#include "KeyboardWidget.hpp"
#include <QHBoxLayout>
#include <QSvgRenderer>
#include <QMouseEvent>
#include <QScrollArea>
#include <QApplication>
#include <QScrollBar>

/* Used for generating transform matrices to map SVG coordinate space */
static QTransform RectToRect(const QRectF& from, const QRectF& to)
{
    QPolygonF orig(from);
    orig.pop_back();
    QPolygonF resize(to);
    resize.pop_back();
    QTransform ret;
    QTransform::quadToQuad(orig, resize, ret);
    return ret;
}

static const QString NaturalKeyNames[] =
{
    QStringLiteral("C"),
    QStringLiteral("D"),
    QStringLiteral("E"),
    QStringLiteral("F"),
    QStringLiteral("G"),
    QStringLiteral("A"),
    QStringLiteral("B")
};

static const QString SharpKeyNames[] =
{
    QStringLiteral("Cs"),
    QStringLiteral("Ds"),
    QStringLiteral("Fs"),
    QStringLiteral("Gs"),
    QStringLiteral("As")
};

static const QString KeyStrings[] =
{
    QStringLiteral("C"),
    QStringLiteral("C#"),
    QStringLiteral("D"),
    QStringLiteral("D#"),
    QStringLiteral("E"),
    QStringLiteral("F"),
    QStringLiteral("F#"),
    QStringLiteral("G"),
    QStringLiteral("G#"),
    QStringLiteral("A"),
    QStringLiteral("A#"),
    QStringLiteral("B")
};

static const int NaturalKeyNumbers[] =
{
    0, 2, 4, 5, 7, 9, 11
};

static const int SharpKeyNumbers[] =
{
    1, 3, 6, 8, 10
};

KeyboardOctave::KeyboardOctave(int octave, const QString& svgPath, QWidget* parent)
: QSvgWidget(svgPath, parent), m_octave(octave)
{
    for (int i = 0; i < 7; ++i)
        if (renderer()->elementExists(NaturalKeyNames[i]))
            m_natural[i] = renderer()->matrixForElement(NaturalKeyNames[i]).
                mapRect(renderer()->boundsOnElement(NaturalKeyNames[i]));

    for (int i = 0; i < 5; ++i)
        if (renderer()->elementExists(SharpKeyNames[i]))
            m_sharp[i] = renderer()->matrixForElement(SharpKeyNames[i]).
                mapRect(renderer()->boundsOnElement(SharpKeyNames[i]));

    /* The parent keyboard manages all mouse events */
    setAttribute(Qt::WA_TransparentForMouseEvents);
}

int KeyboardOctave::getKey(const QPoint& localPos) const
{
    QPointF localPoint = m_widgetToSvg.map(localPos);
    for (int i = 0; i < 5; ++i)
        if (m_sharp[i].contains(localPoint))
            return SharpKeyNumbers[i];
    for (int i = 0; i < 7; ++i)
        if (m_natural[i].contains(localPoint))
            return NaturalKeyNumbers[i];
    return -1;
}

void KeyboardOctave::resizeEvent(QResizeEvent *event)
{
    m_widgetToSvg = RectToRect(rect(), renderer()->viewBoxF());
}

KeyboardWidget::KeyboardWidget(QWidget* parent)
: QWidget(parent)
{
    QHBoxLayout* layout = new QHBoxLayout(this);
    layout->setContentsMargins(QMargins());
    layout->setSpacing(0);

    for (int i = 0; i < 10; ++i)
    {
        m_widgets[i] = new KeyboardOctave(i, QStringLiteral(":/bg/keyboard.svg"), this);
        m_widgets[i]->setGeometry(QRect(0, 0, 141, 50));
        m_widgets[i]->setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred));
        layout->addWidget(m_widgets[i]);
    }

    m_widgets[10] = new KeyboardOctave(10, QStringLiteral(":/bg/keyboard_last.svg"), this);
    m_widgets[10]->setGeometry(QRect(0, 0, 101, 50));
    m_widgets[10]->setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred));
    layout->addWidget(m_widgets[10]);

    setLayout(layout);
    setMouseTracking(true);
}

std::pair<int, int> KeyboardWidget::_getOctaveAndKey(QMouseEvent* event) const
{
    for (KeyboardOctave* oct : m_widgets)
    {
        QPoint localPos = oct->mapFromParent(event->pos());
        if (oct->rect().contains(localPos))
            return {oct->getOctave(), oct->getKey(localPos)};
    }
    return {-1, -1};
}

void KeyboardWidget::_startKey(int octave, int key)
{
    printf("START %d %d\n", octave, key);
}

void KeyboardWidget::_stopKey()
{
    printf("STOP\n");
}

void KeyboardWidget::_moveOnKey(int octave, int key)
{
    if (m_lastOctave != octave || m_lastKey != key)
    {
        m_lastOctave = octave;
        m_lastKey = key;
        if (m_statusFocus)
            m_statusFocus->setMessage(QStringLiteral("%1%2 (%3)").
                arg(KeyStrings[key]).arg(octave - 1).arg(octave * 12 + key));
        if (m_holding)
            _startKey(octave, key);
    }
}

void KeyboardWidget::_pressOnKey(int octave, int key)
{
    _moveOnKey(octave, key);
    m_holding = true;
    _startKey(octave, key);
}

void KeyboardWidget::mouseMoveEvent(QMouseEvent* event)
{
    std::pair<int, int> ok = _getOctaveAndKey(event);
    if (ok.first != -1 && ok.second != -1)
        _moveOnKey(ok.first, ok.second);
}

void KeyboardWidget::mousePressEvent(QMouseEvent* event)
{
    std::pair<int, int> ok = _getOctaveAndKey(event);
    if (ok.first != -1 && ok.second != -1)
        _pressOnKey(ok.first, ok.second);
}

void KeyboardWidget::mouseReleaseEvent(QMouseEvent* event)
{
    _stopKey();
    m_holding = false;
}

void KeyboardWidget::enterEvent(QEvent* event)
{
    if (m_statusFocus)
        m_statusFocus->enter();
}

void KeyboardWidget::leaveEvent(QEvent* event)
{
    if (m_statusFocus)
        m_statusFocus->exit();
}

void KeyboardWidget::wheelEvent(QWheelEvent* event)
{
    if (QScrollArea* scroll = qobject_cast<QScrollArea*>(parentWidget()->parentWidget()))
    {
        /* Send wheel event directly to the scroll bar */
        QApplication::sendEvent(scroll->horizontalScrollBar(), event);
    }
}

void KeyboardWidget::showEvent(QShowEvent* event)
{
    if (QScrollArea* scroll = qobject_cast<QScrollArea*>(parentWidget()->parentWidget()))
    {
        /* Scroll to C2 */
        scroll->ensureVisible(141 * 3 + scroll->width(), 0, 0, 0);
    }
}