/**
 * An autosuggest textbox control.
 * @class
 * @scope public
 */
function AutoSuggestControl(oTextbox /*:HTMLInputElement*/, 
                            oProvider /*:SuggestionProvider*/,
                            onEnterCallback) {
    
    /**
     * The currently selected suggestions.
     * @scope private
     */   
    this.cur /*:int*/ = -1;

    /**
     * The dropdown list layer.
     * @scope private
     */
    this.layer = null;
    
    /**
     * Suggestion provider for the autosuggest feature.
     * @scope private.
     */
    this.provider /*:SuggestionProvider*/ = oProvider;
    
    /**
     * The textbox to capture.
     * @scope private
     */
    this.textbox /*:HTMLInputElement*/ = oTextbox;
    
    this.onEnterCallback = onEnterCallback;

    //initialize the control
    this.init();
    
}

/**
 * Autosuggests one or more suggestions for what the user has typed.
 * If no suggestions are passed in, then no autosuggest occurs.
 * @scope private
 * @param aSuggestions An array of suggestion strings.
 * @param bTypeAhead If the control should provide a type ahead suggestion.
 */
AutoSuggestControl.prototype.autosuggest = function (aSuggestions /*:Array*/,
                                                     bTypeAhead /*:boolean*/) {
    
    //make sure there's at least one suggestion
    if (aSuggestions.length > 0) {
        if (bTypeAhead) {           
           this.typeAhead(aSuggestions[0].word, aSuggestions[0].id);           
        }
        
        this.showSuggestions(aSuggestions);
    } else {
        this.hideSuggestions();
    }
};

/**
 * Creates the dropdown layer to display multiple suggestions.
 * @scope private
 */
AutoSuggestControl.prototype.createDropDown = function () {

    var oThis = this;

    //create the layer and assign styles
    this.layer = document.createElement("div");
    this.layer.className = "suggestions";
    //this.layer.style.visibility = "hidden";
    this.layer.style.display = "none";
    this.layer.style.width = this.textbox.offsetWidth + 'px';
    //this.layer.style.height = '200px';
    this.layer.style.overflowY = 'auto';
    this.layer.style.backgroundColor = '#ffffff';
    
    //when the user clicks on the a suggestion, get the text (innerHTML)
    //and place it into a textbox
    this.layer.onmousedown = 
    this.layer.onmouseup = 
    this.layer.onmouseover = function (oEvent) {
        oEvent = oEvent || window.event;
        oTarget = oEvent.target || oEvent.srcElement;

        if (oEvent.type == "mousedown") {
            if(oTarget != oThis.layer){
              oThis.textbox.value = oTarget.firstChild.nodeValue;
              oThis.textbox.setAttribute('wordid', oTarget.getAttribute('wordid'));
              oThis.hideSuggestions();  
            }          
        } else if (oEvent.type == "mouseover") {
            oThis.highlightSuggestion(oTarget);
        } else {
            oThis.textbox.focus();
        }
    };
    
    
    document.body.appendChild(this.layer);
};

AutoSuggestControl.prototype.getOffsetParent = function(elem)
{
	do
	{
		elem = elem.offsetParent;
	} while (elem && elem.nodeType != 1);
	return elem;
}

/**
 * Gets the left coordinate of the textbox.
 * @scope private
 * @return The left coordinate of the textbox in pixels.
 */
AutoSuggestControl.prototype.getLeft = function () /*:int*/ {

    var oNode = this.textbox;
    var iLeft = 0;
    
    while(oNode && oNode.tagName != "BODY") {
        iLeft += oNode.offsetLeft;
        oNode = this.getOffsetParent(oNode);
    }
    
    return iLeft;
};

/**
 * Gets the top coordinate of the textbox.
 * @scope private
 * @return The top coordinate of the textbox in pixels.
 */
AutoSuggestControl.prototype.getTop = function () /*:int*/ {

    var oNode = this.textbox;
    var iTop = 0;
    
    while(oNode && oNode.tagName != "BODY") {
        iTop += oNode.offsetTop;    
        oNode = this.getOffsetParent(oNode);        
    }
    
    return iTop;
};

/**
 * Handles three keydown events.
 * @scope private
 * @param oEvent The event object for the keydown event.
 */
AutoSuggestControl.prototype.handleKeyDown = function (oEvent /*:Event*/) {

    switch(oEvent.keyCode) {
        case 38: //up arrow
            this.previousSuggestion();
            oEvent.cancelBubble = true;
            if(oEvent.stopPropagation)oEvent.stopPropagation();
            break;
        case 40: //down arrow 
            this.nextSuggestion();
            oEvent.cancelBubble = true;
            if(oEvent.stopPropagation)oEvent.stopPropagation();
            break;
        case 13: //enter
            this.hideSuggestions();
            if(typeof(this.onEnterCallback) == 'function'){                
                this.onEnterCallback();
            }
            return false;
            break;
    }

};

/**
 * Handles keyup events.
 * @scope private
 * @param oEvent The event object for the keyup event.
 */
AutoSuggestControl.prototype.handleKeyUp = function (oEvent /*:Event*/) {

    var iKeyCode = oEvent.keyCode;

    //for backspace (8) and delete (46), shows suggestions without typeahead
    if (iKeyCode == 8 || iKeyCode == 46) {
        this.provider.requestSuggestions(this, false);
        
    //make sure not to interfere with non-character keys
    } else if (iKeyCode < 32 || (iKeyCode >= 33 && iKeyCode < 46) || (iKeyCode >= 112 && iKeyCode <= 123)) {
        //ignore
    } else {
        //request suggestions from the suggestion provider with typeahead
        this.provider.requestSuggestions(this, true);
    }
};

/**
 * Hides the suggestion dropdown.
 * @scope private
 */
AutoSuggestControl.prototype.hideSuggestions = function () {
    //this.layer.style.visibility = "hidden";
    this.layer.style.display = "none";
};

/**
 * Highlights the given node in the suggestions dropdown.
 * @scope private
 * @param oSuggestionNode The node representing a suggestion in the dropdown.
 */
AutoSuggestControl.prototype.highlightSuggestion = function (oSuggestionNode) {
    
    for (var i=0; i < this.layer.childNodes.length; i++) {
        var oNode = this.layer.childNodes[i];
        if (oNode == oSuggestionNode) {
            oNode.className = "current"            
        } else if (oNode.className == "current") {
            oNode.className = "";
        }
    }
};

/**
 * Initializes the textbox with event handlers for
 * auto suggest functionality.
 * @scope private
 */
AutoSuggestControl.prototype.init = function () {

    //save a reference to this object
    var oThis = this;
    
    //assign the onkeyup event handler
    this.textbox.onkeyup = function (oEvent) {
    
        //check for the proper location of the event object
        if (!oEvent) {
            oEvent = window.event;
        }    
        
        //call the handleKeyUp() method with the event object
        oThis.handleKeyUp(oEvent);
    };
    
    //assign onkeydown event handler
    this.textbox.onkeydown = function (oEvent) {
    
        //check for the proper location of the event object
        if (!oEvent) {
            oEvent = window.event;
        }    
        
        //call the handleKeyDown() method with the event object
        oThis.handleKeyDown(oEvent);
    };
    
    //assign onblur event handler (hides suggestions)    
    this.textbox.onblur = function () {
        oThis.hideSuggestions();
    };
    
    this.textbox.onfocus = function () {
        oThis.provider.requestSuggestions(oThis, false);
    };
    
    this.textbox.autocomplete = 'off';
    
    //create the suggestions dropdown
    this.createDropDown();
};

/**
 * Highlights the next suggestion in the dropdown and
 * places the suggestion into the textbox.
 * @scope private
 */
AutoSuggestControl.prototype.nextSuggestion = function () {
    var cSuggestionNodes = this.layer.childNodes;

    if (cSuggestionNodes.length > 0) {
        var index;
        if(this.cur < cSuggestionNodes.length-1){
          index = this.cur + 1;
        }
        else{
          index = 0;
        }
        var oNode = cSuggestionNodes[index];
        this.highlightSuggestion(oNode);
        this.textbox.value = oNode.firstChild.nodeValue;
        this.textbox.setAttribute('wordid', oNode.getAttribute('wordid'));
        //oNode.scrollIntoView();
        this.cur = index;
    }
};

/**
 * Highlights the previous suggestion in the dropdown and
 * places the suggestion into the textbox.
 * @scope private
 */
AutoSuggestControl.prototype.previousSuggestion = function () {
    var cSuggestionNodes = this.layer.childNodes;

    if (cSuggestionNodes.length > 0) {
        var index;
        if(this.cur > 0){
          index = this.cur - 1;
        }
        else{
          index = cSuggestionNodes.length - 1;
        }
        var oNode = cSuggestionNodes[index];
        this.highlightSuggestion(oNode);
        this.textbox.value = oNode.firstChild.nodeValue;
        this.textbox.setAttribute('wordid', oNode.getAttribute('wordid'));
        //oNode.scrollIntoView();
        this.cur = index;
    }
};

/**
 * Selects a range of text in the textbox.
 * @scope public
 * @param iStart The start index (base 0) of the selection.
 * @param iLength The number of characters to select.
 */
AutoSuggestControl.prototype.selectRange = function (iStart /*:int*/, iLength /*:int*/) {

    //use text ranges for Internet Explorer
    if (this.textbox.createTextRange) {
        var oRange = this.textbox.createTextRange(); 
        oRange.moveStart("character", iStart); 
        oRange.moveEnd("character", iLength - this.textbox.value.length);      
        oRange.select();
        
    //use setSelectionRange() for Mozilla
    } else if (this.textbox.setSelectionRange) {
        this.textbox.setSelectionRange(iStart, iLength);
    }     

    //set focus back to the textbox
    this.textbox.focus();      
}; 

/**
 * Builds the suggestion layer contents, moves it into position,
 * and displays the layer.
 * @scope private
 * @param aSuggestions An array of suggestions for the control.
 */
AutoSuggestControl.prototype.showSuggestions = function (aSuggestions /*:Array*/) {
    
    var oDiv = null;
    this.layer.innerHTML = "";  //clear contents of the layer
    
    for (var i=0; i < aSuggestions.length; i++) {
        oDiv = document.createElement("div");
        oDiv.appendChild(document.createTextNode(aSuggestions[i].word));
        oDiv.setAttribute('wordid', aSuggestions[i].id);
        this.layer.appendChild(oDiv);
    }
        
    this.layer.style.left = this.getLeft() + "px";
    this.layer.style.top = (this.getTop()+this.textbox.offsetHeight) + "px";
    //this.layer.style.visibility = "visible";
    this.layer.style.display = "block";
    this.layer.style.position = "absolute";

};

/**
 * Inserts a suggestion into the textbox, highlighting the 
 * suggested part of the text.
 * @scope private
 * @param sSuggestion The suggestion for the textbox.
 */
AutoSuggestControl.prototype.typeAhead = function (sSuggestion /*:String*/, iID) {

    //check for support of typeahead functionality
    if (this.textbox.createTextRange || this.textbox.setSelectionRange){
        var iLen = this.textbox.value.length; 
        this.textbox.value = sSuggestion; 
        this.textbox.setAttribute('wordid', iID);
        this.selectRange(iLen, sSuggestion.length);
    }
};

AutoSuggestControl.prototype.updateProvider = function(oProvider){
    this.provider = oProvider;    
}

/**
 * Provides suggestions for state names (USA).
 * @class
 * @scope public
 */
function Suggestions(ajaxFuncThis, ajaxFunc, ajaxFuncCallback){
    this.words = [];
    this.recentWords = [];
    this.aSuggestions = [];
    
    this.oAutoSuggestControl = null;
            
    this.callAJAX = function(){
        if(typeof(ajaxFunc) == 'function'){
            var oThis = this;
            ajaxFunc.call(ajaxFuncThis, oThis.oAutoSuggestControl.textbox.value, ajaxFuncCallback)
        }        
    }
}

function SuggestionWord(iID, sWord){
    this.id = iID;
    this.word = sWord;    
}


Suggestions.prototype = {
    /**
     * Request suggestions for the given autosuggest control. 
     * @scope protected
     * @param oAutoSuggestControl The autosuggest control to provide suggestions for.
     */
    requestSuggestions: function(oAutoSuggestControl, bTypeAhead){
        var oThis = this;
        oThis.aSuggestions = [];
        oThis.oAutoSuggestControl = oAutoSuggestControl;        
        var sTextboxValue = oAutoSuggestControl.textbox.value.toLowerCase();
        
        if (sTextboxValue.length > 0){    
            //only search if we have at least 2 chars
            if (sTextboxValue.length > 1){
                //make ajax call
                oThis.callAJAX();
                
                return;
            }
            else{   
                //search for match
                for (var i=0,l=this.recentWords.length;i<l;i++){ 
                    var recentWord = this.recentWords[i];
                    if(recentWord.word.toLowerCase().indexOf(sTextboxValue) == 0){
                        oThis.aSuggestions.push(recentWord);
                    } 
                }
            }
        }
        else{
            
            //show top 5 words
            var max = 5;
            var l = (this.recentWords.length>max?max:this.recentWords.length);        
            for (var i=0; i < l; i++) {            
                oThis.aSuggestions.push(this.recentWords[i]);             
            }        
        }

        //provide suggestions to the control
        oAutoSuggestControl.autosuggest(oThis.aSuggestions, bTypeAhead);
    },
    
    updateSuggestions: function(aSuggestions){
        var oThis = this;
        oThis.aSuggestions = aSuggestions;        
        oThis.oAutoSuggestControl.autosuggest(oThis.aSuggestions, false); //no typeahead
        oThis.oAutoSuggestControl.cur = -1;
    }
}