/************************************************************************
 *
 * Copyright 2010-2012 Jakob Leben (jakob.leben@gmail.com)
 *
 * This file is part of Qt GUI for SuperCollider.
 *
 * 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.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ************************************************************************/

#include "QcScopeShm.h"
#include "scope_shm_interface.hpp"
#include "../QcWidgetFactory.h"
#include "../debug.h"

#include <QPainter>
#include <QPainterPath>
#include <QTimer>
#include <QResizeEvent>
#include <QWindow>
#include <QBackingStore>

QC_DECLARE_QWIDGET_FACTORY(QcScopeShm);

QcScopeShm::QcScopeShm():
    _srvPort(-1),
    _scopeIndex(-1),
    _shm(new ScopeShm(this)),
    _running(false),
    _data(0),
    _availableFrames(0),
    xOffset(0.f),
    yOffset(0.f),
    xZoom(1.f),
    yZoom(1.f),
    _style(0),
    _bkg(QColor(0, 0, 0)),
    _fill(true) {
    setAttribute(Qt::WA_OpaquePaintEvent, true);
    setAutoFillBackground(false);

    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

    timer = new QTimer(this);
    timer->setInterval(50);
    connect(timer, SIGNAL(timeout()), this, SLOT(updateScope()));
}

QcScopeShm::~QcScopeShm() { stop(); }

void QcScopeShm::setServerPort(int port) {
    if (_running) {
        qcWarningMsg("QScope: Can not change server port while running!");
        return;
    }

    _srvPort = port;
}

void QcScopeShm::setBufferNumber(int n) {
    if (_running) {
        // TODO: release used reader?
        initScopeReader(_shm, n);
    }
    _scopeIndex = n;
}

void QcScopeShm::setWaveColors(const QVariantList& newColors) {
    colors.clear();
    Q_FOREACH (const QVariant& var, newColors) {
        QColor color = var.value<QColor>();
        if (!color.isValid())
            colors.append(QColor(0, 0, 0));
        else
            colors.append(color);
    }
}

int QcScopeShm::updateInterval() const { return timer->interval(); }

void QcScopeShm::setUpdateInterval(int interval) { timer->setInterval(qMax(0, interval)); }

void QcScopeShm::start() {
    if (_running)
        return;
    if (_srvPort < 0 || _scopeIndex < 0)
        return;

    connectSharedMemory(_srvPort);
    if (!_shm->client) {
        stop();
        return;
    }

    initScopeReader(_shm, _scopeIndex);

    timer->start();

    _running = true;
}

void QcScopeShm::stop() {
    // TODO: release used reader?

    delete _shm->client;
    _shm->client = 0;

    timer->stop();

    _running = false;
}

void QcScopeShm::updateScope() {
    bool valid = _shm->reader.valid();
    // qcDebugMsg(1, tr("valid = %1").arg(valid));
    if (!valid)
        return;

    bool ok = _shm->reader.pull(_availableFrames);
    // qcDebugMsg(1, tr("Got %1 frames").arg(_availableFrames) );
    if (ok) {
        _data = _shm->reader.data();
        update();
    }
}

void QcScopeShm::resizeEvent(QResizeEvent* ev) {
    qreal ratio = backingStore()->window()->devicePixelRatio();
    _pixmap = QPixmap(ev->size() * ratio);
    _pixmap.setDevicePixelRatio(ratio);
}

void QcScopeShm::paintEvent(QPaintEvent* event) {
    Q_UNUSED(event);

    QPainter p;

    _pixmap.fill(_bkg);

    if (_running && _availableFrames) {
        int chanCount = _shm->reader.channels();
        int maxFrames = _shm->reader.max_frames();
        QRect area(_pixmap.rect());
        area.setSize(area.size() / _pixmap.devicePixelRatio());

        p.begin(&_pixmap);

        switch (_style) {
        case 0:
            paint1D(false, chanCount, maxFrames, _availableFrames, area, p);
            break;
        case 1:
            paint1D(true, chanCount, maxFrames, _availableFrames, area, p);
            break;
        case 2:
            paint2D(chanCount, maxFrames, _availableFrames, area, p);
            break;
        }

        p.end();
    }

    p.begin(this);
    p.drawPixmap(0, 0, _pixmap);
}

void QcScopeShm::paint1D(bool overlapped, int chanCount, int maxFrames, int frameCount, const QRect& area,
                         QPainter& painter) {
    // qcDebugMsg( 0, tr("Drawing: data %1 / channels %2 / max-size %3").arg(_data!=0).arg(chanCount).arg(maxFrames) );

    if (frameCount < 2 || area.width() < 1 || area.height() < 1)
        return;

    float yRatio = -yZoom * area.height() * 0.5;
    if (!overlapped)
        yRatio /= chanCount;
    float yHeight = area.height();
    if (!overlapped)
        yHeight /= chanCount;
    QPen pen;
    pen.setWidth(0); // width==0 means width 1 regardless of transformations
    pen.setCapStyle(Qt::FlatCap);

    if (frameCount < area.width()) {
        float xRatio = xZoom * area.width() / (frameCount - 1);

        for (int ch = 0; ch < chanCount; ch++) {
            float* frameData = _data + (ch * maxFrames); // frame vector
            float yOrigin = yHeight * (overlapped ? 0.5 : ch + 0.5);
            QColor strokeColor = ch < colors.count() ? colors[ch] : QColor(255, 255, 255);
            QColor fillColor(strokeColor);
            fillColor.setAlpha(0.65 * 255);
            pen.setColor(strokeColor);

            painter.save();
            painter.translate(area.x(), area.y() + yOrigin);
            painter.scale(xRatio, yRatio);
            painter.setPen(pen);

            QPainterPath path;
            path.moveTo(xOffset, frameData[0]);
            for (int f = 1; f < frameCount; ++f)
                path.lineTo(xOffset + f, frameData[f]);

            if (_fill) {
                path.lineTo(xOffset + frameCount, 0);
                path.lineTo(0, 0);
                path.lineTo(xOffset, frameData[0]);

                painter.fillPath(path, QBrush(fillColor));
            }

            painter.drawPath(path);

            painter.restore();
        }
    } else {
        int w = area.width();
        float fpp = frameCount / (float)w; // frames per x pixel

        for (int ch = 0; ch < chanCount; ch++) {
            float* frameData = _data + (ch * maxFrames); // frame vector
            float yOrigin = yHeight * (overlapped ? 0.5 : ch + 0.5);
            QColor strokeColor = ch < colors.count() ? colors[ch] : QColor(255, 255, 255);
            QColor fillColor(strokeColor);
            fillColor.setAlpha(0.65 * 255);

            painter.save();
            painter.translate(area.x(), area.y() + yOrigin);
            painter.setPen(pen);

            qreal ratio = 1.0 / _pixmap.devicePixelRatio();

            QPainterPath pathLine;
            QPainterPath pathFill;

            int frame = 1;
            float min, max;
            min = max = frameData[0];

            for (qreal pixel = 0; pixel < w; pixel += ratio) {
                for (; frame < fpp * pixel; ++frame) {
                    float const d = frameData[frame];
                    if (d < min)
                        min = d;
                    if (d > max)
                        max = d;
                }

                // Make sure min is always lesser; otherwise if no frames are read
                // this produces odd-looking artifacts as min and max are accidentally
                // swapped twice and a line-pixel-line sequence is drawn.
                // TODO: interpolate in this case somehow?
                if (min > max)
                    std::swap(min, max);

                float y = max * yRatio;
                pathLine.moveTo(pixel, y);
                y = qMax(min * yRatio, y + 1);
                pathLine.lineTo(pixel, y);

                if (_fill) {
                    pathFill.moveTo(pixel, y);
                    pathFill.lineTo(pixel, 0);
                }

                // flip min/max to ensure continuity
                std::swap(min, max);
            }

            pen.setColor(strokeColor);
            painter.strokePath(pathLine, pen);

            if (_fill) {
                pen.setColor(fillColor);
                painter.strokePath(pathFill, pen);
            }

            painter.restore();
        }
    }
}

void QcScopeShm::paint2D(int chanCount, int maxFrames, int frameCount, const QRect& area, QPainter& painter) {
    int minSize = qMin(area.width(), area.height());
    // NOTE: use yZoom for both axis, since both represent value, as opposed to index
    float xRatio = yZoom * minSize * 0.5;
    float yRatio = -yZoom * minSize * 0.5;
    QPoint center = area.center();
    QPen pen;
    pen.setWidth(0); // width==0 means width 1 regardless of transformations
    pen.setCapStyle(Qt::FlatCap);
    pen.setColor(colors.count() ? colors[0] : QColor(255, 255, 255));

    painter.setPen(pen);
    painter.translate(center.x(), center.y());
    painter.scale(xRatio, yRatio);

    if (chanCount >= 2) {
        for (int i = 0; i + 1 < chanCount; i += 2) {
            float* data1 = _data + maxFrames * i;
            float* data2 = _data + maxFrames * (i + 1);

            QPainterPath path;
            path.moveTo(data1[0], data2[0]);
            for (int f = 1; f < frameCount; ++f)
                path.lineTo(data1[f], data2[f]);

            pen.setColor(i < colors.count() ? colors[i] : QColor(255, 255, 255));
            painter.setPen(pen);
            painter.drawPath(path);
        }
    } else {
        float* data1 = _data;
        QPainterPath path;
        path.moveTo(data1[0], 0.f);
        for (int f = 1; f < frameCount; ++f)
            path.lineTo(data1[f], 0.f);
        painter.drawPath(path);
    }
}

void QcScopeShm::connectSharedMemory(int port) {
    try {
        server_shared_memory_client* client = new server_shared_memory_client(port);
        _shm->client = client;
        qcDebugMsg(1, "Shared memory connected");
    } catch (std::exception& e) {
        _shm->client = 0;
        qcErrorMsg(QStringLiteral("Cannot connect to shared memory: %1").arg(e.what()));
    }
}

void QcScopeShm::initScopeReader(ScopeShm* shm, int index) {
    shm->reader = shm->client->get_scope_buffer_reader(index);
    qcDebugMsg(1, QStringLiteral("Initialized scope buffer reader for index %1.").arg(index));
}
