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();
    }

}