// ***************** COPYRIGHT (c) 2009 STEFAN WANER ******************
// *********************** ALL RIGHTS RESERVED ************************



// ***  IT ALSO REMAINS TO DO THE TOPMATTER


// Globals
// window.onerror = myErrorTrap;
var windowcropTally = 20; 
	// will not cut a window in half if more than this number of 
     // pixels pop out of range as a result



var autoY = true;
var autoGridline = true;

var okToRoll = true;

var theString = "";

var theFunction = ""; // the function


var xGridLines = new Array(); // these are screen coordinates
var yGridLines = new Array();
var xGridLinesActual = new Array(); // these are actual coordinates
var yGridLinesActual = new Array();

// var lineColor = 2; // red
// var lineColorLite = lineColor + 7;

var tminVals = new Array(); 
var tmaxVals = new Array();

var arraysize = 0; // number of functions
var xArraysize = 0; // number of x-values in evalautor
var maxnum = 5;  // max number of functions allowed
var maxnumX = 12; // max number of x-values allowed
var theValues = new makeArray2(maxnumX, maxnum); // copy of evalauator data

var fracMode = false; // fraction mode off default
var numSigDigs = 5;  // rounding of y-values default
var maxDenom = 99999;

// ***** Error Messages
if (theLanguage == "en") {
	var enterXMinMsg = "You have not entered a number for xMin.";
	var enterXMaxMsg = "You have not entered a number for xMax.";
	var maxLtMinMsg = "xMax should be greater than xMin";
	var maxyLtMinMsg = "yMax should be greater than yMin";
	var yMinMsg = "Enter a number for yMin or check 'Auto'."; 
	var yMaxMsg = "Enter a number for yMax or check 'Auto'.";
	var enterSmthgMsg = "You must enter at least one function to graph or one point to plot."; 
	var enterXMsg = "You must enter at least one value of x.";
	var numSigDigMsg = "The Number of Significant Digits must be a number. I am setting it back to 5. Change it to another number if you like.";
	}
else {
	var enterXMinMsg = "No ha ingresado un numero para xMin.";
	var enterXMaxMsg = "No ha ingresado un numero para xMax.";
	var maxLtMinMsg = "xMax debe ser mas grande que xMin";
	var maxyLtMinMsg = "yMax debe ser mas grande que yMin";
	var yMinMsg = "Ingrese numero para yMin o marque 'Auto'."; 
	var yMaxMsg = "Ingrese numero para yMax o marque 'Auto'.";
	var enterSmthgMsg = "Debe ingresar al menos una funcion o un punto para trazar.";
	var enterXMsg = "Debe ingresar al menos un valor de x.";
	var numSigDigMsg = "El numero de digitos significados debe ser un numero. Estoy cambiando su valor a 5. Puede cambiarlo a un otro numero si quiere.";
	}


// ** end error messages

// *** end globals


// *** Error Handler ******
function myErrorTrap(message,url,linenumber) {
alert("It looks like you have entered something wrongly (or perhaps need to use an older version). Press 'Show Examples' to see examples of how to format functions.");
return (true);
} // end of on error

// ********************

// **********Utilities to read in the functions *********
// ********************************************************************
function setUp(){

	okToRoll = true;
	with(Math){
		//Step 1: read the inputs into an array and decide
		// how many points there are
		var thexCellName = ""; // these are strings to names x1, x2,.. 

		var theInstruction = ""; // a javascript instuction
		var doIt = 0; // a dummy variable
				
		//Step 2: Fill the y arrays with the functions 
		for (var i = 1; i <= maxnum; i++) { 





			theInstruction = "yVals["+i+"] = stripSpaces(document.theFormA.y"+i+".value);";
			doIt = eval(theInstruction);
			// now take special steps for derivatives
			if ((yVals[i]).substring(0,5) == "deriv") {
				var theLength = (yVals[i]).length;
				var theDerivArg = (yVals[i]).substring(6,theLength-1);
				if (theDerivArg.charAt(0) == "y") {
					var theIndex = parseInt(theDerivArg.charAt(1));
					if (theIndex < i) yVals[i] = stringDeriv(yVals[theIndex]);
					} // is a "yi"
				else yVals[i] = stringDeriv((yVals[i]).substring(6,theLength-1));
// alert(yVals[i]);
				} // if a derivative

	
			
// alert(yVals[i]);
// alert(i);
			} // i
		// Step 3: Compute how many functions there are
		arraysize = maxnum;
// alert(arraysize);
		for (i = 1; i <= maxnum; i++) {
			if (yVals[i] == "") {
// alert(i);
				arraysize = i-1;
				i = maxnum}
			} // i


	} //with math
// Step 4: Read in textarea points
readInTextarea();
if ((arraysize == 0)&&(!plottingPoints)) {alert(enterSmthgMsg); okToRoll = false}
} // setup

// ***********************************************************************
// ************** End of Reading-in Parametric Equations Utility ******
// ***********************************************************************


// ***********************************************************************
// ************** Evaluator Setup Routine ******
// ***********************************************************************
function setUp2() {
	okToRoll = true;
	var aaa = setUp(); // read in the functions
	fracMode = document.theFormC.fracModeButton.checked;
	if(!fracMode) {
		numSigDigs = document.theFormC.acc.value;
		if (isBad(numSigDigs)) {alert(numSigDigMsg); okToRoll = false}
	} // if not fraction mode
	// Now read in the x-values
	with(Math){
		//Step 1: read the inputs into an array and decide
		// how many points there are
		var thexCellName = ""; // these are strings to names x1, x2,.. 

		var theInstruction = ""; // a javascript instuction
		var doIt = 0; // a dummy variable
				
		//Step 2: Fill the x array with the x-values
		// Note: at this point theywill all be strings 
		for (var i = 1; i <= maxnumX; i++) {
			theInstruction = "xVals["+i+"] = stripSpaces(document.theFormC.x"+i+".value);"
			doIt = eval(theInstruction);
			} // i
		// Step 3: Compute how many functions there are
		for (i = 1; i <= maxnumX; i++) {
			if (xVals[i] == "") {
				xArraysize = i-1;
				break
				} // encountered blank
			} // i
		if (xArraysize == 0) {alert(enterXMsg); okToRoll = false}
// alert(xArraysize);
	} //with Math
} // end of function setUp2
// ***********************************************************************
// ************** End of Evaluator Setup Routine ******
// ***********************************************************************


// ***********************************************************************
// ************** Evaluate all Routine ******
// ***********************************************************************

function evaluateAll() {
// This evaluates all the functions in nthe table
// we have arraysize many functions and xArraysize many values of x 

var theStrg = ""; // a dummy string for parsed functions
var theInstruction = ""; // a javascript instuction
var doIt = 0; // a dummy action

// First clear the current y-values
for (var i = 1; i <= maxnum; i++) {
	for (var j = 1; j <= maxnumX; j++) {
		theInstruction = "document.theFormC.y"+i+"x"+j+".value = ''";
		doIt = eval(theInstruction)
		} // j
	} // i

// Now Compute the values
 
for (var j = 1; j <= arraysize; j++) {
	theStrg = myParse(yVals[j]);
	for (var i = 1; i <= xArraysize; i++) {
		x = myEval(xVals[i]); // in case there are inputs like "sin(3)"
		y = checkEval(theStrg);
		if (y > infinity) y = "infinity";
		else if (y < -infinity) y = "-infinity";
		if (!fracMode) theInstruction = "document.theFormC.y"+j+"x"+i+".value = roundSigDig(y,numSigDigs)";
		else theInstruction = "document.theFormC.y"+j+"x"+i+".value = toFrac(y, maxDenom)";
		doIt = eval(theInstruction);
// alert(theInstruction);
		} // end i
	} // end j
} // end of evaluateAll

// ***********************************************************************
// ************** End of Evaluate all Routine ******
// ***********************************************************************

// **************** Plot All Curves ********************

function readAndPlotCurves(theGraph){
// alert(a + " , " + b + " , " + c + " , " + d);
var theyString = "";
var thexMin = 0;
var thexMax = 0;
var colorNumber = 0; 
var theGraphArray = new(Array);
// alert(arraysize);
for (var i = 1; i <= arraysize; i++) {

	theyString = yVals[i];

	theGraphArray [i-1] = [theyString, theGraph.window[0], theGraph.window[1]];
	} // i
theGraph.plottedCurves = theGraphArray;
// alert(theGraphArray);

setUpGraph(theGraph);
// alert(myGraph.yGridStep);
plotAllCurves(theGraph);
// alert("here");

// now the plotted points
var pointsX = new(Array);
var pointsY = new(Array);
pointsX[0] = 0; pointsY[0] = 0;
for (var i = 1; i <= numPoints; i++) {
	pointsX[i] = thePlottedPoints[i][1];
	pointsY[i] = thePlottedPoints[i][2]
	} // i points
theGraph.plottedPointsX = pointsX;
theGraph.plottedPointsY = pointsY;
plotPoints(theGraph, "x", false, "")
} // end of plot

// ******************End of Plot All Curves ***********


// ******** Refreshing Graph During Trace *************

// *** refresh graph
function refreshGraph(theGraph) {
setUpGraph(theGraph);
plotAllCurves(theGraph);
plotPoints(theGraph, "x", false, "");
} // refreshGraph


// *********** Tracing arrows on graphs **************

function addTraceArrows(theGraph) {
var theStr = '<input type=' + quoteMark + 'button' + quoteMark + ' class = ' + quoteMark + 'myButtons' + quoteMark + ' value = ' + quoteMark + '&larr;' + quoteMark + ' onmousedown=' + quoteMark + ' currentGraphjs = ' + theGraph.id + '; directionjs = 0; moveX.start();' + quoteMark + ' onmouseup=' + quoteMark + 'moveX.stop();' + quoteMark + ' onmouseout=' + quoteMark + 'moveX.stop();' + quoteMark + '> &nbsp; <input type=' + quoteMark + 'button' + quoteMark + ' class = ' + quoteMark + 'myButtons' + quoteMark + ' value = ' + quoteMark + '&rarr;' + quoteMark + ' onmousedown=' + quoteMark + ' currentGraphjs = ' + theGraph.id + '; directionjs = 1; moveX.start();' + quoteMark + ' onmouseup=' + quoteMark + 'moveX.stop();' + quoteMark + ' onmouseout=' + quoteMark + 'moveX.stop();' + quoteMark + '>';
document.writeln(theStr);
}


// *********** Recalling Values **************


function rememberValues() {
if (document.theFormC.y1x1.value != "") {
	var theInstruction = ""; // a javascript instuction
	var doIt = 0; // a dummy variable
	for (var i = 1; i <= maxnumX; i++) {
		for (var j = 0; j <= maxnum; j++) {
		if (j > 0) theInstruction = " theValues[i][j] = document.theFormC.y"+j+"x"+i+".value";
		else theInstruction = " theValues[i][j] = document.theFormC.x"+i+".value";
		doIt = eval(theInstruction);
		} // j
	} // i
} // IF THERE IS SOMETHING IN THE FIRST CELL
} // remember values

function bringBackValues() {
	if (document.theFormC.y1x1.value == "") {
		var theInstruction = ""; // a javascript instuction
		var doIt = 0; // a dummy variable
		for (var i = 1; i <= maxnumX; i++) {
			for (var j = 0; j <= maxnum; j++) {
			if (j > 0) theInstruction = " document.theFormC.y"+j+"x"+i+".value = theValues[i][j]";
			else theInstruction = " document.theFormC.x"+i+".value = theValues[i][j]";
			doIt = eval(theInstruction);
			} // j
		} // i
	} // if there is nothing in the first cell
} // remember values


// ********* Added Routines and globals for Plotting Points
var plottingPoints = false;
var tab = unescape( "%09" );	
var cr = unescape( "%0D" );	
var lf = unescape( "%0A" );
var semicolon = unescape( '%3B' );
var comma = ",";
var textareaText = '';
var maxNumPoints = 100; 
var numPoints = 0;
var thePlottedPoints = new makeArray2(maxNumPoints,2);
var yMaxPoints = 0;
var yMinPoints = 0;
var xHeight = 5; // height of the plotted Xs

function rememberValuesPoints() {
if (stripSpaces(document.theFormP.thePoints.value) != '')
textareaText = document.theFormP.thePoints.value;
} // remember values

function restoreValuesPoints() {
if (stripSpaces(document.theFormP.thePoints.value) == '')
document.theFormP.thePoints.value = textareaText;
} // restore values

function readInTextarea() {
// reads in points and calculates maximum and minimum y coords 
var theString = document.theFormP.thePoints.value;
theString = stripSpaces(theString);
theString = replaceChar(theString,comma,tab);
theString = replaceChar(theString,semicolon,cr);
theString = replaceChar(theString,lf,cr);
// now get rid of strings of more than one tab and one cr's in a row
var doubletab = true; var doublecr = true;
while ( (doubletab) || (doublecr) )
	{
	if (checkString(theString,tab+tab,false) == -1) doubletab = false;
	else theString = replaceSubstring(theString,tab+tab,tab);
	if (checkString(theString,cr+cr,false) == -1) doublecr = false;
	else theString = replaceSubstring(theString,cr+cr,cr);
	} // while
theString = replaceSubstring(theString,tab+cr,cr); // get rid of tab + crs
var xyPoints = parser(theString,cr);
var thePoint = new Array;
numPoints = xyPoints[0];
if (theString.indexOf(tab) == -1) numPoints = 0;
if (numPoints > 0) {
	plottingPoints = true;
	for (var i = 1; i <= numPoints; i++) {
		thePoint = parser(xyPoints[i], tab);
		thePlottedPoints[i][1] = parseFloat(thePoint[1]);
		thePlottedPoints[i][2] = parseFloat(thePoint[2]);
		} // i

	// now compute y max and min for these
	yMaxPoints = thePlottedPoints[1][2];
	yMinPoints = yMaxPoints;
	for (var i = 1; i <= numPoints; i++) {
		try
			{
 			if (thePlottedPoints[i][2] > yMaxPoints) yMaxPoints = thePlottedPoints[i][2];
			else if (thePlottedPoints[i][2] < yMinPoints) yMinPoints = thePlottedPoints[i][2];
			}
			catch (error)
			{ 
			}
		} // i
//	alert("numPOints = " + numPoints + "  ; yMax = " + yMaxPoints + "  ; yMin = "+ yMinPoints);
	// now scale up a bit so that not on the edge
	yMinPoints -= .1*Math.abs(yMinPoints);
	yMaxPoints += .1*Math.abs(yMaxPoints);

	} // if more than 0 points
else plottingPoints = false;
} // readInTextarea


var basicsRead = false;
function readBasics(theGraph) {
// alert("here");
var theStrg = "";  // dummy string for evaluating functions
autoY = document.theFormB.autoYButton.checked;
autoGridline = document.theFormB.autoGridButton.checked;
// get the graph window information
	for (var k = 1; k <= 1; k++)
	{
	var aa = document.theFormB.a.value; 
// alert(aa);
	if (aa == "") { alert(enterXMinMsg); okToRoll = false; break;}
//alert(aa);
	a = myEval(aa);
	if (isNaN(a) ) { alert(enterXMinMsg); okToRoll = false; break;}
	var bb = document.theFormB.b.value; 
	if (bb == "") { alert(enterXMaxMsg); okToRoll = false; break}
	b = myEval(bb); 
	if (isNaN(b) ) { alert(enterXMaxMsg); okToRoll = false; break;}
	if ( (okToRoll) && (a >= b)) { alert(maxLtMinMsg); okToRoll = false; break;}
	var ppcTest = document.theFormB.ppc.value;
	if (isNaN(ppcTest) || (ppcTest == '') ) document.theFormB.ppc.value = 1000;
	else myGraph.pointsPerCurve = parseInt(ppcTest);


	if(!autoY) {
// alert("Here autoY is off");
		var cc = document.theFormB.c.value; 
		if (cc == "") { alert(yMinMsg); okToRoll = false; break}
		c = myEval(cc); 
		if (isNaN(c) ) { alert(yMinMsg); okToRoll = false; break;}
		var dd = document.theFormB.d.value; 
		if (dd == "") { alert(yMaxMsg); okToRoll = false; break}
		d = myEval(dd); 
		if (isNaN(d) ) { alert(yMaxMsg); okToRoll = false; break;}
		if ( (okToRoll) && (c >= d)) { alert(maxyLtMinMsg); okToRoll = false; break;}
// alert(a + " , " + b + " , " + c + " , " + d);
		} // end of if autoY
	else {
		document.theFormB.c.value = ''; // cannnot have it both ways
		document.theFormB.d.value = ''; 
		// Must compute ymin and ymax here
		var deltax = (b-a)/theGraph.numX;
// alert(deltax);
		var maxy = 0;
		var miny = 0;
		var firstCheck = true;
		for (var j = 1; j <= arraysize; j++) {
			theStrg = myParse(yVals[j]);
			for (var i = 0; i <= theGraph.numX; i++)
				{
				x = a + i*deltax;
// alert("x = " + x);
				y  = checkEval(theStrg);
				if (!isNaN(y) &&( y < infinity) && (y > -infinity))
					{
					// alert ("y = " + y);
					if (firstCheck) 
						{
						firstCheck = false; 
						maxy = y; 
						miny = y
						}
					if (y > maxy) maxy = y;
					else if (y < miny) miny = y;
					} // end of if y is a legit number
				} // i
// alert(miny);
			} // j
	
// alert("miny = "+miny + "maxy =" + maxy);
			// Now cut down the size of the window if necessary
			// in the case of graphs shooting off to infinity
			// the texhnique is to eliminate "outliers" by cropping 
			// the window.


// *** Why don't we just compute the st deviation and crop to +- 3s
			var cutting_down = true;
			var invisible_tally = 0;
			var maxSteps = 10, steppes = 0;
			while ((cutting_down) && (steppes < maxSteps))
				{
				steppes ++;
				maxy = maxy/2;
				miny = miny/2;
				invisible_tally = 0;
				for (var j = 1; j <= arraysize; j++) {
					theStrg = myParse(yVals[j]);

					for (var i = 0; i <= theGraph.numX; i++)
						{
						x = a + i*deltax;
						y  = checkEval(theStrg);
						if (!isNaN(y) &&( y < infinity) && (y > -infinity))
							{
							if ((y > maxy) || (y < miny))
								{
								invisible_tally++;
								if (invisible_tally > windowcropTally)
									{
									cutting_down = false;
									maxy = 2*maxy;
									miny = 2*miny;
									i = theGraph.numX;
									break;
									} // too many invisible;
								} // if y > ymax
						} // if is a number
					} // i
				} // j
			// by the end of this cutting_down had better be false;
			} // while cutting_down
// alert("miny = "+miny + "maxy =" + maxy);

		
		if (miny == maxy) {miny  = miny-1; maxy += 1}

		// ** following two lines added for plotting points
		if (plottingPoints) {
			if (yMaxPoints > maxy) maxy = yMaxPoints;
			if (yMinPoints < miny) miny = yMinPoints;
			}
		var scalefactor = 150/(maxy - miny); 
// ************
// end of y min and ymax window coords
// ************

		c = eval(roundSigDigUpDown (miny,4, false)); // sets the globals
		d = eval(roundSigDigUpDown (maxy,4, true));
		} // end of else for autoY
// alert("c = " + c + " d = " + d);
// At this point we have the globals a, b, c, d we need
	myGraph.window[0] = a;
	myGraph.window[1] = b;
	myGraph.window[2] = c;
	myGraph.window[3] = d;
	theGraph.xTicsRange = [];
	theGraph.yTicsRange = [];
	if(!autoGridline) {
		var xk = document.theFormB.xg.value;
		if (xk == "") myGraph.xGridStep = 0;
		else myGraph.xGridStep = eval(xk);
		var yk = document.theFormB.yg.value;
		if (yk == "") myGraph.yGridStep = 0;
		else myGraph.yGridStep = eval(yk);
		} // end of if not autoGridline
	else {
		document.theFormB.xg.value = ''; 
		document.theFormB.yg.value = ''; // cannnot have it both ways.
		var pq = (b-a)/10;
		myGraph.xGridStep = pq;
		pq = pq = (d-c)/10;
		myGraph.yGridStep = pq;
		} // end of else for autoGridline
	} // end of single loop (k)
if (okToRoll) basicsRead = true;

// now set up tracing parameters

if (okToRoll) {
	theGraph.traceStep = roundSigDig((b-a)/theGraph.numX,4);
	var theLog = Math.log(abs(theGraph.traceStep))/Math.log(10);
	theGraph.decPlacesX = -Math.round(theLog)+1;
	var theYInterval = (d-c)/theGraph.numX
	theLog = Math.log(abs(theYInterval))/Math.log(10);
	theGraph.decPlacesY = -Math.round(theLog)+1;
	}



//alert(myGraph.yGridStep);
} // readBasics


function makeArray2 (X,Y)
	{
	var count;
	this.length = X+1;
	for (var count = 1; count <= X+1; count++)
		// to allow starting at 1
		this[count] = new makeArray(Y);
	} // makeArray2

function makeArray (Y)
	{
	var count;
	this.length = Y+1;
	for (var count = 1; count <= Y+1; count++)
		this[count] = 0;
	} // makeArray

// ************* miscellaneous fixes
// this cleans up the lower boundary in case of curves tha overshoot

function cleanUp(theGraph) {
with(theGraph) {
	if (surroundColor == "white") ctx.fillStyle =  "rgb(255, 255, 255)";
	else ctx.fillStyle =  "rgb(" + surroundColor [0] + "," + surroundColor [1] + "," + surroundColor [2] + ")";
// alert(" " + theGraph.yLabelMargin + ", " + (theGraph.numY-1) + ", " + theGraph.numX+ theGraph.yLabelMargin+ ", " + 10);

ctx.fillRect(theGraph.yLabelMargin, theGraph.numY-1, theGraph.numX+ theGraph.yLabelMargin, 10);
	} // with theGraph

} // cleanUp
