/*
 Copyright (c) 2010 Brian Silverman, Barry Silverman

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
*/

var frame, chipbg, overlay, hilite, hitbuffer, ctx;
var centerx=300, centery=300;
var zoom=1;
var dragMouseX, dragMouseY, moved;
var statbox;

// Some constants for the graphics presentation
// the canvas is embedded in an 800x600 clipping div
//   which gives rise to some of the 300 and 400 values in the code
//   there are also some 600 values
// the 6502D chip coords are in the box (216,179) to (8983,9807)
// we have 4 canvases all the same size, now 2000 pixels square
//   chip background - the layout
//   overlay - a red/white transparency to show logic high or low
//   hilite - to show the selected polygon
//   hitbuffer - abusing color values to return which polygon is under a point
// we no longer use a scaling transform - we now scale the chip data at 
//   the point of drawing line segments
// if the canvas is any smaller than chip coordinates there will be
//   rounding artifacts, and at high zoom there will be anti-aliasing on edges.
var grMaxZoom=16;
var grChipSize=10000;
var grCanvasSize=2000;
var grLineWidth=1;

// Index of layerNames corresponds to index into drawLayers
var layernames = ['metal', 'switched diffusion', 'inputdiode', 'grounded diffusion', 'powered diffusion', 'polysilicon'];
var colors = ['rgba(128,128,192,0.4)','#FFFF00','#FF00FF','#4DFF4D',
              '#FF4D4D','#801AC0','rgba(128,0,255,0.75)'];
var drawlayers = [true, true, true, true, true, true];
              
var nodes = new Array();
var transistors = {};
var nodenamelist=[];

var ngnd = nodenames['vss'];
var npwr = nodenames['vcc'];

// some modes and parameters which can be passed in from the URL query
var moveHereFirst;
var expertMode=false
var animateChipLayout = true;
var chipLayoutIsVisible = true;
var userCode=[];
var userResetLow;
var userResetHigh;
var userSteps;

/////////////////////////
//
// Drawing Setup
//
/////////////////////////

// try to present a meaningful page before starting expensive work
function setup(){
	statbox = document.getElementById('status');
	setStatus('loading 6502...');
	setTimeout(setup_part2, 0);
}

function setup_part2(){
	frame = document.getElementById('frame');
	statbox = document.getElementById('status');
	setupParams();
	updateExpertMode(expertMode);
	setupNodes();
	setupTransistors();
	if(chipLayoutIsVisible){
		// if user requests no chip layout, we can do no canvas operations at all
		// which saves a lot of memory and allows us to run on small systems
		updateChipLayoutVisibility(true);
	}
	window.onkeypress = function(e){handleKey(e);}
	setStatus('resetting 6502...');
	setTimeout(setup_part3, 0);
}

function setup_part3(){
	setupTable();
	setupNodeNameList();
	loadProgram();
	initChip();
	document.getElementById('stop').style.visibility = 'hidden';
	go();
}

function setupParams(){
	if(location.search=="")
		return
	var queryParts=location.search.slice(1).split('&');
	var panx;
	var pany;
	var zoom;
	var userAddress;
	for(var i=0;i<queryParts.length;i++){
		var params=queryParts[i].split("=");
		if(params.length!=2){
			if(loglevel>0)
				console.log('malformed parameters',params);
			break;
		}
		var name=params[0];
		var value=params[1].replace(/\/$/,""); // chrome sometimes adds trailing slash
		// be (relatively) forgiving in what we accept
		if(name=="loglevel" && parseInt(value)>0){
			updateLoglevel(value);
		} else if(name=="expert" && value.indexOf("t")==0){
			updateExpertMode(true);
		} else if(name=="graphics" && value.indexOf("f")==0){
			updateChipLayoutVisibility(false);
		} else if(name=="panx" && parseInt(value)!=NaN){
			panx=parseInt(value);
		} else if(name=="pany" && parseInt(value)!=NaN){
			pany=parseInt(value);
		} else if(name=="zoom" && parseInt(value)!=NaN){
			zoom=parseInt(value);
		} else if(name=="steps" && parseInt(value)!=NaN){
			userSteps=parseInt(value);
			running=true;
		} else if(name=="a" && parseInt(value,16)!=NaN){
			userAddress=parseInt(value,16);
		} else if(name=="d" && value.match(/[0-9a-fA-F]*/)[0].length==value.length){
			for(var j=0;j<value.length;j+=2)
				userCode[userAddress++]=parseInt(value.slice(j,j+2),16);
		} else if(name=="r" && parseInt(value,16)!=NaN){
			userResetLow=parseInt(value,16)%256;
			userResetHigh=(parseInt(value,16)>>8)%256;
		} else {
			if(loglevel>0)
				console.log('unrecognised parameters:',params);
			break;
		}
	}
	if(panx!=null && pany!=null && zoom!=null)
		moveHereFirst=[panx,pany,zoom];
}

function updateChipLayoutAnimation(isOn){
	// simulation is much faster if we don't update the chip layout on every step
	animateChipLayout=isOn;
	document.getElementById('animateModeCheckbox').checked = animateChipLayout;
}

function setupNodes(){
	for(var i in segdefs){
		var seg = segdefs[i];
		var w = seg[0];
		if(nodes[w]==undefined) 
			nodes[w] = {segs: new Array(), num: w, pullup: seg[1]=='+',
			            state: 'fl', gates: new Array(), c1c2s: new Array()};
		if(w==ngnd) continue;
		if(w==npwr) continue;
		nodes[w].segs.push(seg.slice(3));
	}
}

function setupTransistors(){
	for(i in transdefs){
		var tdef = transdefs[i];
		var name = tdef[0];
		var gate = tdef[1];
		var c1 = tdef[2];
		var c2 = tdef[3];
		var trans = {name: name, on: false, gate: gate, c1: c1, c2: c2};
		nodes[gate].gates.push(name);
		nodes[c1].c1c2s.push(name);
		nodes[c2].c1c2s.push(name);
		transistors[name] = trans;
	}
}

function setupLayerVisibility(){
	var x=document.getElementById('updateShow');
	for (var i=0;i<x.childNodes.length;i++) {
		if(x.childNodes[i].type='checkbox'){
			x.childNodes[i].checked=drawlayers[x.childNodes[i].name];
		}
	}
}

function setupBackground(){
	chipbg = document.getElementById('chipbg');
	chipbg.width = grCanvasSize;
	chipbg.height = grCanvasSize;
	var ctx = chipbg.getContext('2d');
	ctx.fillStyle = '#000000';
	ctx.strokeStyle = 'rgba(255,255,255,0.5)';
	ctx.lineWidth = grLineWidth;
	ctx.fillRect(0,0,grCanvasSize,grCanvasSize);
	for(var i in segdefs){
		var seg = segdefs[i];
		var c = seg[2];
		if (drawlayers[c]) {
			ctx.fillStyle = colors[c];
			drawSeg(ctx, segdefs[i].slice(3));
			ctx.fill();
			if((c==0)||(c==6)) ctx.stroke();
		}
	}		
}

function setupOverlay(){
	overlay = document.getElementById('overlay');
	overlay.width = grCanvasSize;
	overlay.height = grCanvasSize;
	ctx = overlay.getContext('2d');
}

function setupHilite(){
	hilite = document.getElementById('hilite');
	hilite.width = grCanvasSize;
	hilite.height = grCanvasSize;
	var ctx = hilite.getContext('2d');
}

function setupHitBuffer(){
	hitbuffer = document.getElementById('hitbuffer');
	hitbuffer.width = grCanvasSize;
	hitbuffer.height = grCanvasSize;
	hitbuffer.style.visibility = 'hidden';
	var ctx = hitbuffer.getContext('2d');
	for(i in nodes) hitBufferNode(ctx, i, nodes[i].segs);
}

function hitBufferNode(ctx, i, w){
	var low = hexdigit(i&0xf);
	var mid = hexdigit((i>>4)&0xf);
	var high = hexdigit((i>>8)&0xf);
	ctx.fillStyle = '#'+high+'F'+mid+'F'+low+'F';
	for(i in w) {
		drawSeg(ctx, w[i]);
		ctx.fill();
	}
}

function hexdigit(n){return '0123456789ABCDEF'.charAt(n);}


/////////////////////////
//
// Drawing Runtime
//
/////////////////////////

function refresh(){
	if(!chipLayoutIsVisible)
		return;
	ctx.clearRect(0,0,grCanvasSize,grCanvasSize);
	for(i in nodes){
		if(isNodeHigh(i)) overlayNode(nodes[i].segs);
	}
}

function overlayNode(w){
	ctx.fillStyle = 'rgba(255,0,64,0.4)';
	for(i in w) {
		drawSeg(ctx, w[i]);
		ctx.fill();
	}
}

function hiliteNode(n){
	var ctx = hilite.getContext('2d');
	ctx.clearRect(0,0,grCanvasSize,grCanvasSize);
	ctx.fillStyle = 'rgba(255,255,255,0.7)';
	if(n==-1) return;
	if(isNodeHigh(n[0]))
		ctx.fillStyle = 'rgba(255,0,0,0.7)';

	for(var i in n){
		var segs = nodes[n[i]].segs;
		for(var s in segs){drawSeg(ctx, segs[s]); ctx.fill();}
	}
}

function drawSeg(ctx, seg){
	var dx = 400;
	ctx.beginPath();
	ctx.moveTo(grScale(seg[0]+dx), grScale(grChipSize-seg[1]));
	for(var i=2;i<seg.length;i+=2) ctx.lineTo(grScale(seg[i]+dx), grScale(grChipSize-seg[i+1]));
	ctx.lineTo(grScale(seg[0]+dx), grScale(grChipSize-seg[1]));
}

/////////////////////////
//
// User Interface
//
/////////////////////////

function handleKey(e){
	var c = e.charCode;
	c = String.fromCharCode(c);
	if('<>?np'.indexOf(c)==-1) return;
	if(c=='<' && zoom>1) setZoom(zoom/1.2);
	else if(c=='>' && zoom<12) setZoom(zoom*1.2);
	else if(c=='?') setZoom(1);
	else if(c=='n') stepForward();
	else if(c=='p') stepBack();
}

function mouseDown(e){
	e.preventDefault();
	moved=false;	
	dragMouseX = e.clientX;	
	dragMouseY = e.clientY;
	window.onmousemove = function(e){mouseMove(e)};
	window.onmouseup = function(e){mouseUp(e)};
}

function mouseMove(e){
	moved = true;
	if(zoom==1) return;
	var dx = e.clientX-dragMouseX;
	var dy = e.clientY-dragMouseY;
	dragMouseX = e.clientX;
	dragMouseY = e.clientY;
	centerx-=dx/zoom;
	centerx = Math.max(centerx, 400/zoom);
	centerx = Math.min(centerx, 600-400/zoom);
	centery-=dy/zoom;
	centery = Math.max(centery, 300/zoom);
	centery = Math.min(centery, 600-300/zoom);
	recenter();
}

function mouseUp(e){
	if(!moved) handleClick(e);	
	window.onmousemove = undefined;
	window.onmouseup = undefined;
}

function setZoom(n){
	zoom = n;
	setChipStyle({
		width: 600*n+'px',
		height: 600*n+'px'
	});
	recenter();
}

function recenter(){
	var top = -centery*zoom+300;
	top = Math.min(top, 0);
	top = Math.max(top, -600*(zoom-1));
	var left = -centerx*zoom+400;
	left = Math.min(left, 0);
	left = Math.max(left, (zoom==1)?100:-600*zoom+800);
	setChipStyle({
		top: top+'px',
		left: left+'px',
	});
	document.getElementById('linkHere').href=location.pathname+"?"+whereAmIAsQuery();
}

function handleClick(e){
	var x = localx(hilite, e.clientX)/zoom;
	var y = localy(hilite, e.clientY)/zoom;
	var w = findNodeNumber(x,y);
	if(e.shiftKey) hiliteNode(getNodeGroup(w));
	else {var a=new Array(); a.push(w); hiliteNode(a);}
	var cx = Math.round(x*grChipSize/600);
	var cy = Math.round(y*grChipSize/600);	
	if(w==-1) {
		setStatus('x: '+cx, 'y: '+cy);
	} else {
		var s1='x: ' + cx + ' y: ' + cy;
		var s2='node: ' + w + ' ' + nodeName(w);
		setStatus(s1, s2);
		if(ctrace) console.log(s1, s2);
	}
}

function findNodeNumber(x,y){
	var ctx = hitbuffer.getContext('2d');
	var pixels = ctx.getImageData(x*grCanvasSize/600, y*grCanvasSize/600, 2, 2).data;
	if(pixels[0]==0) return -1;
	var high = pixels[0]>>4;
	var mid = pixels[1]>>4;
	var low = pixels[2]>>4;
	return (high<<8)+(mid<<4)+low;
}

function updateLoglevel(value){
	loglevel = value;
	initLogbox(signalSet(loglevel));
}

function updateExpertMode(isOn){
	expertMode=isOn
	document.getElementById('expertModeCheckbox').checked = expertMode;
	if(expertMode){
		document.getElementById('expertControlPanel').style.display = 'block';
		document.getElementById('basicModeText1').style.display = 'none';
		document.getElementById('basicModeText2').style.display = 'none';
		if(loglevel==0)
			updateLoglevel(1);
		if(chipLayoutIsVisible)
			document.getElementById('layoutControlPanel').style.display = 'block';
	} else {
		document.getElementById('expertControlPanel').style.display = 'none';
		document.getElementById('basicModeText1').style.display = 'block';
		document.getElementById('basicModeText2').style.display = 'block';
		if(chipLayoutIsVisible)
			document.getElementById('layoutControlPanel').style.display = 'none';
	}
}

function clearHighlight(){
	// remove red/white overlay according to logic value
	// for easier layout navigation
	ctx.clearRect(0,0,grCanvasSize,grCanvasSize);
}

function updateShow(layer, on){
	drawlayers[layer]=on;
	setupBackground();
}

function updateChipLayoutVisibility(isOn){
	chipLayoutIsVisible=isOn;
	if(chipLayoutIsVisible) {
		document.getElementById('chipsurround').style.display = 'block';
		if(expertMode)
			document.getElementById('layoutControlPanel').style.display = 'block';
		document.getElementById('nochip').style.display = 'none';
		document.getElementById('logstreamscroller').style.height="260px";
		// allow the display to update while we load the graphics
		setStatus('loading graphics...');
		setTimeout(setupChipLayoutGraphics, 0);
	} else {
		// cannot animate the layout if there is no canvas
		updateChipLayoutAnimation(false);
		// replace the layout display with a button to show it
		document.getElementById('chipsurround').style.display = 'none';
		document.getElementById('layoutControlPanel').style.display = 'none';
		document.getElementById('nochip').style.display = 'block';
		document.getElementById('logstreamscroller').style.height="880px";
	}
}

function setupChipLayoutGraphics(){
	setupLayerVisibility();
	setupBackground();
	setupOverlay();
	setupHilite();
	setupHitBuffer();
	recenter();
	refresh();
	document.getElementById('waiting').style.display = 'none';
	setStatus('Ready!');  // would prefer chipStatus but it's not idempotent
	if(moveHereFirst!=null)
		moveHere(moveHereFirst);
	hilite.onmousedown = function(e){mouseDown(e);}
}

// utility function to save graphics pan and zoom
function whereAmIAsQuery(){
	var w=whereAmI();
	return "panx="+w[0]+"&pany="+w[1]+"&zoom="+w[2]
}
function whereAmI(){
	return [centerx, centery, zoom];
}

// restore graphics pan and zoom (perhaps as given in the URL)
function moveHere(place){
	centerx = place[0];
	centery = place[1];
	setZoom(place[2]);
}

/////////////////////////
//
// Etc.
//
/////////////////////////

function setChipStyle(props){
	for(var i in props){
		chipbg.style[i] = props[i];
		overlay.style[i] = props[i];
		hilite.style[i] = props[i];
		hitbuffer.style[i] = props[i];
	}
}

// we draw the chip data scaled down to the canvas
// and so avoid scaling a large canvas
function grScale(x){
	return Math.round(x*grCanvasSize/grChipSize);
}

function localx(el, gx){
	return gx-el.getBoundingClientRect().left;
}

function localy(el, gy){
	return gy-el.getBoundingClientRect().top;
}

function setStatus(){
	var res = '';
	// pad the arguments to make this a three-line display
	// there must be a clean way to do this
	if(arguments[1]==undefined)arguments[1]="";
	if(arguments[2]==undefined)arguments[2]="";
	arguments.length=3;
	for(var i=0;i<arguments.length;i++) res=res+arguments[i]+'<br>';
	statbox.innerHTML = res;
}

function setupNodeNameList(){
	for(var i in nodenames)
		nodenamelist.push(i);
}

function nodeName(n) {
	for(var i in nodenames){
		if(nodenames[i]==n) return i;
	}
	return '';
}

function now(){return  new Date().getTime();}