#include "circularbuffer.hpp"

#include <algorithm>

namespace ZShell::internal {

CircularBuffer::CircularBuffer(QObject* parent) : QObject(parent) {}

int CircularBuffer::capacity() const {
	return m_capacity;
}

void CircularBuffer::setCapacity(int capacity) {
	if (capacity < 0) capacity = 0;
	if (m_capacity == capacity) return;

	const auto old = values();

	m_capacity = capacity;
	m_data.resize(capacity);
	m_data.fill(0.0);
	m_smoothed.resize(capacity);
	m_smoothed.fill(0.0);
	m_head = 0;
	m_count = 0;

	// Re-push old values, keeping the most recent ones
	const auto start = old.size() > capacity ? old.size() - capacity : 0;
	for (auto i = start; i < old.size(); ++i) {
		m_data[m_head] = old[i];
		m_head = (m_head + 1) % m_capacity;
		m_count++;
	}

	recomputeAllSmoothed();

	emit capacityChanged();
	emit countChanged();
	emit valuesChanged();
}

int CircularBuffer::count() const {
	return m_count;
}

QList<qreal> CircularBuffer::values() const {
	QList<qreal> result;
	result.reserve(m_count);
	for (int i = 0; i < m_count; ++i)
		result.append(at(i));
	return result;
}

qreal CircularBuffer::maximum() const {
	if (m_count == 0) return 0.0;

	qreal maxVal = at(0);
	for (int i = 1; i < m_count; ++i)
		maxVal = std::max(maxVal, at(i));
	return maxVal;
}

int CircularBuffer::smoothingRadius() const {
	return m_smoothingRadius;
}

void CircularBuffer::setSmoothingRadius(int radius) {
	radius = std::max(0, radius);
	if (m_smoothingRadius == radius) return;
	m_smoothingRadius = radius;
	recomputeAllSmoothed();
	emit smoothingRadiusChanged();
	emit valuesChanged();
}

void CircularBuffer::push(qreal value) {
	if (m_capacity <= 0) return;

	m_data[m_head] = value;
	m_head = (m_head + 1) % m_capacity;
	if (m_count < m_capacity) {
		m_count++;
		emit countChanged();
	}

	updateSmoothedTail();

	emit valuesChanged();
}

void CircularBuffer::clear() {
	if (m_count == 0) return;

	m_head = 0;
	m_count = 0;
	emit countChanged();
	emit valuesChanged();
}

qreal CircularBuffer::at(int index) const {
	if (index < 0 || index >= m_count) return 0.0;

	const int actualIndex =
		(m_head - m_count + index + m_capacity) % m_capacity;
	return m_data[actualIndex];
}

qreal CircularBuffer::smoothedAt(int index) const {
	if (index < 0 || index >= m_count) return 0.0;

	const int actualIndex =
		(m_head - m_count + index + m_capacity) % m_capacity;
	return m_smoothed[actualIndex];
}

void CircularBuffer::writeSmoothedAt(int logicalIndex) {
	const int actualIndex =
		(m_head - m_count + logicalIndex + m_capacity) % m_capacity;

	if (m_smoothingRadius <= 0) {
		m_smoothed[actualIndex] = m_data[actualIndex];
		return;
	}

	qreal sum = 0.0;
	int sampleCount = 0;
	for (int j = -m_smoothingRadius; j <= m_smoothingRadius; ++j) {
		const int idx = logicalIndex + j;
		if (idx < 0 || idx >= m_count) continue;
		const int a = (m_head - m_count + idx + m_capacity) % m_capacity;
		sum += m_data[a];
		sampleCount++;
	}
	m_smoothed[actualIndex] = sampleCount > 0 ? sum / sampleCount : 0.0;
}

void CircularBuffer::updateSmoothedTail() {
	const int start = std::max(0, m_count - 1 - m_smoothingRadius);
	for (int i = start; i < m_count; ++i)
		writeSmoothedAt(i);
}

void CircularBuffer::recomputeAllSmoothed() {
	for (int i = 0; i < m_count; ++i)
		writeSmoothedAt(i);
}

} // namespace ZShell::internal