#include "sparklineitem.hpp"

#include <qmath.h>
#include <qpainter.h>
#include <qpainterpath.h>
#include <qpen.h>

namespace ZShell::internal {

SparklineItem::SparklineItem(QQuickItem* parent) : QQuickPaintedItem(parent) {
	setAntialiasing(true);
}

void SparklineItem::paint(QPainter* painter) {
	const bool has1 = m_line1 && m_line1->count() >= 2;
	const bool has2 = m_line2 && m_line2->count() >= 2;
	if (!has1 && !has2) return;

	painter->setRenderHint(QPainter::Antialiasing, true);

	// Draw line1 first (behind), then line2 (in front)
	if (has1) drawLine(painter, m_line1, m_line1Color, m_line1FillAlpha);
	if (has2) drawLine(painter, m_line2, m_line2Color, m_line2FillAlpha);
}

void SparklineItem::drawLine(
	QPainter* painter,
	CircularBuffer* buffer,
	const QColor& color,
	qreal fillAlpha) {
	if (m_historyLength < 2) return;

	const qreal w = width();
	const qreal h = height();
	const int len = buffer->count();
	if (len < 2 || m_maxValue <= 0.0) return;

	const qreal stepX = w / static_cast<qreal>(m_historyLength - 1);
	const qreal startX =
		w - (len - 1) * stepX - stepX * m_slideProgress + stepX;

	const qreal strokePad = qCeil(m_lineWidth / 2);
	const qreal curvePad = 3.0;
	const qreal topPad = strokePad + curvePad;
	const qreal bottomPad = strokePad;
	const qreal plotTop = topPad;
	const qreal plotBottom = h - bottomPad;
	const qreal fillBottom = h;
	const qreal plotH = qMax<qreal>(1.0, plotBottom - plotTop);

	QVector<QPointF> points;
	points.reserve(len);

	for (int i = 0; i < len; ++i) {
		const qreal x = startX + i * stepX;
		const qreal value = qBound<qreal>(0.0, buffer->at(i), m_maxValue);
		const qreal y = plotTop + (1.0 - (value / m_maxValue)) * plotH;
		points.append(QPointF(x, y));
	}

	QPainterPath linePath;
	linePath.moveTo(points[0]);

	for (int i = 0; i < points.size() - 1; ++i) {
		const QPointF& p0 = points[i];
		const QPointF& p1 = points[i + 1];

		const qreal ctrlX = (p0.x() + p1.x()) * 0.5;
		const QPointF c1(ctrlX, p0.y());
		const QPointF c2(ctrlX, p1.y());

		linePath.cubicTo(c1, c2, p1);
	}

	QPen pen(color, m_lineWidth);
	pen.setCapStyle(Qt::RoundCap);
	pen.setJoinStyle(Qt::RoundJoin);
	painter->setPen(pen);
	painter->setBrush(Qt::NoBrush);
	painter->drawPath(linePath);

	QPainterPath fillPath = linePath;
	fillPath.lineTo(startX + (len - 1) * stepX, fillBottom);
	fillPath.lineTo(startX, fillBottom);
	fillPath.closeSubpath();

	QColor fillColor = color;
	fillColor.setAlphaF(static_cast<float>(fillAlpha));
	painter->setPen(Qt::NoPen);
	painter->setBrush(fillColor);
	painter->drawPath(fillPath);
}

void SparklineItem::connectBuffer(CircularBuffer* buffer) {
	if (!buffer) return;

	connect(buffer, &CircularBuffer::valuesChanged, this, [this]() {
		update();
	});
	connect(buffer, &QObject::destroyed, this, [this, buffer]() {
		if (m_line1 == buffer) {
			m_line1 = nullptr;
			emit line1Changed();
		}
		if (m_line2 == buffer) {
			m_line2 = nullptr;
			emit line2Changed();
		}
		update();
	});
}

CircularBuffer* SparklineItem::line1() const {
	return m_line1;
}

void SparklineItem::setLine1(CircularBuffer* buffer) {
	if (m_line1 == buffer) return;
	if (m_line1) disconnect(m_line1, nullptr, this, nullptr);
	m_line1 = buffer;
	connectBuffer(buffer);
	emit line1Changed();
	update();
}

CircularBuffer* SparklineItem::line2() const {
	return m_line2;
}

void SparklineItem::setLine2(CircularBuffer* buffer) {
	if (m_line2 == buffer) return;
	if (m_line2) disconnect(m_line2, nullptr, this, nullptr);
	m_line2 = buffer;
	connectBuffer(buffer);
	emit line2Changed();
	update();
}

QColor SparklineItem::line1Color() const {
	return m_line1Color;
}

void SparklineItem::setLine1Color(const QColor& color) {
	if (m_line1Color == color) return;
	m_line1Color = color;
	emit line1ColorChanged();
	update();
}

QColor SparklineItem::line2Color() const {
	return m_line2Color;
}

void SparklineItem::setLine2Color(const QColor& color) {
	if (m_line2Color == color) return;
	m_line2Color = color;
	emit line2ColorChanged();
	update();
}

qreal SparklineItem::line1FillAlpha() const {
	return m_line1FillAlpha;
}

void SparklineItem::setLine1FillAlpha(qreal alpha) {
	if (qFuzzyCompare(m_line1FillAlpha, alpha)) return;
	m_line1FillAlpha = alpha;
	emit line1FillAlphaChanged();
	update();
}

qreal SparklineItem::line2FillAlpha() const {
	return m_line2FillAlpha;
}

void SparklineItem::setLine2FillAlpha(qreal alpha) {
	if (qFuzzyCompare(m_line2FillAlpha, alpha)) return;
	m_line2FillAlpha = alpha;
	emit line2FillAlphaChanged();
	update();
}

qreal SparklineItem::maxValue() const {
	return m_maxValue;
}

void SparklineItem::setMaxValue(qreal value) {
	if (qFuzzyCompare(m_maxValue, value)) return;
	m_maxValue = value;
	emit maxValueChanged();
	update();
}

qreal SparklineItem::slideProgress() const {
	return m_slideProgress;
}

void SparklineItem::setSlideProgress(qreal progress) {
	if (qFuzzyCompare(m_slideProgress, progress)) return;
	m_slideProgress = progress;
	emit slideProgressChanged();
	update();
}

int SparklineItem::historyLength() const {
	return m_historyLength;
}

void SparklineItem::setHistoryLength(int length) {
	if (m_historyLength == length) return;
	m_historyLength = length;
	emit historyLengthChanged();
	update();
}

qreal SparklineItem::lineWidth() const {
	return m_lineWidth;
}

void SparklineItem::setLineWidth(qreal width) {
	if (qFuzzyCompare(m_lineWidth, width)) return;
	m_lineWidth = width;
	emit lineWidthChanged();
	update();
}

} // namespace ZShell::internal