/**
 * DataCell is a wrapper object for all HTML DOM objects of one data item.
 * All usable data units in the application should be of this type.
 * Equivalent to a register
 */

/**
 * DataCell constructor
 * Optional arguments:
 * showID - true if you want to show cell ID
 * serialID - cell's serial ID you would like to show
 * numDigits - number of digits to show in ID (with trailing zeros)
 */
function DataCell(isRegister, showID, serialID, numDigits, first) {
	var itemDivName = "itemdiv" + getNewGUID();
	var itemTextBoxName = itemDivName + "tb";
	var itemSpanName = itemDivName + "sp";
	
	var itemDiv = document.createElement('DIV');
	itemDiv.id = itemDivName;
		
	var itemSpan = document.createElement('SPAN');
	itemSpan.id = itemSpanName;
	itemDiv.appendChild(itemSpan);
	
	var itemTextBox = document.createElement('INPUT');
	itemTextBox.type = 'TEXT';
	itemTextBox.id = itemTextBoxName;
	itemDiv.appendChild(itemTextBox);

	itemDiv.style.height = CELL_HEIGHT;
	itemDiv.style.lineHeight = CELL_HEIGHT;
	itemDiv.style.fontSize = CELL_FONT_SIZE;
	itemDiv.style.fontWeight = "bolder";
	itemDiv.style.fontFamily = "Arial";
	itemDiv.style.textAlign = "center";
	itemDiv.style.verticalAlign = "middle";
	itemDiv.style.padding = "0";
	itemDiv.style.backgroundColor = CELL_COLOR;
	itemDiv.style.borderBottomWidth = "1px";
	itemDiv.style.borderBottomColor = "#000000";
	itemDiv.style.borderBottomStyle = "Solid";
	itemDiv.style.borderRightWidth = "1px";
	itemDiv.style.borderRightColor = "#000000";
	itemDiv.style.borderRightStyle = "Solid";
	if (showID) {
		itemDiv.style.borderLeftWidth = "1px";
		itemDiv.style.borderLeftColor = "#000000";
		itemDiv.style.borderLeftStyle = "Solid";
		//Fix IE/Firefox mismatch
		itemDiv.style.width = (document.all ? "100%" : "96%");
		if (first) {
			itemDiv.style.borderTopWidth = "1px";
			itemDiv.style.borderTopColor = "#000000";
			itemDiv.style.borderTopStyle = "Solid";
		}
	}
	else {
		//Fix IE/Firefox mismatch
		itemDiv.style.width = (document.all ? "100%" : "98%");
	}
	
	itemSpan.style.width = "80%";
	itemSpan.style.height = CELL_HEIGHT;
	itemSpan.style.lineHeight = CELL_HEIGHT;
	itemSpan.style.position = "relative";
	itemSpan.style.left = "0";
	itemSpan.style.top = "0";
	itemSpan.style.fontSize = CELL_FONT_SIZE;
	itemSpan.style.fontWeight = "bolder";
	itemSpan.style.fontFamily = "Arial";
	itemSpan.style.textAlign = "right";
	itemSpan.style.verticalAlign = "middle";
	itemSpan.style.display = "block";
	itemSpan.style.marginRight = "6px";

	itemTextBox.style.width = "100%";
	itemTextBox.style.height = (parseInt(CELL_HEIGHT)  - (document.all ? 2 : 0)) + "px";
	itemTextBox.style.lineHeight = (parseInt(CELL_HEIGHT)  - (document.all ? 2 : 0)) + "px";
	itemTextBox.style.position = "relative";
	itemTextBox.style.left = "0";
	itemTextBox.style.top = (document.all ? "-1" : "0");
	itemTextBox.style.fontSize = CELL_FONT_SIZE;
	itemTextBox.style.fontWeight = "bolder";
	itemTextBox.style.fontFamily = "Arial";
	itemTextBox.style.textAlign = "right";
	itemTextBox.style.verticalAlign = "middle";
	itemTextBox.style.display = "none";
	itemTextBox.maxLength = 3;
	itemTextBox.style.paddingRight = "8px";

	itemDiv.dataCell = this;
	
	this.itemDiv = itemDiv;
	this.textBox = itemTextBox;
	this.span = itemSpan;
	
	//Parent must implement IDataSet
	this.parent = null;
	this.enabled = true;
	
	var that = this;
	
	/**
	 * Mouse down event handler
	 */
	this.itemDiv.onmousedown = function() {
		//Only allow editing if higher cells have values
		if (that.itemDiv.previousSibling && 
			that.itemDiv.previousSibling.dataCell.getValue() == undefined)
			return true;
	
		if (that.parent.enabled && that.enabled && 
				(that.textBox.style.display == "none")) {
			that.textBox.style.display = "block";
			that.span.style.display = "none";
			if (!(navigator && navigator.userAgent && navigator.userAgent.match('Safari') && !navigator.userAgent.match('Chrome'))) {
				that.textBox.focus();
			} else {
				that.textBox.select();
			}
		}
		// Firefox and chrome expect 'false', safari expects 'true'??
		if (navigator && navigator.userAgent && navigator.userAgent.match('Safari') && !(navigator.userAgent.match('Chrome'))) {
			return false;
		} else {
			return false;
		}
	};
	
	/**
	 * Sets cursor to text box
	 * (For IE)
	 */
	this.textBox.onfocus = function() {
		that.textBox.select();
	}

	/**
	 * Textbox unfocus event handler
	 */
	this.textBox.onblur = function() {
/*
if ((navigator && navigator.userAgent && navigator.userAgent.match('Safari') && !navigator.userAgent.match('Chrome'))) {
	alert('SAFARI USER - We are working on some bug fixes. Please switch a browser or try again later');
}
*/
		//if (that.textBox.style.display == "block") {
			if (that.textBox.value === "") {
				that.parent.clearCell(that);
			}
			else
				that.setValue(that.textBox.value, false, true);
			that.textBox.style.display = "none";
			that.span.style.display = "block";
		//}
		if (that.ondatachange) { that.ondatachange(); }
		return true;
	}

	/**
	 * Textbox keypress event handler 
	 */
	this.textBox.onkeypress = function(e) {
		var keyCode, keynum;
		if (window.event) { //IE
			keyCode = event.keyCode;
			keynum = keyCode;
		}
		else {
			keyCode = e.keyCode;
			keynum = e.which;
		}
		
		if (keyCode == 13) {
			//Enter
			if (that.textBox.value === "") {
				that.parent.clearCell(that);
			}
			else
				that.setValue(that.textBox.value, false, true);

			if (that.parent.isCPU && that.parent.computer) {
				that.parent.computer.highlightPCAddress();
			}
			if (that.ondatachange && !that.onenterpressed) that.ondatachange();		
			if (that.onenterpressed) { 
				that.onenterpressed(serialID); 
				if (innerValue != 0) return; 
			}
		}
		//Retrieve Esc keyCode
		var Esc = (window.event) ? 27 : e.DOM_VK_ESCAPE;
		if (keyCode == Esc || keyCode == 13) {
			//Enter or Esc
			that.textBox.style.display = "none";
			that.span.style.display = "block";
			return true;
		}
		else if (keyCode == 8) {
			//Backspace
			return true;
		}
		else if (keynum == 0) {
			//Other control keys (Arrows, etc.)
			return true;
		}
		else {
			//Other - allow only digits and minus, no more than three
			keychar = String.fromCharCode(keynum);
			var numcheck;
			if (that.textBox.value=="")
				numcheck = /[\d\-]/;
			else
				numcheck = /\d/;
				
			var negcheck = /\-\d*/;
			if (negcheck.test(that.textBox.value))
				that.textBox.maxLength = 4;
			else
				that.textBox.maxLength = 3;
				
			return numcheck.test(keychar);
		}
	}

	var innerValue = 0;
	var innerEmpty = true;

	/** 
	 * Sets the value of the Data Cell
	 * Returns an object with property 'overflow'
	 */
	this.setValue = function(stringValue, empty, forceDisplay) {
		if (empty) {
			that.span.innerHTML = "";
			that.textBox.value = "";
			innerValue = 0;
			innerEmpty = true;
			return true;
		}
	
		numcheck = /\-{0,1}\d/;
		if (!numcheck.test(stringValue)) return false;
		var numValue;
		try {
			numValue = parseInt(stringValue, 10);
		} catch (e) {
			return false;
		}
		var overflow = numValue > 999 || numValue < -999;
		if (overflow) return { overflow: true };
		
		var absVal = Math.abs(numValue);
		stringValue = absVal;
		var sign = (numValue < 0) ? '-' : '';
		
		stringValue = sign + stringValue;//.substr(stringValue.length - 3, 3);
		
		//if (that.parent.isInputList) that.parent.ioChip.saveInput();
		if (forceDisplay || !document.computer || document.computer.getAnimation() != ANIMATE_NONE) {
			that.span.innerHTML = stringValue;
			that.textBox.value = stringValue;
		}
		innerValue = stringValue;
		innerEmpty = false;
	
		return { overflow: false };
	}
	
	this.showValue = function() {
		that.span.innerHTML = innerEmpty ? "" : innerValue;
		that.textBox.value = innerEmpty ? "" : innerValue;
	}
	
	/**
	 * Returns DataCell's value
	 */
	this.getValue = function() {
		numcheck = /\-{0,1}\d/;
		if (innerEmpty || !numcheck.test(innerValue)) return (that.parent && that.parent.dataSetType == "DataArray" ? 0 : undefined);
		return parseInt(innerValue, 10);
	}
	
	/**
	 * Returns the string value of this cell (whatever it is)
	 */
	this.getStringValue = function() {
		return that.span.innerHTML;
	}
	
	/**
	 * Clones this DataCell
	 */
	this.clone = function() {
		var newCell = new DataCell();
		newCell.setValue(that.getValue());
		return newCell;
	}
	
	/**
	 * Highlights (or de-highlights) this DataCell
	 */
	this.highlight = function(highlightOn) {
		if (document.computer && document.computer.getAnimation() == ANIMATE_NONE) return;
		var color = highlightOn ? CELL_HIGHLIGHT : CELL_COLOR;
		that.itemDiv.style.backgroundColor = color;
		var flag = false;
		
		if (that.parent.dataSetType == "DataList") {
			flag = (that.parent.frameDiv.scrollTop + that.parent.frameDiv.offsetHeight) 
					< (that.itemDiv.offsetTop + that.itemDiv.offsetHeight) ||
					(that.parent.frameDiv.scrollTop) > (that.itemDiv.offsetTop);
		}
		else if (that.parent.dataSetType == "DataArray") {
			flag = (that.parent.frameDiv.scrollTop + that.parent.frameDiv.offsetHeight) 
					< (that.itemDiv.parentNode.offsetTop + that.itemDiv.parentNode.offsetHeight) ||
					(that.parent.frameDiv.scrollTop) > (that.itemDiv.parentNode.offsetTop);
		}
		if (flag) {
			that.itemDiv.scrollIntoView();
			var item = null;
			if (that.parent.dataSetType == "DataList")
				item = that.itemDiv;
			else if (that.parent.dataSetType == "DataArray")
				item = that.itemDiv.parentNode;
			
			if (Math.abs(that.parent.frameDiv.scrollTop - item.offsetTop) < parseInt(CELL_HEIGHT) + 1)
				that.parent.frameDiv.scrollTop -= 4 + (parseInt(CELL_HEIGHT) * 3);
			if (tooSmall) document.body.scrollTop = 0;
		}
	}
	
	/**
	 * Returns the absolute left position of this cell
	 */
	this.getAbsoluteLeft = function() {
		return getAbsLeft(this.itemDiv);
	}

	/**
	 * Returns the absolute top position of this cell
	 */
	this.getAbsoluteTop = function() {
		return getAbsTop(this.itemDiv);
	}
}