/*
 * 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/.
 */

#include "FontAtlasGeneratorBase.hpp"
#include "FontAtlas.hpp"
#include "Base/Logger.hpp"
#include <filesystem>

namespace OpenVulkano::Scene
{
	void IFontAtlasGenerator::GenerateAtlas(const std::filesystem::path& fontFile, const std::set<uint32_t>& charset)
	{
		GenerateAtlas(Utils::ReadFile(fontFile), charset);
	}

	std::pair<FtLibraryRecPtr, FtFaceRecPtr> 
		FontAtlasGeneratorBase::InitFreetype(const std::span<const uint8_t>& data)
	{
		std::pair<FtLibraryRecPtr, FtFaceRecPtr> result;
		FT_Library library;
		auto error = FT_Init_FreeType(&library);
		if (error)
		{
			throw std::runtime_error(fmt::format("Could not initialize freetype library. Error: {}", GetFreetypeErrorDescription(error)));
		}
		result.first = FtLibraryRecPtr(library);

		FT_Face face;
		error = FT_New_Memory_Face(library, data.data(), data.size(), 0, &face);
		if (error)
		{
			if (error == FT_Err_Unknown_File_Format) throw std::runtime_error("Unknown font file format");
			throw std::runtime_error(fmt::format("Font file could not be read or is corrupted. Error: {}", GetFreetypeErrorDescription(error)));
		}
		result.second = FtFaceRecPtr(face);

		// some fancy font without unicode charmap
		if (face->charmap == nullptr)
		{
			throw std::runtime_error("Selected font doesn't contain unicode charmap");
		}
		return result;
	}

	std::string FontAtlasGeneratorBase::GetFreetypeErrorDescription(FT_Error error)
	{
		if (const char* s = FT_Error_String(error))
		{
			return s;
		}
		return fmt::format("Error code is {}", error);
	}

	void FontAtlasGeneratorBase::SetGlyphData(GlyphInfo& info, Math::Vector2d bearing, Math::Vector2d size,
	                                          const Math::AABB& aabb, double advance)
	{
		const auto& resolution = m_atlasData->GetTexture()->resolution;
		const double l = aabb.min.x;
		const double r = aabb.max.x;
		const double t = aabb.max.y;
		const double b = aabb.min.y;

		info.pos[0].x = bearing.x;
		info.pos[0].y = size.y - bearing.y;
		info.uv[0].x = l / resolution.x;
		info.uv[0].y = b / resolution.y;

		info.pos[1].x = bearing.x + size.x;
		info.pos[1].y = size.y - bearing.y;
		info.uv[1].x = r / resolution.x;
		info.uv[1].y = b / resolution.y;

		info.pos[2].x = bearing.x + size.x;
		info.pos[2].y = bearing.y;
		info.uv[2].x = r / resolution.x;
		info.uv[2].y = t / resolution.y;

		info.pos[3].x = bearing.x;
		info.pos[3].y = bearing.y;
		info.uv[3].x = l / resolution.x;
		info.uv[3].y = t / resolution.y;

		info.advance = advance;
	}

	size_t FontAtlasGeneratorBase::LoadAllGlyphs(std::set<uint32_t>& chars, const FtFaceRecPtr& face)
	{
		chars.clear();
		FT_UInt glyphIndex;
		FT_ULong unicode = FT_Get_First_Char(face.get(), &glyphIndex);
		while (glyphIndex != 0)
		{
			chars.insert(unicode);
			unicode = FT_Get_Next_Char(face.get(), unicode, &glyphIndex);
		}
		return chars.size();
	}
}