/*
Crafter.Build
Copyright (C) 2025 Catcrafts

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;
#include <string>
#include <iostream>
#include <filesystem>
#include <glslang/SPIRV/GlslangToSpv.h>
#include <glslang/Public/ShaderLang.h>
#include <glslang/Public/ResourceLimits.h>
#include "DirStackFileIncluder.h"
#include <fstream>
#include <iterator>
module Crafter.Build;
using namespace Crafter::Build;

Shader::Shader(fs::path path, std::string entrypoint, EShLanguage type): path(path), entrypoint(entrypoint), type(type) {

}

void Shader::Compile(fs::path outputDir) {
	glslang::InitializeProcess();
    EShMessages messages = static_cast<EShMessages>(EShMsgDefault | EShMsgVulkanRules | EShMsgSpvRules);
    std::ifstream fileStream(path, std::ios::in | std::ios::binary);
    if (!fileStream) {
        throw std::ios_base::failure("Failed to open file: " + path.string());
    }
    std::ostringstream contents;
    contents << fileStream.rdbuf();
    std::string src = contents.str();

    const char *file_name_list[1] = {""};
	const char *shader_source     = reinterpret_cast<const char *>(src.data());

    glslang::TShader shader(type);
    shader.setStringsWithLengthsAndNames(&shader_source, nullptr, file_name_list, 1);
	shader.setEntryPoint(entrypoint.c_str());
	shader.setSourceEntryPoint(entrypoint.c_str());
    shader.setEnvTarget(glslang::EShTargetSpv, glslang::EShTargetSpv_1_4);
    DirStackFileIncluder includeDir;
	includeDir.pushExternalLocalDirectory(path.parent_path().generic_string());
    std::string info_log;
    if (!shader.parse(GetDefaultResources(), 100, false, messages, includeDir))
	{
		info_log = std::string(shader.getInfoLog()) + std::string(shader.getInfoDebugLog());
	}
    // Add shader to new program object.
	glslang::TProgram program;
	program.addShader(&shader);

	// Link program.
	if (!program.link(messages))
	{
		info_log = std::string(program.getInfoLog()) + std::string(program.getInfoDebugLog());
	}

	// Save any info log that was generated.
	if (shader.getInfoLog())
	{
		info_log += std::string(shader.getInfoLog()) + std::string(shader.getInfoDebugLog());
	}

	if (program.getInfoLog())
	{
		info_log += std::string(program.getInfoLog()) + std::string(program.getInfoDebugLog());
	}

	glslang::TIntermediate* intermediate = program.getIntermediate(type);
	if (!intermediate)
	{
		info_log += "Failed to get shared intermediate code.";
	}

	spv::SpvBuildLogger logger;
    std::vector<std::uint32_t> spirv;
    std::cout << info_log;
	glslang::GlslangToSpv(*intermediate, spirv, &logger);
	std::cout << logger.getAllMessages();
	glslang::FinalizeProcess();
    path.replace_extension("spirv");
    std::ofstream file(outputDir/path, std::ios::binary);
    file.write(reinterpret_cast<const char*>(spirv.data()), spirv.size() * sizeof(std::uint32_t));
}