/* ============================================================
 *
 * This file is a part of digiKam project
 * http://www.digikam.org
 *
 * Date        : 2009-07-05
 * Description : Access to the properties of a tag in the database
 *
 * Copyright (C) 2010-2011 by Marcel Wiesweg <marcel dot wiesweg at gmx dot de>
 *
 * 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, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for more details.
 *
 * ============================================================ */

#ifndef TAGPROPERTIES_H
#define TAGPROPERTIES_H

// Qt includes

#include <QString>
#include <QStringList>
#include <QList>
#include <QExplicitlySharedDataPointer>

// Local includes

#include "digikam_export.h"

namespace Digikam
{

class DIGIKAM_DATABASE_EXPORT TagProperties
{
public:

    /** This class provides a wrapper over the Database methods
     *  to access the properties of a tag. It is meant to be a
     *  short-lived object, it does not listen to external database changes.
     */

    TagProperties();
    /** Access the properties of the given tag 
     */
    explicit TagProperties(int tagId);

    ~TagProperties();
    TagProperties(const TagProperties& other);
    TagProperties& operator=(const TagProperties& other);

    bool isNull() const;

    int tagId() const;

    /**
     * Finds the tag for the given tag path or creates a new tag.
     * Then returns the tag properties for this tag.
     */
    static TagProperties getOrCreate(const QString& tagPath);

    /// Returns true if the property is set
    bool hasProperty(const QString& key) const;
    /// Returns true if the property is set, with exactly the given value.
    bool hasProperty(const QString& key, const QString& value) const;
    /**
     * Returns the value of the given property.
     * If the property is not set, a null string is returned.
     * But a null string is also returned if the property is set, but without a value.
     * Use hasProperty to check that case.
     */
    QString value(const QString& key) const;
    /// Returns all set property keys
    QStringList propertyKeys() const;
    /// Returns a map of all key->value pairs
    QMap<QString, QString> properties() const;

    /// Set the given property. Replaces all previous occurrences of this property.
    void setProperty(const QString& key, const QString& value);
    /** Adds the given property. Does not change any previous occurrences of this property,
     *  allowing multiple properties with the same key. */
    void addProperty(const QString& key, const QString& value);
    /// Remove the given property/value
    void removeProperty(const QString& key, const QString& value);
    /// Remove all occurrences of the property
    void removeProperties(const QString& key);

public:

    // Declared as public cause it's used by TagPropertiesPrivSharedNull class.
    class TagPropertiesPriv;

private:

    QExplicitlySharedDataPointer<TagPropertiesPriv> d;
};

} // namespace Digikam

#endif // TAGPROPERTIES_H
