/*
 * 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 "Host/SystemFontResolver.hpp"
#include "Base/Logger.hpp"
#include "Base/Utils.hpp"
#include <fontconfig/fontconfig.h>
#include <memory>

namespace OpenVulkano
{
	namespace
	{
		const std::filesystem::path FALLBACK_PATH;
	}

	const std::filesystem::path& SystemFontResolver::GetSystemFontPath(const std::string& fontName)
	{
		// fontName -> fontPath
		static std::map<std::string, std::filesystem::path> fontFilesMapping = ReadSystemFonts();
		std::string fontNameLower = Utils::ToLower(fontName);
		auto it = fontFilesMapping.find(fontNameLower);
		if (it != fontFilesMapping.end()) return it->second;
		it = fontFilesMapping.find(fontNameLower + " regular");
		if (it != fontFilesMapping.end()) return it->second;
		return FALLBACK_PATH;
	}

	std::map<std::string, std::filesystem::path> SystemFontResolver::ReadSystemFonts()
	{
		std::unique_ptr<FcConfig, decltype(&FcConfigDestroy)> config(FcInitLoadConfigAndFonts(), &FcConfigDestroy);
		std::unique_ptr<FcPattern, decltype(&FcPatternDestroy)> pat(FcPatternCreate(), &FcPatternDestroy);
		std::unique_ptr<FcObjectSet, decltype(&FcObjectSetDestroy)> os(FcObjectSetBuild(FC_FAMILY, FC_STYLE, FC_LANG, FC_FILE, NULL), &FcObjectSetDestroy);
		std::unique_ptr<FcFontSet, decltype(&FcFontSetDestroy)> fs(FcFontList(config.get(), pat.get(), os.get()), &FcFontSetDestroy);
		
		if (!fs)
		{
			Logger::DATA->warn("Could not get system fonts");
			return {};
		}

		std::map<std::string, std::filesystem::path> fontFilesMapping;
		for (int i = 0; i < fs->nfont; ++i)
		{
			FcPattern* font = fs->fonts[i];
			FcChar8* file;
			FcChar8* style;
			FcChar8* family;
			if (FcPatternGetString(font, FC_FILE, 0, &file) == FcResultMatch &&
				FcPatternGetString(font, FC_FAMILY, 0, &family) == FcResultMatch &&
				FcPatternGetString(font, FC_STYLE, 0, &style) == FcResultMatch)
			{
				std::string fontFull = std::string(reinterpret_cast<char*>(family)) + " " + 
										std::string(reinterpret_cast<char*>(style));
				Utils::ToLower(fontFull);
				fontFilesMapping[std::move(fontFull)] = std::filesystem::path(reinterpret_cast<char*>(file));
			}
		}
		return fontFilesMapping;
	}
}