if(!Control) var Control = {};
Control.Slider = Class.create();

// options:
//  axis: 'vertical', or 'horizontal' (default)
//
// callbacks:
//  onChange(value)
//  onSlide(value)
Control.Slider.prototype = {
    initialize: function(handle, track, options) {
        var slider = this;

        if(handle instanceof Array) {
            this.handles = handle.collect( function(e) {
                return $(e)
            });
        } else {
            this.handles = [$(handle)];
        }

        this.track   = $(track);
        this.options = options || {};

        this.axis      = this.options.axis || 'horizontal';
        this.increment = this.options.increment || 1;
        this.step      = parseInt(this.options.step || '1');
        this.range     = this.options.range || $R(0,1);

        this.value     = 0; // assure backwards compat
        this.values    = this.handles.map( function() {
            return 0
        });
        this.spans     = this.options.spans ? this.options.spans.map(function(s){
            return $(s)
        }) : false;
        this.options.startSpan = $(this.options.startSpan || null);
        this.options.endSpan   = $(this.options.endSpan || null);

        this.restricted = this.options.restricted || false;

        this.maximum   = this.options.maximum || this.range.end;
        this.minimum   = this.options.minimum || this.range.start;

        // Will be used to align the handle onto the track, if necessary
        this.alignX = parseInt(this.options.alignX || '0');
        this.alignY = parseInt(this.options.alignY || '0');

        this.trackLength = this.maximumOffset() - this.minimumOffset();

        this.handleLength = this.isVertical() ?
        (this.handles[0].offsetHeight != 0 ?
            this.handles[0].offsetHeight : this.handles[0].style.height.replace(/px$/,"")) :
        (this.handles[0].offsetWidth != 0 ? this.handles[0].offsetWidth :
            this.handles[0].style.width.replace(/px$/,""));

        this.active   = false;
        this.dragging = false;
        this.disabled = false;

        if(this.options.disabled) this.setDisabled();

        // Allowed values array
        this.allowedValues = this.options.values ? this.options.values.sortBy(Prototype.K) : false;
        if(this.allowedValues) {
            this.minimum = this.allowedValues.min();
            this.maximum = this.allowedValues.max();
        }

        this.eventMouseDown = this.startDrag.bindAsEventListener(this);
        this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
        this.eventMouseMove = this.update.bindAsEventListener(this);

        // Initialize handles in reverse (make sure first handle is active)
        this.handles.each( function(h,i) {
            i = slider.handles.length-1-i;
            slider.setValue(parseFloat(
                (slider.options.sliderValue instanceof Array ?
                    slider.options.sliderValue[i] : slider.options.sliderValue) ||
                slider.range.start), i);
            Element.makePositioned(h); // fix IE
            Event.observe(h, "mousedown", slider.eventMouseDown);
        });

        Event.observe(this.track, "mousedown", this.eventMouseDown);
        Event.observe(document, "mouseup", this.eventMouseUp);
        Event.observe(this.track.parentNode.parentNode, "mousemove", this.eventMouseMove);

        this.initialized = true;
    },
    dispose: function() {
        var slider = this;
        Event.stopObserving(this.track, "mousedown", this.eventMouseDown);
        Event.stopObserving(document, "mouseup", this.eventMouseUp);
        Event.stopObserving(this.track.parentNode.parentNode, "mousemove", this.eventMouseMove);
        this.handles.each( function(h) {
            Event.stopObserving(h, "mousedown", slider.eventMouseDown);
        });
    },
    setDisabled: function(){
        this.disabled = true;
    },
    setEnabled: function(){
        this.disabled = false;
    },
    getNearestValue: function(value){
        if(this.allowedValues){
            if(value >= this.allowedValues.max()) return(this.allowedValues.max());
            if(value <= this.allowedValues.min()) return(this.allowedValues.min());

            var offset = Math.abs(this.allowedValues[0] - value);
            var newValue = this.allowedValues[0];
            this.allowedValues.each( function(v) {
                var currentOffset = Math.abs(v - value);
                if(currentOffset <= offset){
                    newValue = v;
                    offset = currentOffset;
                }
            });
            return newValue;
        }
        if(value > this.range.end) return this.range.end;
        if(value < this.range.start) return this.range.start;
        return value;
    },
    setValue: function(sliderValue, handleIdx){
        if(!this.active) {
            this.activeHandleIdx = handleIdx || 0;
            this.activeHandle    = this.handles[this.activeHandleIdx];
            this.updateStyles();
        }
        handleIdx = handleIdx || this.activeHandleIdx || 0;
        if(this.initialized && this.restricted) {
            if((handleIdx>0) && (sliderValue<this.values[handleIdx-1]))
                sliderValue = this.values[handleIdx-1];
            if((handleIdx < (this.handles.length-1)) && (sliderValue>this.values[handleIdx+1]))
                sliderValue = this.values[handleIdx+1];
        }
        sliderValue = this.getNearestValue(sliderValue);
        this.values[handleIdx] = sliderValue;
        this.value = this.values[0]; // assure backwards compat

        this.handles[handleIdx].style[this.isVertical() ? 'top' : 'left'] =
        this.translateToPx(sliderValue);

        this.drawSpans();
        if(!this.dragging || !this.event) this.updateFinished();
    },
    setValueBy: function(delta, handleIdx) {
        this.setValue(this.values[handleIdx || this.activeHandleIdx || 0] + delta,
            handleIdx || this.activeHandleIdx || 0);
    },
    translateToPx: function(value) {
        return Math.round(
            ((this.trackLength-this.handleLength)/(this.range.end-this.range.start)) *
            (value - this.range.start)) + "px";
    },
    translateToValue: function(offset) {
        return ((offset/(this.trackLength-this.handleLength) *
            (this.range.end-this.range.start)) + this.range.start);
    },
    getRange: function(range) {
        var v = this.values.sortBy(Prototype.K);
        range = range || 0;
        return $R(v[range],v[range+1]);
    },
    minimumOffset: function(){
        return(this.isVertical() ? this.alignY : this.alignX);
    },
    maximumOffset: function(){
        return(this.isVertical() ?
            (this.track.offsetHeight != 0 ? this.track.offsetHeight :
                this.track.style.height.replace(/px$/,"")) - this.alignY :
            (this.track.offsetWidth != 0 ? this.track.offsetWidth :
                this.track.style.width.replace(/px$/,"")) - this.alignY);
    },
    isVertical:  function(){
        return (this.axis == 'vertical');
    },
    drawSpans: function() {
        var slider = this;
        if(this.spans)
            $R(0, this.spans.length-1).each(function(r) {
                slider.setSpan(slider.spans[r], slider.getRange(r))
            });
        if(this.options.startSpan)
            this.setSpan(this.options.startSpan,
                $R(0, this.values.length>1 ? this.getRange(0).min() : this.value ));
        if(this.options.endSpan)
            this.setSpan(this.options.endSpan,
                $R(this.values.length>1 ? this.getRange(this.spans.length-1).max() : this.value, this.maximum));
    },
    setSpan: function(span, range) {
        if(this.isVertical()) {
            span.style.top = this.translateToPx(range.start);
            span.style.height = this.translateToPx(range.end - range.start + this.range.start);
        } else {
            span.style.left = this.translateToPx(range.start);
            span.style.width = this.translateToPx(range.end - range.start + this.range.start);
        }
    },
    updateStyles: function() {
        this.handles.each( function(h){
            Element.removeClassName(h, 'selected')
        });
        Element.addClassName(this.activeHandle, 'selected');
    },
    startDrag: function(event) {
        if(Event.isLeftClick(event)) {
            if(!this.disabled){
                this.active = true;

                var handle = Event.element(event);
                var pointer  = [Event.pointerX(event), Event.pointerY(event)];
                var track = handle;
                if(track==this.track) {
                    var offsets  = Position.cumulativeOffset(this.track);
                    this.event = event;
                    this.setValue(this.translateToValue(
                        (this.isVertical() ? pointer[1]-offsets[1] : pointer[0]-offsets[0])-(this.handleLength/2)
                        ));
                    var offsets  = Position.cumulativeOffset(this.activeHandle);
                    this.offsetX = (pointer[0] - offsets[0]);
                    this.offsetY = (pointer[1] - offsets[1]);
                } else {
                    // find the handle (prevents issues with Safari)
                    while((this.handles.indexOf(handle) == -1) && handle.parentNode)
                        handle = handle.parentNode;

                    if(this.handles.indexOf(handle)!=-1) {
                        this.activeHandle    = handle;
                        this.activeHandleIdx = this.handles.indexOf(this.activeHandle);
                        this.updateStyles();

                        var offsets  = Position.cumulativeOffset(this.activeHandle);
                        this.offsetX = (pointer[0] - offsets[0]);
                        this.offsetY = (pointer[1] - offsets[1]);
                    }
                }
            }
            Event.stop(event);
        }
    },
    update: function(event) {
        if(this.active) {
            if(!this.dragging) this.dragging = true;
            this.draw(event);
            if(Prototype.Browser.WebKit) window.scrollBy(0,0);
            Event.stop(event);
        }
    },
    draw: function(event) {
        var pointer = [Event.pointerX(event), Event.pointerY(event)];
        var offsets = Position.cumulativeOffset(this.track);
        pointer[0] -= this.offsetX + offsets[0];
        pointer[1] -= this.offsetY + offsets[1];
        this.event = event;
        this.setValue(this.translateToValue( this.isVertical() ? pointer[1] : pointer[0] ));
        if(this.initialized && this.options.onSlide)
            this.options.onSlide(this.values.length>1 ? this.values : this.value, this);
    },
    endDrag: function(event) {
        if(this.active && this.dragging) {
            this.finishDrag(event, true);
            Event.stop(event);
        }
        this.active = false;
        this.dragging = false;
    },
    finishDrag: function(event, success) {
        this.active = false;
        this.dragging = false;
        this.updateFinished();
    },
    updateFinished: function() {
        if(this.initialized && this.options.onChange)
            this.options.onChange(this.values.length>1 ? this.values : this.value, this);
        this.event = null;
    }
}