/*=========================================================================
| KCalDAV
|--------------------------------------------------------------------------
| (c) 2010  Timothy Pearson
| (c) 2009  Kumaran Santhanam (initial KDE4 version)
|
| This project is released under the GNU General Public License.
| Please see the file COPYING for more details.
|--------------------------------------------------------------------------
| Main interface to the KResource system.
 ========================================================================*/

/*=========================================================================
| INCLUDES
 ========================================================================*/

#ifndef KCAL_RESOURCECALDAV_H
#define KCAL_RESOURCECALDAV_H

#include "preferences.h"
#include <qthread.h>
#include <qptrqueue.h>

#include <libkcal/resourcecached.h>

#include <kabc/locknull.h>

#include <kdepimmacros.h>
#include <kconfig.h>

namespace KCal {

class CalDavReader;
class CalDavWriter;

/*=========================================================================
| CLASS
 ========================================================================*/

/**
 * This class provides a resource for accessing calendars via CalDAV protocol.
 */
class KDE_EXPORT ResourceCalDav : public ResourceCached
{
    Q_OBJECT

public:

    explicit ResourceCalDav( const KConfig *config );
    virtual ~ResourceCalDav();

    void readConfig( const KConfig *config );
    void writeConfig( KConfig *config );

    /**
     * @return This resource preferences.
     */
    CalDavPrefs* prefs() {
        return mPrefs;
    }

    /**
     * @return This resource preferences.
     */
    const CalDavPrefs* prefs() const {
        return mPrefs;
    }

    virtual void setReadOnly(bool v);

protected slots:

    void loadFinished();

    void writingFinished();

protected:

    struct LoadingTask {
        QString url;
    };

    struct WritingTask {
        QString url;
        QString added;
        QString changed;
        QString deleted;
    };


//     virtual bool doLoad( bool syncCache );
//     virtual bool doSave( bool syncCache );

    virtual bool doLoad();
    virtual bool doSave();

    virtual bool doSave( bool syncCache, Incidence *incidence );

    virtual KABC::Lock* lock();

    /**
     * Creates prefs and configures them.
     * @return a newly created preferences object. It should be removed by the caller.
     */
    CalDavPrefs* createPrefs() const;

    /**
     * Initializes internal state.
     * Particulary, sets save and reload policies to default values,
     * creates writing and reading jobs and preferences objects.
     */
    void init();

    /**
     * Initiates calendar loading process.
     * @param url URL to load calendar data from.
     */
    void startLoading(const QString& url);

    /**
     * Checks if the data is correct and can be parsed.
     * @param data ical string to check.
     * @return true if the data is correct, false otherwise.
     */
    bool checkData(const QString& data);

    /**
     * Parses the data and adds events to the calendar.
     * @param data calendar data.
     * @return true on success, false on fail.
     */
    bool parseData(const QString& data);

    /**
     * Initiates calendar writing process.
     * @param url URL to save calendar data to.
     */
    void startWriting(const QString& url);

    /**
     * Returns a list of incidences as a valid iCalendar string.
     * @param inc list of incidences.
     * @return a string in iCalendar format which describes the given incidences.
     */
    QString getICalString(const Incidence::List& inc);

    /**
     * Changes read-only status of incidences from a given list.
     * @param inc list of incidences.
     * @param readOnly read-only status that all the incidences should have after the method finishes.
     */
    static void setIncidencesReadOnly(Incidence::List& inc, bool readOnly);

    /**
     * Ensures incidences' read-only states are the same as the calendar's read-only state.
     */
    void ensureReadOnlyFlagHonored();

    /**
     * If the loading queue is empty or the loader is not ready, does nothing.
     * Otherwise, pops a head element and starts a loading process for it.
     */
    void loadingQueuePop();

    /**
     * Pushes the given loading task to the loading queue.
     * Then calls loadingQueuePop.
     */
    void loadingQueuePush(const LoadingTask *task);

    /**
     * If the writing queue is empty or the writer is not ready, does nothing.
     * Otherwise, pops a head element and starts a writing process for it.
     */
    void writingQueuePop();

    /**
     * Pushes the given writing task to the writing queue.
     * Then calls writingQueuePop.
     */
    void writingQueuePush(const WritingTask *task);

private:

    // constants: =============================================================

    /// Termination waiting time in milliseconds. Used to terminate job threads.
    static const unsigned long TERMINATION_WAITING_TIME;

    /**
     * Resource caches only events which are from the interval [-CACHE_DAYS, CACHE_DAYS].
     */
    static const int CACHE_DAYS;

    static const int DEFAULT_RELOAD_INTERVAL;
    static const int DEFAULT_SAVE_INTERVAL;
    static const int DEFAULT_RELOAD_POLICY;
    static const int DEFAULT_SAVE_POLICY;

    // members: ===============================================================

    KABC::LockNull mLock;
    CalDavPrefs* mPrefs;
    CalDavReader* mLoader;
    CalDavWriter* mWriter;

    bool mLoadingQueueReady;
    QPtrQueue<LoadingTask> mLoadingQueue;

    bool mWritingQueueReady;
    QPtrQueue<WritingTask> mWritingQueue;

};



} // namespace KCal

#endif // KCAL_RESOURCECALDAV_H