/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2008 jOpenDocument, by ILM Informatique. All rights reserved.
 * 
 * The contents of this file are subject to the terms of the GNU
 * General Public License Version 3 only ("GPL").  
 * You may not use this file except in compliance with the License. 
 * You can obtain a copy of the License at http://www.gnu.org/licenses/gpl-3.0.html
 * See the License for the specific language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each file.
 * 
 */

/*
 * Créé le 3 mars 2005
 */
package org.jopendocument.util;

import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;

/**
 * @author Sylvain CUAZ
 */
public class StringUtils {

    // required encoding see
    // http://docs.oracle.com/javase/7/docs/technotes/guides/intl/encoding.doc.html
    public static final Charset UTF8 = Charset.forName("UTF8");
    public static final Charset UTF16 = Charset.forName("UTF-16");
    public static final Charset ASCII = Charset.forName("ASCII");
    public static final Charset ISO8859_1 = Charset.forName("ISO8859_1");
    public static final Charset Cp1252 = Charset.forName("Cp1252");
    public static final Charset Cp850 = Charset.forName("Cp850");

    /**
     * Retourne la chaine avec la première lettre en majuscule et le reste en minuscule.
     * 
     * @param s la chaîne à transformer.
     * @return la chaine avec la première lettre en majuscule et le reste en minuscule.
     */
    public static String firstUpThenLow(String s) {
        if (s.length() == 0) {
            return s;
        }
        if (s.length() == 1) {
            return s.toUpperCase();
        }
        return s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase();
    }

    public static String firstUp(String s) {
        if (s.length() == 0) {
            return s;
        }
        if (s.length() == 1) {
            return s.toUpperCase();
        }
        return s.substring(0, 1).toUpperCase() + s.substring(1);
    }

    static public abstract class Shortener {

        private final int hashSize;
        private final int hashPartSize;
        private final String prefix;
        private final String suffix;
        private final int minStringLength;

        protected Shortener(int hashSize, String prefix, String suffix, int minCharsBeforeAndAfter) {
            super();
            this.hashSize = hashSize;
            this.prefix = prefix;
            this.suffix = suffix;
            this.hashPartSize = this.hashSize + this.prefix.length() + this.suffix.length();
            if (minCharsBeforeAndAfter < 1)
                throw new IllegalArgumentException("minCharsBeforeAndAfter must be at least 1: " + minCharsBeforeAndAfter);
            this.minStringLength = this.hashPartSize + minCharsBeforeAndAfter * 2;
        }

        public final int getMinStringLength() {
            return this.minStringLength;
        }

        public final String getBoundedLengthString(final String s, final int maxLength) {
            // don't test first for s.length, it's more predictable
            // (otherwise boundedString("a", 2) would succeed)
            if (maxLength < this.getMinStringLength())
                throw new IllegalArgumentException("Maximum too low : " + maxLength + "<" + getMinStringLength());
            if (s.length() <= maxLength)
                return s;
            else
                return this.shorten(s, maxLength);
        }

        final String shorten(final String s, final int maxLength) {
            assert s.length() >= this.getMinStringLength();
            final int toRemoveLength = s.length() - maxLength + this.hashPartSize;
            // remove the middle part of encoded
            final int toRemoveStartIndex = s.length() / 2 - toRemoveLength / 2;
            final String toHash = s.substring(toRemoveStartIndex, toRemoveStartIndex + toRemoveLength);

            final String hash = shorten(toHash);
            assert this.hashSize == hash.length();

            final String res = s.substring(0, toRemoveStartIndex) + this.prefix + hash + this.suffix + s.substring(toRemoveStartIndex + toRemoveLength);
            assert res.length() == maxLength;
            return res;
        }

        protected abstract String shorten(String s);

        static public final Shortener Ellipsis = new Shortener(1, "", "", 1) {
            @Override
            protected String shorten(String s) {
                return "…";
            }
        };

        // String.hashCode() is an int written in hex
        static public final Shortener JavaHashCode = new Shortener(Integer.SIZE / 8 * 2, "#", "#", 3) {
            @Override
            protected String shorten(String s) {
                return MessageDigestUtils.asHex(MessageDigestUtils.int2bytes(s.hashCode()));
            }
        };

        // 128 bits written in hex
        static public final Shortener MD5 = new Shortener(128 / 8 * 2, "#", "#", 11) {
            @Override
            protected String shorten(String s) {
                return MessageDigestUtils.getHashString(MessageDigestUtils.getMD5(), s.getBytes(UTF8));
            }
        };

        // order descendant by getMinStringLength()
        static final Shortener[] ORDERED = new Shortener[] { MD5, JavaHashCode, Ellipsis };
    }

    /**
     * The minimum value for {@link #getBoundedLengthString(String, int)}.
     * 
     * @return the minimum value for <code>maxLength</code>.
     */
    public static final int getLeastMaximum() {
        return Shortener.ORDERED[Shortener.ORDERED.length - 1].getMinStringLength();
    }

    private static final Shortener getShortener(final int l) {
        for (final Shortener sh : Shortener.ORDERED) {
            if (l >= sh.getMinStringLength())
                return sh;
        }
        return null;
    }

    /**
     * Return a string built from <code>s</code> that is at most <code>maxLength</code> long.
     * 
     * @param s the string to bound.
     * @param maxLength the maximum length the result must have.
     * @return a string built from <code>s</code>.
     * @throws IllegalArgumentException if <code>maxLength</code> is too small.
     * @see #getLeastMaximum()
     * @see Shortener#getBoundedLengthString(String, int)
     */
    public static final String getBoundedLengthString(final String s, final int maxLength) throws IllegalArgumentException {
        // don't test first for s.length, it's more predictable
        // (otherwise boundedString("a", 2) would succeed)
        if (maxLength < getLeastMaximum())
            throw new IllegalArgumentException("Maximum too low : " + maxLength + "<" + getLeastMaximum());

        final String res;
        if (s.length() <= maxLength) {
            res = s;
        } else {
            // use maxLength to choose the shortener since it's generally a constant
            // and thus the strings returned by this method have the same pattern
            res = getShortener(maxLength).shorten(s, maxLength);
        }
        return res;
    }

    public static final List<String> fastSplit(final String string, final char sep) {
        final List<String> l = new ArrayList<String>();
        final int length = string.length();
        final char[] cars = string.toCharArray();
        int rfirst = 0;

        for (int i = 0; i < length; i++) {
            if (cars[i] == sep) {
                l.add(new String(cars, rfirst, i - rfirst));
                rfirst = i + 1;
            }
        }

        if (rfirst < length) {
            l.add(new String(cars, rfirst, length - rfirst));
        }
        return l;
    }

    /**
     * Split une string s tous les nbCharMaxLine
     * 
     * @param s
     * @param nbCharMaxLine
     * @return
     */
    public static String splitString(String s, int nbCharMaxLine) {

        if (s == null) {
            return s;
        }

        if (s.trim().length() < nbCharMaxLine) {
            return s;
        }
        StringBuffer lastString = new StringBuffer();
        StringBuffer result = new StringBuffer();
        for (int i = 0; i < s.length(); i++) {

            if (lastString.length() == nbCharMaxLine) {
                int esp = lastString.lastIndexOf(" ");
                if (result.length() > 0 && result.charAt(result.length() - 1) != '\n') {
                    result.append("\n");
                }
                if (esp > 0) {
                    result.append(lastString.substring(0, esp).toString().trim());
                    lastString = new StringBuffer(lastString.substring(esp, lastString.length()));
                } else {
                    result.append(lastString.toString().trim());
                    lastString = new StringBuffer();
                }
                result.append("\n");
            }

            char charAt = s.charAt(i);
            if (charAt == '\n') {
                lastString.append(charAt);
                result.append(lastString);
                lastString = new StringBuffer();
            } else {
                lastString.append(charAt);
            }
        }

        if (result.length() > 0 && result.charAt(result.length() - 1) != '\n') {
            result.append("\n");
        }

        result.append(lastString.toString().trim());

        return result.toString();
    }

    static private final Pattern quotePatrn = Pattern.compile("\"", Pattern.LITERAL);
    static private final Pattern slashPatrn = Pattern.compile("(\\\\+)");

    static public String doubleQuote(String s) {
        // http://developer.apple.com/library/mac/#documentation/applescript/conceptual/applescriptlangguide/reference/ASLR_classes.html#//apple_ref/doc/uid/TP40000983-CH1g-SW6
        // http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.5
        // https://developer.mozilla.org/en/JavaScript/Guide/Values%2C_Variables%2C_and_Literals#Escaping_characters
        if (s.length() > 0) {
            s = slashPatrn.matcher(s).replaceAll("$1$1");
            s = quotePatrn.matcher(s).replaceAll("\\\\\"");
        }
        return '"' + s + '"';
    }

    public static final class Escaper {

        // eg '
        private final char esc;

        // eg { '=> S, " => D}
        private final Map<Character, Character> substitution;
        private final Map<Character, Character> inv;

        /**
         * A new escaper that will have <code>esc</code> as escape character.
         * 
         * @param esc the escape character, eg '
         * @param name the character that will be appended to <code>esc</code>, eg with S all
         *        occurrences of ' will be replaced by 'S
         */
        public Escaper(char esc, char name) {
            super();
            this.esc = esc;
            this.substitution = new LinkedHashMap<Character, Character>();
            this.inv = new HashMap<Character, Character>();
            this.add(esc, name);
        }

        public Escaper add(char toRemove, char escapedName) {
            if (this.inv.containsKey(escapedName))
                throw new IllegalArgumentException(escapedName + " already replaces " + this.inv.get(escapedName));
            this.substitution.put(toRemove, escapedName);
            this.inv.put(escapedName, toRemove);
            return this;
        }

        public final Set<Character> getEscapedChars() {
            final Set<Character> res = new HashSet<Character>(this.substitution.keySet());
            res.remove(this.esc);
            return res;
        }

        /**
         * Escape <code>s</code>, so that the resulting string has none of
         * {@link #getEscapedChars()}.
         * 
         * @param s a string to escape.
         * @return the escaped form.
         */
        public final String escape(String s) {
            String res = s;
            // this.esc en premier
            for (final Character toEsc : this.substitution.keySet()) {
                // use Pattern.LITERAL to avoid interpretion
                res = res.replace(toEsc + "", getEscaped(toEsc));
            }
            return res;
        }

        private String getEscaped(final Character toEsc) {
            return this.esc + "" + this.substitution.get(toEsc);
        }

        public final String unescape(String escaped) {
            String res = escaped;
            final List<Character> toEscs = new ArrayList<Character>(this.substitution.keySet());
            Collections.reverse(toEscs);
            for (final Character toEsc : toEscs) {
                res = res.replaceAll(getEscaped(toEsc), toEsc + "");
            }
            return res;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj instanceof Escaper) {
                final Escaper o = (Escaper) obj;
                return this.esc == o.esc && this.substitution.equals(o.substitution);
            } else
                return false;
        }

        @Override
        public int hashCode() {
            return this.esc + this.substitution.hashCode();
        }
    }

    public static String rightAlign(String s, int width) {
        String r = s;
        int n = width - s.length();
        for (int i = 0; i < n; i++) {
            r = ' ' + r;
        }
        return r;
    }

    public static String leftAlign(String s, int width) {
        String r = s;
        int n = width - s.length();
        for (int i = 0; i < n; i++) {
            r += ' ';
        }
        return r;
    }

    public static String trim(final String s, final boolean leading) {
        // from String.trim()
        int end = s.length();
        int st = 0;

        if (leading) {
            while ((st < end) && (s.charAt(st) <= ' ')) {
                st++;
            }
        } else {
            while ((st < end) && (s.charAt(end - 1) <= ' ')) {
                end--;
            }
        }
        return ((st > 0) || (end < s.length())) ? s.substring(st, end) : s;
    }
}