package org.etsi.common;

import java.nio.ByteOrder;

public class ByteHelper {

    public static byte[] changeEndianness(byte [] in) {
        byte[] out = new byte[in.length];
        for(int i=0; i < in.length; i++) {
            out[in.length - i -1] = in[i];
        }
        return out;
    }
    
    public static byte[] intToByteArray(int value, int length, ByteOrder byteOrder) {
        if(byteOrder == ByteOrder.LITTLE_ENDIAN) {
            return changeEndianness(intToByteArray(value, length));
        }
        return intToByteArray(value, length);
    }
    
	public static byte[] intToByteArray(int value, int length) {
        byte[] b = new byte[length];
        for (int i = length - 1; i >= 0; i--) {
            int offset = (b.length - 1 - i) * 8;
            b[i] = (byte) ((value >>> offset) & 0xFF);
        }
        return b;
	}

    public static byte[] longToByteArray(long value, int length, ByteOrder byteOrder) {
        if(byteOrder == ByteOrder.LITTLE_ENDIAN) {
            return changeEndianness(longToByteArray(value, length));
        }
        return longToByteArray(value, length);
    }
    
	public static byte[] longToByteArray(long value, int length) {
        byte[] b = new byte[length];
        for (int i = length - 1; i >= 0; i--) {
            int offset = (b.length - 1 - i) * 8;
            b[i] = (byte) ((value >>> offset) & 0xFF);
        }
        return b;
	}
	
	/** Convert a byte array into a boolean
	 * 
	 * @param b The byte array to convert
	 * @return The boolean value on success, false otherwise
	 */
	public static Boolean byteArrayToBoolean(byte[] b) {
		// Sanity check
		if ((b == null) || (b.length != 1)) {
			return null;
		}

		return new Boolean(b[0] == 0x01);
	} // End of method byteArrayToBoolean
	
    public static Short byteArrayToShort(final byte[] b, ByteOrder byteOrder) {
        if(byteOrder == ByteOrder.LITTLE_ENDIAN) {
            return byteArrayToShort(changeEndianness(b));
        }
        return byteArrayToShort(b);
    }
	
	/** Convert a byte array into a short value assuming that the first byte is the most significant
	 * 
	 * @param b The byte array to convert
	 * @return The short value on success, 'Integer.MAX_VALUE' otherwise
	 */
	public static Short byteArrayToShort(final byte[] b) {
		// Sanity check
		if ((b == null) || ((b.length * Byte.SIZE) > Short.SIZE)) {
			return Short.MAX_VALUE;
		}

		short value = 0;
		for (Short i = 0; i < b.length; i++) {
			value = (short)((value << 8) + (b[i] & 0xff));
		}

		return new Short(value);
	} // End of method byteArrayToInt
	
    public static Integer byteArrayToInt(final byte[] b, ByteOrder byteOrder) {
        if(byteOrder == ByteOrder.LITTLE_ENDIAN) {
            return byteArrayToInt(changeEndianness(b));
        }
        return byteArrayToInt(b);
    }
	
	/** Convert a byte array into an integer assuming that the first byte is the most significant
	 * 
	 * @param b The byte array to convert
	 * @return The integer value on success, 'Integer.MAX_VALUE' otherwise
	 */
	public static Integer byteArrayToInt(final byte[] b) {
		// Sanity check
		if ((b == null) || ((b.length * Byte.SIZE) > Integer.SIZE)) {
			return Integer.MAX_VALUE;
		}

		int value = 0;
		for (int i = 0; i < b.length; i++) {
			value = (value << 8) + (b[i] & 0xff);
		}

		return new Integer(value);
	} // End of method byteArrayToInt
	
    public static Long byteArrayToLong(final byte[] b, ByteOrder byteOrder) {
        if(byteOrder == ByteOrder.LITTLE_ENDIAN) {
            return byteArrayToLong(changeEndianness(b));
        }
        return byteArrayToLong(b);
    }
	
	/** Convert a byte array into a Long assuming that the first byte is the most significant
	 * 
	 * @param b The byte array to convert
	 * @return The Long value on success, 'Long.MAX_VALUE' otherwise
	 */
	public static Long byteArrayToLong(final byte[] b) {
		// Sanity check
		if ((b == null) || ((b.length * Byte.SIZE) > Long.SIZE)) {
			return Long.MAX_VALUE;
		}

		long value = 0;
		for (int i = 0; i < b.length; i++) {
			value = (value << 8) + (b[i] & 0xff);
		}

		return new Long(value);
	} // End of method byteArrayToLong

	public static byte[] hexStringToByteArray(final String s) {
		String str = "";
		for(String ss : s.split("[^0-9A-Fa-f]")) {
			str = str + ss;
		}
	    int len = str.length();
	    byte[] data = new byte[len / 2];
	    for (int i = 0; i < len; i += 2) {
	        data[i / 2] = (byte) ((Character.digit(str.charAt(i), 16) << 4)
	                             + Character.digit(str.charAt(i+1), 16));
	    }
	    return data;
	}
	
	public static byte[] concat(byte[]... arrays) {
		int length = 0;
		for (byte[] array : arrays) {
			if(array != null) {
				length += array.length;
			}
		}
		byte[] result = new byte[length];
		int position = 0;
		for (byte[] array : arrays) {
			if(array != null) {
				System.arraycopy(array, 0, result, position, array.length);
				position += array.length;
			}
		}
		return result;
	}
	
	
	/** Extract a sub part of a byte array
	 * @param array The original array
	 * @param offset The offset to start the extract operation
	 * @param length The number of bytes to extract
	 * @return The sub part of a provided byte array
	 */
	public static byte[] extract(final byte[] array, final int offset, final int length) {
		// Sanity check
		if ((array == null) || (array.length == 0) || (offset > array.length)) {
			return null;
		}

		byte[] result = new byte[length];
		System.arraycopy(array, offset, result, 0, length);
		return result;
	}

	/**
	 * This method convert a byte array containing the couple (length + string) into a string
	 * @param b The byte array to convert
	 * @return A string value
	 */
	public static String byteArrayWithLengthToString(final byte[] b) {
		// Sanity check
		if (b == null) {
			return null;
		} else if (b.length == 0) {
			return "";
		}

		// Extract the length of the string
		int length = byteArrayToInt(extract(b, 0, 4));
		// Extract the the string
		String result = "";
		for (int i = 0; i < length; i++) {
			result += (char)(b[4 + i]);
		} // End of 'for' statement

		return result;
	}

	public static String byteArrayToString(final byte[] buffer) {
	    
	    String result = "";
	    if (buffer != null) {
	        for(int i=0; i < buffer.length; ++i) {
	            result += String.format("%02X", (byte)buffer[i]);
	        }
	    }
        return result;
	}
	
	/**
	 * Dump a byte array in hex/ascii mode.
	 * @param label The dump label
	 * @param buffer The byte array to dump
	 */
    public synchronized static void dump(final String label, final byte[] buffer) 
    {
        if ((buffer != null) && (buffer.length != 0))
        {
            System.out.println(label);
            StringBuilder finalHexLine = new StringBuilder();
            StringBuilder finalCharLine = new StringBuilder();
            int nCounter = 0;
            int nOffset = 0;
            // Flush header.
            System.out.println(" HEX | 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F  : 0 1 2 3 4 5 6 7 8 9 A B C D E F ");
            System.out.println("-----|+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-:--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+");
            for (int i = 0; i < buffer.length; ++i)
            {
                byte c = (byte)buffer[i];

                String fmtHex = String.format("%02x ", c);
                String fmtChar = String.format("%c ", Character.isISOControl((char)c) || c < 0 ? '.' : (char)c);

                if (nOffset % 16 == 0)
                {
                    finalHexLine.append(String.format("%05x| ", nOffset));
                }

                finalHexLine.append(fmtHex);
                finalCharLine.append(fmtChar);
                if (nCounter == 15)
                {
                    // Flush line.
                    System.out.println(String.format("%s : %s", finalHexLine.toString(), finalCharLine.toString()));
                    // Reset buffer.
                    finalHexLine.delete(0, finalHexLine.length());
                    finalCharLine.delete(0, finalCharLine.length());

                    nCounter = 0;
                }
                else
                {
                    nCounter++;
                }
                nOffset++;
            }
            if (nCounter < 16)
            {
                // Pad till 15.
                for (int i = nCounter; i < 16; i++)
                {
                    finalHexLine.append("   ");
                    finalCharLine.append("  ");
                }
                // Flush line.
                System.out.println(String.format("%s : %s", finalHexLine.toString(), finalCharLine.toString()));
            }
        }
    }
}