servDownButton->show();
        connect(d->servDownButton, &QAbstractButton::clicked, this, &KEditListWidget::moveItemDown);

        d->btnsLayout->insertWidget(2, d->servUpButton);
        d->btnsLayout->insertWidget(3, d->servDownButton);
    } else if ((buttons & UpDown) == 0 && d->servUpButton) {
        delete d->servUpButton; d->servUpButton = nullptr;
        delete d->servDownButton; d->servDownButton = nullptr;
    }

    d->buttons = buttons;
}

void KEditListWidget::setCheckAtEntering(bool check)
{
    d->checkAtEntering = check;
}

bool KEditListWidget::checkAtEntering()
{
    return d->checkAtEntering;
}

void KEditListWidget::typedSomething(const QString &text)
{
    if (currentItem() >= 0) {
        if (currentText() != d->lineEdit->text()) {
            // IMHO changeItem() shouldn't do anything with the value
            // of currentItem() ... like changing it or emitting signals ...
            // but TT disagree with me on this one (it's been that way since ages ... grrr)
            bool block = d->listView->signalsBlocked();
            d->listView->blockSignals(true);
            QModelIndex currentIndex = d->selectedIndex();
            if (currentIndex.isValid()) {
                d->model->setData(currentIndex, text);
            }
            d->listView->blockSignals(block);
            emit changed();
        }
    }

    if (!d->servNewButton) {
        return;
    }

    if (!d->lineEdit->hasAcceptableInput()) {
        d->servNewButton->setEnabled(false);
        return;
    }

    if (!d->checkAtEntering) {
        d->servNewButton->setEnabled(!text.isEmpty());
    } else {
        if (text.isEmpty()) {
            d->servNewButton->setEnabled(false);
        } else {
            QStringList list = d->model->stringList();
            bool enable = !list.contains(text, Qt::CaseSensitive);
            d->servNewButton->setEnabled(enable);
        }
    }
}

void KEditListWidget::moveItemUp()
{
    if (!d->listView->isEnabled()) {
        QApplication::beep();
        return;
    }

    QModelIndex index = d->selectedIndex();
    if (index.isValid()) {
        if (index.row() == 0) {
            QApplication::beep();
            return;
        }

        QModelIndex aboveIndex = d->model->index(index.row() - 1, index.column());

        QString tmp = d->model->data(aboveIndex, Qt::DisplayRole).toString();
        d->model->setData(aboveIndex, d->model->data(index, Qt::DisplayRole));
        d->model->setData(index, tmp);

        d->listView->selectionModel()->select(index, QItemSelectionModel::Deselect);
        d->listView->selectionModel()->select(aboveIndex, QItemSelectionModel::Select);
    }

    emit changed();
}

void KEditListWidget::moveItemDown()
{
    if (!d->listView->isEnabled()) {
        QApplication::beep();
        return;
    }

    QModelIndex index = d->selectedIndex();
    if (index.isValid()) {
        if (index.row() == d->model->rowCount() - 1) {
            QApplication::beep();
            return;
        }

        QModelIndex belowIndex = d->model->index(index.row() + 1, index.column());

        QString tmp = d->model->data(belowIndex, Qt::DisplayRole).toString();
        d->model->setData(belowIndex, d->model->data(index, Qt::DisplayRole));
        d->model->setData(index, tmp);

        d->listView->selectionModel()->select(index, QItemSelectionModel::Deselect);
        d->listView->selectionModel()->select(belowIndex, QItemSelectionModel::Select);
    }

    emit changed();
}

void KEditListWidget::addItem()
{
    // when checkAtEntering is true, the add-button is disabled, but this
    // slot can still be called through Key_Return/Key_Enter. So we guard
    // against this.
    if (!d->servNewButton || !d->servNewButton->isEnabled()) {
        return;
    }

    QModelIndex currentIndex = d->selectedIndex();

    const QString &currentTextLE = d->lineEdit->text();
    bool alreadyInList(false);
    //if we didn't check for dupes at the inserting we have to do it now
    if (!d->checkAtEntering) {
        // first check current item instead of dumb iterating the entire list
        if (currentIndex.isValid()) {
            if (d->model->data(currentIndex, Qt::DisplayRole).toString() == currentTextLE) {
                alreadyInList = true;
            }
        } else {
            alreadyInList = d->model->stringList().contains(currentTextLE, Qt::CaseSensitive);
        }
    }
    if (d->servNewButton) {
        // prevent losing the focus by it being moved outside of this widget
        // as well as support the user workflow a little by moving the focus
        // to the lineedit. chances are that users will add some items consecutively,
        // so this will save a manual focus change, and it is also consistent
        // to what happens on the click on the Remove button
        if (d->servNewButton->hasFocus()) {
            d->lineEdit->setFocus(Qt::OtherFocusReason);
        }
        d->servNewButton->setEnabled(false);
    }

    bool block = d->lineEdit->signalsBlocked();
    d->lineEdit->blockSignals(true);
    d->lineEdit->clear();
    d->lineEdit->blockSignals(block);

    d->listView->selectionModel()->setCurrentIndex(currentIndex, QItemSelectionModel::Deselect);

    if (!alreadyInList) {
        block = d->listView->signalsBlocked();

        if (currentIndex.isValid()) {
            d->model->setData(currentIndex, currentTextLE);
        } else {
            QStringList lst;
            lst << currentTextLE;
            lst << d->model->stringList();
            d->model->setStringList(lst);
        }
        emit changed();
        emit added(currentTextLE);   // TODO: pass the index too
    }

    d->updateButtonState();
}

int KEditListWidget::currentItem() const
{
    QModelIndex selectedIndex = d->selectedIndex();
    if (selectedIndex.isValid()) {
        return selectedIndex.row();
    } else {
        return -1;
    }
}

void KEditListWidget::removeItem()
{
    QModelIndex currentIndex = d->selectedIndex();
    if (!currentIndex.isValid()) {
        return;
    }

    if (currentIndex.row() >= 0) {
        // prevent losing the focus by it being moved outside of this widget
        // as well as support the user workflow a little by moving the focus
        // to the lineedit. chances are that users will add some item next,
        // so this will save a manual focus change,
        if (d->servRemoveButton && d->servRemoveButton->hasFocus()) {
            d->lineEdit->setFocus(Qt::OtherFocusReason);
        }

        QString removedText = d->model->data(currentIndex, Qt::DisplayRole).toString();

        d->model->removeRows(currentIndex.row(), 1);

        d->listView->selectionModel()->clear();

        emit changed();

        emit removed(removedText);
    }

    d->updateButtonState();
}

void KEditListWidget::enableMoveButtons(const QModelIndex &newIndex, const QModelIndex &)
{
    int index = newIndex.row();

    // Update the lineEdit when we select a different line.
    if (currentText() != d->lineEdit->text()) {
        d->lineEdit->setText(currentText());
    }

    bool moveEnabled = d->servUpButton && d->servDownButton;

    if (moveEnabled) {
        if (d->model->rowCount() <= 1) {
            d->servUpButton->setEnabled(false);
            d->servDownButton->setEnabled(false);
        } else if (index == (d->model->rowCount() - 1)) {
            d->servUpButton->setEnabled(true);
            d->servDownButton->setEnabled(false);
        } else if (index == 0) {
            d->servUpButton->setEnabled(false);
            d->servDownButton->setEnabled(true);
        } else {
            d->servUpButton->setEnabled(true);
            d->servDownButton->setEnabled(true);
        }
    }

    if (d->servRemoveButton) {
        d->servRemoveButton->setEnabled(true);
    }
}

void KEditListWidget::clear()
{
    d->lineEdit->clear();
    d->model->setStringList(QStringList());
    emit changed();
}

void KEditListWidget::insertStringList(const QStringList &list, int index)
{
    QStringList content = d->model->stringList();
    if (index < 0) {
        content += list;
    } else
        for (int i = 0, j = index; i < list.count(); ++i, ++j) {
            content.insert(j, list[ i ]);
        }

    d->model->setStringList(content);
}

void KEditListWidget::insertItem(const QString &text, int index)
{
    QStringList list = d->model->stringList();

    if (index < 0) {
        list.append(text);
    } else {
        list.insert(index, text);
    }

    d->model->setStringList(list);
}

QString KEditListWidget::text(int index) const
{
    const QStringList list = d->model->stringList();

    return list[ index ];
}

QString KEditListWidget::currentText() const
{
    QModelIndex index = d->selectedIndex();
    if (!index.isValid()) {
        return QString();
    } else {
        return text(index.row());
    }
}

QStringList KEditListWidget::items() const
{
    return d->model->stringList();
}

void KEditListWidget::setItems(const QStringList &items)
{
    d->model->setStringList(items);
}

KEditListWidget::Buttons KEditListWidget::buttons() const
{
    return d->buttons;
}

void KEditListWidget::slotSelectionChanged(const QItemSelection &, const QItemSelection &)
{
    d->updateButtonState();
    QModelIndex index = d->selectedIndex();
    enableMoveButtons(index,  QModelIndex());
    if (index.isValid()) {
        d->lineEdit->setFocus(Qt::OtherFocusReason);
    }
}

bool KEditListWidget::eventFilter(QObject *o, QEvent *e)
{
    if (o == d->lineEdit && e->type() == QEvent::KeyPress) {
        QKeyEvent *keyEvent = (QKeyEvent *)e;
        if (keyEvent->key() == Qt::Key_Down ||
                keyEvent->key() == Qt::Key_Up) {
            return ((QObject *)d->listView)->event(e);
        } else if (keyEvent->key() == Qt::Key_Return || keyEvent->key() == Qt::Key_Enter) {
            return true;
        }
    }

    return false;
}

