/* SPDX-FileCopyrightText: 2026 Project Tick
 * SPDX-FileContributor: Project Tick
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 *   MeshMC - A Custom Launcher for Minecraft
 *   Copyright (C) 2026 Project Tick
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 *  This file incorporates work covered by the following copyright and
 *  permission notice:
 *
 * Copyright 2013-2021 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "VisualGroup.h"

#include <QModelIndex>
#include <QPainter>
#include <QtMath>
#include <QApplication>
#include <QDebug>

#include "InstanceView.h"

VisualGroup::VisualGroup(const QString& text, InstanceView* view)
	: view(view), text(text), collapsed(false)
{
}

VisualGroup::VisualGroup(const VisualGroup* other)
	: view(other->view), text(other->text), collapsed(other->collapsed)
{
}

void VisualGroup::update()
{
	auto temp_items = items();
	auto itemsPerRow = view->itemsPerRow();

	int numRows = qMax(1, qCeil((qreal)temp_items.size() / (qreal)itemsPerRow));
	rows = QVector<VisualRow>(numRows);

	int maxRowHeight = 0;
	int positionInRow = 0;
	int currentRow = 0;
	int offsetFromTop = 0;
	for (auto item : temp_items) {
		if (positionInRow == itemsPerRow) {
			rows[currentRow].height = maxRowHeight;
			rows[currentRow].top = offsetFromTop;
			currentRow++;
			offsetFromTop += maxRowHeight + 5;
			positionInRow = 0;
			maxRowHeight = 0;
		}
		auto itemHeight =
			view->itemDelegate()->sizeHint(view->viewOptions(), item).height();
		if (itemHeight > maxRowHeight) {
			maxRowHeight = itemHeight;
		}
		rows[currentRow].items.append(item);
		positionInRow++;
	}
	rows[currentRow].height = maxRowHeight;
	rows[currentRow].top = offsetFromTop;
}

QPair<int, int> VisualGroup::positionOf(const QModelIndex& index) const
{
	int y = 0;
	for (auto& row : rows) {
		for (auto x = 0; x < row.items.size(); x++) {
			if (row.items[x] == index) {
				return qMakePair(x, y);
			}
		}
		y++;
	}
	qWarning() << "Item" << index.row()
			   << index.data(Qt::DisplayRole).toString()
			   << "not found in visual group" << text;
	return qMakePair(0, 0);
}

int VisualGroup::rowTopOf(const QModelIndex& index) const
{
	auto position = positionOf(index);
	return rows[position.second].top;
}

int VisualGroup::rowHeightOf(const QModelIndex& index) const
{
	auto position = positionOf(index);
	return rows[position.second].height;
}

VisualGroup::HitResults VisualGroup::hitScan(const QPoint& pos) const
{
	VisualGroup::HitResults results = VisualGroup::NoHit;
	int y_start = verticalPosition();
	int body_start = y_start + headerHeight();
	int body_end = body_start + contentHeight() + 5; // FIXME: wtf is this 5?
	int y = pos.y();
	// int x = pos.x();
	if (y < y_start) {
		results = VisualGroup::NoHit;
	} else if (y < body_start) {
		results = VisualGroup::HeaderHit;
		int collapseSize = headerHeight() - 4;

		// the icon
		QRect iconRect = QRect(view->m_leftMargin + 2, 2 + y_start,
							   collapseSize, collapseSize);
		if (iconRect.contains(pos)) {
			results |= VisualGroup::CheckboxHit;
		}
	} else if (y < body_end) {
		results |= VisualGroup::BodyHit;
	}
	return results;
}

void VisualGroup::drawHeader(QPainter* painter,
							 const QStyleOptionViewItem& option)
{
	painter->setRenderHint(QPainter::Antialiasing);

	const QRect optRect = option.rect;
	QFont font(QApplication::font());
	font.setBold(true);
	const QFontMetrics fontMetrics = QFontMetrics(font);

	QColor outlineColor = option.palette.text().color();
	outlineColor.setAlphaF(0.35);

	// BEGIN: top left corner
	{
		painter->save();
		painter->setPen(outlineColor);
		const QPointF topLeft(optRect.topLeft());
		QRectF arc(topLeft, QSizeF(4, 4));
		arc.translate(0.5, 0.5);
		painter->drawArc(arc, 1440, 1440);
		painter->restore();
	}
	// END: top left corner

	// BEGIN: left vertical line
	{
		QPoint start(optRect.topLeft());
		start.ry() += 3;
		QPoint verticalGradBottom(optRect.topLeft());
		verticalGradBottom.ry() += fontMetrics.height() + 5;
		QLinearGradient gradient(start, verticalGradBottom);
		gradient.setColorAt(0, outlineColor);
		gradient.setColorAt(1, Qt::transparent);
		painter->fillRect(QRect(start, QSize(1, fontMetrics.height() + 5)),
						  gradient);
	}
	// END: left vertical line

	// BEGIN: horizontal line
	{
		QPoint start(optRect.topLeft());
		start.rx() += 3;
		QPoint horizontalGradTop(optRect.topLeft());
		horizontalGradTop.rx() += optRect.width() - 6;
		painter->fillRect(QRect(start, QSize(optRect.width() - 6, 1)),
						  outlineColor);
	}
	// END: horizontal line

	// BEGIN: top right corner
	{
		painter->save();
		painter->setPen(outlineColor);
		QPointF topRight(optRect.topRight());
		topRight.rx() -= 4;
		QRectF arc(topRight, QSizeF(4, 4));
		arc.translate(0.5, 0.5);
		painter->drawArc(arc, 0, 1440);
		painter->restore();
	}
	// END: top right corner

	// BEGIN: right vertical line
	{
		QPoint start(optRect.topRight());
		start.ry() += 3;
		QPoint verticalGradBottom(optRect.topRight());
		verticalGradBottom.ry() += fontMetrics.height() + 5;
		QLinearGradient gradient(start, verticalGradBottom);
		gradient.setColorAt(0, outlineColor);
		gradient.setColorAt(1, Qt::transparent);
		painter->fillRect(QRect(start, QSize(1, fontMetrics.height() + 5)),
						  gradient);
	}
	// END: right vertical line

	// BEGIN: checkboxy thing
	{
		painter->save();
		painter->setRenderHint(QPainter::Antialiasing, false);
		painter->setFont(font);
		QColor penColor(option.palette.text().color());
		penColor.setAlphaF(0.6);
		painter->setPen(penColor);
		QRect iconSubRect(option.rect);
		iconSubRect.setTop(iconSubRect.top() + 7);
		iconSubRect.setLeft(iconSubRect.left() + 7);

		int sizing = fontMetrics.height();
		int even = ((sizing - 1) % 2);

		iconSubRect.setHeight(sizing - even);
		iconSubRect.setWidth(sizing - even);
		painter->drawRect(iconSubRect);

		/*
		if(collapsed)
			painter->drawText(iconSubRect, Qt::AlignHCenter | Qt::AlignVCenter,
		"+"); else painter->drawText(iconSubRect, Qt::AlignHCenter |
		Qt::AlignVCenter, "-");
		*/
		painter->setBrush(option.palette.text());
		painter->fillRect(iconSubRect.x(),
						  iconSubRect.y() + iconSubRect.height() / 2,
						  iconSubRect.width(), 2, penColor);
		if (collapsed) {
			painter->fillRect(iconSubRect.x() + iconSubRect.width() / 2,
							  iconSubRect.y(), 2, iconSubRect.height(),
							  penColor);
		}

		painter->restore();
	}
	// END: checkboxy thing

	// BEGIN: text
	{
		QRect textRect(option.rect);
		textRect.setTop(textRect.top() + 7);
		textRect.setLeft(textRect.left() + 7 + fontMetrics.height() + 7);
		textRect.setHeight(fontMetrics.height());
		textRect.setRight(textRect.right() - 7);

		painter->save();
		painter->setFont(font);
		QColor penColor(option.palette.text().color());
		penColor.setAlphaF(0.6);
		painter->setPen(penColor);
		painter->drawText(textRect, Qt::AlignLeft | Qt::AlignVCenter, text);
		painter->restore();
	}
	// END: text
}

int VisualGroup::totalHeight() const
{
	return headerHeight() + 5 + contentHeight(); // FIXME: wtf is that '5'?
}

int VisualGroup::headerHeight() const
{
	QFont font(QApplication::font());
	font.setBold(true);
	QFontMetrics fontMetrics(font);

	const int height = fontMetrics.height() + 1 /* 1 pixel-width gradient */
					   + 11 /* top and bottom separation */;
	return height;
	/*
	int raw = view->viewport()->fontMetrics().height() + 4;
	// add english. maybe. depends on font height.
	if (raw % 2 == 0)
		raw++;
	return std::min(raw, 25);
	*/
}

int VisualGroup::contentHeight() const
{
	if (collapsed) {
		return 0;
	}
	auto last = rows[numRows() - 1];
	return last.top + last.height;
}

int VisualGroup::numRows() const
{
	return rows.size();
}

int VisualGroup::verticalPosition() const
{
	return m_verticalPosition;
}

QList<QModelIndex> VisualGroup::items() const
{
	QList<QModelIndex> indices;
	for (int i = 0; i < view->model()->rowCount(); ++i) {
		const QModelIndex index = view->model()->index(i, 0);
		if (index.data(InstanceViewRoles::GroupRole).toString() == text) {
			indices.append(index);
		}
	}
	return indices;
}