/*
 *   Copyright 2006-2007 Aaron Seigo <aseigo@kde.org>
 *
 *   This program 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, 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 Library General Public License for more details
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef PLASMA_ABSTRACTRUNNER_H
#define PLASMA_ABSTRACTRUNNER_H

#include <QObject>
#include <QStringList>
#include <QAction>
#include <QMimeData>

#include <kconfiggroup.h>
#include <kservice.h>
#include <kdeversion.h>

#include <plasma/plasma_export.h>
#include <plasma/querymatch.h>
#include <plasma/runnercontext.h>
#include <plasma/runnersyntax.h>

class KCompletion;

namespace Plasma
{

class QueryMatch;
class AbstractRunnerPrivate;

/**
 * @class AbstractRunner plasma/abstractrunner.h <Plasma/AbstractRunner>
 *
 * @short An abstract base class for Plasma Runner plugins.
 *
 * Be aware that runners have to be thread-safe. This is due to the fact that
 * each runner is executed in its own thread for each new term. Thus, a runner
 * may be executed more than once at the same time. See match() for details.
 */
class PLASMA_EXPORT AbstractRunner : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString id READ id)
    Q_PROPERTY(QString description READ description)
    Q_PROPERTY(QString name READ name)
    Q_PROPERTY(QIcon icon READ icon)
    public:
        /** Specifies a nominal speed for the runner */
        enum Speed {
            SlowSpeed,
            NormalSpeed
        };

        /** Specifies a priority for the runner */
        enum Priority {
            LowestPriority = 0,
            LowPriority,
            NormalPriority,
            HighPriority,
            HighestPriority
        };

        /** An ordered list of runners */
        typedef QList<AbstractRunner*> List;

        virtual ~AbstractRunner();

        /**
         * This is the main query method. It should trigger creation of
         * QueryMatch instances through RunnerContext::addMatch and
         * RunnerContext::addMatches.
         *
         * If the runner can run precisely the requested term (RunnerContext::query()),
         * it should create an exact match by setting the type to RunnerContext::ExactMatch.
         * The first runner that creates a QueryMatch will be the
         * default runner. Other runner's matches will be suggested in the
         * interface. Non-exact matches should be offered via RunnerContext::PossibleMatch.
         *
         * The match will be activated via run() if the user selects it.
         *
         * Each runner is executed in its own thread. Whenever the user input changes this
         * method is called again. Thus, it needs to be thread-safe. Also, all matches need
         * to be reported once this method returns. Asynchronous runners therefore need
         * to make use of a local event loop to wait for all matches.
         *
         * It is recommended to use local status data in async runners. The simplest way is
         * to have a separate class doing all the work like so:
         *
         * \code
         * void MyFancyAsyncRunner::match( RunnerContext& context )
         * {
         *     QEventLoop loop;
         *     MyAsyncWorker worker( context );
         *     connect( &worker, SIGNAL(finished()),
         *              &loop, SLOT(quit()) );
         *     worker.work();
         *     loop.exec();
         * }
         * \endcode
         *
         * Here MyAsyncWorker creates all the matches and calls RunnerContext::addMatch
         * in some internal slot. It emits the finished() signal once done which will
         * quit the loop and make the match() method return. The local status is kept
         * entirely in MyAsyncWorker which makes match() trivially thread-safe.
         *
         * If a particular match supports multiple actions, set up the corresponding
         * actions in the actionsForMatch method. Do not call any of the action methods
         * within this method!
         *
         * Execution of the correct action should be handled in the run method.
         * @caution This method needs to be thread-safe since KRunner will simply
         * start a new thread for each new term.
         *
         * @warning Returning from this method means to end execution of the runner.
         *
         * @sa run(), RunnerContext::addMatch, RunnerContext::addMatches, QueryMatch
         */
        virtual void match(Plasma::RunnerContext &context);

        /**
         * Called whenever a match associated with this runner is triggered.
         *
         * @param match The actual match to run/execute.
         */
        virtual void run(const Plasma::QueryMatch &match);

        /**
         * The nominal speed of the runner.
         * @see setSpeed
         */
        Speed speed() const;

        /**
         * The priority of the runner.
         * @see setPriority
         */
        Priority priority() const;

        /**
         * Returns the OR'ed value of all the Information types (as defined in RunnerContext::Type)
         * this runner is not interested in.
         * @return OR'ed value of black listed types
         */
        RunnerContext::Types ignoredTypes() const;

        /**
         * Sets the types this runner will ignore
         * @param types OR'ed listed of ignored types
         */
        void setIgnoredTypes(RunnerContext::Types types);

        /**
          * @return the user visible engine name for the Runner
          */
        QString name() const;

        /**
          * @return an id string for the Runner
          */
        QString id() const;

        /**
          * @return the description of this Runner
          */
        QString description() const;

        /**
         * @return the icon for this Runner
         */
        QIcon icon() const;

        /**
         * Signal runner to reload its configuration.
         */
        virtual void reloadConfiguration();

        /**
         * @return the syntaxes the runner has registered that it accepts and understands
         * @since 4.3
         */
        QList<RunnerSyntax> syntaxes() const;

    protected:
        friend class RunnerManager;
        friend class RunnerManagerPrivate;

        explicit AbstractRunner(const KService::Ptr service, QObject *parent = 0);

        AbstractRunner(QObject *parent, const QVariantList &args);

        /**
         * Provides access to the runner's configuration object.
         */
        KConfigGroup config() const;

        /**
         * Sets the nominal speed of the runner. Only slow runners need
         * to call this within their constructor because the default
         * speed is NormalSpeed. Runners that use DBUS should call
         * this within their constructors.
         */
        void setSpeed(Speed newSpeed);

        /**
         * Sets the priority of the runner. Lower priority runners are executed
         * only after higher priority runners.
         */
        void setPriority(Priority newPriority);

        /**
         * Reimplement this method if you want your runner to support drag and drop.
         * @since 4.5
         */
        virtual QMimeData* mimeDataForMatch(const Plasma::QueryMatch &match);

        /**
         * A given match can have more than action that can be performed on it.
         * For example, a song match returned by a music player runner can be queued,
         * added to the playlist, or played.
         *
         * Call this method to add actions that can be performed by the runner.
         * Actions must first be added to the runner's action registry.
         * Note: execution of correct action is left up to the runner.
         */
        virtual QList<QAction*> actionsForMatch(const Plasma::QueryMatch &match);

        /**
         * Creates and then adds an action to the action registry.
         * AbstractRunner assumes ownership of the created action.
         *
         * @param id A unique identifier string
         * @param icon The icon to display
         * @param text The text to display
         * @return the created QAction
         */
        QAction* addAction(const QString &id, const QIcon &icon, const QString &text);

        /**
         * Adds an action to the runner's action registry.
         *
         * The QAction must be created within the GUI thread;
         * do not create it within the match method of AbstractRunner.
         *
         * @param id A unique identifier string
         * @param action The QAction to be stored
         */
        void addAction(const QString &id, QAction *action);

        /**
         * Removes the action from the action registry.
         * AbstractRunner deletes the action once removed.
         *
         * @param id The id of the action to be removed
         */
        void removeAction(const QString &id);

        /**
         * Returns the action associated with the id
         */
        QAction* action(const QString &id) const;

        /**
         * Returns all registered actions
         */
        QHash<QString, QAction*> actions() const;

        /**
         * Clears the action registry.
         * The action pool deletes the actions.
         */
        void clearActions();

        /**
         * Adds a registered syntax that this runner understands. This is used to
         * display to the user what this runner can understand and how it can be
         * used.
         *
         * @param syntax the syntax to register
         * @since 4.3
         */
        void addSyntax(const RunnerSyntax &syntax);

        /**
         * Sets the list of syntaxes; passing in an empty list effectively clears
         * the syntaxes.
         *
         * @param the syntaxes to register for this runner
         * @since 4.3
         */
        void setSyntaxes(const QList<RunnerSyntax> &syns);

    protected Q_SLOTS:
        /**
         * Reimplement this slot to run any initialization routines on first load.
         * By default, it calls reloadConfiguration()
         */
        void init();

    private:
        AbstractRunnerPrivate *const d;
};

} // Plasma namespace

#define K_EXPORT_PLASMA_RUNNER( libname, classname )     \
K_PLUGIN_FACTORY(classname ## Factory, registerPlugin<classname>();) \
K_EXPORT_PLUGIN(classname ## Factory("plasma_runner_" #libname))

/**
 * These plugins are Used by the plugin selector dialog to show
 * configuration options specific to this runner. These options
 * must be runner global and not pertain to a specific match.
 */
#define K_EXPORT_RUNNER_CONFIG( name, classname )     \
K_PLUGIN_FACTORY(classname ## Factory, registerPlugin<classname>("kcm_krunner_" #name);) \
K_EXPORT_PLUGIN(classname ## Factory("kcm_krunner_" #name))

#endif