/*************************************************************************/
/*  shader_rd.cpp                                                        */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/*************************************************************************/

#include "shader_rd.h"

#include "core/string/string_builder.h"
#include "renderer_compositor_rd.h"
#include "servers/rendering/rendering_device.h"

void ShaderRD::setup(const char *p_vertex_code, const char *p_fragment_code, const char *p_compute_code, const char *p_name) {
	name = p_name;
	//split vertex and shader code (thank you, shader compiler programmers from you know what company).
	if (p_vertex_code) {
		String defines_tag = "\nVERSION_DEFINES";
		String globals_tag = "\nVERTEX_SHADER_GLOBALS";
		String material_tag = "\nMATERIAL_UNIFORMS";
		String code_tag = "\nVERTEX_SHADER_CODE";
		String code = p_vertex_code;

		int cpos = code.find(defines_tag);
		if (cpos != -1) {
			vertex_codev = code.substr(0, cpos).ascii();
			code = code.substr(cpos + defines_tag.length(), code.length());
		}

		cpos = code.find(material_tag);

		if (cpos == -1) {
			vertex_code0 = code.ascii();
		} else {
			vertex_code0 = code.substr(0, cpos).ascii();
			code = code.substr(cpos + material_tag.length(), code.length());

			cpos = code.find(globals_tag);

			if (cpos == -1) {
				vertex_code1 = code.ascii();
			} else {
				vertex_code1 = code.substr(0, cpos).ascii();
				String code2 = code.substr(cpos + globals_tag.length(), code.length());

				cpos = code2.find(code_tag);
				if (cpos == -1) {
					vertex_code2 = code2.ascii();
				} else {
					vertex_code2 = code2.substr(0, cpos).ascii();
					vertex_code3 = code2.substr(cpos + code_tag.length(), code2.length()).ascii();
				}
			}
		}
	}

	if (p_fragment_code) {
		String defines_tag = "\nVERSION_DEFINES";
		String globals_tag = "\nFRAGMENT_SHADER_GLOBALS";
		String material_tag = "\nMATERIAL_UNIFORMS";
		String code_tag = "\nFRAGMENT_SHADER_CODE";
		String light_code_tag = "\nLIGHT_SHADER_CODE";
		String code = p_fragment_code;

		int cpos = code.find(defines_tag);
		if (cpos != -1) {
			fragment_codev = code.substr(0, cpos).ascii();
			code = code.substr(cpos + defines_tag.length(), code.length());
		}

		cpos = code.find(material_tag);
		if (cpos == -1) {
			fragment_code0 = code.ascii();
		} else {
			fragment_code0 = code.substr(0, cpos).ascii();
			//print_line("CODE0:\n"+String(fragment_code0.get_data()));
			code = code.substr(cpos + material_tag.length(), code.length());
			cpos = code.find(globals_tag);

			if (cpos == -1) {
				fragment_code1 = code.ascii();
			} else {
				fragment_code1 = code.substr(0, cpos).ascii();
				//print_line("CODE1:\n"+String(fragment_code1.get_data()));

				String code2 = code.substr(cpos + globals_tag.length(), code.length());
				cpos = code2.find(light_code_tag);

				if (cpos == -1) {
					fragment_code2 = code2.ascii();
				} else {
					fragment_code2 = code2.substr(0, cpos).ascii();
					//print_line("CODE2:\n"+String(fragment_code2.get_data()));

					String code3 = code2.substr(cpos + light_code_tag.length(), code2.length());

					cpos = code3.find(code_tag);
					if (cpos == -1) {
						fragment_code3 = code3.ascii();
					} else {
						fragment_code3 = code3.substr(0, cpos).ascii();
						//print_line("CODE3:\n"+String(fragment_code3.get_data()));
						fragment_code4 = code3.substr(cpos + code_tag.length(), code3.length()).ascii();
						//print_line("CODE4:\n"+String(fragment_code4.get_data()));
					}
				}
			}
		}
	}

	if (p_compute_code) {
		is_compute = true;

		String defines_tag = "\nVERSION_DEFINES";
		String globals_tag = "\nCOMPUTE_SHADER_GLOBALS";
		String material_tag = "\nMATERIAL_UNIFORMS";
		String code_tag = "\nCOMPUTE_SHADER_CODE";
		String code = p_compute_code;

		int cpos = code.find(defines_tag);
		if (cpos != -1) {
			compute_codev = code.substr(0, cpos).ascii();
			code = code.substr(cpos + defines_tag.length(), code.length());
		}

		cpos = code.find(material_tag);

		if (cpos == -1) {
			compute_code0 = code.ascii();
		} else {
			compute_code0 = code.substr(0, cpos).ascii();
			code = code.substr(cpos + material_tag.length(), code.length());

			cpos = code.find(globals_tag);

			if (cpos == -1) {
				compute_code1 = code.ascii();
			} else {
				compute_code1 = code.substr(0, cpos).ascii();
				String code2 = code.substr(cpos + globals_tag.length(), code.length());

				cpos = code2.find(code_tag);
				if (cpos == -1) {
					compute_code2 = code2.ascii();
				} else {
					compute_code2 = code2.substr(0, cpos).ascii();
					compute_code3 = code2.substr(cpos + code_tag.length(), code2.length()).ascii();
				}
			}
		}
	}
}

RID ShaderRD::version_create() {
	//initialize() was never called
	ERR_FAIL_COND_V(variant_defines.size() == 0, RID());

	Version version;
	version.dirty = true;
	version.valid = false;
	version.initialize_needed = true;
	version.variants = nullptr;
	return version_owner.make_rid(version);
}

void ShaderRD::_clear_version(Version *p_version) {
	//clear versions if they exist
	if (p_version->variants) {
		for (int i = 0; i < variant_defines.size(); i++) {
			RD::get_singleton()->free(p_version->variants[i]);
		}

		memdelete_arr(p_version->variants);
		p_version->variants = nullptr;
	}
}

void ShaderRD::_compile_variant(uint32_t p_variant, Version *p_version) {
	if (!variants_enabled[p_variant]) {
		return; //variant is disabled, return
	}

	Vector<RD::ShaderStageData> stages;

	String error;
	String current_source;
	RD::ShaderStage current_stage = RD::SHADER_STAGE_VERTEX;
	bool build_ok = true;

	if (!is_compute) {
		//vertex stage

		StringBuilder builder;

		builder.append(vertex_codev.get_data()); // version info (if exists)
		builder.append("\n"); //make sure defines begin at newline
		builder.append(general_defines.get_data());
		builder.append(variant_defines[p_variant].get_data());

		for (int j = 0; j < p_version->custom_defines.size(); j++) {
			builder.append(p_version->custom_defines[j].get_data());
		}

		builder.append(vertex_code0.get_data()); //first part of vertex

		builder.append(p_version->uniforms.get_data()); //uniforms (same for vertex and fragment)

		builder.append(vertex_code1.get_data()); //second part of vertex

		builder.append(p_version->vertex_globals.get_data()); // vertex globals

		builder.append(vertex_code2.get_data()); //third part of vertex

		builder.append(p_version->vertex_code.get_data()); // code

		builder.append(vertex_code3.get_data()); //fourth of vertex

		current_source = builder.as_string();
		RD::ShaderStageData stage;
		stage.spir_v = RD::get_singleton()->shader_compile_from_source(RD::SHADER_STAGE_VERTEX, current_source, RD::SHADER_LANGUAGE_GLSL, &error);
		if (stage.spir_v.size() == 0) {
			build_ok = false;
		} else {
			stage.shader_stage = RD::SHADER_STAGE_VERTEX;
			stages.push_back(stage);
		}
	}

	if (!is_compute && build_ok) {
		//fragment stage
		current_stage = RD::SHADER_STAGE_FRAGMENT;

		StringBuilder builder;

		builder.append(fragment_codev.get_data()); // version info (if exists)
		builder.append("\n"); //make sure defines begin at newline

		builder.append(general_defines.get_data());
		builder.append(variant_defines[p_variant].get_data());
		for (int j = 0; j < p_version->custom_defines.size(); j++) {
			builder.append(p_version->custom_defines[j].get_data());
		}

		builder.append(fragment_code0.get_data()); //first part of fragment

		builder.append(p_version->uniforms.get_data()); //uniforms (same for fragment and fragment)

		builder.append(fragment_code1.get_data()); //first part of fragment

		builder.append(p_version->fragment_globals.get_data()); // fragment globals

		builder.append(fragment_code2.get_data()); //third part of fragment

		builder.append(p_version->fragment_light.get_data()); // fragment light

		builder.append(fragment_code3.get_data()); //fourth part of fragment

		builder.append(p_version->fragment_code.get_data()); // fragment code

		builder.append(fragment_code4.get_data()); //fourth part of fragment

		current_source = builder.as_string();
		RD::ShaderStageData stage;
		stage.spir_v = RD::get_singleton()->shader_compile_from_source(RD::SHADER_STAGE_FRAGMENT, current_source, RD::SHADER_LANGUAGE_GLSL, &error);
		if (stage.spir_v.size() == 0) {
			build_ok = false;
		} else {
			stage.shader_stage = RD::SHADER_STAGE_FRAGMENT;
			stages.push_back(stage);
		}
	}

	if (is_compute) {
		//compute stage
		current_stage = RD::SHADER_STAGE_COMPUTE;

		StringBuilder builder;

		builder.append(compute_codev.get_data()); // version info (if exists)
		builder.append("\n"); //make sure defines begin at newline
		builder.append(general_defines.get_data());
		builder.append(variant_defines[p_variant].get_data());

		for (int j = 0; j < p_version->custom_defines.size(); j++) {
			builder.append(p_version->custom_defines[j].get_data());
		}

		builder.append(compute_code0.get_data()); //first part of compute

		builder.append(p_version->uniforms.get_data()); //uniforms (same for compute and fragment)

		builder.append(compute_code1.get_data()); //second part of compute

		builder.append(p_version->compute_globals.get_data()); // compute globals

		builder.append(compute_code2.get_data()); //third part of compute

		builder.append(p_version->compute_code.get_data()); // code

		builder.append(compute_code3.get_data()); //fourth of compute

		current_source = builder.as_string();
		RD::ShaderStageData stage;
		stage.spir_v = RD::get_singleton()->shader_compile_from_source(RD::SHADER_STAGE_COMPUTE, current_source, RD::SHADER_LANGUAGE_GLSL, &error);
		if (stage.spir_v.size() == 0) {
			build_ok = false;
		} else {
			stage.shader_stage = RD::SHADER_STAGE_COMPUTE;
			stages.push_back(stage);
		}
	}

	if (!build_ok) {
		MutexLock lock(variant_set_mutex); //properly print the errors
		ERR_PRINT("Error compiling " + String(current_stage == RD::SHADER_STAGE_COMPUTE ? "Compute " : (current_stage == RD::SHADER_STAGE_VERTEX ? "Vertex" : "Fragment")) + " shader, variant #" + itos(p_variant) + " (" + variant_defines[p_variant].get_data() + ").");
		ERR_PRINT(error);

#ifdef DEBUG_ENABLED
		ERR_PRINT("code:\n" + current_source.get_with_code_lines());
#endif
		return;
	}

	RID shader = RD::get_singleton()->shader_create(stages);
	{
		MutexLock lock(variant_set_mutex);
		p_version->variants[p_variant] = shader;
	}
}

RS::ShaderNativeSourceCode ShaderRD::version_get_native_source_code(RID p_version) {
	Version *version = version_owner.getornull(p_version);
	RS::ShaderNativeSourceCode source_code;
	ERR_FAIL_COND_V(!version, source_code);

	source_code.versions.resize(variant_defines.size());

	for (int i = 0; i < source_code.versions.size(); i++) {
		if (!is_compute) {
			//vertex stage

			StringBuilder builder;

			builder.append(vertex_codev.get_data()); // version info (if exists)
			builder.append("\n"); //make sure defines begin at newline
			builder.append(general_defines.get_data());
			builder.append(variant_defines[i].get_data());

			for (int j = 0; j < version->custom_defines.size(); j++) {
				builder.append(version->custom_defines[j].get_data());
			}

			builder.append(vertex_code0.get_data()); //first part of vertex

			builder.append(version->uniforms.get_data()); //uniforms (same for vertex and fragment)

			builder.append(vertex_code1.get_data()); //second part of vertex

			builder.append(version->vertex_globals.get_data()); // vertex globals

			builder.append(vertex_code2.get_data()); //third part of vertex

			builder.append(version->vertex_code.get_data()); // code

			builder.append(vertex_code3.get_data()); //fourth of vertex

			RS::ShaderNativeSourceCode::Version::Stage stage;
			stage.name = "vertex";
			stage.code = builder.as_string();

			source_code.versions.write[i].stages.push_back(stage);
		}

		if (!is_compute) {
			//fragment stage

			StringBuilder builder;

			builder.append(fragment_codev.get_data()); // version info (if exists)
			builder.append("\n"); //make sure defines begin at newline

			builder.append(general_defines.get_data());
			builder.append(variant_defines[i].get_data());
			for (int j = 0; j < version->custom_defines.size(); j++) {
				builder.append(version->custom_defines[j].get_data());
			}

			builder.append(fragment_code0.get_data()); //first part of fragment

			builder.append(version->uniforms.get_data()); //uniforms (same for fragment and fragment)

			builder.append(fragment_code1.get_data()); //first part of fragment

			builder.append(version->fragment_globals.get_data()); // fragment globals

			builder.append(fragment_code2.get_data()); //third part of fragment

			builder.append(version->fragment_light.get_data()); // fragment light

			builder.append(fragment_code3.get_data()); //fourth part of fragment

			builder.append(version->fragment_code.get_data()); // fragment code

			builder.append(fragment_code4.get_data()); //fourth part of fragment

			RS::ShaderNativeSourceCode::Version::Stage stage;
			stage.name = "fragment";
			stage.code = builder.as_string();

			source_code.versions.write[i].stages.push_back(stage);
		}

		if (is_compute) {
			//compute stage

			StringBuilder builder;

			builder.append(compute_codev.get_data()); // version info (if exists)
			builder.append("\n"); //make sure defines begin at newline
			builder.append(general_defines.get_data());
			builder.append(variant_defines[i].get_data());

			for (int j = 0; j < version->custom_defines.size(); j++) {
				builder.append(version->custom_defines[j].get_data());
			}

			builder.append(compute_code0.get_data()); //first part of compute

			builder.append(version->uniforms.get_data()); //uniforms (same for compute and fragment)

			builder.append(compute_code1.get_data()); //second part of compute

			builder.append(version->compute_globals.get_data()); // compute globals

			builder.append(compute_code2.get_data()); //third part of compute

			builder.append(version->compute_code.get_data()); // code

			builder.append(compute_code3.get_data()); //fourth of compute

			RS::ShaderNativeSourceCode::Version::Stage stage;
			stage.name = "compute";
			stage.code = builder.as_string();

			source_code.versions.write[i].stages.push_back(stage);
		}
	}

	return source_code;
}

void ShaderRD::_compile_version(Version *p_version) {
	_clear_version(p_version);

	p_version->valid = false;
	p_version->dirty = false;

	p_version->variants = memnew_arr(RID, variant_defines.size());
#if 1

	RendererThreadPool::singleton->thread_work_pool.do_work(variant_defines.size(), this, &ShaderRD::_compile_variant, p_version);
#else
	for (int i = 0; i < variant_defines.size(); i++) {
		_compile_variant(i, p_version);
	}
#endif

	bool all_valid = true;
	for (int i = 0; i < variant_defines.size(); i++) {
		if (!variants_enabled[i]) {
			continue; //disabled
		}
		if (p_version->variants[i].is_null()) {
			all_valid = false;
			break;
		}
	}

	if (!all_valid) {
		//clear versions if they exist
		for (int i = 0; i < variant_defines.size(); i++) {
			if (!variants_enabled[i]) {
				continue; //disabled
			}
			if (!p_version->variants[i].is_null()) {
				RD::get_singleton()->free(p_version->variants[i]);
			}
		}
		memdelete_arr(p_version->variants);
		p_version->variants = nullptr;
		return;
	}

	p_version->valid = true;
}

void ShaderRD::version_set_code(RID p_version, const String &p_uniforms, const String &p_vertex_globals, const String &p_vertex_code, const String &p_fragment_globals, const String &p_fragment_light, const String &p_fragment_code, const Vector<String> &p_custom_defines) {
	ERR_FAIL_COND(is_compute);

	Version *version = version_owner.getornull(p_version);
	ERR_FAIL_COND(!version);
	version->vertex_globals = p_vertex_globals.utf8();
	version->vertex_code = p_vertex_code.utf8();
	version->fragment_light = p_fragment_light.utf8();
	version->fragment_globals = p_fragment_globals.utf8();
	version->fragment_code = p_fragment_code.utf8();
	version->uniforms = p_uniforms.utf8();

	version->custom_defines.clear();
	for (int i = 0; i < p_custom_defines.size(); i++) {
		version->custom_defines.push_back(p_custom_defines[i].utf8());
	}

	version->dirty = true;
	if (version->initialize_needed) {
		_compile_version(version);
		version->initialize_needed = false;
	}
}

void ShaderRD::version_set_compute_code(RID p_version, const String &p_uniforms, const String &p_compute_globals, const String &p_compute_code, const Vector<String> &p_custom_defines) {
	ERR_FAIL_COND(!is_compute);

	Version *version = version_owner.getornull(p_version);
	ERR_FAIL_COND(!version);
	version->compute_globals = p_compute_globals.utf8();
	version->compute_code = p_compute_code.utf8();
	version->uniforms = p_uniforms.utf8();

	version->custom_defines.clear();
	for (int i = 0; i < p_custom_defines.size(); i++) {
		version->custom_defines.push_back(p_custom_defines[i].utf8());
	}

	version->dirty = true;
	if (version->initialize_needed) {
		_compile_version(version);
		version->initialize_needed = false;
	}
}

bool ShaderRD::version_is_valid(RID p_version) {
	Version *version = version_owner.getornull(p_version);
	ERR_FAIL_COND_V(!version, false);

	if (version->dirty) {
		_compile_version(version);
	}

	return version->valid;
}

bool ShaderRD::version_free(RID p_version) {
	if (version_owner.owns(p_version)) {
		Version *version = version_owner.getornull(p_version);
		_clear_version(version);
		version_owner.free(p_version);
	} else {
		return false;
	}

	return true;
}

void ShaderRD::set_variant_enabled(int p_variant, bool p_enabled) {
	ERR_FAIL_COND(version_owner.get_rid_count() > 0); //versions exist
	ERR_FAIL_INDEX(p_variant, variants_enabled.size());
	variants_enabled.write[p_variant] = p_enabled;
}

bool ShaderRD::is_variant_enabled(int p_variant) const {
	ERR_FAIL_INDEX_V(p_variant, variants_enabled.size(), false);
	return variants_enabled[p_variant];
}

void ShaderRD::initialize(const Vector<String> &p_variant_defines, const String &p_general_defines) {
	ERR_FAIL_COND(variant_defines.size());
	ERR_FAIL_COND(p_variant_defines.size() == 0);

	general_defines = p_general_defines.utf8();

	for (int i = 0; i < p_variant_defines.size(); i++) {
		variant_defines.push_back(p_variant_defines[i].utf8());
		variants_enabled.push_back(true);
	}
}

ShaderRD::~ShaderRD() {
	List<RID> remaining;
	version_owner.get_owned_list(&remaining);
	if (remaining.size()) {
		ERR_PRINT(itos(remaining.size()) + " shaders of type " + name + " were never freed");
		while (remaining.size()) {
			version_free(remaining.front()->get());
			remaining.pop_front();
		}
	}
}
