/* This file is part of the KDE project
 * Copyright (C) 2006-2007 Thomas Zander <zander@kde.org>
 * Copyright (C) 2009 Boudewijn Rempt <boud@valdyas.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.
 */
#include "KoProgressUpdater.h"

#include <QApplication>
#include <QString>
#include <QTextStream>
#include <QTimer>

#include "KoUpdaterPrivate_p.h"
#include "KoUpdater.h"
#include "KoProgressProxy.h"


// 4 updates per second should be enough
#define PROGRESSUPDATER_GUITIMERINTERVAL 250

class Q_DECL_HIDDEN KoProgressUpdater::Private
{
public:

    Private(KoProgressUpdater *_parent, KoProgressProxy *p, Mode _mode,
            QTextStream *output_ = 0)
        : parent(_parent)
        , progressBar(p)
        , mode(_mode)
        , totalWeight(0)
        , currentProgress(0)
        , updated(false)
        , output(output_)
        , updateGuiTimer(_parent)
        , canceled(false)
    {
    }

    KoProgressUpdater *parent;
    KoProgressProxy *progressBar;
    Mode mode;
    int totalWeight;
    int currentProgress;
    bool updated;          // is true whenever the progress needs to be recomputed
    QTextStream *output;
    QTimer updateGuiTimer; // fires regularly to update the progress bar widget
    QList<QPointer<KoUpdaterPrivate> > subtasks;
    QList<QPointer<KoUpdater> > subTaskWrappers; // We delete these
    QTime referenceTime;

    static void logEvents(QTextStream& out, KoProgressUpdater::Private *updater,
                          const QTime& startTime, const QString& prefix);
    bool canceled;
};

// NOTE: do not make the KoProgressUpdater object part of the QObject
// hierarchy. Do not make KoProgressProxy its parent (note that KoProgressProxy
// is not necessarily castable to QObject ). This prevents proper functioning
// of progress reporting in multi-threaded environments.
KoProgressUpdater::KoProgressUpdater(KoProgressProxy *progressBar,
                                     Mode mode, QTextStream *output)
    : d (new Private(this, progressBar, mode, output))
{
    Q_ASSERT(d->progressBar);
    connect(&d->updateGuiTimer, SIGNAL(timeout()), SLOT(updateUi()));
}

KoProgressUpdater::~KoProgressUpdater()
{
    if (d->output) {
        Private::logEvents(*d->output, d, referenceTime(), "");
    }
    d->progressBar->setValue(d->progressBar->maximum());

    // make sure to stop the timer to avoid accessing
    // the data we are going to delete right now
    d->updateGuiTimer.stop();

    qDeleteAll(d->subtasks);
    d->subtasks.clear();

    qDeleteAll(d->subTaskWrappers);
    d->subTaskWrappers.clear();

    delete d;
}

void KoProgressUpdater::setReferenceTime(const QTime &referenceTime)
{
    d->referenceTime = referenceTime;
}

QTime KoProgressUpdater::referenceTime() const
{
    return d->referenceTime;
}

void KoProgressUpdater::start(int range, const QString &text)
{
    d->updateGuiTimer.start(PROGRESSUPDATER_GUITIMERINTERVAL);

    qDeleteAll(d->subtasks);
    d->subtasks.clear();

    qDeleteAll(d->subTaskWrappers);
    d->subTaskWrappers.clear();

    d->progressBar->setRange(0, range-1);
    d->progressBar->setValue(0);

    if(!text.isEmpty()) {
        d->progressBar->setFormat(text);
    }
    d->totalWeight = 0;
    d->canceled = false;
}

QPointer<KoUpdater> KoProgressUpdater::startSubtask(int weight,
                                                    const QString &name)
{
    KoUpdaterPrivate *p = new KoUpdaterPrivate(this, weight, name);
    d->totalWeight += weight;
    d->subtasks.append(p);
    connect(p, SIGNAL(sigUpdated()), SLOT(update()));

    QPointer<KoUpdater> updater = new KoUpdater(p);
    d->subTaskWrappers.append(updater);

    if (!d->updateGuiTimer.isActive()) {
        // we maybe need to restart the timer if it was stopped in updateUi() cause
        // other sub-tasks created before this one finished already.
        d->updateGuiTimer.start(PROGRESSUPDATER_GUITIMERINTERVAL);
    }

    return updater;
}

void KoProgressUpdater::cancel()
{
    foreach(KoUpdaterPrivate *updater, d->subtasks) {
        updater->setProgress(100);
        updater->interrupt();
    }
    d->canceled = true;
    updateUi();
}

void KoProgressUpdater::update()
{
    d->updated = true;
    if (d->mode == Unthreaded) {
        qApp->processEvents();
    }
}

void KoProgressUpdater::updateUi()
{
    // This function runs in the app main thread. All the progress
    // updates arrive at the KoUpdaterPrivate instances through
    // queued connections, so until we relinquish control to the
    // event loop, the progress values cannot change, and that
    // won't happen until we return from this function (which is
    // triggered by a timer)

    if (d->updated) {
        int totalProgress = 0;
        foreach(QPointer<KoUpdaterPrivate> updater, d->subtasks) {
            if (updater->interrupted()) {
                d->currentProgress = -1;
                return;
            }

            int progress = updater->progress();
            if (progress > 100 || progress < 0) {
                progress = updater->progress();
            }

            totalProgress += progress *updater->weight();
        }

        d->currentProgress = totalProgress / d->totalWeight;
        d->updated = false;
    }

    if (d->currentProgress == -1) {
        d->progressBar->setValue( d->progressBar->maximum() );
        // should we hide the progressbar after a little while?
        return;
    }

    if (d->currentProgress >= d->progressBar->maximum()) {
        // we're done
        d->updateGuiTimer.stop(); // 10 updates/second should be enough?
    }
    d->progressBar->setValue(d->currentProgress);
}

bool KoProgressUpdater::interrupted() const
{
    return d->canceled;
}

bool KoProgressUpdater::hasOutput() const
{
    return d->output != 0;
}

void KoProgressUpdater::Private::logEvents(QTextStream& out,
                                           KoProgressUpdater::Private *updater,
                                           const QTime& startTime,
                                           const QString& prefix) {
    // initial implementation: write out the names of all events
    foreach (QPointer<KoUpdaterPrivate> p, updater->subtasks) {
        if (!p) continue;
        foreach (const KoUpdaterPrivate::TimePoint &tp, p->getPoints()) {
            out << prefix+p->objectName() << '\t'
                    << startTime.msecsTo(tp.time) << '\t' << tp.value << endl;
        }
    }
}