/*
jquery-circle-progress - jQuery Plugin to draw animated circular progress bars

URL: http://kottenator.github.io/jquery-circle-progress/
Author: Rostyslav Bryzgunov <kottenator@gmail.com>
Version: 1.1.2
License: MIT
*/
(function($) {
    function CircleProgress(config) {
        this.init(config);
    }

    CircleProgress.prototype = {
        //----------------------------------------------- public options -----------------------------------------------
        /**
         * This is the only required option. It should be from 0.0 to 1.0
         * @type {number}
         */
        value: 0.0,

        /**
         * Size of the circle / canvas in pixels
         * @type {number}
         */
        size: 100.0,

        /**
         * Initial angle for 0.0 value in radians
         * @type {number}
         */
        startAngle: -Math.PI,

        /**
         * Width of the arc. By default it's auto-calculated as 1/14 of size, but you may set it explicitly in pixels
         * @type {number|string}
         */
        thickness: 'auto',

        /**
         * Fill of the arc. You may set it to:
         *   - solid color:
         *     - { color: '#3aeabb' }
         *     - { color: 'rgba(255, 255, 255, .3)' }
         *   - linear gradient (left to right):
         *     - { gradient: ['#3aeabb', '#fdd250'], gradientAngle: Math.PI / 4 }
         *     - { gradient: ['red', 'green', 'blue'], gradientDirection: [x0, y0, x1, y1] }
         *   - image:
         *     - { image: 'http://i.imgur.com/pT0i89v.png' }
         *     - { image: imageObject }
         *     - { color: 'lime', image: 'http://i.imgur.com/pT0i89v.png' } - color displayed until the image is loaded
         */
        fill: {
            gradient: ['#3aeabb', '#fdd250']
        },

        /**
         * Color of the "empty" arc. Only a color fill supported by now
         * @type {string}
         */
        emptyFill: 'rgba(0, 0, 0, .1)',

        /**
         * Animation config (see jQuery animations: http://api.jquery.com/animate/)
         */
        animation: {
            duration: 1200,
            easing: 'circleProgressEasing'
        },

        /**
         * Default animation starts at 0.0 and ends at specified `value`. Let's call this direct animation.
         * If you want to make reversed animation then you should set `animationStartValue` to 1.0.
         * Also you may specify any other value from 0.0 to 1.0
         * @type {number}
         */
        animationStartValue: 0.0,

        /**
         * Reverse animation and arc draw
         * @type {boolean}
         */
        reverse: false,

        /**
         * Arc line cap ('butt' (default), 'round' and 'square')
         * Read more: https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D.lineCap
         * @type {string}
         */
        lineCap: 'butt',

        //-------------------------------------- protected properties and methods --------------------------------------
        /**
         * @protected
         */
        constructor: CircleProgress,

        /**
         * Container element. Should be passed into constructor config
         * @protected
         * @type {jQuery}
         */
        el: null,

        /**
         * Canvas element. Automatically generated and prepended to the {@link CircleProgress.el container}
         * @protected
         * @type {HTMLCanvasElement}
         */
        canvas: null,

        /**
         * 2D-context of the {@link CircleProgress.canvas canvas}
         * @protected
         * @type {CanvasRenderingContext2D}
         */
        ctx: null,

        /**
         * Radius of the outer circle. Automatically calculated as {@link CircleProgress.size} / 2
         * @protected
         * @type {number}
         */
        radius: 0.0,

        /**
         * Fill of the main arc. Automatically calculated, depending on {@link CircleProgress.fill} option
         * @protected
         * @type {string|CanvasGradient|CanvasPattern}
         */
        arcFill: null,

        /**
         * Last rendered frame value
         * @protected
         * @type {number}
         */
        lastFrameValue: 0.0,

        /**
         * Init/re-init the widget
         * @param {object} config Config
         */
        init: function(config) {
            $.extend(this, config);
            this.radius = this.size / 2;
            this.initWidget();
            this.initFill();
            this.draw();
        },

        /**
         * @protected
         */
        initWidget: function() {
            var canvas = this.canvas = this.canvas || $('<canvas>').prependTo(this.el)[0];
            canvas.width = this.size;
            canvas.height = this.size;
            this.ctx = canvas.getContext('2d');
        },

        /**
         * This method sets {@link CircleProgress.arcFill}
         * It could do this async (on image load)
         * @protected
         */
        initFill: function() {
            var self = this,
                fill = this.fill,
                ctx = this.ctx,
                size = this.size;

            if (!fill)
                throw Error("The fill is not specified!");

            if (fill.color)
                this.arcFill = fill.color;

            if (fill.gradient) {
                var gr = fill.gradient;

                if (gr.length == 1) {
                    this.arcFill = gr[0];
                } else if (gr.length > 1) {
                    var ga = fill.gradientAngle || 0, // gradient direction angle; 0 by default
                        gd = fill.gradientDirection || [
                            size / 2 * (1 - Math.cos(ga)), // x0
                            size / 2 * (1 + Math.sin(ga)), // y0
                            size / 2 * (1 + Math.cos(ga)), // x1
                            size / 2 * (1 - Math.sin(ga))  // y1
                        ];

                    var lg = ctx.createLinearGradient.apply(ctx, gd);

                    for (var i = 0; i < gr.length; i++) {
                        var color = gr[i],
                            pos = i / (gr.length - 1);

                        if ($.isArray(color)) {
                            pos = color[1];
                            color = color[0];
                        }

                        lg.addColorStop(pos, color);
                    }

                    this.arcFill = lg;
                }
            }

            if (fill.image) {
                var img;

                if (fill.image instanceof Image) {
                    img = fill.image;
                } else {
                    img = new Image();
                    img.src = fill.image;
                }

                if (img.complete)
                    setImageFill();
                else
                    img.onload = setImageFill;
            }

            function setImageFill() {
                var bg = $('<canvas>')[0];
                bg.width = self.size;
                bg.height = self.size;
                bg.getContext('2d').drawImage(img, 0, 0, size, size);
                self.arcFill = self.ctx.createPattern(bg, 'no-repeat');
                self.drawFrame(self.lastFrameValue);
            }
        },

        draw: function() {
            if (this.animation)
                this.drawAnimated(this.value);
            else
                this.drawFrame(this.value);
        },

        /**
         * @protected
         * @param {number} v Frame value
         */
        drawFrame: function(v) {
            this.lastFrameValue = v;
            this.ctx.clearRect(0, 0, this.size, this.size);
            this.drawEmptyArc(v);
            this.drawArc(v);
        },

        /**
         * @protected
         * @param {number} v Frame value
         */
        drawArc: function(v) {
            var ctx = this.ctx,
                r = this.radius,
                t = this.getThickness(),
                a = this.startAngle;

            ctx.save();
            ctx.beginPath();

            if (!this.reverse) {
                ctx.arc(r, r, r - t / 2, a, a + Math.PI * 2 * v);
            } else {
                ctx.arc(r, r, r - t / 2, a - Math.PI * 2 * v, a);
            }

            ctx.lineWidth = t;
            ctx.lineCap = this.lineCap;
            ctx.strokeStyle = this.arcFill;
            ctx.stroke();
            ctx.restore();
        },

        /**
         * @protected
         * @param {number} v Frame value
         */
        drawEmptyArc: function(v) {
            var ctx = this.ctx,
                r = this.radius,
                t = this.getThickness(),
                a = this.startAngle;

            if (v < 1) {
                ctx.save();
                ctx.beginPath();

                if (v <= 0) {
                    ctx.arc(r, r, r - t / 2, 0, Math.PI * 2);
                } else {
                    if (!this.reverse) {
                        ctx.arc(r, r, r - t / 2, a + Math.PI * 2 * v, a);
                    } else {
                        ctx.arc(r, r, r - t / 2, a, a - Math.PI * 2 * v);
                    }
                }

                ctx.lineWidth = t;
                ctx.strokeStyle = this.emptyFill;
                ctx.stroke();
                ctx.restore();
            }
        },

        /**
         * @protected
         * @param {number} v Value
         */
        drawAnimated: function(v) {
            var self = this,
                el = this.el;

            el.trigger('circle-animation-start');

            $(this.canvas)
                .stop(true, true)
                .css({ animationProgress: 0 })
                .animate({ animationProgress: 1 }, $.extend({}, this.animation, {
                    step: function(animationProgress) {
                        var stepValue = self.animationStartValue * (1 - animationProgress) + v * animationProgress;
                        self.drawFrame(stepValue);
                        el.trigger('circle-animation-progress', [animationProgress, stepValue]);
                    },
                    complete: function() {
                        el.trigger('circle-animation-end');
                    }
                }));
        },

        /**
         * @protected
         * @returns {number}
         */
        getThickness: function() {
            return $.isNumeric(this.thickness) ? this.thickness : this.size / 14;
        }
    };

    //-------------------------------------------- Initiating jQuery plugin --------------------------------------------
    $.circleProgress = {
        // Default options (you may override them)
        defaults: CircleProgress.prototype
    };

    // ease-in-out-cubic
    $.easing.circleProgressEasing = function(x, t, b, c, d) {
        if ((t /= d / 2) < 1)
            return c / 2 * t * t * t + b;
        return c / 2 * ((t -= 2) * t * t + 2) + b;
    };

    /**
     * Draw animated circular progress bar.
     *
     * Appends <canvas> to the element or updates already appended one.
     *
     * If animated, throws 3 events:
     *
     *   - circle-animation-start(jqEvent)
     *   - circle-animation-progress(jqEvent, animationProgress, stepValue) - multiple event;
     *                                                                        animationProgress: from 0.0 to 1.0;
     *                                                                        stepValue: from 0.0 to value
     *   - circle-animation-end(jqEvent)
     *
     * @param config Example: { value: 0.75, size: 50, animation: false };
     *                you may set any of public options;
     *                `animation` may be set to false;
     *                you may also use .circleProgress('widget') to get the canvas
     */
    $.fn.circleProgress = function(config) {
        var dataName = 'circle-progress';

        if (config == 'widget') {
            var data = this.data(dataName);
            return data && data.canvas;
        }

        return this.each(function() {
            var el = $(this),
                instance = el.data(dataName),
                cfg = $.isPlainObject(config) ? config : {};

            if (instance) {
                instance.init(cfg);
            } else {
                cfg.el = el;
                instance = new CircleProgress(cfg);
                el.data(dataName, instance);
            }
        });
    };
})(jQuery);
