<div id="main">
	<h1 id="title">Compressa</h1>
</div>

@font-face {
	src: url('https://res.cloudinary.com/dr6lvwubh/raw/upload/v1529908256/CompressaPRO-GX.woff2');
	font-family:'Compressa VF';
	font-style: normal;
}
html {
	height:100%;
}
body {
	padding: 0;
	margin: 0;
	overflow: hidden;
	background-color: #211D26;
	display: flex;
	justify-content: center;
	height: 100%;
	align-items: center;
}

h1 {
	font-family:'Compressa VF';
	text-rendering: optimizeSpeed;
	color: #D11B3D;
	width: 100%;
	user-select: none;
	line-height: 0.8em;
	margin: 0 auto;
	text-transform: uppercase;
	font-weight: 100;
	text-align: center;
	width: 100vw;
}
h1 span {
	transform: translateY(-10px);
	user-select: none;
}
h1.flex {
	display: flex;
	justify-content: space-between;
}
h1.stroke span {
	position: relative;
	color: #211D26;
	line-height: inherit;
}
h1.stroke span:after {
	content: attr(data-char);
	-webkit-text-stroke-width: 3px;
	-webkit-text-stroke-color: #FE6730;
	position: absolute;
	left: 0;
	line-height: inherit;
	color: transparent;
	z-index: -1;
}

var maxDist;
var mouse = { x: 0, y: 0 };
var cursor = {
    x: window.innerWidth,
    y: window.innerHeight
};

Math.dist = function(a, b) {
    var dx = b.x - a.x;
    var dy = b.y - a.y;
    return Math.sqrt(Math.pow(dx, 2), Math.pow(dy, 2));
}

window.addEventListener("mousemove", function(e) {
    cursor.x = e.clientX;
    cursor.y = e.clientY;
});

window.addEventListener("touchmove", function(e) {
    var t = e.touches[0];
    cursor.x = t.clientX;
    cursor.y = t.clientY;
}, {
    passive: false
});

var Char = function(container, char) {
    var span = document.createElement("span");
    span.setAttribute('data-char', char);
    span.innerText = char;
    container.appendChild(span);
    this.getDist = function() {
        this.pos = span.getBoundingClientRect();
        return Math.dist(mouse, {
            x: this.pos.x + (this.pos.width / 1.75),
            y: this.pos.y
        });
    }
    this.getAttr = function(dist, min, max) {
        var wght = max - Math.abs((max * dist / maxDist));
        return Math.max(min, wght + min);
    }
    this.update = function(args) {
        var dist = this.getDist();
        this.wdth = args.wdth ? ~~this.getAttr(dist, 5, 200) : 100;
        this.wght = args.wght ? ~~this.getAttr(dist, 100, 800) : 400;
        this.alpha = args.alpha ? this.getAttr(dist, 0, 1).toFixed(2) : 1;
        this.ital = args.ital ? this.getAttr(dist, 0, 1).toFixed(2) : 0;
        this.draw();
    }
    this.draw = function() {
        var style = "";
        style += "opacity: " + this.alpha + ";";
        style += "font-variation-settings: 'wght' " + this.wght + ", 'wdth' " + this.wdth + ", 'ital' " + this.ital + ";";
        span.style = style;
    }
    return this;
}

var VFont = function() {
    this.scale = false;
    this.flex = true;
    this.alpha = false;
    this.stroke = false;
    this.width = true;
    this.weight = true;
    this.italic = true;
    var title, str, chars = [];

    this.init = function() {
        title = document.getElementById("title");
        str = title.innerText;
        title.innerHTML = "";
        for (var i = 0; i < str.length; i++) {
            var _char = new Char(title, str[i]);
            chars.push(_char);
        }
        this.set();
        window.addEventListener("resize", this.setSize.bind(this));
    }

    this.set = function() {
        title.className = "";
        title.className += this.flex ? " flex" : "";
        title.className += this.stroke ? " stroke" : "";
        this.setSize();
    }

    this.setSize = function() {
        var fontSize = window.innerWidth / (str.length / 2);
        title.style = "font-size: " + fontSize + "px;";
        if (this.scale) {
            var scaleY = (window.innerHeight / title.getBoundingClientRect().height).toFixed(2);
            var lineHeight = scaleY * 0.8;
            title.style = "font-size: " + fontSize + "px; transform: scale(1," + scaleY + "); line-height: " + lineHeight + "em;"
        }
    }

    this.animate = function() {
        mouse.x += (cursor.x - mouse.x) / 20;
        mouse.y += (cursor.y - mouse.y) / 20;
        requestAnimationFrame(this.animate.bind(this));
        this.render();
    }

    this.render = function() {
        maxDist = title.getBoundingClientRect().width / 2;
        for (var i = 0; i < chars.length; i++) {
            chars[i].update({
                wght: this.weight,
                wdth: this.width,
                ital: this.italic,
                alpha: this.alpha
            });
        }
    }
    this.init();
    this.animate();
    return this;
}

var txt = new VFont();
var gui = new dat.GUI();
gui.add(txt, 'flex').onChange(txt.set.bind(txt));
gui.add(txt, 'scale').onChange(txt.set.bind(txt));
gui.add(txt, 'alpha').onChange(txt.set.bind(txt));
gui.add(txt, 'stroke').onChange(txt.set.bind(txt));
// gui.add(txt, 'width').onChange(txt.set.bind(txt));
gui.add(txt, 'weight').onChange(txt.set.bind(txt));
gui.add(txt, 'italic').onChange(txt.set.bind(txt));