/*******************************************************************************
 * Copyright (c) 2005, 2007 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
 *
 
 *******************************************************************************/
package org.eclipse.dltk.compiler.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import org.eclipse.dltk.compiler.CharOperation;



public class Util {

	private static final int DEFAULT_READING_SIZE = 8192;
	public final static String UTF_8 = "UTF-8";	//$NON-NLS-1$			
	public static String LINE_SEPARATOR = System.getProperty("line.separator"); //$NON-NLS-1$

	/**
	 * Returns the given input stream's contents as a byte array.
	 * If a length is specified (ie. if length != -1), only length bytes
	 * are returned. Otherwise all bytes in the stream are returned.
	 * Note this doesn't close the stream.
	 * @throws IOException if a problem occured reading the stream.
	 */
	public static byte[] getInputStreamAsByteArray(InputStream stream, int length)
		throws IOException {
		byte[] contents;
		if (length == -1) {
			contents = new byte[0];
			int contentsLength = 0;
			int amountRead = -1;
			do {
				int amountRequested = Math.max(stream.available(), DEFAULT_READING_SIZE);  // read at least 8K
				
				// resize contents if needed
				if (contentsLength + amountRequested > contents.length) {
					System.arraycopy(
						contents,
						0,
						contents = new byte[contentsLength + amountRequested],
						0,
						contentsLength);
				}

				// read as many bytes as possible
				amountRead = stream.read(contents, contentsLength, amountRequested);

				if (amountRead > 0) {
					// remember length of contents
					contentsLength += amountRead;
				}
			} while (amountRead != -1); 

			// resize contents if necessary
			if (contentsLength < contents.length) {
				System.arraycopy(
					contents,
					0,
					contents = new byte[contentsLength],
					0,
					contentsLength);
			}
		} else {
			contents = new byte[length];
			int len = 0;
			int readSize = 0;
			while ((readSize != -1) && (len != length)) {
				// See PR 1FMS89U
				// We record first the read size. In this case len is the actual read size.
				len += readSize;
				readSize = stream.read(contents, len, length - len);
			}
		}

		return contents;
	}
	
	/**
	/**
	 * Returns the contents of the given file as a byte array.
	 * @throws IOException if a problem occured reading the file.
	 */
	public static byte[] getFileByteContent(File file) throws IOException {
		InputStream stream = null;
		try {
			stream = new FileInputStream(file);
			return getInputStreamAsByteArray(stream, (int) file.length());
		} finally {
			if (stream != null) {
				try {
					stream.close();
				} catch (IOException e) {
					// ignore
				}
			}
		}
	} 
	/*a character array.
	 * If a length is specified (ie. if length != -1), this represents the number of bytes in the stream.
	 * Note this doesn't close the stream.
	 * @throws IOException if a problem occured reading the stream.
	 */
	public static char[] getInputStreamAsCharArray(InputStream stream, int length, String encoding)
		throws IOException {
		InputStreamReader reader = null;
		try {
			reader = encoding == null
						? new InputStreamReader(stream)
						: new InputStreamReader(stream, encoding);
		} catch (UnsupportedEncodingException e) {
			// encoding is not supported
			reader =  new InputStreamReader(stream);
		}
		char[] contents;
		int totalRead = 0;
		if (length == -1) {
			contents = CharOperation.NO_CHAR;
		} else {
			// length is a good guess when the encoding produces less or the same amount of characters than the file length
			contents = new char[length]; // best guess
		}

		while (true) {
			int amountRequested;
			if (totalRead < length) {
				// until known length is met, reuse same array sized eagerly
				amountRequested = length - totalRead;
			} else {
				// reading beyond known length
				int current = reader.read(); 
				if (current < 0) break;
				
				amountRequested = Math.max(stream.available(), DEFAULT_READING_SIZE);  // read at least 8K
				
				// resize contents if needed
				if (totalRead + 1 + amountRequested > contents.length)
					System.arraycopy(contents, 	0, 	contents = new char[totalRead + 1 + amountRequested], 0, totalRead);
				
				// add current character
				contents[totalRead++] = (char) current; // coming from totalRead==length
			}
			// read as many chars as possible
			int amountRead = reader.read(contents, totalRead, amountRequested);
			if (amountRead < 0) break;
			totalRead += amountRead;
		}

		// Do not keep first character for UTF-8 BOM encoding
		int start = 0;
		if (totalRead > 0 && UTF_8.equals(encoding)) {
			if (contents[0] == 0xFEFF) { // if BOM char then skip
				totalRead--;
				start = 1;
			}
		}
		
		// resize contents if necessary
		if (totalRead < contents.length)
			System.arraycopy(contents, start, contents = new char[totalRead], 	0, 	totalRead);

		return contents;
	}	
	/**
	 * Returns true iff str.toLowerCase().endsWith(".zip") || str.toLowerCase().endsWith(".zip")
	 * implementation is not creating extra strings.
	 */
	public final static boolean isArchiveFileName(String name) {
		//System.err.println("TODO: Util.isArchiveFileName always return false for:" + name);
		//return false;
		if( name == null ) {
			return false;
		}
		return name.toLowerCase().endsWith(".zip") || name.toLowerCase().endsWith(".zip");
	}	
	/* TODO (philippe) should consider promoting it to CharOperation
	 * Returns whether the given resource path matches one of the inclusion/exclusion
	 * patterns.
	 * NOTE: should not be asked directly using pkg root pathes
	 */
	public final static boolean isExcluded(char[] path, char[][] inclusionPatterns, char[][] exclusionPatterns, boolean isFolderPath) {
		if (inclusionPatterns == null && exclusionPatterns == null) return false;

		inclusionCheck: if (inclusionPatterns != null) {
			for (int i = 0, length = inclusionPatterns.length; i < length; i++) {
				char[] pattern = inclusionPatterns[i];
				char[] folderPattern = pattern;
				if (isFolderPath) {
					int lastSlash = CharOperation.lastIndexOf('/', pattern);
					if (lastSlash != -1 && lastSlash != pattern.length-1){ // trailing slash -> adds '**' for free (see http://ant.apache.org/manual/dirtasks.html)
						int star = CharOperation.indexOf('*', pattern, lastSlash);
						if ((star == -1
								|| star >= pattern.length-1 
								|| pattern[star+1] != '*')) {
							folderPattern = CharOperation.subarray(pattern, 0, lastSlash);
						}
					}
				}
				if (CharOperation.pathMatch(folderPattern, path, true, '/')) {
					break inclusionCheck;
				}
			}
			return true; // never included
		}
		if (isFolderPath) {
			path = CharOperation.concat(path, new char[] {'*'}, '/');
		}
		if (exclusionPatterns != null) {
			for (int i = 0, length = exclusionPatterns.length; i < length; i++) {
				if (CharOperation.pathMatch(exclusionPatterns[i], path, true, '/')) {
					return true;
				}
			}
		}
		return false;
	}	

	/**
	 * Returns the contents of the given file as a char array.
	 * When encoding is null, then the platform default one is used
	 * @throws IOException if a problem occured reading the file.
	 */
	public static char[] getFileCharContent(File file, String encoding) throws IOException {
		InputStream stream = null;
		try {
			stream = new FileInputStream(file);
			return getInputStreamAsCharArray(stream, (int) file.length(), encoding);
		} finally {
			if (stream != null) {
				try {
					stream.close();
				} catch (IOException e) {
					// ignore
				}
			}
		}
	}
}
