// ---------------------
// | setup of three.js |
// ---------------------

// shaders for sphere outline
// https://stemkoski.github.io/Three.js/Shader-Glow.html
const vertexShaderGlow = `
uniform vec3 viewVector;
uniform float c;
uniform float p;
varying float intensity;
varying vec3 vColor;

vec3 hsv2rgb(vec3 c) {
	vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
	vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
	return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

void main() 
{
	vec3 vNormal = normalize( normalMatrix * normal );
	vec3 vNormel = normalize( normalMatrix * viewVector );
	intensity = pow( c - dot(vNormal, vNormel), p );

	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
	vColor = hsv2rgb(vec3(fract(gl_Position[2] / 270.0), 0.7, 0.7));
	//vColor = vec3((sin(position[2] / 360.0) + 1.0) * 0.5, (sin(position[2] / 1000.0) + 1.0) * 0.5, (sin(position[2] / 70.0) + 1.0) * 0.5);
	//vColor = vec3(0.5, 0, 0.5);
}
`;

const fragmentShaderGlow = `
varying vec3 vColor;
varying float intensity;
void main() 
{
	vec3 glow = vColor * intensity;
		gl_FragColor = vec4( glow, 1.0 );
}
`;

// shaders for tunnel border
const fragmentShader = `
#include <common>
 
uniform vec3 iResolution;
uniform float iTime;
uniform sampler2D iChannel0;
 
// By Daedelus: https://www.shadertoy.com/user/Daedelus
// license: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
#define TIMESCALE 0.25 
#define TILES 8
#define COLOR 0.7, 1.6, 2.8
 
varying vec2 vUv;
varying float z;
 
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	vec2 uv = fragCoord.xy / iResolution.xy;
	uv.x *= iResolution.x / iResolution.y;
	
	vec4 noise = texture2D(iChannel0, floor(uv * float(TILES)) / float(TILES));
	float p = 1.0 - mod(noise.r + noise.g + noise.b + (iTime + z) * float(TIMESCALE), 1.0);
	p = min(max(p * 3.0 - 1.8, 0.1), 2.0);
	
	vec2 r = mod(uv * float(TILES), 1.0);
	r = vec2(pow(r.x - 0.5, 2.0), pow(r.y - 0.5, 2.0));
	p *= 1.0 - pow(min(1.0, 12.0 * dot(r, r)), 2.0);
	
	fragColor = vec4(COLOR, 1.0) * p;
}
 
void main() {
	mainImage(gl_FragColor, vUv * iResolution.xy);
}
`;
const vertexShader = `
	varying vec2 vUv;
	varying float z;
	void main() {
	vUv = uv;
	z = -position[1];
	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
	}
`;

// size of the tunnel
const tunnelRadius = 100;
// z interval of new obstacles
const spawnInterval = 40;
// coordinate of newest obstacle
let lastSpawned = 0;

// gyroscope variables
var gn;
let headSet = false;
let gammaReference = 0.0;
let leftRightMove = 0.0;
let upDownMove = 0.0;

// current player speed
const initialSpeed = 5.0;
let speed = initialSpeed;
// score points
let score = 0;
// amount of sphere objects removed
let removed = 0;
// player is actively racing
let running = false;
// obstacles
const spheres = [];
// wall segments
const borders = [];
let time = Date.now() / 1000.0;
let averageFps = 60.0;

function logger(text) {
	console.log(text);
}

function init_gn() {
	const args = {
		logger: logger
	};

	gn = new GyroNorm();

	gn.init(args).then(function() {
		const isAvailable = gn.isAvailable();
		if (!isAvailable.deviceOrientationAvailable) {
			console.log({
				message: 'Device orientation is not available.'
			});
		}

		if (!isAvailable.accelerationAvailable) {
			console.log({
				message: 'Device acceleration is not available.'
			});
		}

		if (!isAvailable.accelerationIncludingGravityAvailable) {
			console.log({
				message: 'Device acceleration incl. gravity is not available.'
			});
		}

		if (!isAvailable.rotationRateAvailable) {
			console.log({
				message: 'Device rotation rate is not available.'
			});
		}

		start_gn();
	}).catch(function(e) {
		console.error(e);		
		document.getElementById("start").disabled = false;
	});

	document.addEventListener('keydown', e => {
		if (e.key === "ArrowLeft") {
			leftRightMove = -10.0;
		} else if (e.key === "ArrowRight") {
			leftRightMove = 10.0;
		} else if (e.key === "ArrowDown") {
			upDownMove = -10.0;
		} else if (e.key === "ArrowUp") {
			upDownMove = 10.0;
		}
	});
	document.addEventListener('keyup', e => {
		if (e.key === "ArrowLeft") {
			leftRightMove = 0;
		} else if (e.key === "ArrowRight") {
			leftRightMove = 0;
		} else if (e.key === "ArrowDown") {
			upDownMove = 0;
		} else if (e.key === "ArrowUp") {
			upDownMove = 0;
		}
	});
}

function stop_gn() {
	gn.stop();
}

function start_gn() {
	gn.start(gnCallBack);
}

function gnCallBack(data) {
	if (!headSet) {
		gammaReference = data.do.gamma;
	} else {
		// leftRight = data.do.beta > 0 ? "right" : "left";
		leftRightMove = data.do.beta;
		// upDown = data.do.gamma > gammaReference ? "up" : "down";
		upDownMove = data.do.gamma - gammaReference;
	}
}

function set_head_gn() {
	try {
		gn.setHeadDirection();
	} catch (e) {
		// fails if the sensor is not available
	}
	headSet = true;
}

init_gn();

// setup three.js: materials, geometries, scene, lighting and camera
let scene, renderer;
scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 0.1, 5000);

// obstacle geometry and material
const geometrySphere = new THREE.SphereGeometry(11, 16, 16);
const materialSphere = new THREE.MeshBasicMaterial();
const customMaterial = new THREE.ShaderMaterial({
	uniforms: {
		"c": {
			type: "f",
			value: 0.8
		},
		"p": {
			type: "f",
			value: 2.4
		},
		viewVector: {
			type: "v3",
			value: camera.position
		}
	},
	vertexShader: vertexShaderGlow,
	fragmentShader: fragmentShaderGlow,
	side: THREE.FrontSide,
	blending: THREE.AdditiveBlending,
	transparent: true
});

// wall texture
const loader = new THREE.TextureLoader();
const texture = loader.load('./bayer.png');
texture.minFilter = THREE.NearestFilter;
texture.magFilter = THREE.NearestFilter;
texture.wrapS = THREE.RepeatWrapping;
texture.wrapT = THREE.RepeatWrapping;
const uniforms = {
	iTime: {
		value: 0
	},
	iResolution: {
		value: new THREE.Vector3(1, 1, 1)
	},
	iChannel0: {
		value: texture
	},
};
const material = new THREE.ShaderMaterial({
	vertexShader,
	fragmentShader,
	uniforms,
});
const borderGeometry = new THREE.PlaneGeometry(1, 1);


init();
animate();

document.getElementById("start").onclick = () => {
	set_head_gn();
	try {
		document.body.requestFullscreen();
		window.screen.orientation.lock.call(window.screen.orientation, 'landscape');
	} catch (e) {
		// browser doesn't support this API, try another hack
		window.scrollTo(0,1);
	}
	document.getElementById("start").style.zIndex = -10;
	document.getElementById("start").style.visibility = "hidden";
	// reset variables
	speed = initialSpeed;
	score = 0;
	for (let i = 0; i < spheres.length; i++) {
		scene.remove(spheres[i]);
	}
	spheres.length = 0;
	for (let i = 0; i < borders.length; i++) {
		scene.remove(borders[i]);
	}
	borders.length = 0;
	removed = 0;
	lastSpawned = 0;
	camera.position.set(0, 10, 25);
	camera.lookAt(scene.position);
	running = true;
}

function gameOver() {
	running = false;
	headSet = false;
	document.getElementById("score").innerText = document.getElementById("score").innerText + " - Game Over!";
	document.getElementById("start").style.zIndex = 0;
	document.getElementById("start").style.visibility = "visible";
	document.getElementById("start").innerText = "Restart";
}

function init() {

	camera.position.set(0, 10, 25);
	camera.lookAt(scene.position);

	const ambientLight = new THREE.AmbientLight(0xffffff, 0.7);
	scene.add(ambientLight);

	const pointLight = new THREE.PointLight(0xffffff, 0.8);
	camera.add(pointLight);
	scene.add(camera);


	renderer = new THREE.WebGLRenderer();
	renderer.setPixelRatio(window.devicePixelRatio);
	renderer.setSize(window.innerWidth, window.innerHeight);
	document.body.appendChild(renderer.domElement);


	window.addEventListener('resize', onWindowResize);

}

function onWindowResize() {

	camera.aspect = window.innerWidth / window.innerHeight;
	camera.updateProjectionMatrix();

	renderer.setSize(window.innerWidth, window.innerHeight);

}

// main render/update function called once per frame
function animate() {

	let now = Date.now() / 1000.0;
	let delta = now - time;
	time = now;
	averageFps = (4 * averageFps + 1.0 / delta ) / 5.0;

	requestAnimationFrame(animate);

	uniforms.iTime.value += delta;

	if (running) {

		if (Math.abs(camera.position.x) > tunnelRadius || Math.abs(camera.position.y) > tunnelRadius) {
			// out of bounds
			gameOver();
		}

		// collision checks
		for (let i = 0; i < spheres.length; i++) {
			if (spheres[i].material !== materialSphere) {
				continue;
			}
			let x1 = spheres[i].position.x;
			let y1 = spheres[i].position.y;
			let z1 = spheres[i].position.z;
			let x2 = camera.position.x;
			let y2 = camera.position.y;
			let z2 = camera.position.z;
			if (z2 > z1) {
				// account for very fast speeds
				// (prevents clipping through obstacles)
				z2 = Math.max(z1, z2 - speed);
			}
			let dist_squared = (x1 - x2) ** 2 + (y1 - y2) ** 2 + (z1 - z2) ** 2;
			if (dist_squared <= (spheres[i].geometry.parameters.radius * spheres[i].scale.x) ** 2) {
				gameOver();
				break;
			}
		}
	}

	if (running) {

		// advance player position, increase speed, handle movement input
		camera.position.z -= 0.5 * speed * delta * 60.0;
		speed += 0.01;
		if (!Number.isNaN(leftRightMove)) {
			camera.position.x += 0.1 * leftRightMove;
		}
		if (!Number.isNaN(upDownMove)) {
			camera.position.y += 0.1 * upDownMove;
		}

		// create new obstacles as needed
		while (camera.position.z < lastSpawned - spawnInterval) {
			lastSpawned -= spawnInterval;

			// randomly spawn large spheres
			let scale = Math.random() < 0.1 ? 5.0 : 1.0;

			const meshCube = new THREE.Mesh(geometrySphere, materialSphere);
			meshCube.position.z = camera.position.z - speed * 210;
			meshCube.position.x = (2 * Math.random() - 1.0) * tunnelRadius;
			meshCube.position.y = (2 * Math.random() - 1.0) * 0.9 * tunnelRadius;
			meshCube.scale.multiplyScalar(scale);

			const outlineMesh = new THREE.Mesh(geometrySphere, customMaterial);
			outlineMesh.scale.multiplyScalar(scale * 1.17);
			outlineMesh.position.z = meshCube.position.z;
			outlineMesh.position.x = meshCube.position.x;
			outlineMesh.position.y = meshCube.position.y;
			meshCube.add(outlineMesh);
			scene.add(outlineMesh);
			spheres.push(outlineMesh);

			scene.add(meshCube);
			spheres.push(meshCube);
		}
	}
	renderer.render(scene, camera);


	// clean up game elements behind the camera
	for (let i = 0; i < spheres.length; i++) {
		if (spheres[i].position.z > camera.position.z + spheres[i].geometry.parameters.radius * spheres[i].scale.x + 20) {
			scene.remove(spheres[i]);
			spheres.splice(i, 1);
			i--;
			removed++;
		}
	}
	if (removed >= 2 || score == 0) {
		score += removed / 2;
		removed = 0;
		document.getElementById("score").innerText = score;
	}
	if (averageFps < 30.0 && renderer.getPixelRatio() == window.devicePixelRatio) {
		renderer.setPixelRatio(window.devicePixelRatio / 2);
	}

	// create new wall segments on demand
	if (borders.length == 0 || borders[borders.length - 1].position.z - camera.position.z > -1200) {
		const newZ = borders.length == 0 ? -200 : borders[borders.length - 1].position.z - tunnelRadius * 2;

		let border = new THREE.Mesh(borderGeometry, material);
		border.position.y = -tunnelRadius;
		border.rotation.x = -Math.PI / 2;
		border.position.z = newZ;
		border.scale.multiplyScalar(tunnelRadius * 2);
		scene.add(border);
		borders.push(border);

		border = new THREE.Mesh(borderGeometry, material);
		border.position.y = tunnelRadius;
		border.rotation.x = Math.PI / 2;
		border.position.z = newZ;
		border.scale.multiplyScalar(tunnelRadius * 2);
		scene.add(border);
		borders.push(border);

		border = new THREE.Mesh(borderGeometry, material);
		border.position.x = -tunnelRadius;
		border.rotation.y = Math.PI / 2;
		border.position.z = newZ;
		border.scale.multiplyScalar(tunnelRadius * 2);
		scene.add(border);
		borders.push(border);

		border = new THREE.Mesh(borderGeometry, material);
		border.position.x = tunnelRadius;
		border.rotation.y = -Math.PI / 2;
		border.position.z = newZ;
		border.scale.multiplyScalar(tunnelRadius * 2);
		scene.add(border);
		borders.push(border);
	}
	// clean up wall segments behind the camera
	for (let i = 0; i < borders.length; i++) {
		if (borders[i].position.z > camera.position.z + tunnelRadius + 50) {
			scene.remove(borders[i]);
			borders.splice(i, 1);
			i--;
		}
	}
}