/**
 * Created by Administrator on 2016/6/29.
 */
$(function(){
    var canvas = document.querySelector('canvas'),
        ctx = canvas.getContext('2d')
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    ctx.lineWidth = .3;
    ctx.strokeStyle = (new Color(150)).style;

    var mousePosition = {
        x: 30 * canvas.width / 100,
        y: 30 * canvas.height / 100
    };

    var dots = {
        nb: 750,
        distance: 50,
        d_radius: 100,
        array: []
    };

    function colorValue(min) {
        return Math.floor(Math.random() * 255 + min);
    }

    function createColorStyle(r,g,b) {
        return 'rgba(' + r + ',' + g + ',' + b + ', 0.8)';
    }

    function mixComponents(comp1, weight1, comp2, weight2) {
        return (comp1 * weight1 + comp2 * weight2) / (weight1 + weight2);
    }

    function averageColorStyles(dot1, dot2) {
        var color1 = dot1.color,
            color2 = dot2.color;

        var r = mixComponents(color1.r, dot1.radius, color2.r, dot2.radius),
            g = mixComponents(color1.g, dot1.radius, color2.g, dot2.radius),
            b = mixComponents(color1.b, dot1.radius, color2.b, dot2.radius);
        return createColorStyle(Math.floor(r), Math.floor(g), Math.floor(b));
    }

    function Color(min) {
        min = min || 0;
        this.r = colorValue(min);
        this.g = colorValue(min);
        this.b = colorValue(min);
        this.style = createColorStyle(this.r, this.g, this.b);
    }

    function Dot(){
        this.x = Math.random() * canvas.width;
        this.y = Math.random() * canvas.height;

        this.vx = -.5 + Math.random();
        this.vy = -.5 + Math.random();

        this.radius = Math.random() * 2;

        this.color = new Color();
    }

    Dot.prototype = {
        draw: function(){
            ctx.beginPath();
            ctx.fillStyle = this.color.style;
            ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false);
            ctx.fill();
        }
    };

    function createDots(){
        for(i = 0; i < dots.nb; i++){
            dots.array.push(new Dot());
        }
    }

    function moveDots() {
        for(i = 0; i < dots.nb; i++){

            var dot = dots.array[i];

            if(dot.y < 0 || dot.y > canvas.height){
                dot.vx = dot.vx;
                dot.vy = - dot.vy;
            }
            else if(dot.x < 0 || dot.x > canvas.width){
                dot.vx = - dot.vx;
                dot.vy = dot.vy;
            }
            dot.x += dot.vx;
            dot.y += dot.vy;
        }
    }

    function connectDots() {
        for(i = 0; i < dots.nb; i++){
            for(j = 0; j < dots.nb; j++){
                i_dot = dots.array[i];
                j_dot = dots.array[j];

                if((i_dot.x - j_dot.x) < dots.distance && (i_dot.y - j_dot.y) < dots.distance && (i_dot.x - j_dot.x) > - dots.distance && (i_dot.y - j_dot.y) > - dots.distance){
                    if((i_dot.x - mousePosition.x) < dots.d_radius && (i_dot.y - mousePosition.y) < dots.d_radius && (i_dot.x - mousePosition.x) > - dots.d_radius && (i_dot.y - mousePosition.y) > - dots.d_radius){
                        ctx.beginPath();
                        ctx.strokeStyle = averageColorStyles(i_dot, j_dot);
                        ctx.moveTo(i_dot.x, i_dot.y);
                        ctx.lineTo(j_dot.x, j_dot.y);
                        ctx.stroke();
                        ctx.closePath();
                    }
                }
            }
        }
    }

    function drawDots() {
        for(i = 0; i < dots.nb; i++){
            var dot = dots.array[i];
            dot.draw();
        }
    }

    function animateDots() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        moveDots();
        connectDots();
        drawDots();

        requestAnimationFrame(animateDots);
    }

    $('canvas').on('mousemove', function(e){
        mousePosition.x = e.pageX;
        mousePosition.y = e.pageY;
    });

    $('canvas').on('mouseleave', function(e){
        mousePosition.x = canvas.width / 2;
        mousePosition.y = canvas.height / 2;
    });

    createDots();
    requestAnimationFrame(animateDots);
});