// codice originale: http://www.nczonline.net/downloads/
// modifiche e adattamenti: Cristian Zuddas

function AutoSuggestControl(oTextbox, oHiddenbox, oProvider) {
	this.cur = -1;
	this.layer = null;
	this.provider = oProvider;
	this.textbox = oTextbox;
	this.hiddenbox = oHiddenbox;
	this.init();
}

AutoSuggestControl.prototype.autosuggest = function (aSuggestions, bTypeAhead) {
	if (aSuggestions.length > 0) {
		if (bTypeAhead)		this.typeAhead(aSuggestions[0]);
		this.showSuggestions(aSuggestions);
	}
	else
		this.hideSuggestions();
};

AutoSuggestControl.prototype.createDropDown = function () {
	var oThis = this;
	this.layer = document.createElement("div");
	this.layer.className = "suggestions";
	this.layer.style.visibility = "hidden";
	this.layer.style.width = this.textbox.offsetWidth;
	
	this.layer.onmousedown = 
	this.layer.onmouseup = 
	this.layer.onmouseover = function (oEvent) {
		oEvent = oEvent || window.event;
		oTarget = oEvent.target || oEvent.srcElement;
		
		if (oEvent.type == "mousedown") {
			var this_sugg = oTarget.firstChild.nodeValue.split("] ");
			oThis.textbox.value = this_sugg[1];
			oThis.hiddenbox.value = this_sugg[0].substring(1);
			oThis.hideSuggestions();
		}
		else if (oEvent.type == "mouseover")
			oThis.highlightSuggestion(oTarget);
		else
			oThis.textbox.focus();
	};
	
	document.body.appendChild(this.layer);
};

AutoSuggestControl.prototype.getLeft = function () {
	var oNode = this.textbox;
	var iLeft = 0;
	
	while(oNode.tagName != "BODY") {
		iLeft += oNode.offsetLeft;
		oNode = oNode.offsetParent;
	}
	
	return iLeft;
};

AutoSuggestControl.prototype.getTop = function () {
	var oNode = this.textbox;
	var iTop = 0;
	
	while(oNode.tagName != "BODY") {
		iTop += oNode.offsetTop;
		oNode = oNode.offsetParent;
	}
	
	return iTop;
};

AutoSuggestControl.prototype.handleKeyDown = function (oEvent) {
	switch(oEvent.keyCode) {
		case 38:
			this.previousSuggestion();
			break;
		case 40:
			this.nextSuggestion();
			break;
		case 13:
			this.hideSuggestions();
			break;
	}
};

AutoSuggestControl.prototype.handleKeyUp = function (oEvent) {
	var iKeyCode = oEvent.keyCode;
	if (iKeyCode == 8 || iKeyCode == 46)
		this.provider.requestSuggestions(this, false);
	else if (iKeyCode < 32 || (iKeyCode >= 33 && iKeyCode < 46) || (iKeyCode >= 112 && iKeyCode <= 123)) {
		//ignore
	}
	else
		this.provider.requestSuggestions(this, true);
};

AutoSuggestControl.prototype.hideSuggestions = function () {
	this.layer.style.visibility = "hidden";
};

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 = "";
	}
};

AutoSuggestControl.prototype.init = function () {
	var oThis = this;
	this.textbox.onkeyup = function (oEvent) {
		if (!oEvent)	oEvent = window.event;
		oThis.handleKeyUp(oEvent);
	};
	
	this.textbox.onkeydown = function (oEvent) {
		if (!oEvent)	oEvent = window.event;
		oThis.handleKeyDown(oEvent);
	};
	
	this.textbox.onblur = function () {
		oThis.hideSuggestions();
	};
	
	this.createDropDown();
};

AutoSuggestControl.prototype.nextSuggestion = function () {
	var cSuggestionNodes = this.layer.childNodes;
	if (cSuggestionNodes.length > 0 && this.cur < cSuggestionNodes.length-1) {
		var oNode = cSuggestionNodes[++this.cur];
		this.highlightSuggestion(oNode);
		var this_sugg = oNode.firstChild.nodeValue.split("] ");
		this.textbox.value = this_sugg[1];
		this.hiddenbox.value = this_sugg[0].substring(1);
	}
};

AutoSuggestControl.prototype.previousSuggestion = function () {
	var cSuggestionNodes = this.layer.childNodes;
	if (cSuggestionNodes.length > 0 && this.cur > 0) {
		var oNode = cSuggestionNodes[--this.cur];
		this.highlightSuggestion(oNode);
		var this_sugg = oNode.firstChild.nodeValue.split("] ");
		this.textbox.value = this_sugg[1];
		this.hiddenbox.value = this_sugg[0].substring(1);
	}
};

AutoSuggestControl.prototype.selectRange = function (iStart, iLength) {
	if (this.textbox.createTextRange) {
		var oRange = this.textbox.createTextRange();
		oRange.moveStart("character", iStart);
		oRange.moveEnd("character", iLength - this.textbox.value.length);
		oRange.select();
	}
	else if (this.textbox.setSelectionRange)
		this.textbox.setSelectionRange(iStart, iLength);
	
	this.textbox.focus();
}; 

AutoSuggestControl.prototype.showSuggestions = function (aSuggestions) {
	var oDiv = null;
	this.layer.innerHTML = "";
	for (var i=0; i < aSuggestions.length; i++) {
		oDiv = document.createElement("div");
		oDiv.appendChild(document.createTextNode(aSuggestions[i]));
		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";
};

AutoSuggestControl.prototype.typeAhead = function (sSuggestion) {
	if (this.textbox.createTextRange || this.textbox.setSelectionRange) {
		var iLen = this.textbox.value.length;
		var this_sugg = sSuggestion.split("] ");
		this.textbox.value = this_sugg[1];
		this.hiddenbox.value = this_sugg[0].substring(1);
		this.selectRange(iLen, sSuggestion.length);
	}
};