////============================================
//// yarrow05c.js, 12/22/08, by ralph abraham
//// js script for yarrow05c.html
//// clean up and get first heap to show
////============================================

//// GLOBALS

	var tapcount = 0; // counter for number of taps
	var linecode = [ 0, 0, 0, 0, 0, 0 ]; // array of six values of {6,7,8,9} (aka hexcode)
	var binlistA = [ 0, 0, 0, 0, 0, 0 ]; // array for A hexagram (first) as a binary list
	var binlistB = [ 0, 0, 0, 0, 0, 0 ]; // array for B hexagram (second) as a binary list
	var binlistC = [ 0, 0, 0, 0, 0, 0 ]; // array for C hexagram (changes) as a binary list

//// SETUP

	// wait for the browser to load
	window.onload = function() {
	// set up background basic template
		base00(); // white rect
		//base01(); // yellow tableau
		//base02(); // red disk
		drawStalks(); // initial heap, new to 05c
	};
	
    // setup single white canvas
	function base00()  {
		var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
		// setup whole rectangle (x0, y0, width, height)
		ctx.clearRect(0, 0, 320, 360);
 		ctx.fillStyle = "white"; //  white
 		ctx.fillRect (0, 0, 320, 360);
	};
    
    // draw yellow tableau
	function base01() {
		var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
		// draw tableau 
		ctx.clearRect(20, 20, 280, 200); // clear the yellow tableau
 		ctx.fillStyle = "yellow"; // redraw it
 		ctx.fillRect (20, 20, 280, 200); // (x0, y0, width, height)
	};
	
	// draw red disk, cf resig p. 298
	function base02() {
		var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
		// draw circle 
		ctx.save();
		ctx.beginPath();
			ctx.arc(160,120,100,0,Math.PI*2,true); // full circle
			ctx.strokeStyle = "red";
		ctx.fillStyle = "red"; //  red
		ctx.fill();
		ctx.restore();
	};


//// GRAPHICS DRAWING

	// draw all stalks on tableau
	function drawStalks() {
		var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
		// line attributes
        ctx.save();
		ctx.strokeStyle = "blue";
		ctx.lineWidth = 1;
		base01(); // clear yellow tableau
		base02(); // redraw red disk
		// now draw 49 stalks
		var u1 = Math.random(); // random init u1
		var u2 = Math.random(); // random init u2
		var v1 = logistic(u1); // begin trajectory of u1
		var v2 = logistic(u2); // begin trajectory of u2
		// alert(v1 + ", " + v2);
		for(count = 1; count < 49;count++) {
			var top = 1.5 * Math.PI; // JS angles are clockwise from x-axis
			var spread = 0.9; // width of spectrum in radians
			var hand = 18; // width of hand
			var newU0 = - (hand/2) + hand * v1; // x-offset in pixels
			var newV0 = top - spread / 2 + spread * v2; // the angle in radians
			var newX0 = Math.round( 160 + 80 * Math.cos(newV0) + newU0 ); // x-center + radius * cos(radians) + offset
			var newY0 = Math.round( 120 + 80 * Math.sin(newV0) ); // y-center ...
			var newX1 = Math.round( 160 - 80 * Math.cos(newV0) + newU0 );
			var newY1 = Math.round( 120 - 80 * Math.sin(newV0) ); // y-center ...
			ctx.moveTo(newX0,newY0);
			ctx.lineTo(newX1,newY1);
			ctx.stroke();
			v1 = logistic(v1); // move v1 along orbit
			v2 = logistic(v2); // move v2 along orbit
		};
        ctx.restore();
	};
    
    // draw one yang bar at (x0, y0, c0): init x0, init y0, color c0
    function drawYang(x0, y0, c0) {
        var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
        ctx.save();
		// line attributes
		ctx.strokeStyle = c0;
        ctx.lineWidth = 2;
		// now draw line (only need to repeat these three commands)
        ctx.moveTo(x0,y0);
        ctx.lineTo(x0 + 70, y0);
		ctx.stroke();
        ctx.restore();
    };
    
    // draw one yin bar at (x0, y0)
    function drawYin(x0, y0, c0) {
        var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
        ctx.save();
		// line attributes
		ctx.strokeStyle = c0;
        ctx.lineWidth = 2;
		// now draw line (only need to repeat these three commands)
        ctx.moveTo(x0,y0);
        ctx.lineTo(x0 + 30, y0);
		ctx.stroke();
		ctx.moveTo(x0 + 40,y0);
        ctx.lineTo(x0 + 70, y0);
		ctx.stroke();
        ctx.restore();
    };
    
    // draw a pair of bars
    function draw2bars( hy )
    {
    	var canvas = document.getElementById("canvas"); // only one canvas
		var ctx = canvas.getContext("2d");
		ctx.save();
    	var delta = 6;
    	switch( hyline )
    		{
    		case 6: // old yin (yin to yang)
    		    drawYin(40, 280 - (tapcount + 1 ) * delta, "red"); // in first hexagram
        		drawYang(210, 280 - (tapcount + 1 ) * delta, "green"); // in 2nd hexagram
        		break;
        	case 7: // young yang (yang to yang)
    		    drawYang(40, 280 - (tapcount + 1 ) * delta, "green"); // in first hexagram
        		drawYang(210, 280 - (tapcount + 1 ) * delta, "green"); // in 2nd hexagram
        		break;
    		case 8: // young yin (yin to yin)
    		    drawYin(40, 280 - (tapcount + 1 ) * delta, "green"); // in first hexagram
        		drawYin(210, 280 - (tapcount + 1 ) * delta, "green"); // in 2nd hexagram
        		break;
    		case 9: // old yang (yang to yin)
    		    drawYang(40, 280 - (tapcount + 1 ) * delta, "red"); // in first hexagram
        		drawYin(210, 280 - (tapcount + 1 ) * delta, "green"); // in 2nd hexagram
        	default:
        		break;
    		};
        ctx.restore();
    };
    
//// MATH

	// reduce a number mod four and return the remainder
    function reduce(coord)
    {
        var x = coord;
        var xmod4 = Math.floor(x/4);
        var xrem = x - 4 * xmod4;
        return xrem;
    };

	// extract pair of remainders to a line type (ie, a 6, 7, 8, or 9)
	function extract(xrem, yrem)
	{
		if ((xrem == 0) && (yrem == 0)) { return 6; } 
		else if (xrem == yrem) { return 9; } 
		else if ( (xrem == (yrem - 1)) || ((xrem == 3 ) && (yrem == 1)) || ((xrem == 0 ) && (yrem == 3)) ) { return 7; } 
		else { return 8; }
	};

	//logistic function, added 10 jan 2009 from mc-draw-funcs.as of 16 july 2007
	function logistic(unow){
		return 3.95 * unow * (1-unow) // hardware R param for now
	}

//// CAST-TO-GRAM transl of cast2gram.as of 30 dec 2007

// first hexagram from hexcast
//// first we convert a line (a 6, 7, 8, or 9) to a bit for the A hexagram (before)
function line2bitA(ln) {
	switch (ln) {
		case 6:
			return 0;
			break;
		case 7:
			return 1;
			break;
		case 8:
			return 0;
			break;
		case 9:
			return 1;
			break;
		}
}

//// now convert hexcast to binlistA as a procedure
function hexcast2binlistA(hc) {
	for (var i = 0; i <= 5; i++) {
		binlistA[i] = line2bitA( linecode[i] );
	}
}

// second (B) hexagram from hexcast
//// first we convert a line (a 6, 7, 8, or 9) to a bit for the B hexagram (after)
function line2bitB(ln) {
	switch (ln) {
		case 6:
			return 1;
			break;
		case 7:
			return 1;
			break;
		case 8:
			return 0;
			break;
		case 9:
			return 0;
			break;
		}
}

//// now convert hexcast to binlistB as a procedure
function hexcast2binlistB(hc) {
	for (var i = 0; i <= 5; i++) {
		binlistB[i] = line2bitB(hc[i]);
	}
}

// binlist of changes from hexcast
//// first we convert a line (a 6, 7, 8, or 9) to a bit for the changes
function line2bitC(ln) {
	switch (ln) {
		case 6:
			return 1;
			break;
		case 7:
			return 0;
			break;
		case 8:
			return 0;
			break;
		case 9:
			return 1;
			break;
		}
}

//// now convert hexcast to binlistC as a procedure
function hexcast2binlistC(hc) {
	for (var i = 0; i <= 5; i++) {
		binlistC[i] = line2bitC(hc[i]);
	}
}

//// compute leibniz number from a binlist
function binlist2leib(bl) {
	return bl[0]*32 + bl[1]*16 + bl[2]*8 + bl[3]*4 + bl[4]*2 + bl[5];
}

//// look up table to convert leibniz to king wen
var KingWen = [	 2, 23,  8, 20, 16, 35, 45, 12,
		   	15, 52, 39, 53, 62, 56, 31, 33,
			 7,  4, 29, 59, 40, 64, 47,  6,
			 46, 18, 48, 57, 32, 50, 28, 44,
			 24, 27,  3, 42, 51, 21, 17, 25,
			 36, 22, 63, 37, 55, 30, 49, 13,
			 19, 41, 60, 61, 54, 38, 58, 10,
			 11, 26,  5,  9, 34, 14, 43,  1 ];

	var MID = 3*(KWB + KWA);
	var MIDdays = Math.floor(MID/24);
	var MIDhrs = MID - (MIDdays*24);

// insertion on 30 dec 2007: hexcast to probability
// this gives the yarrow probability of each hypaerline (times 16M)
function line2prob(ln) {
	switch (ln) {
		case 6:
			return 1;
			break;
		case 7:
			return 5;
			break;
		case 8:
			return 7;
			break;
		case 9:
			return 3;
			break;
		}
}

// this computes the yarrow factor and its adjective of a hexcast
function hexcast2prob() {
	var tmp1 = line2prob(linecode[0]) * line2prob(linecode[1]) * line2prob(linecode[2]) * line2prob(linecode[3]) * line2prob(linecode[4]) * line2prob(linecode[5]);
	var tmp2 = "adjective";
	if ( tmp1 < 29412 ) {
		tmp2 = "very rare";
	} else if ( tmp1 < 58824 ) {
		tmp2 = "rare";
	} else if ( tmp1 < 88236 ) {
		tmp2 = "common";
	} else {
		tmp2 = "very common";
	}
	return tmp1 + " (" + tmp2 + ")";
}
// end of insertion of 30 dec 2007

//// EVENTS

	// action for tap event
	function mouseup( event )
	{
  		var ctx = document.getElementById('canvas').getContext('2d');
  		if ( tapcount < 6 )
  			{
  			drawStalks(); // prepare tableau for next tap
  			var xnow = event.clientX;
  			var ynow = event.clientY;
  			var xrem = reduce(xnow);
  			var yrem = reduce(ynow);
  			hyline = extract(xrem, yrem);
  			// update linecode array
  			linecode[tapcount] = hyline;
  			tapcount ++; // increment tap count
  			draw2bars( hyline ); // add new pair of bars for this tap
			}
		else
			{
			hexcast2binlistA(linecode); // here we convert hexcast to binlistA
			hexcast2binlistB(linecode); // here we convert hexcast to binlistB
			hexcast2binlistC(linecode); // here we convert hexcast to binlistC
			var KWA = KingWen[binlist2leib(binlistA)]; // king wen number of the A hexagram
			var KWB = KingWen[binlist2leib(binlistB)]; // ditto, B hexagram
			var MID = 3*(KWB + KWA); // for the landaker algorithm (time window)
			var MIDdays = Math.floor(MID/24);
			var MIDhrs = MID - (MIDdays*24);
			var temp3 = "First Hexagram is KingWen # " + KWA + "<br>";
			var temp4 = hex[KWA][0] + "<br>";
			var temp5 = "Second Hexagram is KingWen # " + KWB + "<br>";
			var temp6 = hex[KWB][0] + "<br>";
			var tempC1 = ""; // text of the changing lines
			var tempC2 = "";
			var tempC3 = "";
			var tempC4 = "";
			var tempC5 = "";
			var tempC6 = "";
			var tempC7 = "No Changing lines.<br>";
			if (binlistC[0] == 1) {
				tempC1 = "Change in Line 1: " + hex[KWA][1];
				tempC7 = "";
			}
			if (binlistC[1] == 1) {
				tempC2 = "Change in Line 2: " + hex[KWA][2];
				tempC7 = "";
			}
			if (binlistC[2] == 1) {
				tempC3 = "Change in Line 3: " + hex[KWA][3];
				tempC7 = "";
			}
			if (binlistC[3] == 1) {
				tempC4 = "Change in Line 4: " + hex[KWA][4];
				tempC7 = "";
			}
			if (binlistC[4] == 1) {
				tempC5 = "Change in Line 5: " + hex[KWA][5];
				tempC7 = "";
			}
			if (binlistC[5] == 1) {
				tempC6 = "Change in Line 6: " + hex[KWA][6];
				tempC7 = "";
			}
			var tempM = "WHEN: in a six-hour window beginning " + MID + " hours <br>(" + MIDdays + " days and " + MIDhrs + " hours) from now.";
			var tempP = "PROBABILITY FACTOR: " + hexcast2prob();
			var d = document;
			d.open("text/plain");
			d.write(hex[0]);
			d.write("<p>");
			d.write(temp3 + temp4);
			d.write(temp5 + temp6);
			d.write(tempC1 + tempC2 + tempC3 + tempC4 + tempC5 + tempC6 + tempC7);
			d.write("<br>");
			d.write(tempM);
			d.write("<p>");
			d.write(tempP);
			d.close();
			};
	};
	
////////// END ///////////