package ij.util;
import ij.process.*;
import java.awt.Color;
import java.util.*;
import java.io.*;
import java.util.Comparator;
import java.nio.channels.FileChannel;
import java.nio.file.*;
import java.security.MessageDigest;


/** This class contains static utility methods. */
 public class Tools {
	/** This array contains the 16 hex digits '0'-'F'. */
	public static final char[] hexDigits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};

	/** Converts a Color to an 7 byte hex string starting with '#'. */
	public static String c2hex(Color c) {
		int i = c.getRGB();
		char[] buf7 = new char[7];
		buf7[0] = '#';
		for (int pos=6; pos>=1; pos--) {
			buf7[pos] = hexDigits[i&0xf];
			i >>>= 4;
		}
		return new String(buf7);
	}

	/** Converts a float to an 9 byte hex string starting with '#'. */
	public static String f2hex(float f) {
		int i = Float.floatToIntBits(f);
		char[] buf9 = new char[9];
		buf9[0] = '#';
		for (int pos=8; pos>=1; pos--) {
			buf9[pos] = hexDigits[i&0xf];
			i >>>= 4;
		}
		return new String(buf9);
	}

	/** Converts an int to a zero-padded hex string of fixed length 'digits'.
	 *  If the number is too high, it gets truncated, keeping only the lowest 'digits' characters. */
	public static String int2hex(int i, int digits) {
		char[] buf = new char[digits];
		for (int pos=buf.length-1; pos>=0; pos--) {
			buf[pos] = hexDigits[i&0xf];
			i >>>= 4;
		}
		return new String(buf);
	}

	public static ImageStatistics getStatistics(double[] a) {
		ImageProcessor ip = new FloatProcessor(a.length, 1, a);
		return ip.getStats();
	}

	/** Determines the minimum and maximum value in the array <code>a</code>
	 *  and returns them as 2-element array {minimum, maximum}. */
	public static double[] getMinMax(double[] a) {
		double min = Double.NaN;
		double max = Double.NaN;
		int i=0;
		for (; i<a.length; i++)
			if (!Double.isNaN(a[i]))
				break;
		if (i<a.length) {
			min = a[i];
			max = a[i];
		}
		for (; i<a.length; i++) {
			double value = a[i];
			if (value<min)
				min = value;
			else if (value>max)
				max = value;
		}
		double[] minAndMax = new double[2];
		minAndMax[0] = min;
		minAndMax[1] = max;
		return minAndMax;
	}

	/** Determines the minimum and maximum value in the array <code>a</code>
	 *  and returns them as 2-element array {minimum, maximum}. */
	public static double[] getMinMax(float[] a) {
		float min = Float.NaN;
		float max = Float.NaN;
		int i=0;
		for (; i<a.length; i++)
			if (!Float.isNaN(a[i]))
				break;
		if (i<a.length) {
			min = a[i];
			max = a[i];
		}
		for (; i<a.length; i++) {
			float value = a[i];
			if (value<min)
				min = value;
			else if (value>max)
				max = value;
		}
		double[] minAndMax = new double[2];
		minAndMax[0] = min;
		minAndMax[1] = max;
		return minAndMax;
	}

	/** Converts the float array 'a' to a double array. */
	public static double[] toDouble(float[] a) {
		int len = a.length;
		double[] d = new double[len];
		for (int i=0; i<len; i++)
			d[i] = a[i];
		return d;
	}

	/** Converts the double array 'a' to a float array. */
	public static float[] toFloat(double[] a) {
		if (a==null)
			return null;
		int len = a.length;
		float[] f = new float[len];
		for (int i=0; i<len; i++)
			f[i] = (float)a[i];
		return f;
	}

	/** Adds a number to all array elements */
	public static void addToArray(float[] a, float value) {
		for (int i=0; i<a.length; i++)
			a[i] += value;
	}

	/** Converts carriage returns to line feeds. */
	public static String fixNewLines(String s) {
		if (s==null)
			return null;
		char[] chars = s.toCharArray();
		for (int i=0; i<chars.length; i++)
			{if (chars[i]=='\r') chars[i] = '\n';}
		return new String(chars);
	}

	/**
	* Returns a double containg the value represented by the
	* specified <code>String</code>.
	*
	* @param      s   the string to be parsed.
	* @param      defaultValue   the value returned if <code>s</code>
	*	does not contain a parsable double
	* @return     The double value represented by the string argument or
	*	<code>defaultValue</code> if the string does not contain a parsable double
	*/
	public static double parseDouble(String s, double defaultValue) {
		if (s==null)
			return defaultValue;
		try {
			defaultValue = Double.parseDouble(s);
		} catch (NumberFormatException e) {}
		return defaultValue;
	}

	/**
	* Returns a double containg the value represented by the
	* specified <code>String</code>.
	*
	* @param      s   the string to be parsed.
	* @return     The double value represented by the string argument or
	*	Double.NaN if the string does not contain a parsable double
	*/
	public static double parseDouble(String s) {
		return parseDouble(s, Double.NaN);
	}

	/** Returns the number of decimal places needed to display a
		number, or -2 if exponential notation should be used. */
	public static int getDecimalPlaces(double n) {
		if ((int)n==n || Double.isNaN(n))
			return 0;
		String s = ""+n;
		if (s.contains("E"))
			return -2;
		while (s.endsWith("0"))
			s = s.substring(0,s.length()-1);
		int index = s.indexOf(".");
		if (index==-1) return 0;
		int digits = s.length() - index - 1;
		if (digits>4) digits=4;
		return digits;
	}

	/** Returns the number of decimal places needed to display two numbers,
		or -2 if exponential notation should be used. */
	public static int getDecimalPlaces(double n1, double n2) {
		if ((int)n1==n1 && (int)n2==n2)
			return 0;
		int digits = getDecimalPlaces(n1);
		int digits2 = getDecimalPlaces(n2);
		if (digits==0)
			return digits2;
		if (digits2==0)
			return digits;
		if (digits<0 || digits2<0)
			return digits;
		if (digits2>digits)
			digits = digits2;
		return digits;
	}

	/** Splits a string into substrings using the default delimiter set,
	which is " \t\n\r" (space, tab, newline and carriage-return). */
	public static String[] split(String str) {
		return split(str, " \t\n\r");
	}

	/** Splits a string into substring using the characters
	contained in the second argument as the delimiter set. */
	public static String[] split(String str, String delim) {
		if (delim.equals("\n"))
			return splitLines(str);
		StringTokenizer t = new StringTokenizer(str, delim);
		int tokens = t.countTokens();
		String[] strings;
		if (tokens>0) {
			strings = new String[tokens];
			for(int i=0; i<tokens; i++)
				strings[i] = t.nextToken();
		} else
			strings = new String[0];
		return strings;
	}

	static String[] splitLines(String str) {
		Vector v = new Vector();
		try {
			BufferedReader br  = new BufferedReader(new StringReader(str));
			String line;
			while (true) {
				line = br.readLine();
				if (line == null) break;
				v.addElement(line);
			}
			br.close();
		} catch(Exception e) { }
		String[] lines = new String[v.size()];
		v.copyInto((String[])lines);
		return lines;
	}

	/** Returns a sorted list of indices of the specified double array.
		Modified from: http://stackoverflow.com/questions/951848 by N.Vischer.
	*/
	public static int[] rank(double[] values) {
		int n = values.length;
		final Integer[] indexes = new Integer[n];
		final Double[] data = new Double[n];
		for (int i=0; i<n; i++) {
			indexes[i] = Integer.valueOf(i);
			data[i] = Double.valueOf(values[i]);
		}
		Arrays.sort(indexes, new Comparator<Integer>() {
			public int compare(final Integer o1, final Integer o2) {
				return data[o1].compareTo(data[o2]);
			}
		});
		int[] indexes2 = new int[n];
		for (int i=0; i<n; i++)
			indexes2[i] = indexes[i].intValue();
		return indexes2;
	}

	/** Returns a sorted list of indices of the specified String array. */
	public static int[] rank(final String[] data) {
		int n = data.length;
		final Integer[] indexes = new Integer[n];
		for (int i=0; i<n; i++)
			indexes[i] = Integer.valueOf(i);
		Arrays.sort(indexes, new Comparator<Integer>() {
			public int compare(final Integer o1, final Integer o2) {
				return data[o1].compareToIgnoreCase(data[o2]);
			}
		});
		int[] indexes2 = new int[n];
		for (int i=0; i<n; i++)
			indexes2[i] = indexes[i].intValue();
		return indexes2;
	}

	/** Returns an array linearly resampled to a different length. */
	public static double[] resampleArray(double[] y1, int len2) {
		int len1 = y1.length;
		double factor =  (double)(len2-1)/(len1-1);
		double[] y2 = new double[len2];
		if(len1 == 0){
		    return y2;
		}
		if(len1 == 1){
		    for (int jj=0; jj<len2; jj++)
			    y2[jj] = y1[0];
		    return(y2);
		}
		double[] f1 = new double[len1];//fractional positions
		double[] f2 = new double[len2];
		for (int jj=0; jj<len1; jj++)
			f1[jj] = jj*factor;
		for (int jj=0; jj<len2; jj++)
			f2[jj] = jj/factor;
		for (int jj=0; jj<len2-1; jj++) {
			double pos = f2[jj];
			int leftPos = (int)Math.floor(pos);
			int rightPos = (int)Math.floor(pos)+1;
			double fraction = pos-Math.floor(pos);
			double value = y1[leftPos] + fraction*(y1[rightPos]-y1[leftPos]);
			y2[jj] = value;
		}
		y2[len2-1] = y1[len1-1];
		return y2;
	}

	/** Opens a text file in ij.jar as a String (example path: "/macros/Circle_Tool.txt"). */
	public static String openFromIJJarAsString(String path) {
		return (new ij.plugin.MacroInstaller()).openFromIJJar(path);
	}

	/** Copies the contents of the file at 'path1' to 'path2', returning an error message
		(as a non-empty string) if there is an error. Based on the method with the
		same name in Tobias Pietzsch's TifBenchmark class.
	*/
	public static String copyFile(String path1, String path2) {
		File f1 = new File(path1);
		File f2 = new File(path2);
		try {
			if (!f1.exists() )
				return "Source file does not exist";
			if (!f2.exists() )
				f2.createNewFile();
			long time = f1.lastModified();
			FileInputStream stream1 = new FileInputStream(f1);
			FileChannel channel1 = stream1.getChannel();
			FileOutputStream stream2 = new FileOutputStream(f2);
			final FileChannel channel2 = stream2.getChannel();
			if (channel2!=null && channel1!=null )
				channel2.transferFrom(channel1, 0, channel1.size());
			channel1.close();
			stream1.close();
			channel2.close();
			stream2.close();
			f2.setLastModified(time);
		} catch(Exception e) {
			return e.getMessage();
		}
		return "";
	}

	/** Retrieves a number form a list of key-number pairs like "value1=1234.5 area=1.2e6".
	 *  The "=" (if present) must be part of the 'key' string. Delimiters may be commas, semicolons or whitespace.
	 *  There must be no whitespace between key and number.
	 *  Returns Double.NaN if 'list' is null, if the key is not found, if the number is 'NaN' or invalid. */
	public static double getNumberFromList(String list, String key) {
		return getNumberFromList(list, key, Double.NaN);
	}

	public static double getNumberFromList(String list, String key, double defaultValue) {
		if (list == null) return defaultValue;
		int i = list.indexOf(key);
		if (i < 0) return defaultValue;
		int start = i + key.length();
		int n = start;
		while (n < list.length() && !isDelimiter(list.charAt(n))) n++;
		double value = parseDouble(list.substring(start, n));
		return Double.isNaN(value)?defaultValue:value;
	}

	/** Retrieves a String form a list of key-number pairs like "value1="abc" str='the Text'".
	 *  The "=" (if present) must be part of the 'key' string.
	 *  Strings containing commas, semicolons or whitespace must be enclosed in single or double quotes.
	 *  There must be no whitespace between key and quotes or key and unquoted String.
	 *  Strings must not contain a key. In case of doubt, e.g., replace the '=' with '\='
	 *  Escape sequences with backslashes are recognized, also backslash-u???? for unicode.
	 *  Returns null if 'list' is null or if the key is not found */
	public static String getStringFromList(String list, String key) {
		return getStringFromList(list, key, null);
	}

	public static String getStringFromList(String list, String key, String defaultValue) {
		if (list == null) return defaultValue;
		int i = list.indexOf(key);
		if (i < 0) return defaultValue;
		int start = i + key.length();
		if (list.length() == start) return "";
		char quote = list.charAt(start);
		boolean hasQuotes = quote == '\'' || quote == '\"';
		if (hasQuotes) start++;
		String str = decodeEscaped(list.substring(start), hasQuotes ? quote : (char)-2);
		if (str==null)
			str = defaultValue;
		return str;
	}

	/** Decodes backslash-escaped characters from the String until the character 'delim' is found.
	 *  With 'delim'=-1, does not search for a delimiter, with 'delim'=(char)-2, (unescaped)
	 *  whitespace, commas and semicolons are interpreted as delimiters.
	 *  Also decodes unicode backslash-u???? characters */
	public static String decodeEscaped(String str, char delim) {
		StringBuilder sb = new StringBuilder();
		for (int i=0; i<str.length(); i++) {
			char c = str.charAt(i);
			if ((delim == (char)-2 && isDelimiter(c)) || c == delim) break;
			if (c == '\\' && i+1 < str.length()) {    //escaped by backslash
				i++;
				c = str.charAt(i);
				if (c == 'u' && i+4 < str.length())
					try {
						c = (char)Integer.parseInt(str.substring(i+1, i+5), 16);
						i += 4;
					} catch (NumberFormatException e) {}
				else
					c = withBackslash(c);           // decodes backslash-t for tab etc.
			}
			sb.append(c);
		}
		return sb.toString();
	}

	private static boolean isDelimiter(char c) {
		return Character.isWhitespace(c) || c==',' || c==';';
	}

	/** Returns the escaped character if there was a preceding backslash.
	 *  Returns 'c' if there is no known escape sequence backslash-c */
	private static char withBackslash(char c) {
		switch (c) {
			case 'b': return '\b';
			case 't': return '\t';
			case 'f': return '\f';
			case 'r': return '\r';
			case 'n': return '\n';
			default: return c;
		}
	}
	
	/** Returns the checksum of a string or file, or "0" if no success.
	The 'method' argument must be "MD5" or "SHA-256".
	*/
	public static String getHash(String method, boolean fromFile, String pathOrString) {
		method = method.toUpperCase();
		boolean md5 = method.contains("MD5");
		boolean sha_256 = method.contains("SHA-256");
		try {
			MessageDigest digest = null;
			if (md5)
				digest = MessageDigest.getInstance("MD5");
			else if(sha_256)
				 digest = MessageDigest.getInstance("SHA-256");
			else
				return "0";
			Path path = Paths.get(pathOrString);
			byte[] encodedhash;
			if (fromFile)
				encodedhash = digest.digest(Files.readAllBytes(path));
			else
				encodedhash = digest.digest(pathOrString.getBytes());

			return bytesToHex(encodedhash);

		} catch (Exception e) {}
		return "0";
	}

	private static String bytesToHex(byte[] hash) {
		StringBuilder hexString = new StringBuilder(2 * hash.length);
		for (int i = 0; i < hash.length; i++) {
			String hex = Integer.toHexString(0xff & hash[i]);
			if (hex.length() == 1) {
				hexString.append('0');
			}
			hexString.append(hex);
		}
		return hexString.toString();
	}

}