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#include "submiteditorwidget.h"
#include "submitfieldwidget.h"
#include "ui_submiteditorwidget.h"

#include <QtCore/QDebug>
#include <QtCore/QPointer>
#include <QtCore/QTimer>
#include <QtCore/QScopedPointer>

#include <QtGui/QPushButton>
#include <QtGui/QMenu>
#include <QtGui/QHBoxLayout>
#include <QtGui/QToolButton>
#include <QtGui/QSpacerItem>

enum { debug = 0 };
enum { defaultLineWidth = 72 };

enum { checkableColumn = 0 };

/*!
    \class Utils::SubmitEditorWidget

    \brief Presents a VCS commit message in a text editor and a
     checkable list of modified files in a list window.

    The user can delete files from the list by unchecking them or diff the selection
    by doubleclicking. A list model which contains the file in a column
    specified by fileNameColumn should be set using setFileModel().

    Additionally, standard creator actions  can be registered:
    Undo/redo will be set up to work with the description editor.
    Submit will be set up to be enabled according to checkstate.
    Diff will be set up to trigger diffSelected().

    Note that the actions are connected by signals; in the rare event that there
    are several instances of the SubmitEditorWidget belonging to the same
    context active, the actions must be registered/unregistered in the editor
    change event.
    Care should be taken to ensure the widget is deleted properly when the
    editor closes.
*/

namespace Utils {

// QActionPushButton: A push button tied to an action
// (similar to a QToolButton)
class QActionPushButton : public QPushButton
{
    Q_OBJECT
public:
    explicit QActionPushButton(QAction *a);

private slots:
    void actionChanged();
};

QActionPushButton::QActionPushButton(QAction *a) :
     QPushButton(a->icon(), a->text())
{
    connect(a, SIGNAL(changed()), this, SLOT(actionChanged()));
    connect(this, SIGNAL(clicked()), a, SLOT(trigger()));
    setEnabled(a->isEnabled());
}

void QActionPushButton::actionChanged()
{
    if (const QAction *a = qobject_cast<QAction*>(sender())) {
        setEnabled(a->isEnabled());
        setText(a->text());
    }
}

// A helper parented on a QAction,
// making QAction::setText() a slot (which it currently is not).
class QActionSetTextSlotHelper : public QObject
{
    Q_OBJECT
public:
    explicit QActionSetTextSlotHelper(QAction *a) : QObject(a) {}

public slots:
    void setText(const QString &t) {
        if (QAction *action = qobject_cast<QAction *>(parent()))
            action->setText(t);
    }
};

// Helpers to retrieve model data
static inline bool listModelChecked(const QAbstractItemModel *model, int row, int column = 0)
{
    const QModelIndex checkableIndex = model->index(row, column, QModelIndex());
    return model->data(checkableIndex, Qt::CheckStateRole).toInt() == Qt::Checked;
}

static void setListModelChecked(QAbstractItemModel *model, bool checked, int column = 0)
{
    const QVariant data = QVariant(int(checked ? Qt::Checked : Qt::Unchecked));
    const int count = model->rowCount();
    for (int i = 0; i < count; i++) {
        const QModelIndex checkableIndex = model->index(i, column, QModelIndex());
        model->setData(checkableIndex, data, Qt::CheckStateRole);
    }
}

static inline QString listModelText(const QAbstractItemModel *model, int row, int column)
{
    const QModelIndex index = model->index(row, column, QModelIndex());
    return model->data(index, Qt::DisplayRole).toString();
}

// Convenience to extract a list of selected indexes
QList<int> selectedRows(const QAbstractItemView *view)
{
    const QModelIndexList indexList = view->selectionModel()->selectedRows(0);
    if (indexList.empty())
        return QList<int>();
    QList<int> rc;
    const QModelIndexList::const_iterator cend = indexList.constEnd();
    for (QModelIndexList::const_iterator it = indexList.constBegin(); it != cend; ++it)
        rc.push_back(it->row());
    return rc;
}

// -----------  SubmitEditorWidgetPrivate

struct SubmitEditorWidgetPrivate
{
    // A pair of position/action to extend context menus
    typedef QPair<int, QPointer<QAction> > AdditionalContextMenuAction;

    SubmitEditorWidgetPrivate();

    Ui::SubmitEditorWidget m_ui;
    bool m_filesSelected;
    int m_fileNameColumn;
    int m_activatedRow;
    bool m_emptyFileListEnabled;

    QList<AdditionalContextMenuAction> descriptionEditContextMenuActions;
    QVBoxLayout *m_fieldLayout;
    QList<SubmitFieldWidget *> m_fieldWidgets;
    int m_lineWidth;

    bool m_commitEnabled;
};

SubmitEditorWidgetPrivate::SubmitEditorWidgetPrivate() :
    m_filesSelected(false),
    m_fileNameColumn(1),
    m_activatedRow(-1),
    m_emptyFileListEnabled(false),
    m_fieldLayout(0),
    m_lineWidth(defaultLineWidth),
    m_commitEnabled(false)
{
}

SubmitEditorWidget::SubmitEditorWidget(QWidget *parent) :
    QWidget(parent),
    m_d(new SubmitEditorWidgetPrivate)
{
    m_d->m_ui.setupUi(this);
    m_d->m_ui.description->setContextMenuPolicy(Qt::CustomContextMenu);
    m_d->m_ui.description->setLineWrapMode(QTextEdit::NoWrap);
    m_d->m_ui.description->setWordWrapMode(QTextOption::WordWrap);
    connect(m_d->m_ui.description, SIGNAL(customContextMenuRequested(QPoint)),
            this, SLOT(editorCustomContextMenuRequested(QPoint)));
    connect(m_d->m_ui.description, SIGNAL(textChanged()),
            this, SLOT(updateSubmitAction()));

    // File List
    m_d->m_ui.fileView->setContextMenuPolicy(Qt::CustomContextMenu);
    connect(m_d->m_ui.fileView, SIGNAL(customContextMenuRequested(QPoint)),
            this, SLOT(fileListCustomContextMenuRequested(QPoint)));
    m_d->m_ui.fileView->setSelectionMode(QAbstractItemView::ExtendedSelection);
    m_d->m_ui.fileView->setRootIsDecorated(false);
    connect(m_d->m_ui.fileView, SIGNAL(doubleClicked(QModelIndex)),
            this, SLOT(diffActivated(QModelIndex)));

    setFocusPolicy(Qt::StrongFocus);
    setFocusProxy(m_d->m_ui.description);
}

SubmitEditorWidget::~SubmitEditorWidget()
{
    delete m_d;
}

void SubmitEditorWidget::registerActions(QAction *editorUndoAction, QAction *editorRedoAction,
                         QAction *submitAction, QAction *diffAction)
{
    if (editorUndoAction) {
        editorUndoAction->setEnabled(m_d->m_ui.description->document()->isUndoAvailable());
        connect(m_d->m_ui.description, SIGNAL(undoAvailable(bool)), editorUndoAction, SLOT(setEnabled(bool)));
        connect(editorUndoAction, SIGNAL(triggered()), m_d->m_ui.description, SLOT(undo()));
    }
    if (editorRedoAction) {
        editorRedoAction->setEnabled(m_d->m_ui.description->document()->isRedoAvailable());
        connect(m_d->m_ui.description, SIGNAL(redoAvailable(bool)), editorRedoAction, SLOT(setEnabled(bool)));
        connect(editorRedoAction, SIGNAL(triggered()), m_d->m_ui.description, SLOT(redo()));
    }

    if (submitAction) {
        if (debug) {
            int count = 0;
            if (const QAbstractItemModel *model = m_d->m_ui.fileView->model())
                count = model->rowCount();
            qDebug() << Q_FUNC_INFO << submitAction << count << "items";
        }
        m_d->m_commitEnabled = !canSubmit();
        connect(this, SIGNAL(submitActionEnabledChanged(bool)), submitAction, SLOT(setEnabled(bool)));
        // Wire setText via QActionSetTextSlotHelper.
        QActionSetTextSlotHelper *actionSlotHelper = submitAction->findChild<QActionSetTextSlotHelper *>();
        if (!actionSlotHelper)
            actionSlotHelper = new QActionSetTextSlotHelper(submitAction);
        connect(this, SIGNAL(submitActionTextChanged(QString)), actionSlotHelper, SLOT(setText(QString)));
        m_d->m_ui.buttonLayout->addWidget(new QActionPushButton(submitAction));
    }
    if (diffAction) {
        if (debug)
            qDebug() << diffAction << m_d->m_filesSelected;
        diffAction->setEnabled(m_d->m_filesSelected);
        connect(this, SIGNAL(fileSelectionChanged(bool)), diffAction, SLOT(setEnabled(bool)));
        connect(diffAction, SIGNAL(triggered()), this, SLOT(triggerDiffSelected()));
        m_d->m_ui.buttonLayout->addWidget(new QActionPushButton(diffAction));
    }
}

void SubmitEditorWidget::unregisterActions(QAction *editorUndoAction,  QAction *editorRedoAction,
                                           QAction *submitAction, QAction *diffAction)
{
    if (editorUndoAction) {
        disconnect(m_d->m_ui.description, SIGNAL(undoAvailableChanged(bool)), editorUndoAction, SLOT(setEnabled(bool)));
        disconnect(editorUndoAction, SIGNAL(triggered()), m_d->m_ui.description, SLOT(undo()));
    }
    if (editorRedoAction) {
        disconnect(m_d->m_ui.description, SIGNAL(redoAvailableChanged(bool)), editorRedoAction, SLOT(setEnabled(bool)));
        disconnect(editorRedoAction, SIGNAL(triggered()), m_d->m_ui.description, SLOT(redo()));
    }

    if (submitAction) {
        disconnect(this, SIGNAL(submitActionEnabledChanged(bool)), submitAction, SLOT(setEnabled(bool)));
        // Just deactivate the QActionSetTextSlotHelper on the action
        disconnect(this, SIGNAL(submitActionTextChanged(QString)), 0, 0);
    }

    if (diffAction) {
         disconnect(this, SIGNAL(fileSelectionChanged(bool)), diffAction, SLOT(setEnabled(bool)));
         disconnect(diffAction, SIGNAL(triggered()), this, SLOT(triggerDiffSelected()));
    }
}

// Make sure we have one terminating NL. Do not trim front as leading space might be
// required for some formattings.
static inline QString trimMessageText(QString t)
{
    if (t.isEmpty())
        return t;
    // Trim back of string.
    const int last = t.size() - 1;
    int lastWordCharacter = last;
    for ( ; lastWordCharacter >= 0 && t.at(lastWordCharacter).isSpace() ; lastWordCharacter--) ;
    if (lastWordCharacter != last)
        t.truncate(lastWordCharacter + 1);
    t += QLatin1Char('\n');
    return t;
}

// Extract the wrapped text from a text edit, which performs
// the wrapping only optically.
static QString wrappedText(const QTextEdit *e)
{
    const QChar newLine = QLatin1Char('\n');
    QString rc;
    QTextCursor cursor(e->document());
    cursor.movePosition(QTextCursor::Start);
    while (!cursor.atEnd()) {
        cursor.select(QTextCursor::LineUnderCursor);
        rc += cursor.selectedText();
        rc += newLine;
        cursor.movePosition(QTextCursor::EndOfLine); // Mac needs it
        cursor.movePosition(QTextCursor::Right);
    }
    return rc;
}

QString SubmitEditorWidget::descriptionText() const
{
    QString rc = trimMessageText(lineWrap() ? wrappedText(m_d->m_ui.description) :
                                              m_d->m_ui.description->toPlainText());
    // append field entries
    foreach(const SubmitFieldWidget *fw, m_d->m_fieldWidgets)
        rc += fw->fieldValues();
    return cleanupDescription(rc);
}

void SubmitEditorWidget::setDescriptionText(const QString &text)
{
    m_d->m_ui.description->setPlainText(text);
}

bool SubmitEditorWidget::lineWrap() const
{
    return m_d->m_ui.description->lineWrapMode() != QTextEdit::NoWrap;
}

void SubmitEditorWidget::setLineWrap(bool v)
{
    if (debug)
        qDebug() << Q_FUNC_INFO << v;
    if (v) {
        m_d->m_ui.description->setLineWrapColumnOrWidth(m_d->m_lineWidth);
        m_d->m_ui.description->setLineWrapMode(QTextEdit::FixedColumnWidth);
    } else {
        m_d->m_ui.description->setLineWrapMode(QTextEdit::NoWrap);
    }
}

int SubmitEditorWidget::lineWrapWidth() const
{
    return m_d->m_lineWidth;
}

void SubmitEditorWidget::setLineWrapWidth(int v)
{
    if (debug)
        qDebug() << Q_FUNC_INFO << v << lineWrap();
    if (m_d->m_lineWidth == v)
        return;
    m_d->m_lineWidth = v;
    if (lineWrap())
        m_d->m_ui.description->setLineWrapColumnOrWidth(v);
}

int SubmitEditorWidget::fileNameColumn() const
{
    return m_d->m_fileNameColumn;
}

void SubmitEditorWidget::setFileNameColumn(int c)
{
    m_d->m_fileNameColumn = c;
}

QAbstractItemView::SelectionMode SubmitEditorWidget::fileListSelectionMode() const
{
    return m_d->m_ui.fileView->selectionMode();
}

void SubmitEditorWidget::setFileListSelectionMode(QAbstractItemView::SelectionMode sm)
{
    m_d->m_ui.fileView->setSelectionMode(sm);
}

void SubmitEditorWidget::setFileModel(QAbstractItemModel *model)
{
    m_d->m_ui.fileView->clearSelection(); // trigger the change signals

    m_d->m_ui.fileView->setModel(model);

    if (model->rowCount()) {
        const int columnCount = model->columnCount();
        for (int c = 0;  c < columnCount; c++)
            m_d->m_ui.fileView->resizeColumnToContents(c);
    }

    connect(model, SIGNAL(dataChanged(QModelIndex,QModelIndex)),
            this, SLOT(updateSubmitAction()));
    connect(model, SIGNAL(modelReset()),
            this, SLOT(updateSubmitAction()));
    connect(model, SIGNAL(rowsInserted(QModelIndex,int,int)),
            this, SLOT(updateSubmitAction()));
    connect(model, SIGNAL(rowsRemoved(QModelIndex,int,int)),
            this, SLOT(updateSubmitAction()));
    connect(m_d->m_ui.fileView->selectionModel(), SIGNAL(selectionChanged(QItemSelection, QItemSelection)),
            this, SLOT(updateDiffAction()));
    updateActions();
}

QAbstractItemModel *SubmitEditorWidget::fileModel() const
{
    return m_d->m_ui.fileView->model();
}

QStringList SubmitEditorWidget::selectedFiles() const
{
    const QList<int> selection = selectedRows(m_d->m_ui.fileView);
    if (selection.empty())
        return QStringList();

    QStringList rc;
    const QAbstractItemModel *model = m_d->m_ui.fileView->model();
    const int count = selection.size();
    for (int i = 0; i < count; i++)
        rc.push_back(listModelText(model, selection.at(i), fileNameColumn()));
    return rc;
}

QStringList SubmitEditorWidget::checkedFiles() const
{
    QStringList rc;
    const QAbstractItemModel *model = m_d->m_ui.fileView->model();
    if (!model)
        return rc;
    const int count = model->rowCount();
    for (int i = 0; i < count; i++)
        if (listModelChecked(model, i, checkableColumn))
            rc.push_back(listModelText(model, i, fileNameColumn()));
    return rc;
}

QTextEdit *SubmitEditorWidget::descriptionEdit() const
{
    return m_d->m_ui.description;
}

void SubmitEditorWidget::triggerDiffSelected()
{
    const QStringList sel = selectedFiles();
    if (!sel.empty())
        emit diffSelected(sel);
}

void SubmitEditorWidget::diffActivatedDelayed()
{
    const QStringList files = QStringList(listModelText(m_d->m_ui.fileView->model(), m_d->m_activatedRow, fileNameColumn()));
    emit diffSelected(files);
}

void SubmitEditorWidget::diffActivated(const QModelIndex &index)
{
    // We need to delay the signal, otherwise, the diff editor will not
    // be in the foreground.
    m_d->m_activatedRow = index.row();
    QTimer::singleShot(0, this, SLOT(diffActivatedDelayed()));
}

void SubmitEditorWidget::updateActions()
{
    updateSubmitAction();
    updateDiffAction();
}

// Enable submit depending on having checked files
void SubmitEditorWidget::updateSubmitAction()
{
    const unsigned checkedCount = checkedFilesCount();
    const bool newCommitState = canSubmit();
    // Emit signal to update action
    if (m_d->m_commitEnabled != newCommitState) {
        m_d->m_commitEnabled = newCommitState;
        emit submitActionEnabledChanged(m_d->m_commitEnabled);
    }
    if (m_d->m_ui.fileView && m_d->m_ui.fileView->model()) {
        // Update button text.
        const int fileCount = m_d->m_ui.fileView->model()->rowCount();
        const QString msg = checkedCount ?
                            tr("Commit %1/%n Files", 0, fileCount).arg(checkedCount) :
                            tr("Commit");
        emit submitActionTextChanged(msg);
    }
}

// Enable diff depending on selected files
void SubmitEditorWidget::updateDiffAction()
{
    const bool filesSelected = hasSelection();
    if (m_d->m_filesSelected != filesSelected) {
        m_d->m_filesSelected = filesSelected;
        emit fileSelectionChanged(m_d->m_filesSelected);
    }
}

bool SubmitEditorWidget::hasSelection() const
{
    // Not present until model is set
    if (const QItemSelectionModel *sm = m_d->m_ui.fileView->selectionModel())
        return sm->hasSelection();
    return false;
}

unsigned SubmitEditorWidget::checkedFilesCount() const
{
    unsigned checkedCount = 0;
    if (const QAbstractItemModel *model = m_d->m_ui.fileView->model()) {
        const int count = model->rowCount();
        for (int i = 0; i < count; i++)
            if (listModelChecked(model, i, checkableColumn))
                checkedCount++;
    }
    return checkedCount;
}

QString SubmitEditorWidget::cleanupDescription(const QString &input) const
{
    return input;
}

void SubmitEditorWidget::changeEvent(QEvent *e)
{
    QWidget::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        m_d->m_ui.retranslateUi(this);
        break;
    default:
        break;
    }
}

void SubmitEditorWidget::insertTopWidget(QWidget *w)
{
    m_d->m_ui.vboxLayout->insertWidget(0, w);
}

bool SubmitEditorWidget::canSubmit() const
{
    const unsigned checkedCount = checkedFilesCount();
    return m_d->m_emptyFileListEnabled || checkedCount > 0;
}

void SubmitEditorWidget::addSubmitFieldWidget(SubmitFieldWidget *f)
{
    if (!m_d->m_fieldLayout) {
        // VBox with horizontal, expanding spacer
        m_d->m_fieldLayout = new QVBoxLayout;
        QHBoxLayout *outerLayout = new QHBoxLayout;
        outerLayout->addLayout(m_d->m_fieldLayout);
        outerLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Expanding, QSizePolicy::Ignored));
        QBoxLayout *descrLayout = qobject_cast<QBoxLayout*>(m_d->m_ui.descriptionBox->layout());
        Q_ASSERT(descrLayout);
        descrLayout->addLayout(outerLayout);
    }
    m_d->m_fieldLayout->addWidget(f);
    m_d->m_fieldWidgets.push_back(f);
}

QList<SubmitFieldWidget *> SubmitEditorWidget::submitFieldWidgets() const
{
    return m_d->m_fieldWidgets;
}

void SubmitEditorWidget::addDescriptionEditContextMenuAction(QAction *a)
{
    m_d->descriptionEditContextMenuActions.push_back(SubmitEditorWidgetPrivate::AdditionalContextMenuAction(-1, a));
}

void SubmitEditorWidget::insertDescriptionEditContextMenuAction(int pos, QAction *a)
{
    m_d->descriptionEditContextMenuActions.push_back(SubmitEditorWidgetPrivate::AdditionalContextMenuAction(pos, a));
}

void SubmitEditorWidget::editorCustomContextMenuRequested(const QPoint &pos)
{
    QScopedPointer<QMenu> menu(m_d->m_ui.description->createStandardContextMenu());
    // Extend
    foreach (const SubmitEditorWidgetPrivate::AdditionalContextMenuAction &a, m_d->descriptionEditContextMenuActions) {
        if (a.second) {
            if (a.first >= 0) {
                menu->insertAction(menu->actions().at(a.first), a.second);
            } else {
                menu->addAction(a.second);
            }
        }
    }
    menu->exec(m_d->m_ui.description->mapToGlobal(pos));
}

void SubmitEditorWidget::checkAll()
{
    setListModelChecked(m_d->m_ui.fileView->model(), true, checkableColumn);
}

void SubmitEditorWidget::uncheckAll()
{
    setListModelChecked(m_d->m_ui.fileView->model(), false, checkableColumn);
}

void SubmitEditorWidget::fileListCustomContextMenuRequested(const QPoint & pos)
{
    // Execute menu offering to check/uncheck all
    QMenu menu;
    //: Check all for submit
    QAction *checkAllAction = menu.addAction(tr("Check All"));
    //: Uncheck all for submit
    QAction *uncheckAllAction = menu.addAction(tr("Uncheck All"));
    QAction *action = menu.exec(m_d->m_ui.fileView->mapToGlobal(pos));
    if (action == checkAllAction) {
        checkAll();
        return;
    }
    if (action == uncheckAllAction) {
        uncheckAll();
        return;
    }
}

bool SubmitEditorWidget::isEmptyFileListEnabled() const
{
    return m_d->m_emptyFileListEnabled;
}

void SubmitEditorWidget::setEmptyFileListEnabled(bool e)
{
    if (e != m_d->m_emptyFileListEnabled) {
        m_d->m_emptyFileListEnabled = e;
        updateSubmitAction();
    }
}

} // namespace Utils

#include "submiteditorwidget.moc"
