/**
 * Autocompleter
 *
 * @version     1.1.1
 *
 * @todo: Caching, no-result handling!
 *
 *
 * @license     MIT-style license
 * @author      Harald Kirschner <mail [at] digitarald.de>
 * @copyright   Author
 */
var Autocompleter = {};

Autocompleter.Base = new Class({

    options: {
        minLength: 1,
        markQuery: true,
        width: 'inherit',
        maxChoices: 10,
        injectChoice: null,
        customChoices: null,
        className: 'autocompleter-choices',
        zIndex: 42,
        delay: 400,
        observerOptions: {},
        fxOptions: {},
        onOver: $empty,
        onSelect: $empty,
        onSelection: $empty,
        onShow: $empty,
        onHide: $empty,
        onBlur: $empty,
        onFocus: $empty,

        autoSubmit: false,
        overflow: false,
        overflowMargin: 25,
        selectFirst: false,
        filter: null,
        filterCase: false,
        filterSubset: false,
        forceSelect: false,
        selectMode: true,
        choicesMatch: null,

        multiple: false,
        separator: ', ',
        separatorSplit: /\s*[,;]\s*/,
        autoTrim: true,
        allowDupes: false,

        cache: true,
        relative: false
    },

    initialize: function(element, options) {
        this.element = $(element);
        this.setOptions(options);
        this.build();
        this.observer = new Observer(this.element, this.prefetch.bind(this), $merge({
            'delay': this.options.delay
        }, this.options.observerOptions));
        this.queryValue = null;
        if (this.options.filter) this.filter = this.options.filter.bind(this);
        var mode = this.options.selectMode;
        this.typeAhead = (mode == 'type-ahead');
        this.selectMode = (mode === true) ? 'selection' : mode;
        this.cached = [];
    },

    /**
     * build - Initialize DOM
     *
     * Builds the html structure for choices and appends the events to the element.
     * Override this function to modify the html generation.
     */
    build: function() {
        if ($(this.options.customChoices)) {
            this.choices = this.options.customChoices;
        } else {
            this.choices = new Element('ul', {
                'class': this.options.className,
                'styles': {
                    'zIndex': this.options.zIndex
                }
            }).inject(document.body);
            this.relative = false;
            if (this.options.relative) {
                this.choices.inject(this.element, 'after');
                this.relative = this.element.getOffsetParent();
            }
            this.fix = new OverlayFix(this.choices);
        }
        if (!this.options.separator.test(this.options.separatorSplit)) {
            this.options.separatorSplit = this.options.separator;
        }
        this.fx = (!this.options.fxOptions) ? null : new Fx.Tween(this.choices, $merge({
            'property': 'opacity',
            'link': 'cancel',
            'duration': 200
        }, this.options.fxOptions)).addEvent('onStart', Chain.prototype.clearChain).set(0);
        this.element.setProperty('autocomplete', 'off')
            .addEvent((Browser.Engine.trident || Browser.Engine.webkit) ? 'keydown' : 'keypress', this.onCommand.bind(this))
            .addEvent('click', this.onCommand.bind(this, [false]))
            .addEvent('focus', this.toggleFocus.create({bind: this, arguments: true, delay: 100}))
            .addEvent('blur', this.toggleFocus.create({bind: this, arguments: false, delay: 100}));
    },

    destroy: function() {
        if (this.fix) this.fix.destroy();
        this.choices = this.selected = this.choices.destroy();
    },

    toggleFocus: function(state) {
        this.focussed = state;
        if (!state) this.hideChoices(true);
        this.fireEvent((state) ? 'onFocus' : 'onBlur', [this.element]);
    },

    onCommand: function(e) {
        if (!e && this.focussed) return this.prefetch();
        if (e && e.key && !e.shift) {
            switch (e.key) {
                case 'enter':
                    if (this.element.value != this.opted) return true;
                    if (this.selected && this.visible) {
                        this.choiceSelect(this.selected);
                        return !!(this.options.autoSubmit);
                    }
                    break;
                case 'up': case 'down':
                    if (!this.prefetch() && this.queryValue !== null) {
                        var up = (e.key == 'up');
                        this.choiceOver((this.selected || this.choices)[
                            (this.selected) ? ((up) ? 'getPrevious' : 'getNext') : ((up) ? 'getLast' : 'getFirst')
                        ](this.options.choicesMatch), true);
                    }
                    return false;
                case 'esc': case 'tab':
                    this.hideChoices(true);
                    break;
            }
        }
        return true;
    },

    setSelection: function(finish) {
        var input = this.selected.inputValue, value = input;
        var start = this.queryValue.length, end = input.length;
        if (input.substr(0, start).toLowerCase() != this.queryValue.toLowerCase()) start = 0;
        if (this.options.multiple) {
            var split = this.options.separatorSplit;
            value = this.element.value;
            start += this.queryIndex;
            end += this.queryIndex;
            var old = value.substr(this.queryIndex).split(split, 1)[0];
            value = value.substr(0, this.queryIndex) + input + value.substr(this.queryIndex + old.length);
            if (finish) {
                var space = /[^\s,]+/;
                var tokens = value.split(this.options.separatorSplit).filter(space.test, space);
                if (!this.options.allowDupes) tokens = [].combine(tokens);
                var sep = this.options.separator;
                value = tokens.join(sep) + sep;
                end = value.length;
            }
        }
        this.observer.setValue(value);
        this.opted = value;
        if (finish || this.selectMode == 'pick') start = end;
        this.element.selectRange(start, end);
        this.fireEvent('onSelection', [this.element, this.selected, value, input]);
    },

    showChoices: function() {
        var match = this.options.choicesMatch, first = this.choices.getFirst(match);
        this.selected = this.selectedValue = null;
        if (this.fix) {
            var pos = this.element.getCoordinates(this.relative), width = this.options.width || 'auto';
            this.choices.setStyles({
                'left': pos.left,
                'top': pos.bottom,
                'width': (width === true || width == 'inherit') ? pos.width : width
            });
        }
        if (!first) return;
        if (!this.visible) {
            this.visible = true;
            this.choices.setStyle('display', '');
            if (this.fx) this.fx.start(1);
            this.fireEvent('onShow', [this.element, this.choices]);
        }
        if (this.options.selectFirst || this.typeAhead || first.inputValue == this.queryValue) this.choiceOver(first, this.typeAhead);
        var items = this.choices.getChildren(match), max = this.options.maxChoices;
        var styles = {'overflowY': 'hidden', 'height': ''};
        this.overflown = false;
        if (items.length > max) {
            var item = items[max - 1];
            styles.overflowY = 'scroll';
            styles.height = item.getCoordinates(this.choices).bottom;
            this.overflown = true;
        };
        this.choices.setStyles(styles);
        this.fix.show();
    },

    hideChoices: function(clear) {
        if (clear) {
            var value = this.element.value;
            if (this.options.forceSelect) value = this.opted;
            if (this.options.autoTrim) {
                value = value.split(this.options.separatorSplit).filter($arguments(0)).join(this.options.separator);
            }
            this.observer.setValue(value);
        }
        if (!this.visible) return;
        this.visible = false;
        this.observer.clear();
        var hide = function(){
            this.choices.setStyle('display', 'none');
            this.fix.hide();
        }.bind(this);
        if (this.fx) this.fx.start(0).chain(hide);
        else hide();
        this.fireEvent('onHide', [this.element, this.choices]);
    },

    prefetch: function() {
        var value = this.element.value, query = value;
        if (this.options.multiple) {
            var split = this.options.separatorSplit;
            var values = value.split(split);
            var index = this.element.getCaretPosition();
            var toIndex = value.substr(0, index).split(split);
            var last = toIndex.length - 1;
            index -= toIndex[last].length;
            query = values[last];
        }
        if (query.length < this.options.minLength) {
            this.hideChoices();
        } else {
            if (query === this.queryValue || (this.visible && query == this.selectedValue)) {
                if (this.visible) return false;
                this.showChoices();
            } else {
                this.queryValue = query;
                this.queryIndex = index;
                if (!this.fetchCached()) this.query();
            }
        }
        return true;
    },

    fetchCached: function() {
        return false;
        if (!this.options.cache
            || !this.cached
            || !this.cached.length
            || this.cached.length >= this.options.maxChoices
            || this.queryValue) return false;
        this.update(this.filter(this.cached));
        return true;
    },

    update: function(tokens) {
        this.choices.empty();
        this.cached = tokens;
        if (!tokens || !tokens.length) {
            this.hideChoices();
        } else {
            if (this.options.maxChoices < tokens.length && !this.options.overflow) tokens.length = this.options.maxChoices;
            tokens.each(this.options.injectChoice || function(token){
                var choice = new Element('li', {'html': this.markQueryValue(token)});
                choice.inputValue = token;
                this.addChoiceEvents(choice).inject(this.choices);
            }, this);
            this.showChoices();
        }
    },

    choiceOver: function(choice, selection) {
        if (!choice || choice == this.selected) return;
        if (this.selected) this.selected.removeClass('autocompleter-selected');
        this.selected = choice.addClass('autocompleter-selected');
        this.fireEvent('onSelect', [this.element, this.selected, selection]);
        if (!selection) return;
        this.selectedValue = this.selected.inputValue;
        if (this.overflown) {
            var coords = this.selected.getCoordinates(this.choices), margin = this.options.overflowMargin,
                top = this.choices.scrollTop, height = this.choices.offsetHeight, bottom = top + height;
            if (coords.top - margin < top && top) this.choices.scrollTop = Math.max(coords.top - margin, 0);
            else if (coords.bottom + margin > bottom) this.choices.scrollTop = Math.min(coords.bottom - height + margin, bottom);
        }
        if (this.selectMode) this.setSelection();
    },

    choiceSelect: function(choice) {
        if (choice) this.choiceOver(choice);
        this.setSelection(true);
        this.queryValue = false;
        this.hideChoices();
    },

    filter: function(tokens) {
        var regex = new RegExp(((this.options.filterSubset) ? '' : '^') + this.queryValue.escapeRegExp(), (this.options.filterCase) ? '' : 'i');
        return (tokens || this.tokens).filter(regex.test, regex);
    },

    /**
     * markQueryValue
     *
     * Marks the queried word in the given string with <span class="autocompleter-queried">*</span>
     * Call this i.e. from your custom parseChoices, same for addChoiceEvents
     *
     * @param       {String} Text
     * @return      {String} Text
     */
    markQueryValue: function(str) {
        return (!this.options.markQuery || !this.queryValue) ? str
            : str.replace(new RegExp('(' + ((this.options.filterSubset) ? '' : '^') + this.queryValue.escapeRegExp() + ')', (this.options.filterCase) ? '' : 'i'), '<span class="autocompleter-queried">$1</span>');
    },

    /**
     * addChoiceEvents
     *
     * Appends the needed event handlers for a choice-entry to the given element.
     *
     * @param       {Element} Choice entry
     * @return      {Element} Choice entry
     */
    addChoiceEvents: function(el) {
        return el.addEvents({
            'mouseover': this.choiceOver.bind(this, [el]),
            'click': this.choiceSelect.bind(this, [el])
        });
    }
});

Autocompleter.Base.implement(new Events);
Autocompleter.Base.implement(new Options);

Autocompleter.Local = new Class({

    Extends: Autocompleter.Base,

    options: {
        minLength: 0,
        delay: 200
    },

    initialize: function(element, tokens, options) {
        this.parent(element, options);
        this.tokens = tokens;
    },

    query: function() {
        this.update(this.filter());
    }

});

Autocompleter.Ajax = {};

Autocompleter.Ajax.Base = new Class({

    Extends: Autocompleter.Base,

    options: {
        postVar: 'value',
        postData: {},
        ajaxOptions: {},
        onRequest: $empty,
        onComplete: $empty
    },

    initialize: function(element, options) {
        this.parent(element, options);
        var indicator = $(this.options.indicator);
        if (indicator) {
            this.addEvents({
                'onRequest': indicator.show.bind(indicator),
                'onComplete': indicator.hide.bind(indicator)
            }, true);
        }
    },

    query: function(){
        var data = $unlink(this.options.postData);
        data[this.options.postVar] = this.queryValue;
        this.fireEvent('onRequest', [this.element, this.request, data, this.queryValue]);
        this.request.send({'data': data});
    },

    /**
     * queryResponse - abstract
     *
     * Inherated classes have to extend this function and use this.parent(resp)
     *
     * @param       {String} Response
     */
    queryResponse: function() {
        this.fireEvent('onComplete', [this.element, this.request, this.response]);
    }

});

Autocompleter.Ajax.Json = new Class({

    Extends: Autocompleter.Ajax.Base,

    initialize: function(el, url, options) {
        this.parent(el, options);
        this.request = new Request.JSON($merge({
            'url': url,
            'link': 'cancel'
        }, this.options.ajaxOptions)).addEvent('onComplete', this.queryResponse.bind(this));
    },

    queryResponse: function(response) {
        this.parent();
        this.update(response);
    }

});

Autocompleter.Ajax.Xhtml = new Class({

    Extends: Autocompleter.Ajax.Base,

    initialize: function(el, url, options) {
        this.parent(el, options);
        this.request = new Request.HTML($merge({
            'url': url,
            'link': 'cancel',
            'update': this.choices
        }, this.options.ajaxOptions)).addEvent('onComplete', this.queryResponse.bind(this));
    },

    queryResponse: function(tree, elements) {
        this.parent();
        if (!elements || !elements.length) {
            this.hideChoices();
        } else {
            this.choices.getChildren(this.options.choicesMatch).each(this.options.injectChoice || function(choice) {
                var value = choice.innerHTML;
                choice.inputValue = value;
                this.addChoiceEvents(choice.set('html', this.markQueryValue(value)));
            }, this);
            this.showChoices();
        }

    }

});


var OverlayFix = new Class({

    initialize: function(el) {
        if (Browser.Engine.trident) {
            this.element = $(el);
            this.relative = this.element.getOffsetParent();
            this.fix = new Element('iframe', {
                'frameborder': '0',
                'scrolling': 'no',
                'src': 'javascript:false;',
                'styles': {
                    'position': 'absolute',
                    'border': 'none',
                    'display': 'none',
                    'filter': 'progid:DXImageTransform.Microsoft.Alpha(opacity=0)'
                }
            }).inject(this.element, 'after');
        }
    },

    show: function() {
        if (this.fix) {
            var coords = this.element.getCoordinates(this.relative);
            delete coords.right;
            delete coords.bottom;
            this.fix.setStyles($extend(coords, {
                'display': '',
                'zIndex': (this.element.getStyle('zIndex') || 1) - 1
            }));
        }
        return this;
    },

    hide: function() {
        if (this.fix) this.fix.setStyle('display', 'none');
        return this;
    },

    destroy: function() {
        this.fix = this.fix.destroy();
    }

});

/**
 * @todo Clean that up or check if they exist already
 */
Element.implement({

    getOffsetParent: function() {
        var body = this.getDocument().body;
        if (this == body) return null;
        if (!Browser.Engine.trident) return $(this.offsetParent);
        var el = this;
        while ((el = el.parentNode)){
            if (el == body || Element.getComputedStyle(el, 'position') != 'static') return $(el);
        }
        return null;
    },

    getCaretPosition: function() {
        if (!Browser.Engine.trident) return this.selectionStart;
        this.focus();
        var work = document.selection.createRange();
        var all = this.createTextRange();
        work.setEndPoint('StartToStart', all);
        return work.text.length;
    },

    selectRange: function(start, end) {
        if (Browser.Engine.trident) {
            var range = this.createTextRange();
            range.collapse(true);
            range.moveEnd('character', end);
            range.moveStart('character', start);
            range.select();
        } else {
            this.focus();
            this.setSelectionRange(start, end);
        }
        return this;
    }

});