/*
 * HelperUtility.java
 *
 * Copyright 2012 Thomas Buck <xythobuz@me.com>
 *
 * This file is part of LED-Cube.
 *
 * LED-Cube is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * LED-Cube is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with LED-Cube.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Helper class which runs our native library, which is loaded from inside the Jar.
 * @author Thomas Buck
 * @version 1.0
 */
import java.io.*;
import java.nio.channels.*;
import java.nio.*;
import java.util.StringTokenizer;

public class HelperUtility {

	// Load libraries, copy from Jar if needed
	// Inspired by:
	// http://stackoverflow.com/questions/1611357/how-to-make-a-jar-file-that-include-dll-files
	static {
		loadFromJar();
	}

	/**
	 * When packaged into JAR extracts DLLs, places these into
	 */
	private static void loadFromJar() {
		// we need to put DLL to temp dir
		String os = System.getProperty("os.name").toLowerCase();
		String path = "CC_";
		if (os.indexOf("windows") > -1) {
			loadLib(path, "Serial.dll");
		} else if (os.indexOf("mac") > -1) {
			loadLib(path, "libSerial.jnilib");
		} else { // Hopefully unix/linux...
			loadLib(path, "libSerial.so");
		}
	}

	/**
	 * Puts library to temp dir and loads to memory
	 * @param path Put in front of file name
	 * @param Complete name of file to load (w/ lib & .dll)
	 */
	private static void loadLib(String path, String name) {
		try {
			// have to use a stream
			InputStream in = HelperUtility.class.getResourceAsStream(name);
			File fileOut = new File(System.getProperty("java.io.tmpdir") + "/" + path + name);
			OutputStream out = new FileOutputStream(fileOut);
			ReadableByteChannel inChannel = Channels.newChannel(in);
			WritableByteChannel outChannel = Channels.newChannel(out);
			fastChannelCopy(inChannel, outChannel);
			inChannel.close();
			outChannel.close();
			path = fileOut.getPath();
			try {
				System.load(path);
			} catch (UnsatisfiedLinkError e) {
				System.out.println("ERROR: Library does not exist!");
				return;
			} catch (SecurityException e) {
				System.out.println("ERROR: Not allowed to load Library!");
				return;
			} catch (NullPointerException e) {
				System.out.println("ERROR: Library name is null!");
				return;
			} catch (Exception e) {
				System.out.println("ERROR: " + e.toString());
				return;
			}
			System.out.println("Loaded Serial Library at \"" + path + "\"");
			return;
		} catch (Exception e) {
			System.out.println("ERROR: Failed to load Serial Library:");
			e.printStackTrace();
			return;
		}
	}

	/**
	 * Get the names of all available serial ports.
	 * 
	 * @return Array of port names. First entry is "No serial ports!" if no
	 *         others
	 */
	// Get ports as single String from getPortsOS() and put them in an array
	public static String[] getPorts() {
		String portLines = getPortsOS();
		if (portLines == null) {
			String[] ports = { "No serial ports!" };
			return ports;
		} else {
			StringTokenizer sT = new StringTokenizer(portLines, "\n");
			int size = sT.countTokens();
			String[] ports = new String[size];
			for (int i = 0; i < size; i++) {
				ports[i] = sT.nextToken();
			}
			return ports;
		}
	}

	/**
	 * Get all the existing serial port names
	 * 
	 * @return List of port names. \n between entries
	 */
	private static String getPortsOS() {
		String os = System.getProperty("os.name").toLowerCase();
		try {
			if (os.indexOf("windows") > -1) {
				return getThePorts("COM");
			} else if (os.indexOf("mac") > -1) {
				return getThePorts("tty.");
			} else {
				return getThePorts("tty");
			} 
		} catch (UnsatisfiedLinkError e) {
			System.out.println("ERROR: Library not loaded! (getPorts)");
			return "Serial Library Error!\n";
		}
	}

	private static native String getThePorts(String search);

	/**
	 * Open Connection to a port
	 * 
	 * @return TRUE if successful
	 * @param name
	 *            Port to open
	 */
	public static boolean openPort(String name) {
		try {
			return openPortNative(name);
		} catch (UnsatisfiedLinkError e) {
			System.out.println("ERROR: Library not loaded! (openPort)");
			return false;
		}
	}

	private static native boolean openPortNative(String name);

	/**
	 * Close Connection to port
	 */
	public static void closePort() {
		try {
			closePortNative();
		} catch (UnsatisfiedLinkError e) {
			System.out.println("ERROR: Library not loaded! (closePort)");
		}
	}

	private static native void closePortNative();

	/**
	 * Read data from Cube
	 * 
	 * @param length Amount of data to read
	 * @return Data read, empty on error
	 */
	public static short[] readData(int length) {
		try {
			return readDataNative(length);
		} catch (UnsatisfiedLinkError e) {
			System.out.println("ERROR: Library not loaded! (readData)");
			return null;
		}
	}

	private static native short[] readDataNative(int length);

	/**
	 * Write data to Cube
	 * 
	 * @param data
	 *            Data to write
	 * @param length
	 *            Length of data
	 *
	 * @return TRUE on success, FALSE on error
	 */
	public static boolean writeData(short[] data, int length) {
		try {
			return writeDataNative(data, length);
		} catch (UnsatisfiedLinkError e) {
			System.out.println("ERROR: Library not loaded! (writeData)");
			return false;
		}
	}

	private static native boolean writeDataNative(short[] data, int length);

	// http://thomaswabner.wordpress.com/2007/10/09/fast-stream-copy-using-javanio-channels/
	private static void fastChannelCopy(ReadableByteChannel src, WritableByteChannel dest) throws IOException {
		ByteBuffer buffer = ByteBuffer.allocateDirect(16 * 1024);
		while (src.read(buffer) != -1) {
			// prepare the buffer to be drained
			buffer.flip();
			// write to the channel, may block
			dest.write(buffer);
			// If partial transfer, shift remainder down
			// If buffer is empty, same as doing clear()
			buffer.compact();
		}
		// EOF will leave buffer in fill state
		buffer.flip();
		// make sure the buffer is fully drained.
		while (buffer.hasRemaining()) {
			dest.write(buffer);
		}
	}
}