/*
 * Copyright 2023 Comcast Cable Communications Management, LLC
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

import { valuesAreEqual } from '../../lib/utils.js';
import {
  BorderTemplate,
  type BorderProps,
} from '../templates/BorderTemplate.js';
import type { Vec4 } from '../../renderers/webgl/internal/ShaderUtils.js';
import type { WebGlShaderType } from '../../renderers/webgl/WebGlShaderNode.js';

export const Border: WebGlShaderType<BorderProps> = {
  props: BorderTemplate.props,
  update(node) {
    this.uniform4fa('u_borderWidth', this.props!.width as Vec4);
    this.uniformRGBA('u_borderColor', this.props!.color);
  },
  vertex: `
    # ifdef GL_FRAGMENT_PRECISION_HIGH
    precision highp float;
    # else
    precision mediump float;
    # endif

    attribute vec2 a_position;
    attribute vec2 a_textureCoords;
    attribute vec4 a_color;
    attribute vec2 a_nodeCoords;

    uniform vec2 u_resolution;
    uniform float u_pixelRatio;
    uniform vec2 u_dimensions;

    uniform vec4 u_radius;
    uniform vec4 u_borderWidth;

    varying vec4 v_color;
    varying vec2 v_textureCoords;
    varying vec2 v_nodeCoords;

    varying vec2 v_innerSize;
    varying vec2 v_halfDimensions;

    void main() {
      vec2 normalized = a_position * u_pixelRatio;
      vec2 screenSpace = vec2(2.0 / u_resolution.x, -2.0 / u_resolution.y);

      v_color = a_color;
      v_nodeCoords = a_nodeCoords;
      v_textureCoords = a_textureCoords;

      v_halfDimensions = u_dimensions * 0.5;
      v_innerSize = vec2(u_dimensions.x - (u_borderWidth[3] + u_borderWidth[1]), u_dimensions.y - (u_borderWidth[0] + u_borderWidth[2])) * 0.5 - 0.5;

      gl_Position = vec4(normalized.x * screenSpace.x - 1.0, normalized.y * -abs(screenSpace.y) + 1.0, 0.0, 1.0);
      gl_Position.y = -sign(screenSpace.y) * gl_Position.y;
    }
  `,
  fragment: `
    # ifdef GL_FRAGMENT_PRECISION_HIGH
    precision highp float;
    # else
    precision mediump float;
    # endif

    uniform vec2 u_resolution;
    uniform float u_pixelRatio;
    uniform float u_alpha;

    uniform vec2 u_dimensions;
    uniform sampler2D u_texture;

    uniform vec4 u_borderWidth;
    uniform vec4 u_borderColor;

    varying vec4 v_color;
    varying vec2 v_nodeCoords;
    varying vec2 v_textureCoords;

    varying vec2 v_innerSize;
    varying vec2 v_halfDimensions;

    float box(vec2 p, vec2 s) {
      vec2 q = abs(p) - s;
      return (min(max(q.x, q.y), 0.0) + length(max(q, 0.0)));
    }

    void main() {
      vec4 color = texture2D(u_texture, v_textureCoords) * v_color;
      vec2 boxUv = v_nodeCoords.xy * u_dimensions - v_halfDimensions;

      boxUv.x += u_borderWidth.y > u_borderWidth.w ? (u_borderWidth.y - u_borderWidth.w) * 0.5 : -(u_borderWidth.w - u_borderWidth.y) * 0.5;
      boxUv.y += u_borderWidth.z > u_borderWidth.x ? (u_borderWidth.z - u_borderWidth.x) * 0.5 : -(u_borderWidth.x - u_borderWidth.z) * 0.5;

      float innerDist = box(boxUv, v_innerSize);
      float innerAlpha = 1.0 - smoothstep(0.0, 1.0, innerDist);

      vec4 resColor = mix(u_borderColor, color, innerAlpha);
      gl_FragColor = resColor * u_alpha;
    }
  `,
};