#include "alignaudit.hpp"

#include <QDateTime>
#include <QFile>
#include <QGuiApplication>
#include <QQmlContext>
#include <QRegularExpression>
#include <QScreen>
#include <QTextStream>
#include <QTimer>
#include <QQuickItem>
#include <QQuickWindow>
#include <cmath>
#include <functional>
#include <qobject.h>

#ifdef ALIGN_AUDIT_USE_QML_PRIVATE
#include <private/qqmldata_p.h>
#endif

namespace ZShell {
namespace {

bool isOff(double v, double tol) {
	return std::abs(v - std::round(v)) > tol;
}

QString num(double v, bool off) {
	return QString::number(v, 'f', 2) + (off ? QStringLiteral("*") : QString());
}

QString typeName(const QQuickItem* item) {
	static const QRegularExpression suffix(QStringLiteral("_QML(TYPE)?_\\d+$"));
	QString name = QString::fromUtf8(item->metaObject()->className());
	name.remove(suffix);
	if (name.startsWith(QLatin1String("QQuick"))) {
		name.remove(0, 6);
	}
	return name;
}

QString label(const QQuickItem* item) {
	QString s = typeName(item);
	if (!item->objectName().isEmpty()) {
		s += QLatin1Char('#') + item->objectName();
	}
	return s;
}

QString ancestry(const QQuickItem* item, int maxDepth = 8) {
	QStringList parts;
	for (const QQuickItem* i = item; i && parts.size() < maxDepth;
		 i = i->parentItem()) {
		parts.prepend(label(i));
	}
	return parts.join(QLatin1String(" > "));
}

struct Source {
	QString file;
	int line = 0;
	int column = 0;
};

Source sourceOf(QQuickItem* item) {
	Source s;
	if (const QQmlContext* ctx = qmlContext(item)) {
		const QUrl url = ctx->baseUrl();
		s.file = url.isLocalFile() ? url.toLocalFile() : url.toString();
	}
#ifdef ALIGN_AUDIT_USE_QML_PRIVATE
	if (const QQmlData* d = QQmlData::get(item, false)) {
		s.line = int(d->lineNumber);
		s.column = int(d->columnNumber);
	}
#endif
	return s;
}

void visit(QQuickItem* item, const std::function<void(QQuickItem*)>& fn) {
	if (!item->isVisible() || item->opacity() <= 0.0) {
		return; // whole subtree is invisible
	}
	fn(item);
	for (QQuickItem* child : item->childItems()) {
		visit(child, fn);
	}
}

int auditWindow(QQuickWindow* window, const Options& o, QTextStream& out) {
	const double dpr = window->effectiveDevicePixelRatio();
	const double tol = o.tolerance;
	int count = 0;

	visit(window->contentItem(), [&](QQuickItem* item) {
		if (item->width() <= 0 || item->height() <= 0) {
			return;
		}
		if (o.paintedOnly &&
			!item->flags().testFlag(QQuickItem::ItemHasContents) &&
			!item->clip()) {
			return;
		}

		const bool isText = item->inherits("QQuickText");

		const QRectF r =
			item->mapRectToScene(QRectF(0, 0, item->width(), item->height()));
		const double l = r.left() * dpr, t = r.top() * dpr;
		const double rt = r.right() * dpr, b = r.bottom() * dpr;

		const bool offL = isOff(l, tol), offT = isOff(t, tol);
		const bool offR = !isText && isOff(rt, tol);
		const bool offB = !isText && isOff(b, tol);
		if (!(offL || offT || offR || offB)) {
			return;
		}

		const bool own = isOff(item->x() * dpr, tol) ||
						 isOff(item->y() * dpr, tol) ||
						 (!isText && (isOff(item->width() * dpr, tol) ||
									  isOff(item->height() * dpr, tol)));
		if (!own && !o.includeInherited) {
			return;
		}

		const Source src = sourceOf(item);
		out << src.file;
		if (src.line > 0) {
			out << ':' << src.line << ':' << src.column;
		}
		out << ": " << label(item) << " unaligned ("
			<< (own ? "own" : "inherited") << ")\n"
			<< "    device px: left=" << num(l, offL) << " top=" << num(t, offT)
			<< " right=" << num(rt, offR) << " bottom=" << num(b, offB) << "\n"
			<< "    local:     x=" << item->x() << " y=" << item->y()
			<< " w=" << item->width() << " h=" << item->height() << "\n"
			<< "    path:      " << ancestry(item) << "\n";
		++count;
	});
	return count;
}

} // namespace

struct ScreenReport {
	double dpr = 1.0;
	int windows = 0;
	int count = 0;
	QString body;
};

int run(const Options& options) {
	QMap<QString, ScreenReport> reports;

	for (QWindow* w : QGuiApplication::allWindows()) {
		auto* qw = qobject_cast<QQuickWindow*>(w);
		if (!qw || !qw->isVisible() || !qw->contentItem()) {
			continue;
		}

		const QString name = qw->screen() ? qw->screen()->name()
										  : QStringLiteral("?");
		ScreenReport& report = reports[name];
		report.dpr = qw->effectiveDevicePixelRatio();
		++report.windows;

		QString windowBody;
		QTextStream stream(&windowBody);
		report.count += auditWindow(qw, options, stream);
		stream.flush();
		report.body += windowBody;
	}

	QFile file(options.outputPath);
	if (!file.open(
			QIODevice::WriteOnly | QIODevice::Truncate | QIODevice::Text)) {
		qWarning() << "AlignAudit: cannot open" << options.outputPath;
		return -1;
	}
	QTextStream out(&file);

	int total = 0;
	for (const ScreenReport& r : std::as_const(reports)) {
		total += r.count;
	}

	out << "# align audit "
		<< QDateTime::currentDateTime().toString(Qt::ISODate)
		<< "  ('*' marks the off edges, values are device pixels)\n"
		<< "# total: " << total << "\n\n";

	for (auto it = reports.cbegin(); it != reports.cend(); ++it) {
		out << "# screen " << it.key() << "  dpr=" << it.value().dpr
			<< "  windows=" << it.value().windows
			<< "  offenders=" << it.value().count << "\n"
			<< it.value().body << "\n";
	}
	return total;
}

void runLater(int delayMs, const Options& options) {
	QTimer::singleShot(delayMs, qApp, [options] { run(options); });
}

} // namespace ZShell