// ----------------------------------------------------------------------------
//  This confidential and proprietary software may be used only as authorised
//  by a licensing agreement from Arm Limited.
//      (C) COPYRIGHT 2011-2019 Arm Limited, ALL RIGHTS RESERVED
//  The entire notice above must be reproduced on all authorised copies and
//  copies may only be made to the extent permitted by a licensing agreement
//  from Arm Limited.
// ----------------------------------------------------------------------------

/**
 * @brief Functions to decompress a symbolic block.
 */

#include "astc_codec_internals.h"
#include "softfloat.h"

#include <stdio.h>

int compute_value_of_texel_int(int texel_to_get, const decimation_table * it, const int *weights)
{
	int i;
	int summed_value = 8;
	int weights_to_evaluate = it->texel_num_weights[texel_to_get];
	for (i = 0; i < weights_to_evaluate; i++)
	{
		summed_value += weights[it->texel_weights[texel_to_get][i]] * it->texel_weights_int[texel_to_get][i];
	}
	return summed_value >> 4;
}

ushort4 lerp_color_int(astc_decode_mode decode_mode, ushort4 color0, ushort4 color1, int weight, int plane2_weight, int plane2_color_component	// -1 in 1-plane mode
	)
{
	int4 ecolor0 = int4(color0.x, color0.y, color0.z, color0.w);
	int4 ecolor1 = int4(color1.x, color1.y, color1.z, color1.w);

	int4 eweight1 = int4(weight, weight, weight, weight);
	switch (plane2_color_component)
	{
	case 0:
		eweight1.x = plane2_weight;
		break;
	case 1:
		eweight1.y = plane2_weight;
		break;
	case 2:
		eweight1.z = plane2_weight;
		break;
	case 3:
		eweight1.w = plane2_weight;
		break;
	default:
		break;
	}

	int4 eweight0 = int4(64, 64, 64, 64) - eweight1;

	if (decode_mode == DECODE_LDR_SRGB)
	{
		ecolor0 = ecolor0 >> 8;
		ecolor1 = ecolor1 >> 8;
	}
	int4 color = (ecolor0 * eweight0) + (ecolor1 * eweight1) + int4(32, 32, 32, 32);
	color = color >> 6;
	if (decode_mode == DECODE_LDR_SRGB)
		color = color | (color << 8);

	ushort4 rcolor = ushort4(color.x, color.y, color.z, color.w);
	return rcolor;
}

void decompress_symbolic_block(astc_decode_mode decode_mode,
							   int xdim, int ydim, int zdim,   // dimensions of block
							   int xpos, int ypos, int zpos,   // position of block
							   const symbolic_compressed_block * scb, imageblock * blk)
{
	blk->xpos = xpos;
	blk->ypos = ypos;
	blk->zpos = zpos;

	int i;

	// if we detected an error-block, blow up immediately.
	if (scb->error_block)
	{
		if (decode_mode == DECODE_LDR_SRGB)
		{
			for (i = 0; i < xdim * ydim * zdim; i++)
			{
				blk->orig_data[4 * i] = 1.0f;
				blk->orig_data[4 * i + 1] = 0.0f;
				blk->orig_data[4 * i + 2] = 1.0f;
				blk->orig_data[4 * i + 3] = 1.0f;
				blk->rgb_lns[i] = 0;
				blk->alpha_lns[i] = 0;
				blk->nan_texel[i] = 0;
			}
		}
		else
		{
			for (i = 0; i < xdim * ydim * zdim; i++)
			{
				blk->orig_data[4 * i] = 0.0f;
				blk->orig_data[4 * i + 1] = 0.0f;
				blk->orig_data[4 * i + 2] = 0.0f;
				blk->orig_data[4 * i + 3] = 0.0f;
				blk->rgb_lns[i] = 0;
				blk->alpha_lns[i] = 0;
				blk->nan_texel[i] = 1;
			}
		}

		imageblock_initialize_work_from_orig(blk, xdim * ydim * zdim);
		update_imageblock_flags(blk, xdim, ydim, zdim);
		return;
	}

	if (scb->block_mode < 0)
	{
		float red = 0, green = 0, blue = 0, alpha = 0;
		int use_lns = 0;
		int use_nan = 0;

		if (scb->block_mode == -2)
		{
			// For sRGB decoding, we should return only the top 8 bits.
			int mask = (decode_mode == DECODE_LDR_SRGB) ? 0xFF00 : 0xFFFF;

			red = sf16_to_float(unorm16_to_sf16(scb->constant_color[0] & mask));
			green = sf16_to_float(unorm16_to_sf16(scb->constant_color[1] & mask));
			blue = sf16_to_float(unorm16_to_sf16(scb->constant_color[2] & mask));
			alpha = sf16_to_float(unorm16_to_sf16(scb->constant_color[3] & mask));
			use_lns = 0;
			use_nan = 0;
		}
		else
		{
			switch (decode_mode)
			{
			case DECODE_LDR_SRGB:
				red = 1.0f;
				green = 0.0f;
				blue = 1.0f;
				alpha = 1.0f;
				use_lns = 0;
				use_nan = 0;
				break;
			case DECODE_LDR:
				red = 0.0f;
				green = 0.0f;
				blue = 0.0f;
				alpha = 0.0f;
				use_lns = 0;
				use_nan = 1;
				break;
			case DECODE_HDR:
				// constant-color block; unpack from FP16 to FP32.
				red = sf16_to_float(scb->constant_color[0]);
				green = sf16_to_float(scb->constant_color[1]);
				blue = sf16_to_float(scb->constant_color[2]);
				alpha = sf16_to_float(scb->constant_color[3]);
				use_lns = 1;
				use_nan = 0;
				break;
			}
		}

		for (i = 0; i < xdim * ydim * zdim; i++)
		{
			blk->orig_data[4 * i] = red;
			blk->orig_data[4 * i + 1] = green;
			blk->orig_data[4 * i + 2] = blue;
			blk->orig_data[4 * i + 3] = alpha;
			blk->rgb_lns[i] = use_lns;
			blk->alpha_lns[i] = use_lns;
			blk->nan_texel[i] = use_nan;
		}

		imageblock_initialize_work_from_orig(blk, xdim * ydim * zdim);
		update_imageblock_flags(blk, xdim, ydim, zdim);
		return;
	}

	// get the appropriate partition-table entry
	int partition_count = scb->partition_count;
	const partition_info *pt = get_partition_table(xdim, ydim, zdim, partition_count);
	pt += scb->partition_index;

	// get the appropriate block descriptor
	const block_size_descriptor *bsd = get_block_size_descriptor(xdim, ydim, zdim);
	const decimation_table *const *ixtab2 = bsd->decimation_tables;

	const decimation_table *it = ixtab2[bsd->block_modes[scb->block_mode].decimation_mode];

	int is_dual_plane = bsd->block_modes[scb->block_mode].is_dual_plane;

	int weight_quantization_level = bsd->block_modes[scb->block_mode].quantization_mode;

	// decode the color endpoints
	ushort4 color_endpoint0[4];
	ushort4 color_endpoint1[4];
	int rgb_hdr_endpoint[4];
	int alpha_hdr_endpoint[4];
	int nan_endpoint[4];

	for (i = 0; i < partition_count; i++)
		unpack_color_endpoints(decode_mode,
							   scb->color_formats[i],
							   scb->color_quantization_level, scb->color_values[i], &(rgb_hdr_endpoint[i]), &(alpha_hdr_endpoint[i]), &(nan_endpoint[i]), &(color_endpoint0[i]), &(color_endpoint1[i]));

	// first unquantize the weights
	int uq_plane1_weights[MAX_WEIGHTS_PER_BLOCK];
	int uq_plane2_weights[MAX_WEIGHTS_PER_BLOCK];
	int weight_count = it->num_weights;

	const quantization_and_transfer_table *qat = &(quant_and_xfer_tables[weight_quantization_level]);

	for (i = 0; i < weight_count; i++)
	{
		uq_plane1_weights[i] = qat->unquantized_value[scb->plane1_weights[i]];
	}

	if (is_dual_plane)
	{
		for (i = 0; i < weight_count; i++)
			uq_plane2_weights[i] = qat->unquantized_value[scb->plane2_weights[i]];
	}

	// then undecimate them.
	int weights[MAX_TEXELS_PER_BLOCK];
	int plane2_weights[MAX_TEXELS_PER_BLOCK];

	int texels_per_block = xdim * ydim * zdim;
	for (i = 0; i < texels_per_block; i++)
		weights[i] = compute_value_of_texel_int(i, it, uq_plane1_weights);

	if (is_dual_plane)
		for (i = 0; i < texels_per_block; i++)
			plane2_weights[i] = compute_value_of_texel_int(i, it, uq_plane2_weights);

	int plane2_color_component = scb->plane2_color_component;

	// now that we have endpoint colors and weights, we can unpack actual colors for
	// each texel.
	for (i = 0; i < texels_per_block; i++)
	{
		int partition = pt->partition_of_texel[i];

		ushort4 color = lerp_color_int(decode_mode,
									   color_endpoint0[partition],
									   color_endpoint1[partition],
									   weights[i],
									   plane2_weights[i],
									   is_dual_plane ? plane2_color_component : -1);

		blk->rgb_lns[i] = rgb_hdr_endpoint[partition];
		blk->alpha_lns[i] = alpha_hdr_endpoint[partition];
		blk->nan_texel[i] = nan_endpoint[partition];

		blk->work_data[4 * i] = color.x;
		blk->work_data[4 * i + 1] = color.y;
		blk->work_data[4 * i + 2] = color.z;
		blk->work_data[4 * i + 3] = color.w;
	}

	imageblock_initialize_orig_from_work(blk, xdim * ydim * zdim);

	update_imageblock_flags(blk, xdim, ydim, zdim);
}

float compute_imageblock_difference(int xdim, int ydim, int zdim, const imageblock * p1, const imageblock * p2, const error_weight_block * ewb)
{
	int i;
	int texels_per_block = xdim * ydim * zdim;
	float summa = 0.0f;
	const float *f1 = p1->work_data;
	const float *f2 = p2->work_data;

	for (i = 0; i < texels_per_block; i++)
	{
		float rdiff = fabsf(f1[4 * i] - f2[4 * i]);
		float gdiff = fabs(f1[4 * i + 1] - f2[4 * i + 1]);
		float bdiff = fabs(f1[4 * i + 2] - f2[4 * i + 2]);
		float adiff = fabs(f1[4 * i + 3] - f2[4 * i + 3]);
		rdiff = MIN(rdiff, 1e15f);
		gdiff = MIN(gdiff, 1e15f);
		bdiff = MIN(bdiff, 1e15f);
		adiff = MIN(adiff, 1e15f);

		summa += rdiff * rdiff * ewb->error_weights[i].x + gdiff * gdiff * ewb->error_weights[i].y + bdiff * bdiff * ewb->error_weights[i].z + adiff * adiff * ewb->error_weights[i].w;
	}

	return summa;
}