#include "visualizerbars.hpp"

#include <algorithm>
#include <cmath>
#include <qbrush.h>
#include <qpainter.h>
#include <qpainterpath.h>
#include <qpen.h>

namespace ZShell::internal {

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

void VisualizerBars::advance(qreal dt) {
	if (m_displayValues.isEmpty() || m_settled)
		return;

	// dt is in seconds (from FrameAnimation.frameTime), convert to ms
	const qreal dtMs = dt * 1000.0;
	const qreal tau = m_animationDuration / 3.0;
	const qreal alpha = 1.0 - std::exp(-dtMs / tau);

	bool allSettled = true;

	for (qsizetype i = 0; i < m_displayValues.size(); ++i) {
		const double diff = m_targetValues[i] - m_displayValues[i];

		if (std::abs(diff) > 0.001) {
			m_displayValues[i] += diff * alpha;
			allSettled = false;
		} else {
			m_displayValues[i] = m_targetValues[i];
		}
	}

	update();

	if (allSettled && !m_settled) {
		m_settled = true;
		emit settledChanged();
	}
}

void VisualizerBars::paint(QPainter* painter) {
	if (m_displayValues.isEmpty())
		return;

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

	const qreal h = height();
	const qreal maxBarHeight = h * 0.4;

	QLinearGradient gradient(0, h - maxBarHeight, 0, h);
	gradient.setColorAt(0, m_primaryColor);
	gradient.setColorAt(1, m_secondaryColor);
	painter->setBrush(gradient);

	drawSide(painter, false);
	drawSide(painter, true);
}

void VisualizerBars::drawSide(QPainter* painter, bool rightSide) {
	const qreal w = width();
	const qreal h = height();
	const auto count = m_displayValues.size();

	if (count == 0)
		return;

	const qreal sideWidth = w * 0.4;
	const qreal slotWidth = sideWidth / static_cast<qreal>(count);
	const qreal barWidth = slotWidth - m_spacing;

	if (barWidth <= 0)
		return;

	const qreal sideOffset = rightSide ? w * 0.6 : 0;
	const qreal maxBarHeight = h * 0.4;

	for (qsizetype i = 0; i < count; ++i) {
		const qsizetype valueIndex = rightSide ? i : (count - i - 1);
		const qreal value = std::clamp(m_displayValues[valueIndex], 0.0, 1.0);
		const qreal barHeight = value * maxBarHeight;

		if (barHeight <= 0)
			continue;

		const qreal x = static_cast<qreal>(i) * slotWidth + sideOffset;
		const qreal y = h - barHeight;
		const qreal r = std::min({ m_rounding, barWidth / 2.0, barHeight });

		QPainterPath path;
		path.moveTo(x, h);
		path.lineTo(x, y + r);

		if (r > 0) {
			path.arcTo(x, y, r * 2, r * 2, 180, -90);
			path.lineTo(x + barWidth - r, y);
			path.arcTo(x + barWidth - r * 2, y, r * 2, r * 2, 90, -90);
		} else {
			path.lineTo(x, y);
			path.lineTo(x + barWidth, y);
		}

		path.lineTo(x + barWidth, h);
		path.closeSubpath();

		painter->drawPath(path);
	}
}

QVector<double> VisualizerBars::values() const {
	return m_targetValues;
}

void VisualizerBars::setValues(const QVector<double>& values) {
	m_targetValues = values;

	if (m_displayValues.size() != values.size()) {
		m_displayValues.resize(values.size(), 0.0);
	}

	if (m_settled) {
		m_settled = false;
		emit settledChanged();
	}

	emit valuesChanged();
}

bool VisualizerBars::settled() const {
	return m_settled;
}

QColor VisualizerBars::primaryColor() const {
	return m_primaryColor;
}

void VisualizerBars::setPrimaryColor(const QColor& color) {
	if (m_primaryColor == color)
		return;
	m_primaryColor = color;
	emit primaryColorChanged();
	update();
}

QColor VisualizerBars::secondaryColor() const {
	return m_secondaryColor;
}

void VisualizerBars::setSecondaryColor(const QColor& color) {
	if (m_secondaryColor == color)
		return;
	m_secondaryColor = color;
	emit secondaryColorChanged();
	update();
}

qreal VisualizerBars::rounding() const {
	return m_rounding;
}

void VisualizerBars::setRounding(qreal rounding) {
	if (qFuzzyCompare(m_rounding, rounding))
		return;
	m_rounding = rounding;
	emit roundingChanged();
	update();
}

qreal VisualizerBars::spacing() const {
	return m_spacing;
}

void VisualizerBars::setSpacing(qreal spacing) {
	if (qFuzzyCompare(m_spacing, spacing))
		return;
	m_spacing = spacing;
	emit spacingChanged();
	update();
}

int VisualizerBars::animationDuration() const {
	return m_animationDuration;
}

void VisualizerBars::setAnimationDuration(int duration) {
	if (m_animationDuration == duration)
		return;
	m_animationDuration = duration;
	emit animationDurationChanged();
}

} // namespace ZShell::internal