/* $Id: OSCByteArrayToJavaConverter.java,v 1.1.1.1 2006/11/13 14:47:22 modin Exp $
 * Created on 28.10.2003
 */
package com.illposed.osc.utility;

import java.math.BigInteger;
import java.util.Date;

import com.illposed.osc.*;

/**
 * @author cramakrishnan
 *
 * Copyright (C) 2003, C. Ramakrishnan / Auracle
 * All rights reserved.
 * 
 * See license.txt (or license.rtf) for license information.
 */
public class OSCByteArrayToJavaConverter {

    byte[] bytes;
    int bytesLength;
    int streamPosition;

    private byte[] intBytes   = new byte[4];
    private byte[] floatBytes = new byte[4];

    private    byte[] secondBytes = new byte[8];
    private    byte[] picosecBytes = new byte[8];

    /**
     * Helper object for converting from a byte array to Java objects
     */
    /*public OSCByteArrayToJavaConverter() {
        super();
    }*/

    public OSCPacket convert(byte[] byteArray, int bytesLength) {
        bytes = byteArray;
        this.bytesLength = bytesLength;
        streamPosition = 0;
        if (isBundle())
            return convertBundle();
        else
            return convertMessage();
    }

    private boolean isBundle() {
        // only need the first 7 to check if it is a bundle
        String bytesAsString = new String(bytes, 0, 7);
        return bytesAsString.startsWith("#bundle");
    }                               
                               
    private OSCBundle convertBundle() {
        // skip the "#bundle " stuff
        streamPosition = 8;
        Date timestamp = readTimeTag();
        OSCBundle bundle = new OSCBundle(timestamp);
        OSCByteArrayToJavaConverter myConverter = new OSCByteArrayToJavaConverter();
        while (streamPosition < bytesLength) {
            // recursively read through the stream and convert packets you find
            int packetLength = ((Integer) readInteger()).intValue();
            byte[] packetBytes = new byte[packetLength];
            //streamPosition++;
            System.arraycopy(bytes,streamPosition,packetBytes,0,packetLength);
            streamPosition+=packetLength;
            //for (int i = 0; i < packetLength; i++)
            //    packetBytes[i] = bytes[streamPosition++];
            OSCPacket packet = myConverter.convert(packetBytes, packetLength);
            bundle.addPacket(packet);
        }
        return bundle;
    }

    private OSCMessage convertMessage() {
        OSCMessage message = new OSCMessage();
        message.setAddress(readString());
        char[] types = readTypes();
        if (null == types) {
            // we are done
            return message;
        }
        moveToFourByteBoundry();
        for (int i = 0; i < types.length; i++) {
            if ('[' == types[i]) {
                // we're looking at an array -- read it in
                message.addArgument(readArray(types, i));
                // then increment i to the end of the array
                while (']' != types[i])
                    i++;
            } else
                message.addArgument(readArgument(types[i]));
        }
        return message;
    }

    private String readString() {
        int strLen = lengthOfCurrentString();
        char[] stringChars = new char[strLen];
        //System.arraycopy(bytes,streamPosition,stringChars,0,strLen);
        //streamPosition+=strLen;
        for (int i = 0; i < strLen; i++)
            stringChars[i] = (char) bytes[streamPosition++];
        moveToFourByteBoundry();
        return new String(stringChars);
    }

    /**
     * @return a char array with the types of the arguments
     */
    private char[] readTypes() {
        // the next byte should be a ","
        if (bytes[streamPosition] != 0x2C)
            return null;
        streamPosition++;
        // find out how long the list of types is
        int typesLen = lengthOfCurrentString();
        if (0 == typesLen) {
            return null;
        }
        // read in the types
        char[] typesChars = new char[typesLen];
        for (int i = 0; i < typesLen; i++) {
            typesChars[i] = (char) bytes[streamPosition++];
        }
        return typesChars;
    }

    /**
     * @param c type of argument
     * @return a Java representation of the argument
     */
    private Object readArgument(char c) {
        switch (c) {
            case 'i' :
                return readInteger();
            case 'h' :
                return readBigInteger();
            case 'f' :
                return readFloat();
            case 'd' :
                return readDouble();
            case 's' :
                return readString();
            case 'c' :
                return readChar();
            case 'T' :
                return Boolean.TRUE;
            case 'F' :
                return Boolean.FALSE;
        }

        return null;
    }

    /**
     * @return a Character
     */
    private Object readChar() {
        return new Character((char) bytes[streamPosition++]);
    }

    /**
     * @return a Double
     */
    private Object readDouble() {
        return readFloat();
    }

    /**
     * @return a Float
     */
    private Object readFloat() {
        //byte[] floatBytes = new byte[4];
        floatBytes[0] = bytes[streamPosition++];
        floatBytes[1] = bytes[streamPosition++];
        floatBytes[2] = bytes[streamPosition++];
        floatBytes[3] = bytes[streamPosition++];

        int floatBits = 
            ((floatBytes[3] & 0xFF) ) +
            ((floatBytes[2] & 0xFF) << 8) +
            ((floatBytes[1] & 0xFF) << 16) +
            ((floatBytes[0] & 0xFF) << 24);
        
        return new Float(Float.intBitsToFloat(floatBits));
    }

    /**
     * @return a BigInteger
     */
    private Object readBigInteger() {
        //byte[] intBytes = new byte[4];
        intBytes[0] = bytes[streamPosition++];
        intBytes[1] = bytes[streamPosition++];
        intBytes[2] = bytes[streamPosition++];
        intBytes[3] = bytes[streamPosition++];

        int intBits = 
            ((intBytes[3] & 0xFF) ) +
            ((intBytes[2] & 0xFF) << 8) +
            ((intBytes[1] & 0xFF) << 16) +
            ((intBytes[0] & 0xFF) << 24);
        
        return new Integer(intBits);
    }

    /**
     * @return an Integer
     */
    private Object readInteger() {
        //byte[] intBytes = new byte[4];
        intBytes[0] = bytes[streamPosition++];
        intBytes[1] = bytes[streamPosition++];
        intBytes[2] = bytes[streamPosition++];
        intBytes[3] = bytes[streamPosition++];

        int intBits = 
            ((intBytes[3] & 0xFF) ) +
            ((intBytes[2] & 0xFF) << 8) +
            ((intBytes[1] & 0xFF) << 16) +
            ((intBytes[0] & 0xFF) << 24);
        
        return new Integer(intBits);
    }
    
    /**
     * @return a Date
     */
    private Date readTimeTag() {
        //byte[] secondBytes = new byte[8];
        //byte[] picosecBytes = new byte[8];
        /*for (int i = 4; i < 8; i++)
            secondBytes[i] = bytes[streamPosition++];
        for (int i = 4; i < 8; i++)
            picosecBytes[i] = bytes[streamPosition++];*/
        System.arraycopy(bytes,streamPosition,secondBytes,4,4);
        streamPosition+=4;
        System.arraycopy(bytes,streamPosition,picosecBytes,4,4);
        streamPosition+=4;
        
        BigInteger secsSince1900 = new BigInteger(secondBytes);
        long secsSince1970 =  secsSince1900.longValue() - OSCBundle.SECONDS_FROM_1900_to_1970.longValue();
        if (secsSince1970 < 0) secsSince1970 = 0; // no point maintaining times in the distant past
        BigInteger picosecs = new BigInteger(picosecBytes);
        long millisecs = (secsSince1970 * 1000) + (picosecs.longValue() / 1000);
        return new Date(millisecs);
    }

    /**
     * @param types
     * @param i
     * @return an Array
     */
    private Object[] readArray(char[] types, int i) {
        int arrayLen = 0;
        while (types[i + arrayLen] != ']')
            arrayLen++;
        Object[] array = new Object[arrayLen];
        for (int j = 0; i < arrayLen; j++) {
            array[j] = readArgument(types[i + j]);
        }
        return array;
    }

    private int lengthOfCurrentString() {
        int i = 0;
        while (bytes[streamPosition + i] != 0)
            i++;
        return i;
    }

    private void moveToFourByteBoundry() {
        // If i'm already at a 4 byte boundry, I need to move to the next one
        int mod = streamPosition % 4;
        streamPosition += (4 - mod);
    }

}