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

import {ShaderModule} from '../../lib/shader-module/shader-module';

export type FloatColorsProps = {
  /**
   * When true, semantic colors are interpreted as 0-255 byte-style values and normalized in shader code.
   * When false, semantic colors are interpreted directly as floats.
   */
  useByteColors?: boolean;
};

export type FloatColorsUniforms = {
  /** Controls whether shader helpers normalize semantic colors from byte space. */
  useByteColors: boolean;
};

const GLSL_UNIFORMS = /* glsl */ `\
layout(std140) uniform floatColorsUniforms {
  float useByteColors;
} floatColors;

vec3 floatColors_normalize(vec3 inputColor) {
  return floatColors.useByteColors > 0.5 ? inputColor / 255.0 : inputColor;
}

vec4 floatColors_normalize(vec4 inputColor) {
  return floatColors.useByteColors > 0.5 ? inputColor / 255.0 : inputColor;
}

vec4 floatColors_premultiplyAlpha(vec4 inputColor) {
  return vec4(inputColor.rgb * inputColor.a, inputColor.a);
}

vec4 floatColors_unpremultiplyAlpha(vec4 inputColor) {
  return inputColor.a > 0.0 ? vec4(inputColor.rgb / inputColor.a, inputColor.a) : vec4(0.0);
}

vec4 floatColors_premultiply_alpha(vec4 inputColor) {
  return floatColors_premultiplyAlpha(inputColor);
}

vec4 floatColors_unpremultiply_alpha(vec4 inputColor) {
  return floatColors_unpremultiplyAlpha(inputColor);
}
`;

const WGSL_UNIFORMS = /* wgsl */ `\
struct floatColorsUniforms {
  useByteColors: f32
};

@group(0) @binding(auto) var<uniform> floatColors : floatColorsUniforms;

fn floatColors_normalize(inputColor: vec3<f32>) -> vec3<f32> {
  return select(inputColor, inputColor / 255.0, floatColors.useByteColors > 0.5);
}

fn floatColors_normalize4(inputColor: vec4<f32>) -> vec4<f32> {
  return select(inputColor, inputColor / 255.0, floatColors.useByteColors > 0.5);
}

fn floatColors_premultiplyAlpha(inputColor: vec4<f32>) -> vec4<f32> {
  return vec4<f32>(inputColor.rgb * inputColor.a, inputColor.a);
}

fn floatColors_unpremultiplyAlpha(inputColor: vec4<f32>) -> vec4<f32> {
  return select(
    vec4<f32>(0.0),
    vec4<f32>(inputColor.rgb / inputColor.a, inputColor.a),
    inputColor.a > 0.0
  );
}

fn floatColors_premultiply_alpha(inputColor: vec4<f32>) -> vec4<f32> {
  return floatColors_premultiplyAlpha(inputColor);
}

fn floatColors_unpremultiply_alpha(inputColor: vec4<f32>) -> vec4<f32> {
  return floatColors_unpremultiplyAlpha(inputColor);
}
`;

export const floatColors = {
  name: 'floatColors',
  props: {} as FloatColorsProps,
  uniforms: {} as FloatColorsUniforms,
  vs: GLSL_UNIFORMS,
  fs: GLSL_UNIFORMS,
  source: WGSL_UNIFORMS,
  uniformTypes: {
    useByteColors: 'f32'
  },
  defaultUniforms: {
    useByteColors: true
  }
} as const satisfies ShaderModule<FloatColorsProps, FloatColorsUniforms>;