#include "cpu.hpp"

#include "sensorslib.hpp"

#include <cmath>
#include <qfile.h>
#include <qregularexpression.h>

namespace ZShell::services {

Cpu::Cpu(QObject* parent)
	: TickingService(parent) {
	readNameOnce();
}

QString Cpu::name() const {
	return m_name;
}

qreal Cpu::percentage() const {
	return m_percentage;
}

qreal Cpu::temperature() const {
	return m_temperature;
}

void Cpu::tick() {
	if (!m_nameLoaded) {
		readNameOnce();
	}
	refreshPercentage();
	refreshTemperature();
}

void Cpu::readNameOnce() {
	QFile f(QStringLiteral("/proc/cpuinfo"));
	if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
		return;
	}
	const QByteArray data = f.readAll();
	f.close();

	static const QRegularExpression re(QStringLiteral("model name\\s*:\\s*(.+)"));
	const auto match = re.match(QString::fromLatin1(data));
	if (!match.hasMatch()) {
		return;
	}

	const QString cleaned = cleanName(match.captured(1));
	m_nameLoaded = true;
	if (cleaned == m_name) {
		return;
	}
	m_name = cleaned;
	Q_EMIT nameChanged();
}

void Cpu::refreshPercentage() {
	QFile f(QStringLiteral("/proc/stat"));
	if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
		return;
	}
	const QByteArray data = f.readAll();
	f.close();

	static const QRegularExpression re(
		QStringLiteral("^cpu\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)"));
	const auto match = re.match(QString::fromLatin1(data));
	if (!match.hasMatch()) {
		return;
	}

	quint64 total = 0;
	quint64 idle = 0;
	for (int i = 1; i <= 7; ++i) {
		const quint64 v = match.captured(i).toULongLong();
		total += v;
		if (i == 4 || i == 5) {
			idle += v;
		}
	}

	const quint64 totalDiff = total > m_lastTotal ? total - m_lastTotal : 0;
	const quint64 idleDiff = idle > m_lastIdle ? idle - m_lastIdle : 0;
	const qreal newPerc = totalDiff > 0 ? 1.0 - static_cast<qreal>(idleDiff) / static_cast<qreal>(totalDiff) : 0.0;

	m_lastTotal = total;
	m_lastIdle = idle;

	if (std::abs(newPerc - m_percentage) > 0.0001) {
		m_percentage = newPerc;
		Q_EMIT percentageChanged();
	}
}

void Cpu::refreshTemperature() {
	const auto t = sensorslib::cpuPackageTemp();
	const qreal newTemp = t.value_or(0.0);
	if (std::abs(newTemp - m_temperature) > 0.05) {
		m_temperature = newTemp;
		Q_EMIT temperatureChanged();
	}
}

QString Cpu::cleanName(QString s) {
	static const QRegularExpression noise(
		QStringLiteral("\\(R\\)|\\(TM\\)|CPU|\\d+(?:th|nd|rd|st) Gen |Core |Processor"),
		QRegularExpression::CaseInsensitiveOption);
	static const QRegularExpression spaces(QStringLiteral("\\s+"));

	s.replace(noise, QString());
	s.replace(spaces, QStringLiteral(" "));
	return s.trimmed();
}

} // namespace ZShell::services