/*
 html5slider - a JS implementation of <input type=range> for Firefox 16 and up
 https://github.com/fryn/html5slider

 Copyright (c) 2010-2012 Frank Yan, <http://frankyan.com>

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 */

(function () {

// test for native support
    var test = document.createElement('input');
    try {
        test.type = 'range';
        if (test.type == 'range')
            return;
    } catch (e) {
        return;
    }

// test for required property support
    test.style.background = 'linear-gradient(red, red)';
    if (!test.style.backgroundImage || !('MozAppearance' in test.style) || !document.mozSetImageElement || !this.MutationObserver)
        return;

    var scale;
    var isMac = navigator.platform == 'MacIntel';
    var thumb = {
        radius: isMac ? 9 : 6,
        width: isMac ? 22 : 12,
        height: isMac ? 16 : 20
    };
    var track = 'linear-gradient(transparent ' + (isMac ?
        '6px, #999 6px, #999 7px, #ccc 8px, #bbb 9px, #bbb 10px, transparent 10px' :
        '9px, #999 9px, #bbb 10px, #fff 11px, transparent 11px') +
        ', transparent)';
    var styles = {
        'min-width': thumb.width + 'px',
        'min-height': thumb.height + 'px',
        'max-height': thumb.height + 'px',
        padding: '0 0 ' + (isMac ? '2px' : '1px'),
        border: 0,
        'border-radius': 0,
        cursor: 'default',
        'text-indent': '-999999px' // -moz-user-select: none; breaks mouse capture
    };
    var options = {
        attributes: true,
        attributeFilter: ['min', 'max', 'step', 'value']
    };
    var forEach = Array.prototype.forEach;
    var onChange = document.createEvent('HTMLEvents');
    onChange.initEvent('change', true, false);

    if (document.readyState == 'loading')
        document.addEventListener('DOMContentLoaded', initialize, true);
    else
        initialize();

    function initialize() {
        // create initial sliders
        forEach.call(document.querySelectorAll('input[type=range]'), transform);
        // create sliders on-the-fly
        new MutationObserver(function (mutations) {
            mutations.forEach(function (mutation) {
                if (mutation.addedNodes)
                    forEach.call(mutation.addedNodes, function (node) {
                        check(node);
                        if (node.childElementCount)
                            forEach.call(node.querySelectorAll('input'), check);
                    });
            });
        }).observe(document, { childList: true, subtree: true });
    }

    function check(input) {
        if (input.localName == 'input' && input.type != 'range' &&
            input.getAttribute('type') == 'range')
            transform(input);
    }

    function transform(slider) {

        var isValueSet, areAttrsSet, isChanged, isClick, prevValue, rawValue, prevX;
        var min, max, step, range, value = slider.value;

        // lazily create shared slider affordance
        if (!scale) {
            scale = document.body.appendChild(document.createElement('hr'));
            style(scale, {
                '-moz-appearance': isMac ? 'scale-horizontal' : 'scalethumb-horizontal',
                display: 'block',
                visibility: 'visible',
                opacity: 1,
                position: 'fixed',
                top: '-999999px'
            });
            document.mozSetImageElement('__sliderthumb__', scale);
        }

        // reimplement value and type properties
        var getValue = function () {
            return '' + value;
        };
        var setValue = function setValue(val) {
            value = '' + val;
            isValueSet = true;
            draw();
            delete slider.value;
            slider.value = value;
            slider.__defineGetter__('value', getValue);
            slider.__defineSetter__('value', setValue);
        };
        slider.__defineGetter__('value', getValue);
        slider.__defineSetter__('value', setValue);
        slider.__defineGetter__('type', function () {
            return 'range';
        });

        // sync properties with attributes
        ['min', 'max', 'step'].forEach(function (prop) {
            if (slider.hasAttribute(prop))
                areAttrsSet = true;
            slider.__defineGetter__(prop, function () {
                return this.hasAttribute(prop) ? this.getAttribute(prop) : '';
            });
            slider.__defineSetter__(prop, function (val) {
                val === null ? this.removeAttribute(prop) : this.setAttribute(prop, val);
            });
        });

        // initialize slider
        slider.readOnly = true;
        style(slider, styles);
        update();

        new MutationObserver(function (mutations) {
            mutations.forEach(function (mutation) {
                if (mutation.attributeName != 'value') {
                    update();
                    areAttrsSet = true;
                }
                // note that value attribute only sets initial value
                else if (!isValueSet) {
                    value = slider.getAttribute('value');
                    draw();
                }
            });
        }).observe(slider, options);

        slider.addEventListener('mousedown', onDragStart, true);
        slider.addEventListener('keydown', onKeyDown, true);
        slider.addEventListener('focus', onFocus, true);
        slider.addEventListener('blur', onBlur, true);

        function onDragStart(e) {
            isClick = true;
            setTimeout(function () {
                isClick = false;
            }, 0);
            if (e.button || !range)
                return;
            var width = parseFloat(getComputedStyle(this, 0).width);
            var multiplier = (width - thumb.width) / range;
            if (!multiplier)
                return;
            // distance between click and center of thumb
            var dev = e.clientX - this.getBoundingClientRect().left - thumb.width / 2 -
                (value - min) * multiplier;
            // if click was not on thumb, move thumb to click location
            if (Math.abs(dev) > thumb.radius) {
                isChanged = true;
                this.value -= -dev / multiplier;
            }
            rawValue = value;
            prevX = e.clientX;
            this.addEventListener('mousemove', onDrag, true);
            this.addEventListener('mouseup', onDragEnd, true);
        }

        function onDrag(e) {
            var width = parseFloat(getComputedStyle(this, 0).width);
            var multiplier = (width - thumb.width) / range;
            if (!multiplier)
                return;
            rawValue += (e.clientX - prevX) / multiplier;
            prevX = e.clientX;
            isChanged = true;
            this.value = rawValue;
        }

        function onDragEnd() {
            this.removeEventListener('mousemove', onDrag, true);
            this.removeEventListener('mouseup', onDragEnd, true);
        }

        function onKeyDown(e) {
            if (e.keyCode > 36 && e.keyCode < 41) { // 37-40: left, up, right, down
                onFocus.call(this);
                isChanged = true;
                this.value = value + (e.keyCode == 38 || e.keyCode == 39 ? step : -step);
            }
        }

        function onFocus() {
            if (!isClick)
                this.style.boxShadow = !isMac ? '0 0 0 2px #fb0' :
                    'inset 0 0 20px rgba(0,127,255,.1), 0 0 1px rgba(0,127,255,.4)';
        }

        function onBlur() {
            this.style.boxShadow = '';
        }

        // determines whether value is valid number in attribute form
        function isAttrNum(value) {
            return !isNaN(value) && +value == parseFloat(value);
        }

        // validates min, max, and step attributes and redraws
        function update() {
            min = isAttrNum(slider.min) ? +slider.min : 0;
            max = isAttrNum(slider.max) ? +slider.max : 100;
            if (max < min)
                max = min > 100 ? min : 100;
            step = isAttrNum(slider.step) && slider.step > 0 ? +slider.step : 1;
            range = max - min;
            draw(true);
        }

        // recalculates value property
        function calc() {
            if (!isValueSet && !areAttrsSet)
                value = slider.getAttribute('value');
            if (!isAttrNum(value))
                value = (min + max) / 2;
            ;
            // snap to step intervals (WebKit sometimes does not - bug?)
            value = Math.round((value - min) / step) * step + min;
            if (value < min)
                value = min;
            else if (value > max)
                value = min + ~~(range / step) * step;
        }

        // renders slider using CSS background ;)
        function draw(attrsModified) {
            calc();
            if (isChanged && value != prevValue)
                slider.dispatchEvent(onChange);
            isChanged = false;
            if (!attrsModified && value == prevValue)
                return;
            prevValue = value;
            var position = range ? (value - min) / range * 100 : 0;
            var bg = '-moz-element(#__sliderthumb__) ' + position + '% no-repeat, ';
            style(slider, { background: bg + track });
        }

    }

    function style(element, styles) {
        for (var prop in styles)
            element.style.setProperty(prop, styles[prop], 'important');
    }

})();