package jas.util;
import java.math.BigDecimal;
import java.text.FieldPosition;
import java.text.Format;
import java.text.ParsePosition;

/**
 * This code formats numbers in Scientific Notation. The input Number object is returned
 * as a ScientificFormated string. There are two output styles: Pure and Standard scientific
 * notation. Pure formatted numbers have precisely the number of digits specified by the
 * significant digits (sigDig) parameter and always specify a Base 10 Exponential(E). 
 * Standard formated numbers have the number of digits specified by the significant
 * digits (sigDig) parameter but will not have a Base 10 Exponential(E) if the number of digits
 * in the mantissa <= maxWidth.
 *  
 * @author Paul Spence
 * @version 03/20/2000  
 */

public class ScientificFormat extends Format
{
	/**
	 * The number of significant digits the number is formatted to is recorded by sigDigit.
	 * The maximum width allowed fro the returned String is recorded by MaxWidth  
	 */
	private int sigDigit = 5;
	private int maxWidth = 8;
	private boolean SciNote = false; //set to true for pure Scientific Notation

	public ScientificFormat() {
	
	}
	
	/**
	 * Sets the significant digits, maximum allowable width and number formatting style 
	 * (SciNote == true for Pure formatting). 
	 */
	public ScientificFormat(int sigDigit, int maxWidth, boolean SciNote)
	{
		setSigDigits(sigDigit);
		setMaxWidth(maxWidth);
		setScientificNotationStyle(SciNote);
	}
	
	/**
	 * Implementation of inherited abstract method. Checks to see if object to be formatted
	 * is of type Number. If so casts the Number object to double and calls the format method.
	 * Returns the result.
	 */
	public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos)
	{
		if (obj instanceof Number)
		{	
			String result = format(((Number) obj).doubleValue());
			return toAppendTo.append(result);
		}
		else if (obj instanceof DoubleWithError)
		{
			DoubleWithError dwe = (DoubleWithError) obj;
			toAppendTo.append(format(dwe.getValue()));
			toAppendTo.append(dwe.plusorminus);
			int errorSigDigit = resolveErrorSigDigit(dwe.getValue(),dwe.getError());
			toAppendTo.append(formatError(errorSigDigit,dwe.getError()));
			return toAppendTo;
		}
        else throw new IllegalArgumentException("Cannot format given Object as a Number");
	}
	
	/**Dummy implementation of inherited abstract method.
	 */
	public Object parseObject (String source, ParsePosition pos)
	{
		return null;
	}

	/**
	 * Returns the number of significant digits
	 */
	public int getSigDigits()
	{
		return sigDigit;
	}

	/**
	 * Returns the maximum allowable width of formatted number excluding any exponentials
	 */
	public int getMaxWidth()
	{
		return maxWidth;
	}
	
	/**
	 * Returns the formatting style: True means Pure scientific formatting, False means standard. 
	 */
	public boolean getScientificNotationStyle()
	{
		return SciNote;
	}
	
	/**
	 * Sets the number of significant digits for the formatted number 
	 */
	public void setSigDigits(int SigDigit) 
	{
		if (SigDigit < 1) throw new IllegalArgumentException ("sigDigit");
		sigDigit = SigDigit;
	}
	
	/**
	 * Sets the maximum allowable length of the formattted number mantissa before exponential notation
	 * is used.
	 */
	public void setMaxWidth(int mWidth)
	{
		if (mWidth < 3) throw new IllegalArgumentException ("maxWidth");
		maxWidth = mWidth;
	}
	/**
	 * Sets the format style used.
	 * There are two output styles: Pure and Standard scientific
	 * notation. Pure formatted numbers have precisely the number of digits specified by the
	 * significant digits (sigDig) parameter and always specify a Base 10 Exponential(E). 
	 * Standard formated numbers have the number of digits specified by the significant
	 * digits (sigDig) parameter but will not have a Base 10 Exponential(E) if the number of digits
	 * in the mantissa <= maxWidth.
	 */	
	public void setScientificNotationStyle(boolean sciNote)
	{								   
		SciNote = sciNote;
	}
	
	
	//simplify method for taking log base 10 of x
	private final static double k = 1/Math.log(10);
	private double Log10(double x) 
	{
		if (x==0) return 0;
		else return Math.log(x)*k;
	}
	
	private int resolveErrorSigDigit(double x, double dx){
		//dx should never be negative
		dx = Math.abs(dx);
		//make x +ve cause negative doesn't effect sigdigits
		x=Math.abs(x);
		
		//these circumstances errorsigdit does equal sigdigit, excluding infinity and Nan which are handled by format
		if(dx == 0 || Double.isInfinite(dx) || Double.isNaN(dx) || dx >= x) return sigDigit;
		
		//fail cases for log, method fails to handle
		if(x==0||Double.isInfinite(x) || Double.isNaN(x))return sigDigit;
		
		//other wise solve for cases when dx< x
		int log =(int)Math.round(Log10(dx/x));//always will return negative number
		int errorsigdigit = sigDigit+log;
		if(errorsigdigit <1) return 1;
		return errorsigdigit;
	}
	
	/**
	 * Format the number using scientific notation
	 */ 	
	public String format(double d) 
	{	
		// Deal with a few special values first
		if (Double.isInfinite(d)) return maxWidth < 8 ? "INF" : "Infinite";
		if (Double.isNaN(d)) return "NaN";
		
		String result="";
		double c=0;
		int ShiftNumber = 0;
		int IntOfNumberinput = 0;
		
		//preserve sign
		if (d==0) return "0";
		else  {
		  c=d;
		  d=Math.abs(c); 		
		      }

		// (i.e. 10 -> 1, 100 -> 2,9 -> 0 , .9 -> -1, .0009 -> -4)
		//error here 10 -> 1.0000 floors to 0 
		IntOfNumberinput = (int) Math.floor(Log10(d));//returns largest int value that is smaller than log10(d)
		
		//deal with above error
		if((IntOfNumberinput>-1)&&(d%(Math.pow(10,IntOfNumberinput+1)) == 0)){
			IntOfNumberinput++;
		}
		
		
		//if 0<d<1 then log10(d)is neg, IntofNumberinput is negative
		if (Log10(d)<0){ 
			ShiftNumber = sigDigit - IntOfNumberinput - 1;
		}else {
			ShiftNumber = sigDigit - IntOfNumberinput;
		}
		
		
		//outputs num with all sigdigs to right of decimal place or rounded up one extra
		long temp = Math.round(Math.pow(10,ShiftNumber)*d);
		String Formatted = String.valueOf(temp);
					
		//check rounding method, if neccessary add 1 to IntOfNumberinput
		BigDecimal  tempbunk =new BigDecimal(Math.pow(10,ShiftNumber)*d);
		long bunk =tempbunk.longValue();
		String Formattedbunk = String.valueOf(bunk);
		
		
		if(Formatted.length() > Formattedbunk.length()){
			IntOfNumberinput++;
		}
		
			
		//Do not display in pure sci notattion - limit use of E
		if (SciNote == false)
		{
			if (IntOfNumberinput < 0 ) {  		
				String LoopZero1="";
				for (int a=0; a<(Math.abs(IntOfNumberinput)-1);a++){
					LoopZero1=LoopZero1+"0";		
				}
					result="0"+"."+LoopZero1+Formatted;
				
			}
			
			else{   
				String[] FillDigits = new String[IntOfNumberinput+1];
				for(int a=0;a<=IntOfNumberinput;a++){
					FillDigits[a]="0";
				}
				
				int a = 0;
				
				while((a < Formatted.length()) && a<=IntOfNumberinput){
					FillDigits[a] = Formatted.substring(a,a+1);
					a++;	
				}
				
				for(int i=0; i <= FillDigits.length-1 ; i++){
					result = result + FillDigits[i];	
				}
				
				int length = result.length();
				
							
				if(length <sigDigit){
					String resultaddon ="";
					int i=-1;
					if(IntOfNumberinput==0){
						while(length < sigDigit){
							resultaddon = resultaddon + Formatted.substring(result.length()+i+1,result.length()+i+2);
							length++;
							i++;
							}
					}else{
							i = 0;	
						  while(length < sigDigit){
							resultaddon = resultaddon + Formatted.substring(result.length()+i,result.length()+i+1);
							length++;
							i++;
							}
					}
						  
					result = result+"."+resultaddon;
				}	
			}
			
						
			if(result.length()>maxWidth){
				result=Formatted.substring(0,1)+"."+Formatted.substring(1,sigDigit)+"E"+IntOfNumberinput;
			}
		}	
		
		//output in pure Scientific Notation
		if(SciNote == true){
			result=Formatted.substring(0,1)+"."+Formatted.substring(1,sigDigit)+"E"+IntOfNumberinput;
		}
		
		//regain negative and return
		if(c>0) return result;
		else return "-"+result;
	
	
	}
	/**
	 * Format the number using scientific notation
	 */ 	
	public String formatError(int eSD,double d) 
	{	
		// Deal with a few special values first
		if (Double.isInfinite(d)) return maxWidth < 8 ? "INF" : "Infinite";
		if (Double.isNaN(d)) return "NaN";
		
		int errorSigDigit = eSD;
		
		String result="";
		double c=0;
		int ShiftNumber = 0;
		int IntOfNumberinput = 0;
		
		//preserve sign
		if (d==0) return "0";
		else  {
		  c=d;
		  d=Math.abs(c); 		
		      }

		// (i.e. 10 -> 1, 100 -> 2,9 -> 0 , .9 -> -1, .0009 -> -4)
		//error here 10 -> 1.0000 floors to 0 
		IntOfNumberinput = (int) Math.floor(Log10(d));//returns largest int value that is smaller than log10(d)
		
		//deal with above error
		if((IntOfNumberinput>-1)&&(d%(Math.pow(10,IntOfNumberinput+1)) == 0)){
			IntOfNumberinput++;
		}
		
		
		//if 0<d<1 then log10(d)is neg, IntofNumberinput is negative
		if (Log10(d)<0){ 
			ShiftNumber = errorSigDigit - IntOfNumberinput - 1;
		}else {
			ShiftNumber = errorSigDigit - IntOfNumberinput;
		}
		
		
		//outputs num with all sigdigs to right of decimal place or rounded up one extra
		long temp = Math.round(Math.pow(10,ShiftNumber)*d);
		String Formatted = String.valueOf(temp);
					
		//check rounding method, if neccessary add 1 to IntOfNumberinput
		BigDecimal  tempbunk =new BigDecimal(Math.pow(10,ShiftNumber)*d);
		long bunk =tempbunk.longValue();
		String Formattedbunk = String.valueOf(bunk);
		
		
		if(Formatted.length() > Formattedbunk.length()){
			IntOfNumberinput++;
		}
		
			
		//Do not display in pure sci notattion - limit use of E
		if (SciNote == false)
		{
			if (IntOfNumberinput < 0 ) {  		
				String LoopZero1="";
				for (int a=0; a<(Math.abs(IntOfNumberinput)-1);a++){
					LoopZero1=LoopZero1+"0";		
				}
					result="0"+"."+LoopZero1+Formatted;
				
			}
			
			else{   
				String[] FillDigits = new String[IntOfNumberinput+1];
				for(int a=0;a<=IntOfNumberinput;a++){
					FillDigits[a]="0";
				}
				
				int a = 0;
				
				while((a < Formatted.length()) && a<=IntOfNumberinput){
					FillDigits[a] = Formatted.substring(a,a+1);
					a++;	
				}
				
				for(int i=0; i <= FillDigits.length-1 ; i++){
					result = result + FillDigits[i];	
				}
				
				int length = result.length();
				
							
				if(length <errorSigDigit){
					String resultaddon ="";
					int i=-1;
					if(IntOfNumberinput==0){
						while(length < errorSigDigit){
							resultaddon = resultaddon + Formatted.substring(result.length()+i+1,result.length()+i+2);
							length++;
							i++;
							}
					}else{
							i = 0;	
						  while(length < errorSigDigit){
							resultaddon = resultaddon + Formatted.substring(result.length()+i,result.length()+i+1);
							length++;
							i++;
							}
					}
						  
					result = result+"."+resultaddon;
				}	
			}
			
						
			if(result.length()>maxWidth){
				result=Formatted.substring(0,1)+"."+Formatted.substring(1,errorSigDigit)+"E"+IntOfNumberinput;
			}
		}	
		
		//output in pure Scientific Notation
		if(SciNote == true){
			result=Formatted.substring(0,1)+"."+Formatted.substring(1,errorSigDigit)+"E"+IntOfNumberinput;
		}
		
		//regain negative and return
		if(c>0) return result;
		else return "-"+result;
	
	
	}
	
}