package com.opslab.util;

import com.opslab.Opslab;

import java.io.UnsupportedEncodingException;

/**
 * 字符和字符序列常用方法
 */
public final class CharUtil {


    /**
     * Converts (signed) byte to (unsigned) char.
     */
    public static char toChar(byte b) {
        return (char) (b & 0xFF);
    }

    /**
     * Converts char array into byte array by stripping the high byte of each character.
     */
    public final static byte[] toSimpleByteArray(char[] carr) {
        byte[] barr = new byte[carr.length];
        for (int i = 0; i < carr.length; i++) {
            barr[i] = (byte) carr[i];
        }
        return barr;
    }

    /**
     * Converts char sequence into byte array.
     *
     * @see #toSimpleByteArray(char[])
     */
    public final static byte[] toSimpleByteArray(CharSequence charSequence) {
        byte[] barr = new byte[charSequence.length()];
        for (int i = 0; i < barr.length; i++) {
            barr[i] = (byte) charSequence.charAt(i);
        }
        return barr;
    }

    // ---------------------------------------------------------------- ascii

    /**
     * Converts byte array to char array by simply extending bytes to chars.
     */
    public final static char[] toSimpleCharArray(byte[] barr) {
        char[] carr = new char[barr.length];
        for (int i = 0; i < barr.length; i++) {
            carr[i] = (char) (barr[i] & 0xFF);
        }
        return carr;
    }

    /**
     * Returns ASCII value of a char. In case of overload, 0x3F is returned.
     */
    public final static int toAscii(char c) {
        if (c <= 0xFF) {
            return c;
        } else {
            return 0x3F;
        }
    }

    /**
     * Converts char array into {@link #toAscii(char) ASCII} array.
     */
    public final static byte[] toAsciiByteArray(char[] carr) {
        byte[] barr = new byte[carr.length];
        for (int i = 0; i < carr.length; i++) {
            barr[i] = (byte) ((int) (carr[i] <= 0xFF ? carr[i] : 0x3F));
        }
        return barr;
    }

    // ---------------------------------------------------------------- raw arrays

    /**
     * Converts char sequence into ASCII byte array.
     */
    public final static byte[] toAsciiByteArray(CharSequence charSequence) {
        byte[] barr = new byte[charSequence.length()];
        for (int i = 0; i < barr.length; i++) {
            char c = charSequence.charAt(i);
            barr[i] = (byte) ((int) (c <= 0xFF ? c : 0x3F));
        }
        return barr;
    }

    /**
     * Converts char array into byte array by replacing each character with two bytes.
     */
    public final static byte[] toRawByteArray(char[] carr) {
        byte[] barr = new byte[carr.length << 1];
        for (int i = 0, bpos = 0; i < carr.length; i++) {
            char c = carr[i];
            barr[bpos++] = (byte) ((c & 0xFF00) >> 8);
            barr[bpos++] = (byte) (c & 0x00FF);
        }
        return barr;
    }

    // ---------------------------------------------------------------- encoding

    public final static char[] toRawCharArray(byte[] barr) {
        int carrLen = barr.length >> 1;
        if (carrLen << 1 < barr.length) {
            carrLen++;
        }
        char[] carr = new char[carrLen];
        int i = 0, j = 0;
        while (i < barr.length) {
            char c = (char) (barr[i] << 8);
            i++;

            if (i != barr.length) {
                c += barr[i] & 0xFF;
                i++;
            }
            carr[j++] = c;
        }
        return carr;
    }

    /**
     * Converts char array to byte array using default Jodd encoding.
     */
    public final static byte[] toByteArray(char[] carr) throws UnsupportedEncodingException {
        return new String(carr).getBytes(Opslab.UTF_8);
    }

    /**
     * Converts char array to byte array using provided encoding.
     */
    public final static byte[] toByteArray(char[] carr, String charset) throws UnsupportedEncodingException {
        return new String(carr).getBytes(charset);
    }

    /**
     * Converts byte array of default Jodd encoding to char array.
     */
    public final static char[] toCharArray(byte[] barr) throws UnsupportedEncodingException {
        return new String(barr, Opslab.UTF_8).toCharArray();
    }

    // ---------------------------------------------------------------- find

    /**
     * Converts byte array of specific encoding to char array.
     */
    public final static char[] toCharArray(byte[] barr, String charset) throws UnsupportedEncodingException {
        return new String(barr, charset).toCharArray();
    }

    /**
     * Match if one character equals to any of the given character.
     *
     * @return <code>true</code> if characters match any character from given array,
     * otherwise <code>false</code>
     */
    public final static boolean equalsOne(char c, char[] match) {
        for (char aMatch : match) {
            if (c == aMatch) {
                return true;
            }
        }
        return false;
    }

    /**
     * Finds index of the first character in given array the matches any from the
     * given set of characters.
     *
     * @return index of matched character or -1
     */
    public final static int findFirstEqual(char[] source, int index, char[] match) {
        for (int i = index; i < source.length; i++) {
            if (equalsOne(source[i], match) == true) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Finds index of the first character in given array the matches any from the
     * given set of characters.
     *
     * @return index of matched character or -1
     */
    public final static int findFirstEqual(char[] source, int index, char match) {
        for (int i = index; i < source.length; i++) {
            if (source[i] == match) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Finds index of the first character in given array the differs from the
     * given set of characters.
     *
     * @return index of matched character or -1
     */
    public final static int findFirstDiff(char[] source, int index, char[] match) {
        for (int i = index; i < source.length; i++) {
            if (equalsOne(source[i], match) == false) {
                return i;
            }
        }
        return -1;
    }


    /**
     * Finds index of the first character in given array the differs from the
     * given set of characters.
     *
     * @return index of matched character or -1
     */
    public final static int findFirstDiff(char[] source, int index, char match) {
        for (int i = index; i < source.length; i++) {
            if (source[i] != match) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Returns <code>true</code> if character is a white space ({@code <= ' '}).
     * White space definition is taken from String class (see: <code>trim()</code>).
     */
    public final static boolean isWhitespace(char c) {
        return c <= ' ';
    }

    /**
     * Returns <code>true</code> if specified character is lowercase ASCII.
     * If user uses only ASCIIs, it is much much faster.
     */
    public final static boolean isLowercaseAlpha(char c) {
        return (c >= 'a') && (c <= 'z');
    }

    /**
     * Returns <code>true</code> if specified character is uppercase ASCII.
     * If user uses only ASCIIs, it is much much faster.
     */
    public final static boolean isUppercaseAlpha(char c) {
        return (c >= 'A') && (c <= 'Z');
    }

    public final static boolean isAlphaOrDigit(char c) {
        return isDigit(c) || isAlpha(c);
    }

    public final static boolean isWordChar(char c) {
        return isDigit(c) || isAlpha(c) || (c == '_');
    }


    public final static boolean isPropertyNameChar(char c) {
        return isDigit(c) || isAlpha(c) || (c == '_') || (c == '.') || (c == '[') || (c == ']');
    }

    /**
     * Indicates whether the given character is in the {@code ALPHA} set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isAlpha(char c) {
        return ((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z'));
    }

    /**
     * Indicates whether the given character is in the {@code DIGIT} set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isDigit(char c) {
        return c >= '0' && c <= '9';
    }

    /**
     * Indicates whether the given character is the hexadecimal digit.
     */
    public final static boolean isHexDigit(char c) {
        return (c >= '0' && c <= '9') || ((c >= 'a') && (c <= 'f')) || ((c >= 'A') && (c <= 'F'));
    }

    /**
     * Indicates whether the given character is in the <i>gen-delims</i> set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isGenericDelimiter(int c) {
        switch (c) {
            case ':':
            case '/':
            case '?':
            case '#':
            case '[':
            case ']':
            case '@':
                return true;
            default:
                return false;
        }
    }

    /**
     * Indicates whether the given character is in the <i>sub-delims</i> set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isSubDelimiter(int c) {
        switch (c) {
            case '!':
            case '$':
            case '&':
            case '\'':
            case '(':
            case ')':
            case '*':
            case '+':
            case ',':
            case ';':
            case '=':
                return true;
            default:
                return false;
        }
    }

    /**
     * Indicates whether the given character is in the <i>reserved</i> set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isReserved(char c) {
        return isGenericDelimiter(c) || isSubDelimiter(c);
    }

    /**
     * Indicates whether the given character is in the <i>unreserved</i> set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isUnreserved(char c) {
        return isAlpha(c) || isDigit(c) || c == '-' || c == '.' || c == '_' || c == '~';
    }


    /**
     * Indicates whether the given character is in the <i>pchar</i> set.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
     */
    public final static boolean isPchar(char c) {
        return isUnreserved(c) || isSubDelimiter(c) || c == ':' || c == '@';
    }

    /**
     * Uppers lowercase ASCII char.
     */
    public final static char toUpperAscii(char c) {
        if (isLowercaseAlpha(c)) {
            c -= (char) 0x20;
        }
        return c;
    }

    /**
     * Lowers uppercase ASCII char.
     */
    public final static char toLowerAscii(char c) {
        if (isUppercaseAlpha(c)) {
            c += (char) 0x20;
        }
        return c;
    }


}