// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

/* eslint-disable camelcase */
// Forked from PicoGL: https://github.com/tsherif/picogl.js/blob/master/examples/utils/utils.js
// Copyright (c) 2017 Tarek Sherif, The MIT License (MIT)

import type {TextureLevel} from '@loaders.gl/schema';
import {GL_EXTENSIONS_CONSTANTS} from '../gl-extensions';
import {extractMipmapImages} from '../utils/extract-mipmap-images';

const PVR_CONSTANTS: Record<string, number> = {
  MAGIC_NUMBER: 0x03525650,
  MAGIC_NUMBER_EXTRA: 0x50565203,
  HEADER_LENGTH: 13,
  HEADER_SIZE: 52,
  MAGIC_NUMBER_INDEX: 0,
  PIXEL_FORMAT_INDEX: 2,
  COLOUR_SPACE_INDEX: 4,
  HEIGHT_INDEX: 6,
  WIDTH_INDEX: 7,
  MIPMAPCOUNT_INDEX: 11,
  METADATA_SIZE_INDEX: 12
};

const PVR_PIXEL_FORMATS: Record<number, number[]> = {
  0: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB_PVRTC_2BPPV1_IMG],
  1: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG],
  2: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB_PVRTC_4BPPV1_IMG],
  3: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG],
  6: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB_ETC1_WEBGL],
  7: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB_S3TC_DXT1_EXT],
  9: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_S3TC_DXT3_EXT],
  11: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_S3TC_DXT5_EXT],
  22: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB8_ETC2],
  23: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA8_ETC2_EAC],
  24: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2],
  25: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_R11_EAC],
  26: [GL_EXTENSIONS_CONSTANTS.COMPRESSED_RG11_EAC],
  27: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_4X4_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_4X4_KHR
  ],
  28: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_5X4_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_5X4_KHR
  ],
  29: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_5X5_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_5X5_KHR
  ],
  30: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_6X5_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_6X5_KHR
  ],
  31: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_6X6_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_6X6_KHR
  ],
  32: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_8X5_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_8X5_KHR
  ],
  33: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_8X6_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_8X6_KHR
  ],
  34: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_8X8_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_8X8_KHR
  ],
  35: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_10X5_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_10X5_KHR
  ],
  36: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_10X6_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_10X6_KHR
  ],
  37: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_10X8_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_10X8_KHR
  ],
  38: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_10X10_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_10X10_KHR
  ],
  39: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_12X10_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_12X10_KHR
  ],
  40: [
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_RGBA_ASTC_12X12_KHR,
    GL_EXTENSIONS_CONSTANTS.COMPRESSED_SRGB8_ALPHA8_ASTC_12X12_KHR
  ]
};

const PVR_SIZE_FUNCTIONS: Record<number, (width: number, height: number) => number> = {
  0: pvrtc2bppSize,
  1: pvrtc2bppSize,
  2: pvrtc4bppSize,
  3: pvrtc4bppSize,
  6: dxtEtcSmallSize,
  7: dxtEtcSmallSize,
  9: dxtEtcAstcBigSize,
  11: dxtEtcAstcBigSize,
  22: dxtEtcSmallSize,
  23: dxtEtcAstcBigSize,
  24: dxtEtcSmallSize,
  25: dxtEtcSmallSize,
  26: dxtEtcAstcBigSize,
  27: dxtEtcAstcBigSize,
  28: atc5x4Size,
  29: atc5x5Size,
  30: atc6x5Size,
  31: atc6x6Size,
  32: atc8x5Size,
  33: atc8x6Size,
  34: atc8x8Size,
  35: atc10x5Size,
  36: atc10x6Size,
  37: atc10x8Size,
  38: atc10x10Size,
  39: atc12x10Size,
  40: atc12x12Size
};

/**
 * Check if data is in "PVR" format by its magic number
 * @param data - binary data of compressed texture
 * @returns true - data in "PVR" format, else - false
 */
export function isPVR(data: ArrayBuffer): boolean {
  const header = new Uint32Array(data, 0, PVR_CONSTANTS.HEADER_LENGTH);
  const version = header[PVR_CONSTANTS.MAGIC_NUMBER_INDEX];

  return version === PVR_CONSTANTS.MAGIC_NUMBER || version === PVR_CONSTANTS.MAGIC_NUMBER_EXTRA;
}

/**
 * Parse texture data as "PVR" format
 * @param data - binary data of compressed texture
 * @returns Array of the texture levels
 * @see http://cdn.imgtec.com/sdk-documentation/PVR+File+Format.Specification.pdf
 */
export function parsePVR(data: ArrayBuffer): TextureLevel[] {
  const header = new Uint32Array(data, 0, PVR_CONSTANTS.HEADER_LENGTH);

  const pvrFormat = header[PVR_CONSTANTS.PIXEL_FORMAT_INDEX];
  const colourSpace = header[PVR_CONSTANTS.COLOUR_SPACE_INDEX];
  const pixelFormats = PVR_PIXEL_FORMATS[pvrFormat] || [];
  const internalFormat = pixelFormats.length > 1 && colourSpace ? pixelFormats[1] : pixelFormats[0];

  const sizeFunction = PVR_SIZE_FUNCTIONS[pvrFormat];

  const mipMapLevels = header[PVR_CONSTANTS.MIPMAPCOUNT_INDEX];

  const width = header[PVR_CONSTANTS.WIDTH_INDEX];
  const height = header[PVR_CONSTANTS.HEIGHT_INDEX];

  const dataOffset = PVR_CONSTANTS.HEADER_SIZE + header[PVR_CONSTANTS.METADATA_SIZE_INDEX];

  const image = new Uint8Array(data, dataOffset);

  return extractMipmapImages(image, {
    mipMapLevels,
    width,
    height,
    sizeFunction,
    internalFormat
  });
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_pvrtc/
function pvrtc2bppSize(width: number, height: number): number {
  width = Math.max(width, 16);
  height = Math.max(height, 8);

  return (width * height) / 4;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_pvrtc/
function pvrtc4bppSize(width: number, height: number): number {
  width = Math.max(width, 8);
  height = Math.max(height, 8);

  return (width * height) / 2;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_s3tc/
// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_etc/
// Size for:
// COMPRESSED_RGB_S3TC_DXT1_EXT
// COMPRESSED_R11_EAC
// COMPRESSED_SIGNED_R11_EAC
// COMPRESSED_RGB8_ETC2
// COMPRESSED_SRGB8_ETC2
// COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
// COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
function dxtEtcSmallSize(width: number, height: number): number {
  return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 8;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_s3tc/
// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_etc/
// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
// Size for:
// COMPRESSED_RGBA_S3TC_DXT3_EXT
// COMPRESSED_RGBA_S3TC_DXT5_EXT
// COMPRESSED_RG11_EAC
// COMPRESSED_SIGNED_RG11_EAC
// COMPRESSED_RGBA8_ETC2_EAC
// COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
// COMPRESSED_RGBA_ASTC_4x4_KHR
function dxtEtcAstcBigSize(width: number, height: number): number {
  return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc5x4Size(width: number, height: number): number {
  return Math.floor((width + 4) / 5) * Math.floor((height + 3) / 4) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc5x5Size(width: number, height: number): number {
  return Math.floor((width + 4) / 5) * Math.floor((height + 4) / 5) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc6x5Size(width: number, height: number): number {
  return Math.floor((width + 5) / 6) * Math.floor((height + 4) / 5) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc6x6Size(width: number, height: number): number {
  return Math.floor((width + 5) / 6) * Math.floor((height + 5) / 6) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc8x5Size(width: number, height: number): number {
  return Math.floor((width + 7) / 8) * Math.floor((height + 4) / 5) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc8x6Size(width: number, height: number): number {
  return Math.floor((width + 7) / 8) * Math.floor((height + 5) / 6) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc8x8Size(width: number, height: number): number {
  return Math.floor((width + 7) / 8) * Math.floor((height + 7) / 8) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc10x5Size(width: number, height: number): number {
  return Math.floor((width + 9) / 10) * Math.floor((height + 4) / 5) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc10x6Size(width: number, height: number): number {
  return Math.floor((width + 9) / 10) * Math.floor((height + 5) / 6) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc10x8Size(width: number, height: number): number {
  return Math.floor((width + 9) / 10) * Math.floor((height + 7) / 8) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc10x10Size(width: number, height: number): number {
  return Math.floor((width + 9) / 10) * Math.floor((height + 9) / 10) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc12x10Size(width: number, height: number): number {
  return Math.floor((width + 11) / 12) * Math.floor((height + 9) / 10) * 16;
}

// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
function atc12x12Size(width: number, height: number): number {
  return Math.floor((width + 11) / 12) * Math.floor((height + 11) / 12) * 16;
}