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**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
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** This file is part of Qt Creator.
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** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
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****************************************************************************/

#ifndef ILOCATORFILTER_H
#define ILOCATORFILTER_H

#include "locator_global.h"

#include <QVariant>
#include <QFutureInterface>
#include <QIcon>

namespace Locator {

class ILocatorFilter;

struct FilterEntry
{
    FilterEntry()
        : filter(0)
        , resolveFileIcon(false)
    {}

    FilterEntry(ILocatorFilter *fromFilter, const QString &name, const QVariant &data,
                const QIcon &icon = QIcon())
        : filter(fromFilter)
        , displayName(name)
        , internalData(data)
        , displayIcon(icon)
        , resolveFileIcon(false)
    {}

    bool operator==(const FilterEntry &other) const {
        if (internalData.canConvert(QVariant::String))
            return (internalData.toString() == other.internalData.toString());
        return internalData.constData() == other.internalData.constData();
    }

    /* backpointer to creating filter */
    ILocatorFilter *filter;
    /* displayed string */
    QString displayName;
    /* extra information displayed in light-gray in a second column (optional) */
    QString extraInfo;
    /* can be used by the filter to save more information about the entry */
    QVariant internalData;
    /* icon to display along with the entry */
    QIcon displayIcon;
    /* internal data is interpreted as file name and icon is retrieved from the file system if true */
    bool resolveFileIcon;
};

class LOCATOR_EXPORT ILocatorFilter : public QObject
{
    Q_OBJECT

public:
    enum Priority {High = 0, Medium = 1, Low = 2};

    ILocatorFilter(QObject *parent = 0);
    virtual ~ILocatorFilter() {}

    /* Visible name. */
    virtual QString displayName() const = 0;

    /* Internal name. */
    virtual QString id() const = 0;

    /* Selection list order in case of multiple active filters (high goes on top). */
    virtual Priority priority() const = 0;

    /* String to type to use this filter exclusively. */
    QString shortcutString() const;

    /* List of matches for the given user entry. */
    virtual QList<FilterEntry> matchesFor(QFutureInterface<Locator::FilterEntry> &future, const QString &entry) = 0;

    /* User has selected the given entry that belongs to this filter. */
    virtual void accept(FilterEntry selection) const = 0;

    /* Implement to update caches on user request, if that's a long operation. */
    virtual void refresh(QFutureInterface<void> &future) = 0;

    /* Saved state is used to restore the filter at start up. */
    virtual QByteArray saveState() const;

    /* Used to restore the filter at start up. */
    virtual bool restoreState(const QByteArray &state);

    /* User wants to configure this filter (if supported). Use it to pop up a dialog.
     * needsRefresh is used as a hint to indicate that refresh should be called.
     * The default implementation allows changing the shortcut and whether the filter
     * is enabled by default.
     */
    virtual bool openConfigDialog(QWidget *parent, bool &needsRefresh);

    /* If there is a configure dialog available for this filter. The default
     * implementation returns true. */
    virtual bool isConfigurable() const;

    /* Is this filter used also when the shortcutString is not used? */
    bool isIncludedByDefault() const;

    /* Returns whether the filter should be hidden from configuration and menus. */
    bool isHidden() const;

    /* Returns whether the filter should be enabled and used in menus. */
    bool isEnabled() const;

    static QString trimWildcards(const QString &str) {
        if (str.isEmpty())
            return str;
        int first = 0, last = str.size()-1;
        const QChar asterisk = QLatin1Char('*');
        const QChar question = QLatin1Char('?');
        while (first < str.size() && (str.at(first) == asterisk || str.at(first) == question))
            ++first;
        while (last >= 0 && (str.at(last) == asterisk || str.at(last) == question))
            --last;
        if (first > last)
            return QString();
        return str.mid(first, last-first+1);
    }

public slots:
    /* Enable or disable the filter. */
    void setEnabled(bool enabled);

protected:
    void setShortcutString(const QString &shortcut);
    void setIncludedByDefault(bool includedByDefault);
    void setHidden(bool hidden);

private:
    QString m_shortcut;
    bool m_includedByDefault;
    bool m_hidden;
    bool m_enabled;
};

} // namespace Locator

#endif // ILOCATORFILTER_H