"use strict";

/* global require */

// this would be require('twgl') in a real example
const twgl = require('../../dist/7.x/twgl-full');  /* eslint-disable-line */
const chroma = require('../../3rdparty/chroma.min'); /* eslint-disable-line */
const m4 = twgl.m4;
const primitives = twgl.primitives;

twgl.setDefaults({attribPrefix: "a_"});
const gl = document.querySelector("#c").getContext("webgl");
const programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);

const shapes = [
  primitives.createCubeBufferInfo(gl, 2),
  primitives.createSphereBufferInfo(gl, 1, 24, 12),
  primitives.createPlaneBufferInfo(gl, 2, 2),
  primitives.createTruncatedConeBufferInfo(gl, 1, 0, 2, 24, 1),
];

function rand(min, max) {
  return min + Math.random() * (max - min);
}

// Shared values
const lightWorldPosition = [1, 8, -10];
const lightColor = [1, 1, 1, 1];
const camera = m4.identity();
const view = m4.identity();
const viewProjection = m4.identity();

const tex = twgl.createTexture(gl, {
  min: gl.NEAREST,
  mag: gl.NEAREST,
  src: [
    255, 255, 255, 255,
    192, 192, 192, 255,
    192, 192, 192, 255,
    255, 255, 255, 255,
  ],
});

const objects = [];
const drawObjects = [];
const numObjects = 100;
const baseHue = rand(0, 360);
for (let ii = 0; ii < numObjects; ++ii) {
  const uniforms = {
    u_lightWorldPos: lightWorldPosition,
    u_lightColor: lightColor,
    u_diffuseMult: chroma.hsv((baseHue + rand(0, 60)) % 360, 0.4, 0.8).gl(),
    u_specular: [1, 1, 1, 1],
    u_shininess: 50,
    u_specularFactor: 1,
    u_diffuse: tex,
    u_viewInverse: camera,
    u_world: m4.identity(),
    u_worldInverseTranspose: m4.identity(),
    u_worldViewProjection: m4.identity(),
  };
  drawObjects.push({
    programInfo: programInfo,
    bufferInfo: shapes[ii % shapes.length],
    uniforms: uniforms,
  });
  objects.push({
    translation: [rand(-10, 10), rand(-10, 10), rand(-10, 10)],
    ySpeed: rand(0.1, 0.3),
    zSpeed: rand(0.1, 0.3),
    uniforms: uniforms,
  });
}

function render(time) {
  time *= 0.001;
  twgl.resizeCanvasToDisplaySize(gl.canvas);
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

  gl.enable(gl.DEPTH_TEST);
  gl.enable(gl.CULL_FACE);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  const projection = m4.perspective(30 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.5, 100);
  const eye = [1, 4, -20];
  const target = [0, 0, 0];
  const up = [0, 1, 0];

  m4.lookAt(eye, target, up, camera);
  m4.inverse(camera, view);
  m4.multiply(projection, view, viewProjection);

  objects.forEach(function(obj) {
    const uni = obj.uniforms;
    const world = uni.u_world;
    m4.identity(world);
    m4.rotateY(world, time * obj.ySpeed, world);
    m4.rotateZ(world, time * obj.zSpeed, world);
    m4.translate(world, obj.translation, world);
    m4.rotateX(world, time, world);
    m4.transpose(m4.inverse(world, uni.u_worldInverseTranspose), uni.u_worldInverseTranspose);
    m4.multiply(viewProjection, uni.u_world, uni.u_worldViewProjection);
  });

  twgl.drawObjectList(gl, drawObjects);

  requestAnimationFrame(render);
}
requestAnimationFrame(render);