dojo.provide("dojox.charting.scaler.linear");
dojo.require("dojox.charting.scaler.common");

(function(){
	var deltaLimit = 3,	// pixels
		dc = dojox.charting, dcs = dc.scaler, dcsc = dcs.common,
		findString = dcsc.findString,
		getLabel = dcsc.getNumericLabel;
	
	var calcTicks = function(min, max, kwArgs, majorTick, minorTick, microTick, span){
		kwArgs = dojo.delegate(kwArgs);
		if(!majorTick){
			if(kwArgs.fixUpper == "major"){ kwArgs.fixUpper = "minor"; }
			if(kwArgs.fixLower == "major"){ kwArgs.fixLower = "minor"; }
		}
		if(!minorTick){
			if(kwArgs.fixUpper == "minor"){ kwArgs.fixUpper = "micro"; }
			if(kwArgs.fixLower == "minor"){ kwArgs.fixLower = "micro"; }
		}
		if(!microTick){
			if(kwArgs.fixUpper == "micro"){ kwArgs.fixUpper = "none"; }
			if(kwArgs.fixLower == "micro"){ kwArgs.fixLower = "none"; }
		}
		var lowerBound = findString(kwArgs.fixLower, ["major"]) ?
				Math.floor(kwArgs.min / majorTick) * majorTick :
					findString(kwArgs.fixLower, ["minor"]) ?
						Math.floor(kwArgs.min / minorTick) * minorTick :
							findString(kwArgs.fixLower, ["micro"]) ?
								Math.floor(kwArgs.min / microTick) * microTick : kwArgs.min,
			upperBound = findString(kwArgs.fixUpper, ["major"]) ?
				Math.ceil(kwArgs.max / majorTick) * majorTick :
					findString(kwArgs.fixUpper, ["minor"]) ?
						Math.ceil(kwArgs.max / minorTick) * minorTick :
							findString(kwArgs.fixUpper, ["micro"]) ?
								Math.ceil(kwArgs.max / microTick) * microTick : kwArgs.max;
								
		if(kwArgs.useMin){ min = lowerBound; }
		if(kwArgs.useMax){ max = upperBound; }
		
		var majorStart = (!majorTick || kwArgs.useMin && findString(kwArgs.fixLower, ["major"])) ?
				min : Math.ceil(min / majorTick) * majorTick,
			minorStart = (!minorTick || kwArgs.useMin && findString(kwArgs.fixLower, ["major", "minor"])) ?
				min : Math.ceil(min / minorTick) * minorTick,
			microStart = (! microTick || kwArgs.useMin && findString(kwArgs.fixLower, ["major", "minor", "micro"])) ?
				min : Math.ceil(min / microTick) * microTick,
			majorCount = !majorTick ? 0 : (kwArgs.useMax && findString(kwArgs.fixUpper, ["major"]) ?
				Math.round((max - majorStart) / majorTick) :
				Math.floor((max - majorStart) / majorTick)) + 1,
			minorCount = !minorTick ? 0 : (kwArgs.useMax && findString(kwArgs.fixUpper, ["major", "minor"]) ?
				Math.round((max - minorStart) / minorTick) :
				Math.floor((max - minorStart) / minorTick)) + 1,
			microCount = !microTick ? 0 : (kwArgs.useMax && findString(kwArgs.fixUpper, ["major", "minor", "micro"]) ?
				Math.round((max - microStart) / microTick) :
				Math.floor((max - microStart) / microTick)) + 1,
			minorPerMajor  = minorTick ? Math.round(majorTick / minorTick) : 0,
			microPerMinor  = microTick ? Math.round(minorTick / microTick) : 0,
			majorPrecision = majorTick ? Math.floor(Math.log(majorTick) / Math.LN10) : 0,
			minorPrecision = minorTick ? Math.floor(Math.log(minorTick) / Math.LN10) : 0,
			scale = span / (max - min);
		if(!isFinite(scale)){ scale = 1; }
		
		return {
			bounds: {
				lower:	lowerBound,
				upper:	upperBound,
				from:	min,
				to:		max,
				scale:	scale,
				span:	span
			},
			major: {
				tick:	majorTick,
				start:	majorStart,
				count:	majorCount,
				prec:	majorPrecision
			},
			minor: {
				tick:	minorTick,
				start:	minorStart,
				count:	minorCount,
				prec:	minorPrecision
			},
			micro: {
				tick:	microTick,
				start:	microStart,
				count:	microCount,
				prec:	0
			},
			minorPerMajor:	minorPerMajor,
			microPerMinor:	microPerMinor,
			scaler:			dcs.linear
		};
	};
	
	dojo.mixin(dojox.charting.scaler.linear, {
		buildScaler: function(/*Number*/ min, /*Number*/ max, /*Number*/ span, /*Object*/ kwArgs){
			var h = {fixUpper: "none", fixLower: "none", natural: false};
			if(kwArgs){
				if("fixUpper" in kwArgs){ h.fixUpper = String(kwArgs.fixUpper); }
				if("fixLower" in kwArgs){ h.fixLower = String(kwArgs.fixLower); }
				if("natural"  in kwArgs){ h.natural  = Boolean(kwArgs.natural); }
			}
			
			// update bounds
			if("min" in kwArgs){ min = kwArgs.min; }
			if("max" in kwArgs){ max = kwArgs.max; }
			if(kwArgs.includeZero){
				if(min > 0){ min = 0; }
				if(max < 0){ max = 0; }
			}
			h.min = min;
			h.useMin = true;
			h.max = max;
			h.useMax = true;
			
			if("from" in kwArgs){
				min = kwArgs.from;
				h.useMin = false;
			}
			if("to" in kwArgs){
				max = kwArgs.to;
				h.useMax = false;
			}
			
			// check for erroneous condition
			if(max <= min){
				return calcTicks(min, max, h, 0, 0, 0, span);	// Object
			}
			
			var mag = Math.floor(Math.log(max - min) / Math.LN10),
				major = kwArgs && ("majorTickStep" in kwArgs) ? kwArgs.majorTickStep : Math.pow(10, mag),
				minor = 0, micro = 0, ticks;
				
			// calculate minor ticks
			if(kwArgs && ("minorTickStep" in kwArgs)){
				minor = kwArgs.minorTickStep;
			}else{
				do{
					minor = major / 10;
					if(!h.natural || minor > 0.9){
						ticks = calcTicks(min, max, h, major, minor, 0, span);
						if(ticks.bounds.scale * ticks.minor.tick > deltaLimit){ break; }
					}
					minor = major / 5;
					if(!h.natural || minor > 0.9){
						ticks = calcTicks(min, max, h, major, minor, 0, span);
						if(ticks.bounds.scale * ticks.minor.tick > deltaLimit){ break; }
					}
					minor = major / 2;
					if(!h.natural || minor > 0.9){
						ticks = calcTicks(min, max, h, major, minor, 0, span);
						if(ticks.bounds.scale * ticks.minor.tick > deltaLimit){ break; }
					}
					return calcTicks(min, max, h, major, 0, 0, span);	// Object
				}while(false);
			}
	
			// calculate micro ticks
			if(kwArgs && ("microTickStep" in kwArgs)){
				micro = kwArgs.microTickStep;
				ticks = calcTicks(min, max, h, major, minor, micro, span);
			}else{
				do{
					micro = minor / 10;
					if(!h.natural || micro > 0.9){
						ticks = calcTicks(min, max, h, major, minor, micro, span);
						if(ticks.bounds.scale * ticks.micro.tick > deltaLimit){ break; }
					}
					micro = minor / 5;
					if(!h.natural || micro > 0.9){
						ticks = calcTicks(min, max, h, major, minor, micro, span);
						if(ticks.bounds.scale * ticks.micro.tick > deltaLimit){ break; }
					}
					micro = minor / 2;
					if(!h.natural || micro > 0.9){
						ticks = calcTicks(min, max, h, major, minor, micro, span);
						if(ticks.bounds.scale * ticks.micro.tick > deltaLimit){ break; }
					}
					micro = 0;
				}while(false);
			}
	
			return micro ? ticks : calcTicks(min, max, h, major, minor, 0, span);	// Object
		},
		buildTicks: function(/*Object*/ scaler, /*Object*/ kwArgs){
			var step, next, tick,
				nextMajor = scaler.major.start,
				nextMinor = scaler.minor.start,
				nextMicro = scaler.micro.start;
			if(kwArgs.microTicks && scaler.micro.tick){
				step = scaler.micro.tick, next = nextMicro;
			}else if(kwArgs.minorTicks && scaler.minor.tick){
				step = scaler.minor.tick, next = nextMinor;
			}else if(scaler.major.tick){
				step = scaler.major.tick, next = nextMajor;
			}else{
				// no ticks
				return null;
			}
			// make sure that we have finite bounds
			var revScale = 1 / scaler.bounds.scale;
			if(scaler.bounds.to <= scaler.bounds.from || isNaN(revScale) || !isFinite(revScale) ||
					step <= 0 || isNaN(step) || !isFinite(step)){
				// no ticks
				return null;
			}
			// loop over all ticks
			var majorTicks = [], minorTicks = [], microTicks = [];
			while(next <= scaler.bounds.to + revScale){
				if(Math.abs(nextMajor - next) < step / 2){
					// major tick
					tick = {value: nextMajor};
					if(kwArgs.majorLabels){
						tick.label = getLabel(nextMajor, scaler.major.prec, kwArgs);
					}
					majorTicks.push(tick);
					nextMajor += scaler.major.tick;
					nextMinor += scaler.minor.tick;
					nextMicro += scaler.micro.tick;
				}else if(Math.abs(nextMinor - next) < step / 2){
					// minor tick
					if(kwArgs.minorTicks){
						tick = {value: nextMinor};
						if(kwArgs.minorLabels && (scaler.minMinorStep <= scaler.minor.tick * scaler.bounds.scale)){
							tick.label = getLabel(nextMinor, scaler.minor.prec, kwArgs);
						}
						minorTicks.push(tick);
					}
					nextMinor += scaler.minor.tick;
					nextMicro += scaler.micro.tick;
				}else{
					// micro tick
					if(kwArgs.microTicks){
						microTicks.push({value: nextMicro});
					}
					nextMicro += scaler.micro.tick;
				}
				next += step;
			}
			return {major: majorTicks, minor: minorTicks, micro: microTicks};	// Object
		},
		getTransformerFromModel: function(/*Object*/ scaler){
			var offset = scaler.bounds.from, scale = scaler.bounds.scale;
			return function(x){ return (x - offset) * scale; };	// Function
		},
		getTransformerFromPlot: function(/*Object*/ scaler){
			var offset = scaler.bounds.from, scale = scaler.bounds.scale;
			return function(x){ return x / scale + offset; };	// Function
		}
	});
})();
