// copyright 2010 Laura Shaffer Mills

// keep original size and units so math stays more accurate
var gOrigSize = 0;
var gOrigUnits = 0;
// keep final size and units so math stays more accurate (when calculate backward to clay size)
var gFinalSize = 0;
var gFinalUnits = 0;


// set up "onload" to initialize
window.onload = function() {
	// disable "Enter" key for submitting form
//	document.onKeyPress = ignoreEnterKey;

	// original clay -> final size
	document.getElementById("inClayType").onchange = calcFinal;
	document.getElementById("inOrigUnits").onchange = changeOriginalUnits;
	document.getElementById("inOrigSize").onchange = newOriginalNum;
	document.getElementById("inFinalUnits").onchange = calcFinal;

	// final size -> original clay
	document.getElementById("inClayTypeBack").onchange = calcOriginalBack;
	document.getElementById("inFinalUnitsBack").onchange = changeFinalUnitsBack;
	document.getElementById("inFinalSizeBack").onchange = newFinalNumBack;
	document.getElementById("inOrigUnitsBack").onchange = calcOriginalBack;
//	document.getElementById("inOrigUnitsBack").onchange = function(evt) {myCall(param1,evt);};

	initializeConversions();
	makeShrinkageArray();
	fillDropdownClayTypes("inClayType");
	fillDropdownClayTypes("inClayTypeBack");
}			// onload()


/*
// calculate the final size, after shrinking
function calcFinal() {
	var clayType = document.getElementById("inClayType").value;
	var finalUnits = document.getElementById("inFinalUnits").value;
	var finalSize = 0;

	// find final size, using original size and units
	// don't read original size and units from web page --
	//    used globals for original units and size, so conversions don't mess with accuracy
	finalSize = gOrigSize * (1 - gkaShrink[clayType]);		// final size in original units

	// now change final size to correct units before write to output
	if (gOrigUnits != finalUnits)
		finalSize = convertByUnit(finalSize, gOrigUnits, finalUnits);

	// put answer on page
	replaceNodeText("outFinalSize",finalSize.toFixed(2));
}			// calcFinal()
*/
// calculate the final size, after shrinking
function calcFinal() {
	var clayType = document.getElementById("inClayType").value;
	var finalUnits = document.getElementById("inFinalUnits").value;
	var origSize = 0;

	origSize = gOrigSize;
	// don't read original size and units from web page --
	//    used globals for original units and size, so conversions don't mess with accuracy
	if (gOrigUnits != finalUnits)		// change original size to correct units
		origSize = convertByUnit(gOrigSize, gOrigUnits, finalUnits);

	// put answer on page
	replaceNodeText("outFinalSize",gkaoShrink[clayType].rangeStrShrinkToFired(origSize));
}			// calcFinal()


/*
// calculate the original size, before shrinking
function calcOriginalBack() {
	var clayType = document.getElementById("inClayTypeBack").value;
	var origUnits = document.getElementById("inOrigUnitsBack").value;
	var origSize = 0;

	// find original size, using final size and units
	// don't read 'final' size and units from web page --
	//    used globals for final units and size, so conversions don't mess with accuracy
	origSize = gFinalSize / (1 - gkaShrink[clayType]);		// original size in final units

	// now change original size to correct units before write to output
	if (gFinalUnits != origUnits)
		origSize = convertByUnit(origSize, gFinalUnits, origUnits);

	// put answer on page
	replaceNodeText("outOrigSizeBack",origSize.toFixed(2));
}			// calcOriginalBack()
*/
// calculate the original size, before shrinking
function calcOriginalBack() {
	var clayType = document.getElementById("inClayTypeBack").value;
	var origUnits = document.getElementById("inOrigUnitsBack").value;
	var finalSize = 0;

	finalSize = gFinalSize;
	// don't read 'final' size and units from web page --
	//    used globals for final units and size, so conversions don't mess with accuracy
	if (gFinalUnits != origUnits)		// change original size to correct units
		finalSize = convertByUnit(gFinalSize, gFinalUnits, origUnits);

	// put answer on page
	replaceNodeText("outOrigSizeBack",gkaoShrink[clayType].rangeStrFromClay(finalSize));
}			// calcOriginalBack()



// change the final value to new units
// still keep the value and 'final' units *originally* entered, to keep math more consistent
function changeFinalUnitsBack() {
	var newUnits = document.getElementById("inFinalUnitsBack").value;
	var newFinalSize = 0;

	if (gFinalUnits  == newUnits) {			// units as originally entered
		newFinalSize = gFinalSize;
	}
	else {
		// the 'final' units have changed, so recalculate 'final' size value
		// use gFinalSize for calculation; find newFinalSize in newUnits
		newFinalSize = convertByUnit(gFinalSize, gFinalUnits, newUnits);
	}
	document.getElementById("inFinalSizeBack").value = newFinalSize.toFixed(2);
}			// changeFinalUnitsBack()


// change the original value to new units
// still keep the value and units *originally* entered, to keep math more consistent
function changeOriginalUnits() {
	var newUnits = document.getElementById("inOrigUnits").value;
	var newOrigSize = 0;

	if (gOrigUnits  == newUnits) {			// units as originally entered
		newOrigSize = gOrigSize;
	}
	else {
		// the "original" units have changed, so recalculate "original" size value
		// use gOrigSize for calculation; find newOrigSize in newUnits
		newOrigSize = convertByUnit(gOrigSize, gOrigUnits, newUnits);
	}
	document.getElementById("inOrigSize").value = newOrigSize.toFixed(2);
}			// changeOriginalUnits()


// ignore the enter/return key
function ignoreSubmit() {
	return false;
}			// ignoreSubmit()


// verify input
function newFinalNumBack() {
	// when user changes number for size, reset units to current value
	gFinalUnits = document.getElementById("inFinalUnitsBack").value;
	gFinalSize = validatePosNumber(this.value, "inFinalValidation", "Enter a number.");
	if (-1 == gFinalSize)
		replaceNodeText("outOrigSizeBack","");		// clear result
	else {
		calcOriginalBack();
	}
}			// newFinalNumBack()


// verify input
function newOriginalNum() {
	// when user changes number for size, reset units to current value
	gOrigUnits = document.getElementById("inOrigUnits").value;
	gOrigSize = validatePosNumber(this.value, "inOriginalValidation", "Enter a number.");
	if (-1 == gOrigSize)
		replaceNodeText("outFinalSize","");		// clear result
	else {
		calcFinal();
	}
}			// newOriginalNum()