//by Valerio Proietti (http://mad4milk.net). MIT-style license.
//accordion.js - depends on prototype.js or prototype.lite.js + moo.fx.js
//version 2.0

Fx.Accordion = Class.create();
Fx.Accordion.prototype = Object.extend(new Fx.Base(), {

    extendOptions: function(options) {
        Object.extend(this.options, Object.extend({
            start: 'open-first',
            display: 0,
            fixedHeight: false,
            fixedWidth: false,
            alwaysHide: false,
            wait: false,
            onActive: function() { },
            onBackground: function() { },
            height: true,
            opacity: true,
            width: false
        }, options || {}));
    },

    initialize: function(togglers, elements, options) {
        this.now = {};
        this.elements = $A(elements);
        this.togglers = $A(togglers);
        this.setOptions(options);
        this.extendOptions(options);
        this.previousClick = 'nan';
        this.togglers.each(function(tog, i) {
            if (tog.onclick) tog.prevClick = tog.onclick;
            else tog.prevClick = function() { };
            $(tog).onclick = function() {
                tog.prevClick();
                this.showThisHideOpen(i);
            } .bind(this);
        } .bind(this));
        this.h = {}; this.w = {}; this.o = {};
        this.elements.each(function(el, i) {
            this.now[i + 1] = {};
            el.style.height = '0';
            el.style.overflow = 'hidden';
        } .bind(this));
        switch (this.options.start) {
            case 'first-open': this.elements[this.options.display].style.height = this.elements[this.options.display].scrollHeight + 'px'; break;
            case 'open-first': this.showThisHideOpen(this.options.display); break;
            case 'none': break;
        }
    },

    setNow: function() {
        for (var i in this.from) {
            var iFrom = this.from[i];
            var iTo = this.to[i];
            var iNow = this.now[i] = {};
            for (var p in iFrom) iNow[p] = this.compute(iFrom[p], iTo[p]);
        }
    },

    custom: function(objObjs) {
        if (this.timer && this.options.wait) return;
        var from = {};
        var to = {};
        for (var i in objObjs) {
            var iProps = objObjs[i];
            var iFrom = from[i] = {};
            var iTo = to[i] = {};
            for (var prop in iProps) {
                iFrom[prop] = iProps[prop][0];
                iTo[prop] = iProps[prop][1];
            }
        }
        return this._start(from, to);
    },

    hideThis: function(i) {
        if (this.options.height) this.h = { 'height': [this.elements[i].offsetHeight, 0] };
        if (this.options.width) this.w = { 'width': [this.elements[i].offsetWidth, 0] };
        if (this.options.opacity) this.o = { 'opacity': [this.now[i + 1]['opacity'] || 1, 0] };
    },

    showThis: function(i) {
        if (this.options.height) this.h = { 'height': [this.elements[i].offsetHeight, this.options.fixedHeight || this.elements[i].scrollHeight] };
        if (this.options.width) this.w = { 'width': [this.elements[i].offsetWidth, this.options.fixedWidth || this.elements[i].scrollWidth] };
        if (this.options.opacity) this.o = { 'opacity': [this.now[i + 1]['opacity'] || 0, 1] };
    },

    showThisHideOpen: function(iToShow) {
        if (iToShow != this.previousClick || this.options.alwaysHide) {
            this.previousClick = iToShow;
            var objObjs = {};
            var err = false;
            var madeInactive = false;
            this.elements.each(function(el, i) {
                this.now[i] = this.now[i] || {};
                if (i != iToShow) {
                    this.hideThis(i);
                } else if (this.options.alwaysHide) {
                    if (el.offsetHeight == el.scrollHeight) {
                        this.hideThis(i);
                        madeInactive = true;
                    } else if (el.offsetHeight == 0) {
                        this.showThis(i);
                    } else {
                        err = true;
                    }
                } else if (this.options.wait && this.timer) {
                    this.previousClick = 'nan';
                    err = true;
                } else {
                    this.showThis(i);
                }
                objObjs[i + 1] = Object.extend(this.h, Object.extend(this.o, this.w));
            } .bind(this));
            if (err) return;
            if (!madeInactive) this.options.onActive.call(this, this.togglers[iToShow], iToShow);
            this.togglers.each(function(tog, i) {
                if (i != iToShow || madeInactive) this.options.onBackground.call(this, tog, i);
            } .bind(this));
            return this.custom(objObjs);
        }
    },

    increase: function() {
        for (var i in this.now) {
            var iNow = this.now[i];
            for (var p in iNow) this.setStyle(this.elements[parseInt(i) - 1], p, iNow[p]);
        }
    }

});