function ImagePixel(path, w, h, ratio) {
	const canvas = document.createElement("canvas");
	const ctx = canvas.getContext("2d");
	const width = w;
	const height = h;
	canvas.width = width;
	canvas.height = height;

	ctx.drawImage(path, 0, 0);
	const data = ctx.getImageData(0, 0, width, height).data;
	const position = [];
	const color = [];
	const alpha = [];

	for (let y = 0; y < height; y += ratio) {
		for (let x = 0; x < width; x += ratio) {
			const index = (y * width + x) * 4;
			const r = data[index] / 255;
			const g = data[index + 1] / 255;
			const b = data[index + 2] / 255;
			const a = data[index + 3] / 255;

			const pX = x - width / 2;
			const pY = -(y - height / 2);
			const pZ = 0;

			position.push(pX, pY, pZ), color.push(r, g, b), alpha.push(a);
		}
	}

	return { position, color, alpha };
}

class Stage {
	constructor() {
		this.renderParam = {
			clearColor: 0x000000,
			width: window.innerWidth,
			height: window.innerHeight
		};
		this.cameraParam = {
			fov: 45,
			near: 0.1,
			far: 2000,
			lookAt: new THREE.Vector3(0, 0, 0),
			x: 0,
			y: 0,
			z: 1000
		};

		this.scene = null;
		this.camera = null;
		this.renderer = null;
		this.isInitialized = false;
		this.orbitcontrols = null;
		this.isDev = false;
	}

	init() {
		this._setScene();
		this._setRender();
		this._setCamera();
		this._setDev();
	}

	_setScene() {
		this.scene = new THREE.Scene();
	}

	_setRender() {
		this.renderer = new THREE.WebGLRenderer();
		this.renderer.setPixelRatio(window.devicePixelRatio);
		this.renderer.setClearColor(new THREE.Color(this.renderParam.clearColor));
		this.renderer.setSize(this.renderParam.width, this.renderParam.height);
		const wrapper = document.querySelector("#webgl");
		wrapper.appendChild(this.renderer.domElement);
	}

	_setCamera() {
		if (!this.isInitialized) {
			this.camera = new THREE.PerspectiveCamera(
				0,
				0,
				this.cameraParam.near,
				this.cameraParam.far
			);

			this.camera.position.set(
				this.cameraParam.x,
				this.cameraParam.y,
				this.cameraParam.z
			);
			this.camera.lookAt(this.cameraParam.lookAt);

			this.isInitialized = true;
		}

		const windowWidth = window.innerWidth;
		const windowHeight = window.innerHeight;
		this.camera.aspect = windowWidth / windowHeight;
		this.camera.fov = this.cameraParam.fov;

		this.camera.updateProjectionMatrix();
		this.renderer.setSize(windowWidth, windowHeight);
	}

	_setDev() {
		this.orbitcontrols = new THREE.OrbitControls(
			this.camera,
			this.renderer.domElement
		);
		this.orbitcontrols.enableDamping = true;
		this.isDev = true;
	}

	_render() {
		this.renderer.render(this.scene, this.camera);
		if (this.isDev) this.orbitcontrols.update();
	}

	onResize() {
		this._setCamera();
	}

	onRaf() {
		this._render();
	}
}

class Particle {
	constructor(stage) {
		this.stage = stage;
		this.promiseList = [];
		this.pathList = [
			"https://hisamikurita.github.io/codepen-sample-images/dist/assets/images/logo.png"
		];
		this.imageList = [];
	}

	init() {
		this.pathList.forEach((image) => {
			this.promiseList.push(
				new Promise((resolve) => {
					const img = new Image();
					img.src = image;
					img.crossOrigin = "anonymous";

					img.addEventListener("load", () => {
						this.imageList.push(ImagePixel(img, img.width, img.height, 10.0));
						resolve();
					});
				})
			);
		});
		Promise.all(this.promiseList).then(() => {
			this._setMesh();
			this._setAutoPlay();
		});
	}

	_setMesh() {
		const geometry = new THREE.BufferGeometry();
		const position = new THREE.BufferAttribute(
			new Float32Array(this.imageList[0].position),
			3
		);
		const color = new THREE.BufferAttribute(
			new Float32Array(this.imageList[0].color),
			3
		);
		const alpha = new THREE.BufferAttribute(
			new Float32Array(this.imageList[0].alpha),
			1
		);
		const rand = [];
    const vertces = this.imageList[0].position.length / 3;
    for (let i = 0; i < vertces; i++) {
      rand.push((Math.random() - 1.0) * 2.0, (Math.random() - 1.0) * 2.0);
    }
    const rands = new THREE.BufferAttribute(new Float32Array(rand), 2);
		geometry.setAttribute("position", position);
		geometry.setAttribute("color", color);
		geometry.setAttribute("alpha", alpha);
    geometry.setAttribute('rand', rands);

		const material = new THREE.RawShaderMaterial({
			vertexShader: document.querySelector("#js-vertex-shader").textContent,
			fragmentShader: document.querySelector("#js-fragment-shader").textContent,
			uniforms: {
				u_ratio: { type: "f", value: 0.0 },
				        u_time: { type: 'f', value: 0.0 },
			},
			transparent: true
		});
		this.mesh = new THREE.Points(geometry, material);
		this.stage.scene.add(this.mesh);
	}

	_setDiffusion() {
		gsap.to(this.mesh.material.uniforms.u_ratio, {
			value: 1.0,
			duration: 1.8,
			ease: "power1.inOut",
			repeat: 1,
			yoyo: true
		});
	}

	_setAutoPlay() {
		this._setDiffusion();

		gsap.to(
			{},
			{
				ease: "none",
				duration: 4.2,
				repeat: -1.0,
				onRepeat: () => {
					this._setDiffusion();
				}
			}
		);
	}

	_render() {
    if(this.mesh) this.mesh.material.uniforms.u_time.value += 0.02;
	}

	onResize() {
		//
	}

	onRaf() {
		this._render();
	}
}

class Webgl {
	constructor() {
		const stage = new Stage();
		stage.init();

		const particle = new Particle(stage);
		particle.init();

		window.addEventListener("resize", () => {
			stage.onResize();
			particle.onResize();
		});

		const _raf = () => {
			window.requestAnimationFrame(() => {
				_raf();

				stage.onRaf();
				particle.onRaf();
			});
		};
		_raf();
	}
}

new Webgl();