/*
 * This file is part of the syndication library
 *
 * Copyright (C) 2006 Frank Osterfeld <osterfeld@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.
 *
 */

#ifndef SYNDICATION_FEED_H
#define SYNDICATION_FEED_H

#include <boost/shared_ptr.hpp>

#include "ksyndication_export.h"

class QDomElement;

template <class T> class QList;
template <class K, class T> class QMultiMap;
class QString;

namespace Syndication {

//@cond PRIVATE
class SpecificDocument;
typedef boost::shared_ptr<SpecificDocument> SpecificDocumentPtr;
class Category;
typedef boost::shared_ptr<Category> CategoryPtr;
class Feed;
typedef boost::shared_ptr<Feed> FeedPtr;
class Image;
typedef boost::shared_ptr<Image> ImagePtr;
class Item;
typedef boost::shared_ptr<Item> ItemPtr;
class Person;
typedef boost::shared_ptr<Person> PersonPtr;
//@endcond

/**
 * This class represents a feed document ("Channel" in RSS, "Feed" in Atom).
 * It contains a ordered list of items (e.g., articles) and a description of the
 * feed (title, homepage, etc.). This interface abstracts from format-specific
 * details of e.g. Atom::FeedDocument or RSS::Document and provides a
 * format-agnostic, unified view on the document.
 * This way applications using the syndication library have no need to care
 * about the syndication format jungle at all. If necessary, format details and
 * specialities can be accessed using the specificDocument() method.
 *
 * @author Frank Osterfeld
 */
class SYNDICATION_EXPORT Feed
{
    public:

        /**
         * destructor
         */
        virtual ~Feed();

        /**
         * returns the format-specific document this abstraction wraps.
         * If you want to access format-specific properties, this can be used,
         * in combination with a DocumentVisitor.
         *
         * @return a shared pointer to the wrapped document.
         */
        virtual SpecificDocumentPtr specificDocument() const = 0;

        /**
         * A list of items, in the order they were parsed from the feed source.
         * (usually reverse chronological order, see also Item::datePublished()
         * for sorting purposes).
         *
         * @return list of items
         */
        virtual QList<ItemPtr> items() const = 0;

        /**
         * returns a list of categories this feed is associated with.
         * See Category for more information.
         *
         */
        virtual QList<CategoryPtr> categories() const = 0;

        /**
         * The title of the feed.
         *
         * This string may contain HTML markup.(Importantly, occurrences of
         * the characters &lt;,'\n', '&amp;', '\'' and  '\"' are escaped).
         *
         * @return the title, or a null string if none is specified
         */
        virtual QString title() const = 0;

        /**
         * returns a link pointing to a website associated with this channel.
         * (blog, news site etc.)
         *
         * @return a WWW link, or a null string if none is specified
         */
        virtual QString link() const = 0;

        /**
         * A description of the feed.
         *
         * This string may contain HTML markup.(Importantly, occurrences of
         * the characters &lt;,'\n', '&amp;', '\'' and  '\"' are escaped).
         *
         * @return the description as HTML, or a null string if none is
         * specified
         */
        virtual QString description() const = 0;

        /**
         * returns an image associated with this item.
         *
         * @return an image object, or a null image (Not a null pointer!
         * I.e., image()->isNull() is @c true)
         * if no image is specified in the feed
         *
         */
        virtual ImagePtr image() const = 0;

        /**
         * returns a list of persons who created the feed content. If there is a
         * distinction between authors and contributors (Atom), both are added
         * to the list, where authors are added first.
         *
         * @return list of authors (and possibly other contributing persons)
         */
        virtual QList<PersonPtr> authors() const = 0;

        /**
         * The language used in the feed. This is a global setting, which can
         * be overridden by the contained items.
         *
         * TODO: describe concrete format (language codes)
         */
        virtual QString language() const = 0;

        /**
         * returns copyright information about the feed
         */
        virtual QString copyright() const = 0;

        /**
         * returns a list of feed metadata not covered by this class.
         * Can be used e.g. to access format extensions.
         *
         * The returned map contains key value pairs, where the key
         * is the tag name of the element, namespace prefix are resolved
         * to the corresponding URIs. The value is the XML element as read
         * from the document.
         *
         * For example, to access the &lt;itunes:subtitle> element, use
         * additionalProperties()["http://www.itunes.com/dtds/podcast-1.0.dtdsubtitle"].
         *
         * Currently this is only
         * supported for RSS 0.91..0.94/2.0 and Atom formats, but not for RDF
         * (RSS 0.9 and 1.0).
         */
        virtual QMultiMap<QString, QDomElement> additionalProperties() const = 0;

        /**
         * returns a description of the feed for debugging purposes
         *
         * @return debug string
         */
        virtual QString debugInfo() const;
};

} // namespace Syndication

#endif // SYNDICATION_FEED_H