/* This file is part of the KDE project

   Copyright (C) 2005 Dario Massarin <nekkar@libero.it>

   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 of the License, or (at your option) any later version.
*/

#ifndef JOBQUEUE_H
#define JOBQUEUE_H

/**
 * @brief JobQueue class
 *
 * This class abstracts the concept of queue. A queue is, basically, a
 * group of jobs that should be executed by the scheduler (if the queue
 * is marked as active). The scheduler will execute a maximum of n jobs
 * belonging to this queue at a time, where n can be set calling the
 * setMaxSimultaneousJobs(int n)
 *
 */

#include "kget_export.h"
#include <QList>
#include <QObject>

class Job;
class Scheduler;

class KGET_EXPORT JobQueue : public QObject
{
    Q_OBJECT
public:
    enum Status { Running, Stopped };
    typedef QList<Job *>::iterator iterator;

    JobQueue(Scheduler *parent);
    ~JobQueue() override;

    /**
     * Sets the JobQueue status
     *
     * @param queueStatus the new JobQueue status
     */
    virtual void setStatus(Status queueStatus);

    /**
     * @return the jobQueue status
     */
    Status status() const
    {
        return m_status;
    }

    /**
     * @return the begin of the job's list
     */
    iterator begin()
    {
        return m_jobs.begin();
    }

    /**
     * @return the end of the job's list
     */
    iterator end()
    {
        return m_jobs.end();
    }

    /**
     * @return the last job in the job's list
     */
    Job *last()
    {
        return m_jobs.last();
    }

    /**
     * @return the number of jobs in the queue
     */
    int size() const
    {
        return m_jobs.size();
    }

    /**
     * @param job The job for which we want to find the index
     *
     * @return the job index for the given job. If the given
     *         job can't be found, it returns -1
     */
    int indexOf(Job *job) const
    {
        return m_jobs.indexOf(job);
    }

    /**
     * @returns the Job in the queue at the given index i
     */
    Job *operator[](int i) const
    {
        return m_jobs[i];
    }

    /**
     * @return a list with the running Jobs
     */
    const QList<Job *> runningJobs();

    /**
     * FIXME not implemented
     * Sets the maximum number of jobs belonging to this queue that
     * should executed simultaneously by the scheduler
     *
     * @param n The maximum number of jobs
     */
    void setMaxSimultaneousJobs(int n);

    /**
     * @return the maximum number of jobs the scheduler should ever
     * execute simultaneously (in this queue).
     */
    int maxSimultaneousJobs() const;

protected:
    /**
     * appends a job to the current queue
     *
     * @param job The job to append to the current queue
     */
    void append(Job *job);

    /**
     * appends jobs to the current queue
     *
     * @param jobs to append to the current queue
     */
    void append(const QList<Job *> &jobs);

    /**
     * prepends a job to the current queue
     *
     * @param job The job to prepend to the current queue
     */
    void prepend(Job *job);

    /**
     * inserts a job to the current queue after the given job
     *
     * @param job The job to add in the current queue
     * @param after The job after which to add the job
     */
    void insert(Job *job, Job *after);

    /**
     * removes a job from the current queue
     *
     * @param job The job to remove from the current queue
     */
    void remove(Job *job);

    /**
     * removes jobs from the current queue
     *
     * @param jobs The jobs to remove from the current queue
     */
    void remove(const QList<Job *> jobs);

    /**
     * Moves a job in the queue. Both the given jobs must belong to this queue
     *
     * @param job The job to move
     * @param after The job after which we have to move the given job
     */
    void move(Job *job, Job *after);

    Scheduler *scheduler()
    {
        return m_scheduler;
    }

private:
    QList<Job *> m_jobs;

    int m_maxSimultaneousJobs;

    Scheduler *m_scheduler;
    Status m_status;
};

#endif
