// AUTOGENERATED COPYRIGHT HEADER START
// Copyright (C) 2017-2023 Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
// Copyright (C) 2022 lainon <GermanAizek@yandex.ru>
// AUTOGENERATED COPYRIGHT HEADER END

#include "gfx-mipmapper.hpp"
#include "obs/gs/gs-helper.hpp"
#include "plugin.hpp"

#include "warning-disable.hpp"
#include <sstream>
#include <stdexcept>
// Direct3D 11
#ifdef _WIN32
#include <Windows.h>
#include <atlutil.h>
#include <d3d11.h>
#include <dxgi.h>
#endif
// OpenGL
#include "glad/gl.h"
#include "warning-enable.hpp"

#ifdef _WIN32
struct d3d_info {
	ID3D11Device*        device  = nullptr;
	ID3D11DeviceContext* context = nullptr;
	ID3D11Resource*      target  = nullptr;
};

static void d3d_initialize(d3d_info& info, std::shared_ptr<streamfx::obs::gs::texture> source, std::shared_ptr<streamfx::obs::gs::texture> target)
{
	info.target = reinterpret_cast<ID3D11Resource*>(gs_texture_get_obj(*target));
	info.device = reinterpret_cast<ID3D11Device*>(gs_get_device_obj());
	info.device->GetImmediateContext(&info.context);
}

static void d3d_copy_subregion(d3d_info& info, gs_texture_t* source, uint32_t mip_level, uint32_t width, uint32_t height)
{
	D3D11_BOX box        = {0, 0, 0, width, height, 1};
	auto      source_ref = reinterpret_cast<ID3D11Resource*>(gs_texture_get_obj(source));
	info.context->CopySubresourceRegion(info.target, mip_level, 0, 0, 0, source_ref, 0, &box);
}

#endif

struct opengl_info {
	GLuint target = 0;
	GLuint fbo    = 0;
};

static std::string opengl_translate_error(GLenum error)
{
#define TRANSLATE_CASE(X) \
	case X:               \
		return #X;

	switch (error) {
		TRANSLATE_CASE(GL_NO_ERROR) break;
		TRANSLATE_CASE(GL_INVALID_ENUM) break;
		TRANSLATE_CASE(GL_INVALID_VALUE) break;
		TRANSLATE_CASE(GL_INVALID_OPERATION) break;
		TRANSLATE_CASE(GL_STACK_OVERFLOW) break;
		TRANSLATE_CASE(GL_STACK_UNDERFLOW) break;
		TRANSLATE_CASE(GL_OUT_OF_MEMORY) break;
		TRANSLATE_CASE(GL_INVALID_FRAMEBUFFER_OPERATION) break;
	}

	return std::to_string(error);
#undef TRANSLATE_CASE
}

static std::string opengl_translate_framebuffer_status(GLenum error)
{
#define TRANSLATE_CASE(X) \
	case X:               \
		return #X;

	switch (error) {
		TRANSLATE_CASE(GL_FRAMEBUFFER_COMPLETE) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_UNDEFINED) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_UNSUPPORTED) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE) break;
		TRANSLATE_CASE(GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS) break;
	}

	return std::to_string(error);
#undef TRANSLATE_CASE
}

#define D_OPENGL_CHECK_ERROR(FUNCTION)                            \
	if (auto err = glGetError(); err != GL_NO_ERROR) {            \
		std::stringstream sstr;                                   \
		sstr << opengl_translate_error(err) << " = " << FUNCTION; \
		throw std::runtime_error(sstr.str());                     \
	}

#define D_OPENGL_CHECK_FRAMEBUFFERSTATUS(BUFFER, FUNCTION)                             \
	if (auto err = glCheckFramebufferStatus(BUFFER); err != GL_FRAMEBUFFER_COMPLETE) { \
		std::stringstream sstr;                                                        \
		sstr << opengl_translate_framebuffer_status(err) << " = " << FUNCTION;         \
		throw std::runtime_error(sstr.str());                                          \
	}

static void opengl_initialize(opengl_info& info, std::shared_ptr<streamfx::obs::gs::texture> source, std::shared_ptr<streamfx::obs::gs::texture> target)
{
	info.target = *reinterpret_cast<GLuint*>(gs_texture_get_obj(*target));

	glGenFramebuffers(1, &info.fbo);
}

static void opengl_finalize(opengl_info& info)
{
	glDeleteFramebuffers(1, &info.fbo);
}

static void opengl_copy_subregion(opengl_info& info, gs_texture_t* source, uint32_t mip_level, uint32_t width, uint32_t height)
{
	GLuint source_ref = *reinterpret_cast<GLuint*>(gs_texture_get_obj(source));

	// Source -> Texture Unit 0, Read Color Framebuffer
	glActiveTexture(GL_TEXTURE0);
	D_OPENGL_CHECK_ERROR("glActiveTexture(GL_TEXTURE0);");
	glBindTexture(GL_TEXTURE_2D, source_ref);
	D_OPENGL_CHECK_ERROR("glBindTexture(GL_TEXTURE_2D, origin);");
	glBindFramebuffer(GL_READ_FRAMEBUFFER, info.fbo);
	D_OPENGL_CHECK_ERROR("glBindFramebuffer(GL_READ_FRAMEBUFFER, info.fbo);");
	glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, source_ref,
						   0); // Origin is a render target, not a texture
	D_OPENGL_CHECK_ERROR("glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, origin, mip_level);");
	D_OPENGL_CHECK_FRAMEBUFFERSTATUS(GL_READ_FRAMEBUFFER, "glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, origin, mip_level);");

	// Target -> Texture Unit 1
	glActiveTexture(GL_TEXTURE1);
	D_OPENGL_CHECK_ERROR("glActiveTexture(GL_TEXTURE1);");
	glBindTexture(GL_TEXTURE_2D, info.target);
	D_OPENGL_CHECK_ERROR("glBindTexture(GL_TEXTURE_2D, info.target);");

	// Copy Data
	glCopyTexSubImage2D(GL_TEXTURE_2D, static_cast<GLint>(mip_level), 0, 0, 0, 0, static_cast<GLsizei>(width), static_cast<GLsizei>(height));
	D_OPENGL_CHECK_ERROR("glCopyTexSubImage2D(GL_TEXTURE_2D, mip_level, 0, 0, 0, 0, width, height);");

	// Target -/-> Texture Unit 1
	glActiveTexture(GL_TEXTURE1);
	D_OPENGL_CHECK_ERROR("glActiveTexture(GL_TEXTURE1);");
	glBindTexture(GL_TEXTURE_2D, 0);
	D_OPENGL_CHECK_ERROR("glBindTexture(GL_TEXTURE_2D, 0);");

	// Source -/-> Texture Unit 0, Read Color Framebuffer
	glActiveTexture(GL_TEXTURE0);
	D_OPENGL_CHECK_ERROR("glActiveTexture(GL_TEXTURE0);");
	glBindTexture(GL_TEXTURE_2D, 0);
	D_OPENGL_CHECK_ERROR("glBindTexture(GL_TEXTURE_2D, 0);");
	glBindFramebuffer(GL_READ_FRAMEBUFFER, info.fbo);
	D_OPENGL_CHECK_ERROR("glBindFramebuffer(GL_READ_FRAMEBUFFER, info.fbo);");
	glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
	D_OPENGL_CHECK_ERROR("glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);");
	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
	D_OPENGL_CHECK_ERROR("glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);");
}

streamfx::gfx::mipmapper::~mipmapper()
{
	_effect.reset();
}

streamfx::gfx::mipmapper::mipmapper() : _gfx_util(::streamfx::gfx::util::get())
{
	auto gctx = streamfx::obs::gs::context();

	{
		auto file = streamfx::data_file_path("effects/mipgen.effect");
		try {
			_effect = streamfx::obs::gs::effect::create(file);
		} catch (const std::exception& ex) {
			DLOG_ERROR("Error loading '%s': %s", file.generic_u8string().c_str(), ex.what());
			throw std::runtime_error("Unexpected error loading required effect file.");
		}
	}
}

uint32_t streamfx::gfx::mipmapper::calculate_max_mip_level(uint32_t width, uint32_t height)
{
	return static_cast<uint32_t>(1 + std::lroundl(floor(log2(std::max<GLint>(static_cast<GLint>(width), static_cast<GLint>(height))))));
}

void streamfx::gfx::mipmapper::rebuild(std::shared_ptr<streamfx::obs::gs::texture> source, std::shared_ptr<streamfx::obs::gs::texture> target, mip_generator generator)
{
	{ // Validate arguments and structure.
		if (!source || !target)
			return; // Do nothing if source or target are missing.

		if (!_effect)
			return; // Do nothing if the necessary data failed to load.

		// Ensure texture sizes match
		if ((source->width() != target->width()) || (source->height() != target->height())) {
			throw std::invalid_argument("source and target must have same size");
		}

		// Ensure texture formats match
		if ((source->color_format() != target->color_format())) {
			throw std::invalid_argument("source and target must have same format");
		}
	}

	std::string technique           = "Linear";
	bool        separable_technique = false;
	switch (generator) {
	case mip_generator::MAGIC_KERNEL_SHARP_PLUS_2021:
		separable_technique = true;
		technique           = "MagicKernelSharp2021Separable";
		break;
	case mip_generator::MAGIC_KERNEL_2011:
		separable_technique = false;
		technique           = "MagicKernel2011";
		break;
	case mip_generator::LINEAR:
	default:
		break;
	}

	// Get a unique lock on the graphics context.
	auto gctx = streamfx::obs::gs::context();

	// Initialize some render targets, and their texture storage.
	auto rt0 = streamfx::obs::gs::texrender::pool::instance()->acquire(source->color_format(), GS_ZS_NONE);
	auto rt1 = streamfx::obs::gs::texrender::pool::instance()->acquire(source->color_format(), GS_ZS_NONE);
	auto rt2 = rt1;
	if (separable_technique) {
		rt2 = streamfx::obs::gs::texrender::pool::instance()->acquire(source->color_format(), GS_ZS_NONE);
	}

	// Initialize API Handlers.
	opengl_info oglinfo;
	if (gs_get_device_type() == GS_DEVICE_OPENGL) {
		opengl_initialize(oglinfo, source, target);
	}
#ifdef _WIN32
	d3d_info d3dinfo;
	if (gs_get_device_type() == GS_DEVICE_DIRECT3D_11) {
		d3d_initialize(d3dinfo, source, target);
	}
#endif

	// Use different methods for different types of textures.
	uint32_t width         = source->width();
	uint32_t height        = source->height();
	size_t   max_mip_level = calculate_max_mip_level(width, height);

	{ // Copy mip level 0 to output.
#ifdef _WIN32
		if (gs_get_device_type() == GS_DEVICE_DIRECT3D_11) {
			d3d_copy_subregion(d3dinfo, *source, 0, width, height);
		}
#endif
		if (gs_get_device_type() == GS_DEVICE_OPENGL) {
			opengl_copy_subregion(oglinfo, *source, 0, width, height);
		}
	}

	// Set up rendering state.
	gs_blend_state_push();
	gs_reset_blend_state();
	gs_enable_blending(false);
	gs_blend_function(GS_BLEND_ONE, GS_BLEND_ZERO);
	gs_enable_color(true, true, true, true);
	gs_enable_depth_test(false);
	gs_enable_stencil_test(false);
	gs_enable_stencil_write(false);
	gs_set_cull_mode(GS_NEITHER);

	// sRGB support.
	bool was_srgb_enabled = gs_framebuffer_srgb_enabled();
	bool enable_srgb      = gs_get_linear_srgb();
	gs_enable_framebuffer_srgb(enable_srgb);

	// Render each mip level.
	for (size_t mip = 1; mip < max_mip_level; mip++) {
		uint32_t cwidth  = std::max<uint32_t>(width >> mip, 1);
		uint32_t cheight = std::max<uint32_t>(height >> mip, 1);
		float    iwidth  = 1.f / static_cast<float>(cwidth);
		float    iheight = 1.f / static_cast<float>(cheight);

		if (!separable_technique) {
			try {
				auto op = rt0->render(cwidth, cheight);
				gs_ortho(0, 1, 0, 1, 0, 1);

				if (mip == 1) {
					_effect.get_parameter("image").set_texture(source, enable_srgb);
				} else {
					_effect.get_parameter("image").set_texture(rt1->get_object(), enable_srgb);
				}
				_effect.get_parameter("imageTexel").set_float2(iwidth, iheight);
				_effect.get_parameter("separableTexel").set_float2(iwidth, iheight);
				while (gs_effect_loop(_effect.get_object(), technique.c_str())) {
					_gfx_util->draw_fullscreen_triangle();
				}
			} catch (...) {
			}
		} else {
			for (size_t pass = 0; gs_effect_loop(_effect.get_object(), technique.c_str()); pass++) {
				// Flow:
				// Mip-Level 1:
				// - Pass 0:
				//   - Swap rt0, rt2
				//   - Read from source
				//   - Write to rt0
				// - Pass 1:
				//   - Swap rt0, rt2
				//   - Read from rt2
				//   - Write to rt0
				// - Pass 2:
				//   - Swap rt0, rt2
				//   - Read from rt2
				//   - Write to rt0
				// - Copy rt0 to target
				// - Swap rt0, rt1
				//
				// Mip-Level 2:
				// - Pass 0:
				//   - Swap rt0, rt2
				//   - Read from rt1
				//   - Write to rt0
				// - (identical to Mip-Level 1)
				//
				// This works only if we swap {rt0, rt2} first, otherwise we end up only storing the data from the previous pass.

				// Swap rt0, rt2.
				std::swap(rt0, rt2);

				if (mip == 1) {
					_effect.get_parameter("image").set_texture(source, enable_srgb);
				} else if (pass == 0) {
					_effect.get_parameter("image").set_texture(rt1->get_object(), enable_srgb);
				} else {
					_effect.get_parameter("image").set_texture(rt2->get_object(), enable_srgb);
				}
				_effect.get_parameter("imageTexel").set_float2(iwidth, iheight);
				if ((pass % 2) == 0) {
					_effect.get_parameter("separableTexel").set_float2(iwidth, 0.);
				} else {
					_effect.get_parameter("separableTexel").set_float2(0., iheight);
				}

				try {
					auto op = rt0->render(cwidth, cheight);
					gs_ortho(0, 1, 0, 1, 0, 1);
					_gfx_util->draw_fullscreen_triangle();
				} catch (...) {
				}
			}
		}

		// Copy from the render target to the target mip level.
#ifdef _WIN32
		if (gs_get_device_type() == GS_DEVICE_DIRECT3D_11) {
			d3d_copy_subregion(d3dinfo, rt0->get_object(), static_cast<uint32_t>(mip), cwidth, cheight);
		}
#endif
		if (gs_get_device_type() == GS_DEVICE_OPENGL) {
			opengl_copy_subregion(oglinfo, rt0->get_object(), static_cast<uint32_t>(mip), cwidth, cheight);
		}

		// Swap the render targets.
		std::swap(rt0, rt1);
	}

	// Clean up rendering state.
	gs_enable_framebuffer_srgb(was_srgb_enabled);
	gs_blend_state_pop();

	// Finalize API handlers.
	if (gs_get_device_type() == GS_DEVICE_OPENGL) {
		opengl_finalize(oglinfo);
	}
#ifdef _WIN32
	if (gs_get_device_type() == GS_DEVICE_DIRECT3D_11) {
		//d3d_finalize(d3dinfo);
	}
#endif
}