/****************************************************************************

**

** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the examples of the Qt Toolkit.

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

#include "spectrograph.h"

#include <QPainter>

#include <QMouseEvent>

#include <QDebug>

#include <QTimerEvent>

const int NullTimerId = -1;

const int NullIndex = -1;

const int BarSelectionInterval = 2000;

Spectrograph::Spectrograph(QWidget *parent)

    :   QWidget(parent)

    ,   m_barSelected(NullIndex)

    ,   m_timerId(NullTimerId)

    ,   m_lowFreq(0.0)

    ,   m_highFreq(0.0)

{

    setMinimumHeight(100);

}

Spectrograph::~Spectrograph()

{

}

void Spectrograph::setParams(int numBars, qreal lowFreq, qreal highFreq)

{

    Q_ASSERT(numBars > 0);

    Q_ASSERT(highFreq > lowFreq);

    m_bars.resize(numBars);

    m_lowFreq = lowFreq;

    m_highFreq = highFreq;

    updateBars();

}

void Spectrograph::timerEvent(QTimerEvent *event)

{

    Q_ASSERT(event->timerId() == m_timerId);

    Q_UNUSED(event) // suppress warnings in release builds

    killTimer(m_timerId);

    m_timerId = NullTimerId;

    m_barSelected = NullIndex;

    update();

}

void Spectrograph::paintEvent(QPaintEvent *event)

{

    Q_UNUSED(event)

    QPainter painter(this);

    painter.fillRect(rect(), Qt::black);

    const int numBars = m_bars.count();

    // Highlight region of selected bar

    if (m_barSelected != NullIndex && numBars) {

        QRect regionRect = rect();

        regionRect.setLeft(m_barSelected * rect().width() / numBars);

        regionRect.setWidth(rect().width() / numBars);

        QColor regionColor(202, 202, 64);

        painter.setBrush(Qt::DiagCrossPattern);

        painter.fillRect(regionRect, regionColor);

        painter.setBrush(Qt::NoBrush);

    }

    QColor barColor(51, 204, 102);

    QColor clipColor(255, 255, 0);

    // Draw the outline

    const QColor gridColor = barColor.darker();

    QPen gridPen(gridColor);

    painter.setPen(gridPen);

    painter.drawLine(rect().topLeft(), rect().topRight());

    painter.drawLine(rect().topRight(), rect().bottomRight());

    painter.drawLine(rect().bottomRight(), rect().bottomLeft());

    painter.drawLine(rect().bottomLeft(), rect().topLeft());

    QVector<qreal> dashes;

    dashes << 2 << 2;

    gridPen.setDashPattern(dashes);

    painter.setPen(gridPen);

    // Draw vertical lines between bars

    if (numBars) {

        const int numHorizontalSections = numBars;

        QLine line(rect().topLeft(), rect().bottomLeft());

        for (int i=1; i<numHorizontalSections; ++i) {

            line.translate(rect().width()/numHorizontalSections, 0);

            painter.drawLine(line);

        }

    }

    // Draw horizontal lines

    const int numVerticalSections = 10;

    QLine line(rect().topLeft(), rect().topRight());

    for (int i=1; i<numVerticalSections; ++i) {

        line.translate(0, rect().height()/numVerticalSections);

        painter.drawLine(line);

    }

    barColor = barColor.lighter();

    barColor.setAlphaF(0.75);

    clipColor.setAlphaF(0.75);

    // Draw the bars

    if (numBars) {

        // Calculate width of bars and gaps

        const int widgetWidth = rect().width();

        const int barPlusGapWidth = widgetWidth / numBars;

        const int barWidth = 0.8 * barPlusGapWidth;

        const int gapWidth = barPlusGapWidth - barWidth;

        const int paddingWidth = widgetWidth - numBars * (barWidth + gapWidth);

        const int leftPaddingWidth = (paddingWidth + gapWidth) / 2;

        const int barHeight = rect().height() - 2 * gapWidth;

        for (int i=0; i<numBars; ++i) {

            const qreal value = m_bars[i].value;

            Q_ASSERT(value >= 0.0 && value <= 1.0);

            QRect bar = rect();

            bar.setLeft(rect().left() + leftPaddingWidth + (i * (gapWidth + barWidth)));

            bar.setWidth(barWidth);

            bar.setTop(rect().top() + gapWidth + (1.0 - value) * barHeight);

            bar.setBottom(rect().bottom() - gapWidth);

            QColor color = barColor;

            if (m_bars[i].clipped)

                color = clipColor;

            painter.fillRect(bar, color);

        }

    }

}

void Spectrograph::mousePressEvent(QMouseEvent *event)

{

    const QPoint pos = event->pos();

    const int index = m_bars.count() * (pos.x() - rect().left()) / rect().width();

    selectBar(index);

}

void Spectrograph::reset()

{

    m_spectrum.reset();

    spectrumChanged(m_spectrum);

}

void Spectrograph::spectrumChanged(const FrequencySpectrum &spectrum)

{

    m_spectrum = spectrum;

    updateBars();

}

int Spectrograph::barIndex(qreal frequency) const

{

    Q_ASSERT(frequency >= m_lowFreq && frequency < m_highFreq);

    const qreal bandWidth = (m_highFreq - m_lowFreq) / m_bars.count();

    const int index = (frequency - m_lowFreq) / bandWidth;

    if(index <0 || index >= m_bars.count())

        Q_ASSERT(false);

    return index;

}

QPair<qreal, qreal> Spectrograph::barRange(int index) const

{

    Q_ASSERT(index >= 0 && index < m_bars.count());

    const qreal bandWidth = (m_highFreq - m_lowFreq) / m_bars.count();

    return QPair<qreal, qreal>(index * bandWidth, (index+1) * bandWidth);

}

void Spectrograph::updateBars()

{

    m_bars.fill(Bar());

    FrequencySpectrum::const_iterator i = m_spectrum.begin();

    const FrequencySpectrum::const_iterator end = m_spectrum.end();

    for ( ; i != end; ++i) {

        const FrequencySpectrum::Element e = *i;

        if (e.frequency >= m_lowFreq && e.frequency < m_highFreq) {

            Bar &bar = m_bars[barIndex(e.frequency)];

            bar.value = qMax(bar.value, e.amplitude);

            bar.clipped |= e.clipped;

        }

    }

    update();

}

void Spectrograph::selectBar(int index) {

    const QPair<qreal, qreal> frequencyRange = barRange(index);

    const QString message = QString("%1 - %2 Hz")

                                .arg(frequencyRange.first)

                                .arg(frequencyRange.second);

    emit infoMessage(message, BarSelectionInterval);

    if (NullTimerId != m_timerId)

        killTimer(m_timerId);

    m_timerId = startTimer(BarSelectionInterval);

    m_barSelected = index;

    update();

}