/*
 * Copyright (c) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).
 * All rights reserved.
 * This component and the accompanying materials are made available
 * under the terms of "Eclipse Public License v1.0"
 * which accompanies this distribution, and is available
 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
 *
 * Initial Contributors:
 * Nokia Corporation - initial contribution.
 *
 * Contributors:
 *
 * Description:  Definitions for the class EpocReader
 *
 */
package com.nokia.s60tools.analyzetool.engine;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;

import com.nokia.s60tools.analyzetool.global.Constants;
import com.nokia.s60tools.analyzetool.global.Util;
import com.nokia.s60tools.analyzetool.ui.MainView;

/**
 * Creates new job for polling epocwind.out file
 * 
 * @author kihe
 * 
 */
public class EpocReader extends Job {

	/** Epocwind.out file location */
	private final String emulatorFileLocation;

	/** Is file listening active */
	boolean alreadyStarted = false;

	/** Interval to read file contents */
	static final int POLL_INTERVAL = 1000; // 1 second

	/** Epocwind.out file size */
	long fileSize = -1;

	/**
	 * How many characters we have read We can assume that long is big enough to
	 * store character count because max size of long is 9223372036854775807l
	 */
	long readCharacters = 0;

	/** Project reference */
	IProject project;

	/** Parent class reference */
	MainView main;

	/**
	 * Flag to determinate do we still need to read changes from epocwind.out
	 * file
	 */
	boolean stillRun = true;

	/**
	 * Constructor
	 * 
	 * @param projectRef
	 *            Project reference
	 * @param parentClass
	 *            Parent class reference
	 */
	public EpocReader(IProject projectRef, MainView parentClass) {
		super(Constants.OUTPUT_READER_TITLE);
		emulatorFileLocation = System.getenv("TEMP") + File.separator
				+ "epocwind.out";
		project = projectRef;
		main = parentClass;
	}

	/**
	 * Starts epocwind.out file reading
	 */
	public void start() {

		// if we are already listening epocwind.out file => no need create new
		// job
		if (alreadyStarted) {
			return;
		}

		setPriority(Job.LONG);
		setUser(false);

		// start as soon as possible
		schedule();

		// update listening flag
		alreadyStarted = true;

		// open streams
		main.parser.openStreams(Util.getBldInfFolder(project, true));
	}

	/**
	 * Stops listening emulator
	 */
	public void stop() {
		alreadyStarted = false;
		fileSize = -1;
		readCharacters = 0;
		stillRun = false;
		cancel();
	}

	/**
	 * Reads the epocwind.out file if it has been changed since last time
	 */
	@Override
	protected IStatus run(IProgressMonitor arg0) {

		// stream which are used to read file content
		FileInputStream fis = null;
		BufferedReader br = null;

		// run while user stops the data capturing
		while (stillRun) {
			try {
				// create new file
				File epocFile = new File(emulatorFileLocation);

				// if file exists
				if (epocFile.exists()) {

					// emulator output is not read
					// so we need to thru existing data of emulator output,
					// because we are only interested of new data.
					if (fileSize == -1) {
						fileSize = epocFile.length();

						// open epocwind.out file
						fis = new FileInputStream(epocFile);
						br = new BufferedReader(new InputStreamReader(fis,
								"UTF-8"));

						// skip lines what we have already read
						br.skip(readCharacters);

						String line = "";
						// read all new lines of epocwind.out file
						while ((line = br.readLine()) != null) {
							// update read count
							readCharacters += line.length() + 2; // <== line
							// feed
							// character
						}
						// emulator output contains new/more information than
						// what we are read
					} else if (epocFile.length() > fileSize) {

						// open epocwind.out file
						fis = new FileInputStream(epocFile);
						br = new BufferedReader(new InputStreamReader(fis,
								"UTF-8"));

						// skip lines what we have already read
						br.skip(readCharacters);

						String line = "";
						// read all new lines in epocwind.out
						while ((line = br.readLine()) != null) {
							// update read count
							readCharacters += line.length() + 2; // <== line
							// feed
							// character
							// transfer line to parser
							boolean success = main.parser.parse(line);
							if (!success) {
								main.stop(false);
								return Status.OK_STATUS;
							}
						}

						// update size
						fileSize = epocFile.length();

						// tell AT UI to update online allocation count value
						main.updateAllocNumber();
					} else if (epocFile.length() < fileSize) {
						fileSize = 0;
						readCharacters = 0;
					}
				}
				if (br != null) {
					br.close();
					br = null;
				}

				if (fis != null) {
					fis.close();
					fis = null;
				}

				// sleep this thread
				Thread.sleep(POLL_INTERVAL);
			} catch (InterruptedException ie) {
				// we can shallow the exception
				// because when this exception is raised we can exit
				cancel();
			} catch (Exception e) {
				e.printStackTrace();
				cancel();
			} finally {
				try {
					if (br != null) {
						br.close();
					}
				} catch (IOException ioe) {
					ioe.printStackTrace();
				}

				try {
					if (fis != null) {
						fis.close();
					}
				} catch (IOException ioe) {
					ioe.printStackTrace();
				}
			}
		}

		// parsing is finished
		return Status.OK_STATUS;
	}
}