/*******************************************************************************
 * Copyright (c) 2004, 2016 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * IBM - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.internal.core;

import java.io.IOException;
import java.io.OutputStream;

import org.eclipse.cdt.core.CCorePlugin;
import org.eclipse.cdt.core.IConsoleParser;


/**
 * Intercepts an output to console and forwards it to console parsers for processing
 */
public class ConsoleOutputSniffer {

	/**
	 * Private class to sniff the output stream for this sniffer.
	 */
	private class ConsoleOutputStream extends OutputStream {
		// Stream's private buffer for the stream's read contents.
		private StringBuilder currentLine = new StringBuilder();
		private OutputStream outputStream = null;

		public ConsoleOutputStream(OutputStream outputStream) {
			this.outputStream = outputStream;
		}

		@Override
		public void write(int b) throws IOException {
			currentLine.append((char) b);
			checkLine(false);

			// Continue writing the bytes to the console's output.
			if (outputStream != null) {
				outputStream.write(b);
			}
		}

		@Override
		public void write(byte[] b, int off, int len) throws IOException {
			if (b == null) {
				throw new NullPointerException();
			} else if (off != 0 || (len < 0) || (len > b.length)) {
				throw new IndexOutOfBoundsException();
			} else if (len == 0) {
				return;
			}
			currentLine.append(new String(b, 0, len));
			checkLine(false);

			// Continue writing the bytes to the console's output.
			if (outputStream != null)
				outputStream.write(b, off, len);
		}

		@Override
		public void close() throws IOException {
			checkLine(true);
			closeConsoleOutputStream();
		}

		@Override
		public void flush() throws IOException {
			if (outputStream != null) {
				outputStream.flush();
			}
		}

		/**
		 * Checks to see if the already read input constitutes
		 * a complete line (e.g. does the sniffing).  If so, then
		 * send it to processLine.
		 *
		 * @param flush
		 */
		private void checkLine(boolean flush) {
			if (currentLine.length() == 0) {
				return;
			}

			String buffer = currentLine.toString();
			int i = 0;
			while ((i = buffer.indexOf('\n')) != -1) {
				int eol = i;
				if (i > 0 && buffer.charAt(i-1) == '\r') {
					// also get rid of trailing \r in case of Windows line delimiter "\r\n"
					eol = i - 1;
				}
				String line = buffer.substring(0, eol);
				processLine(line);

				buffer = buffer.substring(i + 1); // skip the \n and advance
			}
			currentLine.setLength(0);
			if (flush) {
				if (buffer.length() > 0) {
					processLine(buffer);
				}
			} else {
				currentLine.append(buffer);
			}
		}

	} // end ConsoleOutputStream class

	private int nOpens = 0;
	private OutputStream consoleOutputStream;
	private OutputStream consoleErrorStream;
	private IConsoleParser[] parsers;

	public ConsoleOutputSniffer(IConsoleParser[] parsers) {
		this.parsers = parsers;
	}

	public ConsoleOutputSniffer(OutputStream outputStream, OutputStream errorStream, IConsoleParser[] parsers) {
		this(parsers);
		this.consoleOutputStream = outputStream;
		this.consoleErrorStream = errorStream;
	}

	/**
	 * Returns an output stream that will be sniffed.
	 * This stream should be hooked up so the command
	 * output stream goes into here.
	 */
	public OutputStream getOutputStream() {
		incNOpens();
		return new ConsoleOutputStream(consoleOutputStream);
	}

	/**
	 * Returns an error stream that will be sniffed.
	 * This stream should be hooked up so the command
	 * error stream goes into here.
	 */
	public OutputStream getErrorStream() {
		incNOpens();
		return new ConsoleOutputStream(consoleErrorStream);
	}

	private synchronized void incNOpens() {
		nOpens++;
	}

	/*
	 */
	public synchronized void closeConsoleOutputStream() throws IOException {
		if (nOpens > 0 && --nOpens == 0) {
			for (int i = 0; i < parsers.length; ++i) {
				try {
					parsers[i].shutdown();
				} catch (Throwable e) {
					// Report exception if any but let all the parsers a chance to shutdown.
					CCorePlugin.log(e);
				}
			}
		}
	}

	/*
	 * Processes the line by passing the line to the parsers.
	 *
	 * @param line
	 */
	private synchronized void processLine(String line) {
		for (IConsoleParser parser : parsers) {
			try {
				// Report exception if any but let all the parsers a chance to process the line.
				parser.processLine(line);
			} catch (Throwable e) {
				CCorePlugin.log(e);
			}
		}
	}

}