/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#pragma once

#include "Math/Math.hpp"
#include <vector>
#include <optional>

struct FT_FaceRec_;

namespace OpenVulkano::Scene
{
	struct GlyphForPacking
	{
		uint32_t code;
		Math::Vector2i size;
		Math::Vector2d atlasPos;
		size_t firstGlyphByteInAtlas;
	};

	struct Shelf
	{
		static std::vector<Shelf> CreateShelves(uint32_t atlasWidth, std::vector<GlyphForPacking>& glyphs, FT_FaceRec_* face, int channelsCount);

		Shelf(uint32_t width, uint32_t height, int pixelSize, uint32_t prevShelvesHeight) 
			: m_width(width), m_height(height), m_remainingWidth(width), m_prevShelvesHeight(prevShelvesHeight), m_pixelSize(pixelSize) {}
		bool HasSpaceForGlyph(uint32_t glyphWidth, uint32_t glyphHeight) const
		{
			return m_remainingWidth >= glyphWidth && m_height >= glyphHeight;
		}
		uint32_t GetWidth() const { return m_width; }
		uint32_t GetHeight() const { return m_height; }
		uint32_t GetNextGlyphPos() const { return m_nextGlyphPos; };
		uint32_t GetOccupiedSize() const { return ((m_width - m_remainingWidth) * m_height); }
		uint32_t GetPrevShelvesHeight() const { return m_prevShelvesHeight; }
		int GetPixelSize() const { return m_pixelSize; }

		std::optional<std::pair<uint32_t, uint32_t>> AddGlyph(uint32_t glyphWidth, uint32_t glyphHeight)
		{
			if (!HasSpaceForGlyph(glyphWidth, glyphHeight))
			{
				return {};
			}
			uint32_t insertionPos = m_nextGlyphPos;
			m_nextGlyphPos += glyphWidth;
			m_remainingWidth -= glyphWidth;

			uint32_t hOffset = m_height - (m_height - glyphHeight);
			uint32_t glyphFirstByte = (insertionPos * m_pixelSize)
			                          + ((hOffset * m_width * m_pixelSize) - (m_width * m_pixelSize))
			                          + (m_prevShelvesHeight * m_width * m_pixelSize);

			return std::make_pair(insertionPos, glyphFirstByte);
		}

	private:
		uint32_t m_width;
		uint32_t m_height;
		uint32_t m_remainingWidth;
		uint32_t m_nextGlyphPos = 0;
		uint32_t m_prevShelvesHeight;
		int m_pixelSize;
	};
}