/**************************************************************************/
/*  image_compress_basisu.cpp                                             */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
/* "Software"), to deal in the Software without restriction, including    */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
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/**************************************************************************/

#include "image_compress_basisu.h"

#include "core/io/image.h"
#include "core/os/os.h"
#include "core/string/print_string.h"
#include "servers/rendering_server.h"

#include <transcoder/basisu_transcoder.h>
#ifdef TOOLS_ENABLED
#include <encoder/basisu_comp.h>
#endif

void basis_universal_init() {
#ifdef TOOLS_ENABLED
	basisu::basisu_encoder_init();
#endif

	basist::basisu_transcoder_init();
}

#ifdef TOOLS_ENABLED
template <typename T>
inline void _basisu_pad_mipmap(const uint8_t *p_image_mip_data, Vector<uint8_t> &r_mip_data_padded, int p_next_width, int p_next_height, int p_width, int p_height, int64_t p_size) {
	// Source mip's data interpreted as 32-bit RGBA blocks to help with copying pixel data.
	const T *mip_src_data = reinterpret_cast<const T *>(p_image_mip_data);

	// Reserve space in the padded buffer.
	r_mip_data_padded.resize(p_next_width * p_next_height * sizeof(T));
	T *data_padded_ptr = reinterpret_cast<T *>(r_mip_data_padded.ptrw());

	// Pad mipmap to the nearest block by smearing.
	int x = 0, y = 0;
	for (y = 0; y < p_height; y++) {
		for (x = 0; x < p_width; x++) {
			data_padded_ptr[p_next_width * y + x] = mip_src_data[p_width * y + x];
		}

		// First, smear in x.
		for (; x < p_next_width; x++) {
			data_padded_ptr[p_next_width * y + x] = data_padded_ptr[p_next_width * y + x - 1];
		}
	}

	// Then, smear in y.
	for (; y < p_next_height; y++) {
		for (x = 0; x < p_next_width; x++) {
			data_padded_ptr[p_next_width * y + x] = data_padded_ptr[p_next_width * y + x - p_next_width];
		}
	}
}

Vector<uint8_t> basis_universal_packer(const Ref<Image> &p_image, Image::UsedChannels p_channels) {
	uint64_t start_time = OS::get_singleton()->get_ticks_msec();

	Ref<Image> image = p_image->duplicate();
	bool is_hdr = false;

	if (image->get_format() <= Image::FORMAT_RGB565) {
		image->convert(Image::FORMAT_RGBA8);
	} else if (image->get_format() <= Image::FORMAT_RGBE9995) {
		image->convert(Image::FORMAT_RGBAF);
		is_hdr = true;
	}

	basisu::basis_compressor_params params;

	params.m_uastc = true;
	params.m_quality_level = basisu::BASISU_QUALITY_MIN;
	params.m_pack_uastc_flags &= ~basisu::cPackUASTCLevelMask;
	params.m_pack_uastc_flags |= basisu::cPackUASTCLevelFastest;

	params.m_rdo_uastc = 0.0f;
	params.m_rdo_uastc_quality_scalar = 0.0f;
	params.m_rdo_uastc_dict_size = 1024;

	params.m_mip_fast = true;
	params.m_multithreading = true;
	params.m_check_for_alpha = false;

	if (!OS::get_singleton()->is_stdout_verbose()) {
		params.m_print_stats = false;
		params.m_compute_stats = false;
		params.m_status_output = false;
	}

	basisu::job_pool job_pool(OS::get_singleton()->get_processor_count());
	params.m_pJob_pool = &job_pool;

	BasisDecompressFormat decompress_format = BASIS_DECOMPRESS_MAX;

	if (is_hdr) {
		decompress_format = BASIS_DECOMPRESS_HDR_RGB;
		params.m_hdr = true;
		params.m_uastc_hdr_options.set_quality_level(0);

	} else {
		switch (p_channels) {
			case Image::USED_CHANNELS_L: {
				decompress_format = BASIS_DECOMPRESS_RGB;
			} break;
			case Image::USED_CHANNELS_LA: {
				params.m_force_alpha = true;
				decompress_format = BASIS_DECOMPRESS_RGBA;
			} break;
			case Image::USED_CHANNELS_R: {
				decompress_format = BASIS_DECOMPRESS_R;
			} break;
			case Image::USED_CHANNELS_RG: {
				params.m_force_alpha = true;
				image->convert_rg_to_ra_rgba8();
				decompress_format = BASIS_DECOMPRESS_RG;
			} break;
			case Image::USED_CHANNELS_RGB: {
				decompress_format = BASIS_DECOMPRESS_RGB;
			} break;
			case Image::USED_CHANNELS_RGBA: {
				params.m_force_alpha = true;
				decompress_format = BASIS_DECOMPRESS_RGBA;
			} break;
		}
	}

	ERR_FAIL_COND_V(decompress_format == BASIS_DECOMPRESS_MAX, Vector<uint8_t>());

	// Copy the source image data with mipmaps into BasisU.
	{
		const int orig_width = image->get_width();
		const int orig_height = image->get_height();

		bool is_res_div_4 = (orig_width % 4 == 0) && (orig_height % 4 == 0);

		// Image's resolution rounded up to the nearest values divisible by 4.
		int next_width = orig_width <= 2 ? orig_width : (orig_width + 3) & ~3;
		int next_height = orig_height <= 2 ? orig_height : (orig_height + 3) & ~3;

		Vector<uint8_t> image_data = image->get_data();
		basisu::vector<basisu::image> basisu_mipmaps;
		basisu::vector<basisu::imagef> basisu_mipmaps_hdr;

		// Buffer for storing padded mipmap data.
		Vector<uint8_t> mip_data_padded;

		for (int32_t i = 0; i <= image->get_mipmap_count(); i++) {
			int64_t ofs, size;
			int width, height;
			image->get_mipmap_offset_size_and_dimensions(i, ofs, size, width, height);

			const uint8_t *image_mip_data = image_data.ptr() + ofs;

			// Pad the mipmap's data if its resolution isn't divisible by 4.
			if (image->has_mipmaps() && !is_res_div_4 && (width > 2 && height > 2) && (width != next_width || height != next_height)) {
				if (is_hdr) {
					_basisu_pad_mipmap<BasisRGBAF>(image_mip_data, mip_data_padded, next_width, next_height, width, height, size);
				} else {
					_basisu_pad_mipmap<uint32_t>(image_mip_data, mip_data_padded, next_width, next_height, width, height, size);
				}

				// Override the image_mip_data pointer with our temporary Vector.
				image_mip_data = reinterpret_cast<const uint8_t *>(mip_data_padded.ptr());

				// Override the mipmap's properties.
				width = next_width;
				height = next_height;
				size = mip_data_padded.size();
			}

			// Get the next mipmap's resolution.
			next_width /= 2;
			next_height /= 2;

			// Copy the source mipmap's data to a BasisU image.
			if (is_hdr) {
				basisu::imagef basisu_image(width, height);
				memcpy(reinterpret_cast<uint8_t *>(basisu_image.get_ptr()), image_mip_data, size);

				if (i == 0) {
					params.m_source_images_hdr.push_back(basisu_image);
				} else {
					basisu_mipmaps_hdr.push_back(basisu_image);
				}

			} else {
				basisu::image basisu_image(width, height);
				memcpy(basisu_image.get_ptr(), image_mip_data, size);

				if (i == 0) {
					params.m_source_images.push_back(basisu_image);
				} else {
					basisu_mipmaps.push_back(basisu_image);
				}
			}
		}

		if (is_hdr) {
			params.m_source_mipmap_images_hdr.push_back(basisu_mipmaps_hdr);
		} else {
			params.m_source_mipmap_images.push_back(basisu_mipmaps);
		}
	}

	// Encode the image data.
	basisu::basis_compressor compressor;
	compressor.init(params);

	int basisu_err = compressor.process();
	ERR_FAIL_COND_V(basisu_err != basisu::basis_compressor::cECSuccess, Vector<uint8_t>());

	const basisu::uint8_vec &basisu_encoded = compressor.get_output_basis_file();

	Vector<uint8_t> basisu_data;
	basisu_data.resize(basisu_encoded.size() + 4);
	uint8_t *basisu_data_ptr = basisu_data.ptrw();

	// Copy the encoded BasisU data into the output buffer.
	*(uint32_t *)basisu_data_ptr = decompress_format;
	memcpy(basisu_data_ptr + 4, basisu_encoded.get_ptr(), basisu_encoded.size());

	print_verbose(vformat("BasisU: Encoding a %dx%d image with %d mipmaps took %d ms.", p_image->get_width(), p_image->get_height(), p_image->get_mipmap_count(), OS::get_singleton()->get_ticks_msec() - start_time));

	return basisu_data;
}
#endif // TOOLS_ENABLED

Ref<Image> basis_universal_unpacker_ptr(const uint8_t *p_data, int p_size) {
	uint64_t start_time = OS::get_singleton()->get_ticks_msec();

	Ref<Image> image;
	ERR_FAIL_NULL_V_MSG(p_data, image, "Cannot unpack invalid BasisUniversal data.");

	const uint8_t *src_ptr = p_data;
	int src_size = p_size;

	basist::transcoder_texture_format basisu_format = basist::transcoder_texture_format::cTFTotalTextureFormats;
	Image::Format image_format = Image::FORMAT_MAX;

	// Get supported compression formats.
	bool bptc_supported = RS::get_singleton()->has_os_feature("bptc");
	bool astc_supported = RS::get_singleton()->has_os_feature("astc");
	bool rgtc_supported = RS::get_singleton()->has_os_feature("rgtc");
	bool s3tc_supported = RS::get_singleton()->has_os_feature("s3tc");
	bool etc2_supported = RS::get_singleton()->has_os_feature("etc2");

	bool needs_ra_rg_swap = false;
	bool needs_rg_trim = false;

	BasisDecompressFormat decompress_format = (BasisDecompressFormat)(*(uint32_t *)(src_ptr));

	switch (decompress_format) {
		case BASIS_DECOMPRESS_R: {
			if (rgtc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC4_R;
				image_format = Image::FORMAT_RGTC_R;
			} else if (s3tc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC1;
				image_format = Image::FORMAT_DXT1;
			} else if (etc2_supported) {
				basisu_format = basist::transcoder_texture_format::cTFETC2_EAC_R11;
				image_format = Image::FORMAT_ETC2_R11;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGBA32;
				image_format = Image::FORMAT_RGBA8;
				needs_rg_trim = true;
			}

		} break;
		case BASIS_DECOMPRESS_RG: {
			if (rgtc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC5_RG;
				image_format = Image::FORMAT_RGTC_RG;
			} else if (s3tc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC3;
				image_format = Image::FORMAT_DXT5_RA_AS_RG;
			} else if (etc2_supported) {
				basisu_format = basist::transcoder_texture_format::cTFETC2_EAC_RG11;
				image_format = Image::FORMAT_ETC2_RG11;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGBA32;
				image_format = Image::FORMAT_RGBA8;
				needs_ra_rg_swap = true;
				needs_rg_trim = true;
			}

		} break;
		case BASIS_DECOMPRESS_RG_AS_RA: {
			if (s3tc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC3;
				image_format = Image::FORMAT_DXT5_RA_AS_RG;
			} else if (etc2_supported) {
				basisu_format = basist::transcoder_texture_format::cTFETC2;
				image_format = Image::FORMAT_ETC2_RA_AS_RG;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGBA32;
				image_format = Image::FORMAT_RGBA8;
				needs_ra_rg_swap = true;
				needs_rg_trim = true;
			}

		} break;
		case BASIS_DECOMPRESS_RGB: {
			if (bptc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC7_M6_OPAQUE_ONLY;
				image_format = Image::FORMAT_BPTC_RGBA;
			} else if (astc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFASTC_4x4_RGBA;
				image_format = Image::FORMAT_ASTC_4x4;
			} else if (s3tc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC1;
				image_format = Image::FORMAT_DXT1;
			} else if (etc2_supported) {
				basisu_format = basist::transcoder_texture_format::cTFETC1;
				image_format = Image::FORMAT_ETC2_RGB8;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGBA32;
				image_format = Image::FORMAT_RGBA8;
			}

		} break;
		case BASIS_DECOMPRESS_RGBA: {
			if (bptc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC7_M5;
				image_format = Image::FORMAT_BPTC_RGBA;
			} else if (astc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFASTC_4x4_RGBA;
				image_format = Image::FORMAT_ASTC_4x4;
			} else if (s3tc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC3;
				image_format = Image::FORMAT_DXT5;
			} else if (etc2_supported) {
				basisu_format = basist::transcoder_texture_format::cTFETC2;
				image_format = Image::FORMAT_ETC2_RGBA8;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGBA32;
				image_format = Image::FORMAT_RGBA8;
			}

		} break;
		case BASIS_DECOMPRESS_HDR_RGB: {
			if (bptc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFBC6H;
				image_format = Image::FORMAT_BPTC_RGBFU;
			} else if (astc_supported) {
				basisu_format = basist::transcoder_texture_format::cTFASTC_HDR_4x4_RGBA;
				image_format = Image::FORMAT_ASTC_4x4_HDR;
			} else {
				// No supported VRAM compression formats, decompress.
				basisu_format = basist::transcoder_texture_format::cTFRGB_9E5;
				image_format = Image::FORMAT_RGBE9995;
			}

		} break;
		default: {
			ERR_FAIL_V(image);
		} break;
	}

	src_ptr += 4;
	src_size -= 4;

	basist::basisu_transcoder transcoder;
	ERR_FAIL_COND_V(!transcoder.validate_header(src_ptr, src_size), image);

	transcoder.start_transcoding(src_ptr, src_size);

	basist::basisu_image_info basisu_info;
	transcoder.get_image_info(src_ptr, src_size, basisu_info, 0);

	// Create the buffer for transcoded/decompressed data.
	Vector<uint8_t> out_data;
	out_data.resize(Image::get_image_data_size(basisu_info.m_width, basisu_info.m_height, image_format, basisu_info.m_total_levels > 1));

	uint8_t *dst = out_data.ptrw();
	memset(dst, 0, out_data.size());

	for (uint32_t i = 0; i < basisu_info.m_total_levels; i++) {
		basist::basisu_image_level_info basisu_level;
		transcoder.get_image_level_info(src_ptr, src_size, basisu_level, 0, i);

		uint32_t mip_block_or_pixel_count = Image::is_format_compressed(image_format) ? basisu_level.m_total_blocks : basisu_level.m_orig_width * basisu_level.m_orig_height;
		int64_t ofs = Image::get_image_mipmap_offset(basisu_info.m_width, basisu_info.m_height, image_format, i);

		bool result = transcoder.transcode_image_level(src_ptr, src_size, 0, i, dst + ofs, mip_block_or_pixel_count, basisu_format);

		if (!result) {
			print_line(vformat("BasisUniversal cannot unpack level %d.", i));
			break;
		}
	}

	image = Image::create_from_data(basisu_info.m_width, basisu_info.m_height, basisu_info.m_total_levels > 1, image_format, out_data);

	if (needs_ra_rg_swap) {
		// Swap uncompressed RA-as-RG texture's color channels.
		image->convert_ra_rgba8_to_rg();
	}

	if (needs_rg_trim) {
		// Remove unnecessary color channels from uncompressed textures.
		if (decompress_format == BASIS_DECOMPRESS_R) {
			image->convert(Image::FORMAT_R8);
		} else if (decompress_format == BASIS_DECOMPRESS_RG || decompress_format == BASIS_DECOMPRESS_RG_AS_RA) {
			image->convert(Image::FORMAT_RG8);
		}
	}

	print_verbose(vformat("BasisU: Transcoding a %dx%d image with %d mipmaps into %s took %d ms.",
			image->get_width(), image->get_height(), image->get_mipmap_count(), Image::get_format_name(image_format), OS::get_singleton()->get_ticks_msec() - start_time));

	return image;
}

Ref<Image> basis_universal_unpacker(const Vector<uint8_t> &p_buffer) {
	return basis_universal_unpacker_ptr(p_buffer.ptr(), p_buffer.size());
}