/*!
 * Snow.js v1.0.0
 * https://github.com/zmfe/snow.js
 *
 * Copyright (c) 2018 undefined
 * Released under the MIT license
 *
 * Date: 2018-01-10T03:01:10.014Z
 */

(function (global, factory) {
  typeof exports === "object" && typeof module !== "undefined"
    ? (module.exports = factory())
    : typeof define === "function" && define.amd
    ? define(factory)
    : (global.Snow = factory());
})(this, function () {
  "use strict";

  var _window = window;
  var document = _window.document;
  var DEFAULT_OPTIONS = {};
  var DEFAULT_SNOWPARTICLE_OPTIONS = {
    index: 0,
    x: 0,
    y: 0,
    context: "",
    color: "rgb(255, 255, 255)",
    r: 1
  };
  function DEG(deg) {
    return Math.PI * (deg / 180);
  }
  function SINDEG(deg) {
    if (deg > DEG(165)) {
      deg -= Math.PI / 4;
    } else if (deg < DEG(15)) {
      deg += Math.PI / 4;
    }
    return deg;
  }
  function COSDEG(deg) {
    // if (deg > DEG(75) && deg <= DEG(90)) {
    // 	deg -= (Math.PI / 8);
    // } else if (deg > DEG(90) && deg <= DEG(165)) {
    // 	deg += (Math.PI / 8);
    // }
    return deg;
  }

  var classCallCheck = function (instance, Constructor) {
    if (!(instance instanceof Constructor)) {
      throw new TypeError("Cannot call a class as a function");
    }
  };

  var createClass = (function () {
    function defineProperties(target, props) {
      for (var i = 0; i < props.length; i++) {
        var descriptor = props[i];
        descriptor.enumerable = descriptor.enumerable || false;
        descriptor.configurable = true;
        if ("value" in descriptor) descriptor.writable = true;
        Object.defineProperty(target, descriptor.key, descriptor);
      }
    }

    return function (Constructor, protoProps, staticProps) {
      if (protoProps) defineProperties(Constructor.prototype, protoProps);
      if (staticProps) defineProperties(Constructor, staticProps);
      return Constructor;
    };
  })();

  var SnowParticle = (function () {
    /**
     * Creates an instance of SnowParticle.
     * @param {Object} option content, x, y, color
     * @memberof Snow
     */
    function SnowParticle() {
      var option =
        arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
      classCallCheck(this, SnowParticle);

      this.option = Object.assign({}, DEFAULT_SNOWPARTICLE_OPTIONS, option);
      var _option = this.option,
        content = _option.content,
        color = _option.color,
        x = _option.x,
        y = _option.y,
        r = _option.r,
        v = _option.v;

      this.color =
        color.replace("rgb", "rgba").split(")")[0] +
        "," +
        (Math.floor(Math.random() * 70) + 30) / 100 +
        ")";
      this.content = content;
      this.r = r * (Math.random() * 0.4 + 0.6);
      this.x = x;
      this.y = y;
      this.v = v;
      this.angle = Math.PI * Math.random() + 0.01;
      // this.init();
    }
    // init() {
    // }

    createClass(SnowParticle, [
      {
        key: "draw",
        value: function draw() {
          var content = this.content,
            color = this.color,
            x = this.x,
            y = this.y,
            r = this.r;

          content.beginPath();
          content.arc(x, y, r, 0, 2 * Math.PI, true);
          content.closePath();
          content.fillStyle = color;
          content.fill();
        }
      },
      {
        key: "move",
        value: function move() {
          var _option2 = this.option,
            width = _option2.width,
            height = _option2.height;

          this.x += this.v * (Math.cos(COSDEG(this.angle)) * 0.5);
          this.y += this.v * Math.sin(SINDEG(this.angle));
          if (this.y > height || this.x > width || this.x < 0) {
            this.y = 0;
            this.x = Math.random() * width;
            this.angle = Math.PI * Math.random() + 0.01;
          }
        }
      }
    ]);
    return SnowParticle;
  })();

  var Snow = (function () {
    /**
     * Creates an instance of Snow.
     * @param {Element} element target
     * @param {Object} [option={}] options
     * @memberof Snow
     */
    function Snow(element) {
      var option =
        arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
      classCallCheck(this, Snow);

      this.element = document.querySelector(element);
      this.canvas = "";
      this.ctx = "";
      this.width = 0;
      this.height = 0;
      this.option = Object.assign({}, DEFAULT_OPTIONS, option);
      this.number = this.option.number;
      this.partiles = [];
      this.init();
    }

    createClass(Snow, [
      {
        key: "init",
        value: function init() {
          var element = this.element;

          var width = element.clientWidth;
          var height = element.clientHeight;
          this.width = width;
          this.height = height;
          this.createCanvas();
          this.createParticle();
        }
      },
      {
        key: "createCanvas",
        value: function createCanvas() {
          var element = this.element,
            width = this.width,
            height = this.height;

          var canvas = document.createElement("canvas");
          canvas.width = width;
          canvas.height = height;
          canvas.style.cssText =
            "position:absolute;top:0;left:0;background:rgba(0,0,0,0);pointer-events:none;";
          element.appendChild(canvas);
          this.canvas = canvas;
          this.ctx = canvas.getContext("2d");
        }
      },
      {
        key: "createParticle",
        value: function createParticle() {
          var _option3 = this.option,
            r = _option3.r,
            v = _option3.v;
          var ctx = this.ctx,
            width = this.width,
            height = this.height,
            number = this.number,
            partiles = this.partiles;

          for (var i = 0; i < number; i += 1) {
            var particle = new SnowParticle({
              color: "rgb(255,255,255)",
              content: ctx,
              y: Math.random() * height,
              x: Math.random() * width,
              r: r,
              v: Math.random() * v,
              width: this.width,
              height: this.height
              // angle: Math.PI,
            });
            partiles.push(particle);
            particle.draw();
          }
          function animate() {
            ctx.clearRect(0, 0, width, height);
            partiles.forEach(function (item) {
              item.move();
              item.draw();
            });
            requestAnimationFrame(animate);
          }
          animate();
        }
      }
    ]);
    return Snow;
  })();

  return Snow;
});

document.addEventListener("DOMContentLoaded", function () {
  new Snow("#snow", {
    number: 50,
    r: 5,
    v: 1.8
  });
});