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

import type {TextureFormat, DeviceFeature} from '@luma.gl/core';
import {decodeTextureFormat} from '@luma.gl/core';
import {GL, GLExtensions} from '@luma.gl/constants';
import {getWebGLExtension} from '../../context/helpers/webgl-extensions';
import {getGLFromVertexType} from './vertex-formats';

/* eslint-disable camelcase */

// TEXTURE FEATURES

// Define local device feature strings to optimize minification
const texture_compression_bc: DeviceFeature = 'texture-compression-bc';
const texture_compression_astc: DeviceFeature = 'texture-compression-astc';
const texture_compression_etc2: DeviceFeature = 'texture-compression-etc2';
const texture_compression_etc1_webgl: DeviceFeature = 'texture-compression-etc1-webgl';
const texture_compression_pvrtc_webgl: DeviceFeature = 'texture-compression-pvrtc-webgl';
const texture_compression_atc_webgl: DeviceFeature = 'texture-compression-atc-webgl';

const float32_renderable: DeviceFeature = 'float32-renderable-webgl';
const float16_renderable: DeviceFeature = 'float16-renderable-webgl';
const rgb9e5ufloat_renderable: DeviceFeature = 'rgb9e5ufloat_renderable-webgl';
const snorm8_renderable: DeviceFeature = 'snorm8-renderable-webgl';
const norm16_renderable: DeviceFeature = 'norm16-renderable-webgl';
const snorm16_renderable: DeviceFeature = 'snorm16-renderable-webgl';

const float32_filterable: DeviceFeature = 'float32-filterable';
const float16_filterable: DeviceFeature = 'float16-filterable-webgl';

// Define local webgl extension strings to optimize minification
const X_S3TC = 'WEBGL_compressed_texture_s3tc'; // BC1, BC2, BC3
const X_S3TC_SRGB = 'WEBGL_compressed_texture_s3tc_srgb'; // BC1, BC2, BC3
const X_RGTC = 'EXT_texture_compression_rgtc'; // BC4, BC5
const X_BPTC = 'EXT_texture_compression_bptc'; // BC6, BC7
const X_ETC2 = 'WEBGL_compressed_texture_etc'; // Renamed from 'WEBGL_compressed_texture_es3'
const X_ASTC = 'WEBGL_compressed_texture_astc';
const X_ETC1 = 'WEBGL_compressed_texture_etc1';
const X_PVRTC = 'WEBGL_compressed_texture_pvrtc';
const X_ATC = 'WEBGL_compressed_texture_atc';

// Define local webgl extension strings to optimize minification
const EXT_texture_norm16 = 'EXT_texture_norm16';
const EXT_render_snorm = 'EXT_render_snorm';
const EXT_color_buffer_float = 'EXT_color_buffer_float';

// prettier-ignore
export const TEXTURE_FEATURES: Partial<Record<DeviceFeature, string[]>> = {
  'float32-renderable-webgl': ['EXT_color_buffer_float'],
  'float16-renderable-webgl': ['EXT_color_buffer_half_float'],
  'rgb9e5ufloat_renderable-webgl': ['WEBGL_render_shared_exponent'],
  'snorm8-renderable-webgl': [EXT_render_snorm],
  'norm16-renderable-webgl': [EXT_texture_norm16],
  'snorm16-renderable-webgl': [EXT_texture_norm16, EXT_render_snorm],

  'float32-filterable': ['OES_texture_float_linear'],
  'float16-filterable-webgl': ['OES_texture_half_float_linear'],
  'texture-filterable-anisotropic-webgl': ['EXT_texture_filter_anisotropic'],

  'texture-blend-float-webgl': ['EXT_float_blend'],

  'texture-compression-bc': [X_S3TC, X_S3TC_SRGB, X_RGTC, X_BPTC],
  // 'texture-compression-bc3-srgb-webgl': [X_S3TC_SRGB],
  // 'texture-compression-bc3-webgl': [X_S3TC],
  'texture-compression-bc5-webgl': [X_RGTC],
  'texture-compression-bc7-webgl': [X_BPTC],
  'texture-compression-etc2': [X_ETC2],
  'texture-compression-astc': [X_ASTC],
  'texture-compression-etc1-webgl': [X_ETC1],
  'texture-compression-pvrtc-webgl': [X_PVRTC],
  'texture-compression-atc-webgl': [X_ATC]
};

/** Return a list of texture feature strings (for Device.features). Mainly compressed texture support */
// export function getTextureFeatures(
//   gl: WebGL2RenderingContext,
//   extensions: GLExtensions
// ): DeviceFeature[] {
//   const textureFeatures = Object.keys(TEXTURE_FEATURES) as DeviceFeature[];
//   return textureFeatures.filter(feature => checkTextureFeature(gl, feature, extensions));
// }

export function isTextureFeature(feature: DeviceFeature): boolean {
  return feature in TEXTURE_FEATURES;
}

/** Checks a texture feature (for Device.features). Mainly compressed texture support */
export function checkTextureFeature(
  gl: WebGL2RenderingContext,
  feature: DeviceFeature,
  extensions: GLExtensions
): boolean {
  const textureExtensions = TEXTURE_FEATURES[feature] || [];
  return textureExtensions.every(extension => getWebGLExtension(gl, extension, extensions));
}

// TEXTURE FORMATS

/** Map a format to webgl and constants */
type Format = {
  gl?: GL;
  /** format requires WebGL2, when using a WebGL 1 context, color renderbuffer formats are limited */
  gl2ext?: string;

  /** (bytes per pixel), for memory usage calculations. */
  b?: number;
  /** channels */
  c?: number;
  bpp?: number;
  /** packed */
  p?: number;
  /** compressed */
  x?: string;
  /** for compressed texture formats */
  f?: DeviceFeature;
  /** renderable if feature is present */
  render?: DeviceFeature;
  /** filterable if feature is present */
  filter?: DeviceFeature;

  /** If not supported on WebGPU */
  wgpu?: false;

  types?: number[];

  dataFormat?: GL;
  /** Depth and stencil format attachment points. If set, needs to be a Renderbuffer unless depthTexture is set  */
  attachment?: GL.DEPTH_ATTACHMENT | GL.STENCIL_ATTACHMENT | GL.DEPTH_STENCIL_ATTACHMENT;
  /** if depthTexture is set this is a depth/stencil format that can be set to a texture  */
  depthTexture?: boolean;
  /** @deprecated can this format be used with renderbuffers */
  rb?: boolean;
};

// TABLES

/**
 * Texture format data -
 * Exported but can change without notice
 */
// prettier-ignore
export const TEXTURE_FORMATS: Record<TextureFormat, Format> = {
  // Unsized formats that leave the precision up to the driver. TODO - Fix bpp constants
  'rgb8unorm-unsized': {gl: GL.RGB, b: 4, c: 2, bpp: 4,
    dataFormat: GL.RGB, types: [GL.UNSIGNED_BYTE, GL.UNSIGNED_SHORT_5_6_5]},
  'rgba8unorm-unsized': {gl: GL.RGBA, b: 4, c: 2, bpp: 4,
    dataFormat: GL.RGBA, types: [GL.UNSIGNED_BYTE, GL.UNSIGNED_SHORT_4_4_4_4, GL.UNSIGNED_SHORT_5_5_5_1]},
  // 'r8unorm-unsized': {gl: GL.LUMINANCE, b: 4, c: 2, bpp: 4},
  // 'rgb8unorm-srgb-unsized': {gl: GL.SRGB_EXT, b: 4, c: 2, bpp: 4, gl1Ext: SRGB},
  // 'rgba8unorm-srgb-unsized': {gl: GL.SRGB_ALPHA_EXT, b: 4, c: 2, bpp: 4, gl1Ext: SRGB},

  // 8-bit formats
  'r8unorm': {gl: GL.R8, b: 1, c: 1, rb: true},
  'r8snorm': {gl: GL.R8_SNORM, b: 1, c: 1, render: snorm8_renderable},
  'r8uint': {gl: GL.R8UI, b: 1, c: 1, rb: true},
  'r8sint': {gl: GL.R8I, b: 1, c: 1, rb: true},

  // 16-bit formats
  'rg8unorm': {gl: GL.RG8, b: 2, c: 2, rb: true},
  'rg8snorm': {gl: GL.RG8_SNORM, b: 2, c: 2, render: snorm8_renderable},
  'rg8uint': {gl: GL.RG8UI, b: 2, c: 2, rb: true},
  'rg8sint': {gl: GL.RG8I, b: 2, c: 2, rb: true},

  'r16uint': {gl: GL.R16UI, b: 2, c: 1, rb: true},
  'r16sint': {gl: GL.R16I, b: 2, c: 1, rb: true},
  'r16float': {gl: GL.R16F, b: 2, c: 1, render: float16_renderable, filter: 'float16-filterable-webgl', rb: true},
  'r16unorm-webgl': {gl: GL.R16_EXT, b:2, c:1, f: norm16_renderable, rb: true},
  'r16snorm-webgl': {gl: GL.R16_SNORM_EXT, b:2, c:1, f: snorm16_renderable},

  // Packed 16-bit formats
  'rgba4unorm-webgl': {gl: GL.RGBA4, b: 2, c: 4, wgpu: false, rb: true},
  'rgb565unorm-webgl': {gl: GL.RGB565, b: 2, c: 4, wgpu: false, rb: true},
  'rgb5a1unorm-webgl': {gl: GL.RGB5_A1, b: 2, c: 4, wgpu: false, rb: true},

  // 24-bit formats
  'rgb8unorm-webgl': {gl: GL.RGB8, b: 3, c: 3, wgpu: false},
  'rgb8snorm-webgl': {gl: GL.RGB8_SNORM, b: 3, c: 3, wgpu: false},

  // 32-bit formats  
  'rgba8unorm': {gl: GL.RGBA8, b: 4, c: 2, bpp: 4},
  'rgba8unorm-srgb': {gl: GL.SRGB8_ALPHA8, b: 4, c: 4, bpp: 4},
  'rgba8snorm': {gl: GL.RGBA8_SNORM, b: 4, c: 4, render: snorm8_renderable},
  'rgba8uint': {gl: GL.RGBA8UI, b: 4, c: 4, bpp: 4},
  'rgba8sint': {gl: GL.RGBA8I, b: 4, c: 4, bpp: 4},
  // reverse colors, webgpu only
  'bgra8unorm': {b: 4, c: 4},
  'bgra8unorm-srgb': {b: 4, c: 4},

  'rg16uint': {gl: GL.RG16UI, b: 4, c: 1, bpp: 4},
  'rg16sint': {gl: GL.RG16I, b: 4, c: 2, bpp: 4},
  // When using a WebGL 2 context and the EXT_color_buffer_float WebGL2 extension
  'rg16float': {gl: GL.RG16F, bpp: 4, b: 4, c: 2, render: float16_renderable, filter: float16_filterable, rb: true},
  'rg16unorm-webgl': {gl: GL.RG16_EXT, b:2, c:2, render: norm16_renderable},
  'rg16snorm-webgl': {gl: GL.RG16_SNORM_EXT, b:2, c:2, render: snorm16_renderable},

  'r32uint': {gl: GL.R32UI, b: 4, c: 1, bpp: 4, rb: true},
  'r32sint': {gl: GL.R32I, b: 4, c: 1, bpp: 4, rb: true},
  'r32float': {gl: GL.R32F, bpp: 4, b: 4, c: 1, render: float32_renderable, filter: float32_filterable},

  // Packed 32-bit formats
  'rgb9e5ufloat': {gl: GL.RGB9_E5, b: 4, c: 3, p: 1, render: rgb9e5ufloat_renderable}, // , filter: true},
  'rg11b10ufloat': {gl: GL.R11F_G11F_B10F, b: 4, c: 3, p: 1,render: float32_renderable, rb: true},
  'rgb10a2unorm': {gl: GL.RGB10_A2, b: 4, c: 4, p: 1, rb: true},
  'rgb10a2uint-webgl': {b: 4, c: 4, gl: GL.RGB10_A2UI, p: 1, wgpu: false, bpp: 4, rb: true},

  // 48-bit formats
  'rgb16unorm-webgl': {gl: GL.RGB16_EXT, b:2, c:3, f: norm16_renderable}, // rgb not renderable
  'rgb16snorm-webgl': {gl: GL.RGB16_SNORM_EXT, b:2, c:3, f: norm16_renderable}, // rgb not renderable

  // 64-bit formats
  'rg32uint': {gl: GL.RG32UI, b: 8, c: 2, rb: true},
  'rg32sint': {gl: GL.RG32I, b: 8, c: 2, rb: true},
  'rg32float': {gl: GL.RG32F, b: 8, c: 2, render: float32_renderable, filter: float32_filterable, rb: true},
  'rgba16uint': {gl: GL.RGBA16UI, b: 8, c: 4, rb: true},
  'rgba16sint': {gl: GL.RGBA16I, b: 8, c: 4, rb: true},
  'rgba16float': {gl: GL.RGBA16F, b: 8, c: 4, render: float16_renderable, filter: float16_filterable},
  'rgba16unorm-webgl': {gl: GL.RGBA16_EXT, b:2, c:4, render: norm16_renderable, rb: true},
  'rgba16snorm-webgl': {gl: GL.RGBA16_SNORM_EXT, b:2, c:4, render: snorm16_renderable},

  // 96-bit formats (deprecated!)
  'rgb32float-webgl': {gl: GL.RGB32F, render: float32_renderable, filter: float32_filterable,
    gl2ext: EXT_color_buffer_float, dataFormat: GL.RGB, types: [GL.FLOAT]},
  
  // 128-bit formats
  'rgba32uint': {gl: GL.RGBA32UI, b: 16, c: 4, rb: true},
  'rgba32sint': {gl: GL.RGBA32I, b: 16, c: 4, rb: true},
  'rgba32float': {gl: GL.RGBA32F, b: 16, c: 4, render: float32_renderable, filter: float32_filterable, rb: true},

  // Depth and stencil formats
  'stencil8': {gl: GL.STENCIL_INDEX8, b: 1, c: 1, attachment: GL.STENCIL_ATTACHMENT, rb: true}, // 8 stencil bits

  'depth16unorm': {gl: GL.DEPTH_COMPONENT16, b: 2, c: 1, attachment: GL.DEPTH_ATTACHMENT, 
    dataFormat: GL.DEPTH_COMPONENT, types: [GL.UNSIGNED_SHORT], rb: true}, // 16 depth bits
  'depth24plus': {gl: GL.DEPTH_COMPONENT24, b: 3, c: 1, attachment: GL.DEPTH_ATTACHMENT,
    dataFormat: GL.DEPTH_COMPONENT, types: [GL.UNSIGNED_INT]},
  'depth32float': {gl: GL.DEPTH_COMPONENT32F, b: 4, c: 1, attachment: GL.DEPTH_ATTACHMENT, 
    dataFormat: GL.DEPTH_COMPONENT, types: [GL.FLOAT], rb: true},

  // The depth component of the "depth24plus" and "depth24plus-stencil8" formats may be implemented as either a 24-bit depth value or a "depth32float" value.
  'depth24plus-stencil8': {gl: GL.DEPTH24_STENCIL8, b: 4, c: 2, p: 1, attachment: GL.DEPTH_STENCIL_ATTACHMENT, rb: true, depthTexture: true,
    dataFormat: GL.DEPTH_STENCIL, types: [GL.UNSIGNED_INT_24_8]},
  // "depth24unorm-stencil8" feature
  'depth24unorm-stencil8': {gl: GL.DEPTH24_STENCIL8, b: 4, c: 2, p: 1, attachment: GL.DEPTH_STENCIL_ATTACHMENT, 
    dataFormat: GL.DEPTH_STENCIL, types: [GL.UNSIGNED_INT_24_8], rb: true},
  // "depth32float-stencil8" feature - TODO below is render buffer only?
  'depth32float-stencil8': {gl: GL.DEPTH32F_STENCIL8, b: 5, c: 2, p: 1, attachment: GL.DEPTH_STENCIL_ATTACHMENT, 
    dataFormat: GL.DEPTH_STENCIL, types: [GL.FLOAT_32_UNSIGNED_INT_24_8_REV], rb: true},

  // BC compressed formats: check device.features.has("texture-compression-bc");

  'bc1-rgb-unorm-webgl': {gl: GL.COMPRESSED_RGB_S3TC_DXT1_EXT, x: X_S3TC, f: texture_compression_bc},
  'bc1-rgb-unorm-srgb-webgl': {gl: GL.COMPRESSED_SRGB_S3TC_DXT1_EXT, x: X_S3TC_SRGB, f: texture_compression_bc},

  'bc1-rgba-unorm': {gl: GL.COMPRESSED_RGBA_S3TC_DXT1_EXT, x: X_S3TC, f: texture_compression_bc},
  'bc1-rgba-unorm-srgb': {gl: GL.COMPRESSED_SRGB_S3TC_DXT1_EXT, x: X_S3TC_SRGB, f: texture_compression_bc},
  'bc2-rgba-unorm': {gl: GL.COMPRESSED_RGBA_S3TC_DXT3_EXT, x: X_S3TC, f: texture_compression_bc},
  'bc2-rgba-unorm-srgb': {gl: GL.COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT, x: X_S3TC_SRGB, f: texture_compression_bc},
  'bc3-rgba-unorm': {gl: GL.COMPRESSED_RGBA_S3TC_DXT5_EXT, x: X_S3TC, f: texture_compression_bc},
  'bc3-rgba-unorm-srgb': {gl: GL.COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT, x: X_S3TC_SRGB, f: texture_compression_bc},
  'bc4-r-unorm': {gl: GL.COMPRESSED_RED_RGTC1_EXT, x: X_RGTC, f: texture_compression_bc},
  'bc4-r-snorm': {gl: GL.COMPRESSED_SIGNED_RED_RGTC1_EXT, x: X_RGTC, f: texture_compression_bc},
  'bc5-rg-unorm': {gl: GL.COMPRESSED_RED_GREEN_RGTC2_EXT, x: X_RGTC, f: texture_compression_bc},
  'bc5-rg-snorm': {gl: GL.COMPRESSED_SIGNED_RED_GREEN_RGTC2_EXT, x: X_RGTC, f: texture_compression_bc},
  'bc6h-rgb-ufloat': {gl: GL.COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_EXT, x: X_BPTC, f: texture_compression_bc},
  'bc6h-rgb-float': {gl: GL.COMPRESSED_RGB_BPTC_SIGNED_FLOAT_EXT, x: X_BPTC, f: texture_compression_bc},
  'bc7-rgba-unorm': {gl: GL.COMPRESSED_RGBA_BPTC_UNORM_EXT, x: X_BPTC, f: texture_compression_bc},
  'bc7-rgba-unorm-srgb': {gl: GL.COMPRESSED_SRGB_ALPHA_BPTC_UNORM_EXT, x: X_BPTC, f: texture_compression_bc},

  // WEBGL_compressed_texture_etc: device.features.has("texture-compression-etc2")
  // Note: Supposedly guaranteed availability compressed formats in WebGL2, but through CPU decompression

  'etc2-rgb8unorm': {gl: GL.COMPRESSED_RGB8_ETC2, f: texture_compression_etc2},
  'etc2-rgb8unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ETC2, f: texture_compression_etc2},
  'etc2-rgb8a1unorm': {gl: GL.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2, f: texture_compression_etc2},
  'etc2-rgb8a1unorm-srgb': {gl: GL.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2, f: texture_compression_etc2},
  'etc2-rgba8unorm': {gl: GL.COMPRESSED_RGBA8_ETC2_EAC, f: texture_compression_etc2},
  'etc2-rgba8unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC, f: texture_compression_etc2},

  'eac-r11unorm': {gl: GL.COMPRESSED_R11_EAC, f: texture_compression_etc2},
  'eac-r11snorm': {gl: GL.COMPRESSED_SIGNED_R11_EAC, f: texture_compression_etc2},
  'eac-rg11unorm': {gl: GL.COMPRESSED_RG11_EAC, f: texture_compression_etc2},
  'eac-rg11snorm': {gl: GL.COMPRESSED_SIGNED_RG11_EAC, f: texture_compression_etc2},

  // X_ASTC compressed formats: device.features.has("texture-compression-astc")

  'astc-4x4-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_4x4_KHR, f: texture_compression_astc},
  'astc-4x4-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR, f: texture_compression_astc},
  'astc-5x4-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_5x4_KHR, f: texture_compression_astc},
  'astc-5x4-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR, f: texture_compression_astc},
  'astc-5x5-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_5x5_KHR, f: texture_compression_astc},
  'astc-5x5-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR, f: texture_compression_astc},
  'astc-6x5-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_6x5_KHR, f: texture_compression_astc},
  'astc-6x5-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR, f: texture_compression_astc},
  'astc-6x6-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_6x6_KHR, f: texture_compression_astc},
  'astc-6x6-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR, f: texture_compression_astc},
  'astc-8x5-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_8x5_KHR, f: texture_compression_astc},
  'astc-8x5-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR, f: texture_compression_astc},
  'astc-8x6-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_8x6_KHR, f: texture_compression_astc},
  'astc-8x6-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR, f: texture_compression_astc},
  'astc-8x8-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_8x8_KHR, f: texture_compression_astc},
  'astc-8x8-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR, f: texture_compression_astc},
  'astc-10x5-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_10x10_KHR, f: texture_compression_astc},
  'astc-10x5-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR, f: texture_compression_astc},
  'astc-10x6-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_10x6_KHR, f: texture_compression_astc},
  'astc-10x6-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR, f: texture_compression_astc},
  'astc-10x8-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_10x8_KHR, f: texture_compression_astc},
  'astc-10x8-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR, f: texture_compression_astc},
  'astc-10x10-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_10x10_KHR, f: texture_compression_astc},
  'astc-10x10-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR, f: texture_compression_astc},
  'astc-12x10-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_12x10_KHR, f: texture_compression_astc},
  'astc-12x10-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR, f: texture_compression_astc},
  'astc-12x12-unorm': {gl: GL.COMPRESSED_RGBA_ASTC_12x12_KHR, f: texture_compression_astc},
  'astc-12x12-unorm-srgb': {gl: GL.COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR, f: texture_compression_astc},

  // WEBGL_compressed_texture_pvrtc

  'pvrtc-rgb4unorm-webgl': {gl: GL.COMPRESSED_RGB_PVRTC_4BPPV1_IMG, f: texture_compression_pvrtc_webgl},
  'pvrtc-rgba4unorm-webgl': {gl: GL.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG, f: texture_compression_pvrtc_webgl},
  'pvrtc-rbg2unorm-webgl': {gl: GL.COMPRESSED_RGB_PVRTC_2BPPV1_IMG, f: texture_compression_pvrtc_webgl},
  'pvrtc-rgba2unorm-webgl': {gl: GL.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG, f: texture_compression_pvrtc_webgl},

  // WEBGL_compressed_texture_etc1

  'etc1-rbg-unorm-webgl': {gl: GL.COMPRESSED_RGB_ETC1_WEBGL, f: texture_compression_etc1_webgl},

  // WEBGL_compressed_texture_atc

  'atc-rgb-unorm-webgl': {gl: GL.COMPRESSED_RGB_ATC_WEBGL, f: texture_compression_atc_webgl},
  'atc-rgba-unorm-webgl': {gl: GL.COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL, f: texture_compression_atc_webgl},
  'atc-rgbai-unorm-webgl': {gl: GL.COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL, f: texture_compression_atc_webgl}
};

/** Legal combinations for internalFormat, format and type *
// [GL.DEPTH_COMPONENT]: {types: [GL.UNSIGNED_SHORT, GL.UNSIGNED_INT, GL.UNSIGNED_INT_24_8]},
// [GL.DEPTH_STENCIL]: ,
// Sized texture format
// R
[GL.R8]: {dataFormat: GL.RED, types: [GL.UNSIGNED_BYTE], gl2: true},
[GL.R16F]: {dataFormat: GL.RED, types: [GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.R8UI]: {dataFormat: GL.RED_INTEGER, types: [GL.UNSIGNED_BYTE], gl2: true},
// // RG
[GL.RG8]: {dataFormat: GL.RG, types: [GL.UNSIGNED_BYTE], gl2: true},
[GL.RG16F]: {dataFormat: GL.RG, types: [GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.RG8UI]: {dataFormat: GL.RG_INTEGER, types: [GL.UNSIGNED_BYTE], gl2: true},
// // RGB
[GL.RGB8]: {dataFormat: GL.RGB, types: [GL.UNSIGNED_BYTE], gl2: true},
[GL.SRGB8]: {dataFormat: GL.RGB, types: [GL.UNSIGNED_BYTE], gl2: true},
[GL.RGB16F]: {dataFormat: GL.RGB, types: [GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.RGB8UI]: {dataFormat: GL.RGB_INTEGER, types: [GL.UNSIGNED_BYTE], gl2: true},
// // RGBA

[GL.RGB565]: {dataFormat: GL.RGB, types: [GL.UNSIGNED_BYTE, GL.UNSIGNED_SHORT_5_6_5], gl2: true},
[GL.R11F_G11F_B10F]: {dataFormat: GL.RGB, types: [GL.UNSIGNED_INT_10F_11F_11F_REV, GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.RGB9_E5]: {dataFormat: GL.RGB, types: [GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.RGBA8]: {dataFormat: GL.RGBA, types: [GL.UNSIGNED_BYTE], gl2: true},
[GL.SRGB8_ALPHA8]: {dataFormat: GL.RGBA, types: [GL.UNSIGNED_BYTE], gl2: true, gl1ext: EXT_SRGB},
[GL.RGB5_A1]: {dataFormat: GL.RGBA, types: [GL.UNSIGNED_BYTE, GL.UNSIGNED_SHORT_5_5_5_1], gl2: true},
[GL.RGBA4]: {dataFormat: GL.RGBA, types: [GL.UNSIGNED_BYTE, GL.UNSIGNED_SHORT_4_4_4_4], gl2: true},
[GL.RGBA16F]: {dataFormat: GL.RGBA, types: [GL.HALF_FLOAT, GL.FLOAT], gl2: true},
[GL.RGBA8UI]: {dataFormat: GL.RGBA_INTEGER, types: [GL.UNSIGNED_BYTE], gl2: true}
*/

/* This table is now baked into the above table
type RenderbufferFormat = {
  bpp: number;
  gl2?: boolean;
  ext?: string;
};

export const RENDERBUFFER_FORMATS: Record<string, RenderbufferFormat> = {
  [GL.DEPTH_COMPONENT16]: {bpp: 2}, // 16 depth bits.
  // TODO - Not clear which webgpu value to map this to.
  // [GL.DEPTH_COMPONENT24]: {gl2: true, bpp: 3},
  [GL.DEPTH_COMPONENT32F]: {gl2: true, bpp: 4},

  [GL.STENCIL_INDEX8]: {bpp: 1}, // 8 stencil bits.

  [GL.DEPTH_STENCIL]: {bpp: 4},
  [GL.DEPTH24_STENCIL8]: {gl2: true, bpp: 4},
  [GL.DEPTH32F_STENCIL8]: {gl2: true, bpp: 5},

  // When using a WebGL 1 context, color renderbuffer formats are limited
  [GL.RGBA4]: {gl2: true, bpp: 2},
  [GL.RGB565]: {gl2: true, bpp: 2},
  [GL.RGB5_A1]: {gl2: true, bpp: 2},

  // When using a WebGL 2 context, the following values are available additionally:
  [GL.R8]: {gl2: true, bpp: 1},
  [GL.R8UI]: {gl2: true, bpp: 1},
  [GL.R8I]: {gl2: true, bpp: 1},
  [GL.R16UI]: {gl2: true, bpp: 2},
  [GL.R16I]: {gl2: true, bpp: 2},
  [GL.R32UI]: {gl2: true, bpp: 4},
  [GL.R32I]: {gl2: true, bpp: 4},
  [GL.RG8]: {gl2: true, bpp: 2},
  [GL.RG8UI]: {gl2: true, bpp: 2},
  [GL.RG8I]: {gl2: true, bpp: 2},
  [GL.RG16UI]: {gl2: true, bpp: 4},
  [GL.RG16I]: {gl2: true, bpp: 4},
  [GL.RG32UI]: {gl2: true, bpp: 8},
  [GL.RG32I]: {gl2: true, bpp: 8},
  [GL.RGB8]: {gl2: true, bpp: 3},
  [GL.RGBA8]: {gl2: true, bpp: 4},
  // [GL.SRGB8_ALPHA8]: {gl2: true, gl1: SRGB}, // When using the EXT_sRGB WebGL1 extension
  [GL.RGB10_A2]: {gl2: true, bpp: 4},
  [GL.RGBA8UI]: {gl2: true, bpp: 4},
  [GL.RGBA8I]: {gl2: true, bpp: 4},
  [GL.RGB10_A2UI]: {gl2: true, bpp: 4},
  [GL.RGBA16UI]: {gl2: true, bpp: 8},
  [GL.RGBA16I]: {gl2: true, bpp: 8},
  [GL.RGBA32I]: {gl2: true, bpp: 16},
  [GL.RGBA32UI]: {gl2: true, bpp: 16},

  // When using a WebGL 2 context and the EXT_color_buffer_float WebGL2 extension
  [GL.R16F]: {ext: EXT_FLOAT_WEBGL2, bpp: 2},
  [GL.RG16F]: {ext: EXT_FLOAT_WEBGL2, bpp: 4},
  [GL.RGBA16F]: {ext: EXT_FLOAT_WEBGL2, bpp: 8},
  [GL.R32F]: {ext: EXT_FLOAT_WEBGL2, bpp: 4},
  [GL.RG32F]: {ext: EXT_FLOAT_WEBGL2, bpp: 8},
  // TODO - can't get WEBGL_color_buffer_float to work on renderbuffers
  [GL.RGBA32F]: {ext: EXT_FLOAT_WEBGL2, bpp: 16},
  // [GL.RGBA32F]: {ext: EXT_FLOAT_WEBGL2},
  [GL.R11F_G11F_B10F]: {ext: EXT_FLOAT_WEBGL2, bpp: 4}
};
*/

/** @deprecated should be removed */
const DATA_FORMAT_CHANNELS = {
  [GL.RED]: 1,
  [GL.RED_INTEGER]: 1,
  [GL.RG]: 2,
  [GL.RG_INTEGER]: 2,
  [GL.RGB]: 3,
  [GL.RGB_INTEGER]: 3,
  [GL.RGBA]: 4,
  [GL.RGBA_INTEGER]: 4,
  [GL.DEPTH_COMPONENT]: 1,
  [GL.DEPTH_STENCIL]: 1,
  [GL.ALPHA]: 1,
  [GL.LUMINANCE]: 1,
  [GL.LUMINANCE_ALPHA]: 2
};

/** @deprecated should be removed */
const TYPE_SIZES = {
  [GL.FLOAT]: 4,
  [GL.UNSIGNED_INT]: 4,
  [GL.INT]: 4,
  [GL.UNSIGNED_SHORT]: 2,
  [GL.SHORT]: 2,
  [GL.HALF_FLOAT]: 2,
  [GL.BYTE]: 1,
  [GL.UNSIGNED_BYTE]: 1
};

// FUNCTIONS

/** Checks if a texture format is supported */
export function isTextureFormatSupported(
  gl: WebGL2RenderingContext,
  format: TextureFormat,
  extensions: GLExtensions
): boolean {
  const info = TEXTURE_FORMATS[format];
  if (!info) {
    return false;
  }
  // Check that we have a GL constant
  if (info.gl === undefined) {
    return false;
  }
  // Check extensions
  const extension = info.x || info.gl2ext;
  if (extension) {
    return Boolean(getWebGLExtension(gl, extension, extensions));
  }
  return true;
}

export function isRenderbufferFormatSupported(
  gl: WebGL2RenderingContext,
  format: TextureFormat,
  extensions: GLExtensions
): boolean {
  // Note: Order is important since the function call initializes extensions.
  return isTextureFormatSupported(gl, format, extensions) && TEXTURE_FORMATS[format]?.rb;
}

/**
 * Map WebGL texture formats (GL constants) to WebGPU-style TextureFormat strings
 */
export function convertGLToTextureFormat(format: GL | TextureFormat): TextureFormat {
  if (typeof format === 'string') {
    return format;
  }
  const entry = Object.entries(TEXTURE_FORMATS).find(([, entry]) => entry.gl === format);
  if (!entry) {
    throw new Error(`Unknown texture format ${format}`);
  }
  return entry[0] as TextureFormat;
}

/**
 * Map WebGPU style texture format strings to GL constants
 */
export function convertTextureFormatToGL(format: TextureFormat): GL | undefined {
  const formatInfo = TEXTURE_FORMATS[format];
  const webglFormat = formatInfo?.gl;
  if (webglFormat === undefined) {
    throw new Error(`Unsupported texture format ${format}`);
  }
  return webglFormat;
}

/** Checks if a texture format is supported */
export function getTextureFormatSupport(
  gl: WebGL2RenderingContext,
  format: TextureFormat,
  extensions: GLExtensions
): {
  supported: boolean;
  filterable?: boolean;
  renderable?: boolean;
  blendable?: boolean;
  storable?: boolean;
} {
  const info = TEXTURE_FORMATS[format];
  if (!info) {
    return {supported: false};
  }
  // let decoded;
  // try {
  //   decoded = decodeTextureFormat(format);
  // } catch {}

  // Support Check that we have a GL constant
  let supported = info.gl === undefined;
  supported = supported && checkTextureFeature(gl, info.f, extensions);

  // Filtering
  // const filterable = info.filter
  //   ? checkTextureFeature(gl, infofilter])
  //   : decoded && !decoded.signed;
  // const renderable = info.filter
  //   ? checkTextureFeature(gl, inforender])
  //   : decoded && !decoded.signed;

  return {
    supported,
    renderable: supported && checkTextureFeature(gl, info.render, extensions),
    filterable: supported && checkTextureFeature(gl, info.filter, extensions),
    blendable: false, // tod,
    storable: false
  };
}

/** Checks whether linear filtering (interpolated sampling) is available for floating point textures */
export function isTextureFormatFilterable(
  gl: WebGL2RenderingContext,
  format: TextureFormat,
  extensions: GLExtensions
): boolean {
  if (!isTextureFormatSupported(gl, format, extensions)) {
    return false;
  }
  if (format.startsWith('depth') || format.startsWith('stencil')) {
    return false;
  }
  try {
    const decoded = decodeTextureFormat(format);
    if (decoded.signed) {
      return false;
    }
  } catch {
    return false;
  }
  if (format.endsWith('32float')) {
    return Boolean(getWebGLExtension(gl, 'OES_texture_float_linear, extensions', extensions));
  }
  if (format.endsWith('16float')) {
    return Boolean(getWebGLExtension(gl, 'OES_texture_half_float_linear, extensions', extensions));
  }
  return true;
}

export function isTextureFormatRenderable(
  gl: WebGL2RenderingContext,
  format: TextureFormat,
  extensions: GLExtensions
): boolean {
  if (!isTextureFormatSupported(gl, format, extensions)) {
    return false;
  }
  if (typeof format === 'number') {
    return false; // isTextureFormatFilterableWebGL(gl, format);
  }
  // TODO depends on device...
  return true;
}

/** Get parameters necessary to work with format in WebGL: internalFormat, dataFormat, type, compressed, */
export function getWebGLTextureParameters(format: TextureFormat) {
  const formatData = TEXTURE_FORMATS[format];
  const webglFormat = convertTextureFormatToGL(format);
  const decoded = decodeTextureFormat(format);
  return {
    format: webglFormat,
    dataFormat:
      formatData?.dataFormat ||
      getWebGLPixelDataFormat(decoded.format, decoded.integer, decoded.normalized, webglFormat),
    // depth formats don't have a type
    type: decoded.dataType
      ? getGLFromVertexType(decoded.dataType)
      : formatData?.types?.[0] || GL.UNSIGNED_BYTE,
    // @ts-expect-error
    compressed: decoded.compressed
  };
}

export function getDepthStencilAttachmentWebGL(
  format: TextureFormat
): GL.DEPTH_ATTACHMENT | GL.STENCIL_ATTACHMENT | GL.DEPTH_STENCIL_ATTACHMENT {
  const info = TEXTURE_FORMATS[format];
  if (!info?.attachment) {
    throw new Error(`${format} is not a depth stencil format`);
  }
  return info.attachment;
}

/** TODO - VERY roundabout legacy way of calculating bytes per pixel */
export function getTextureFormatBytesPerPixel(format: TextureFormat): number {
  // TODO remove webgl1 support
  const params = getWebGLTextureParameters(format);
  // NOTE(Tarek): Default to RGBA bytes
  const channels = DATA_FORMAT_CHANNELS[params.dataFormat] || 4;
  const channelSize = TYPE_SIZES[params.type] || 1;
  return channels * channelSize;
}

// DATA TYPE HELPERS

function getWebGLPixelDataFormat(
  dataFormat: string,
  integer: boolean,
  normalized: boolean,
  format: GL
): GL {
  // WebGL1 formats use same internalFormat
  if (format === GL.RGBA || format === GL.RGB) {
    return format;
  }
  // prettier-ignore
  switch (dataFormat) {
    case 'r': return integer && !normalized ? GL.RED_INTEGER : GL.RED;
    case 'rg': return integer && !normalized ? GL.RG_INTEGER : GL.RG;
    case 'rgb': return integer && !normalized ? GL.RGB_INTEGER : GL.RGB;
    case 'rgba': return integer && !normalized ? GL.RGBA_INTEGER : GL.RGBA;
    default: return GL.RGBA;
  }
}