/**

  * SQL-DK

  * Copyright © 2013 František Kučera (frantovo.cz)

  *

  * This program 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.

  *

  * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.

  */

 package info.globalcode.sql.dk;

 import info.globalcode.sql.dk.configuration.NameIdentified;

 import java.io.BufferedReader;

 import java.io.File;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.PrintWriter;

 import java.util.Arrays;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.Map;

 /**

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 public class Functions {

 	private Functions() {

 	}

 	public static boolean equalz(Object a, Object b) {

 		return a == null ? b == null : a.equals(b);

 	}

 	/**

 	 *

 	 * @param text String to be examinated

 	 * @param trim whether text should be trimmed before examination

 	 * @return whether text is not empty and one or more characters long (after prospective trim)

 	 */

 	public static boolean isEmpty(String text, boolean trim) {

 		if (text == null) {

 			return true;

 		} else {

 			if (trim) {

 				text = text.trim();

 			}

 			return text.isEmpty();

 		}

 	}

 	/**

 	 * @see #isEmpty(java.lang.String, boolean)

 	 */

 	public static boolean isNotEmpty(String text, boolean trim) {

 		return !isEmpty(text, trim);

 	}

 	public boolean isEmpty(Collection c) {

 		return c == null || c.isEmpty();

 	}

 	public boolean isNotEmpty(Collection c) {

 		return !isEmpty(c);

 	}

 	public boolean isEmpty(Map m) {

 		return m == null || m.isEmpty();

 	}

 	public boolean isNotEmpty(Map m) {

 		return !isEmpty(m);

 	}

 	/**

 	 * @return empty collection if given one is null | or the original one

 	 */

 	public static <T> Collection<T> notNull(Collection<T> c) {

 		if (c == null) {

 			return Collections.emptyList();

 		} else {

 			return c;

 		}

 	}

 	public static <T extends NameIdentified> T findByName(Collection<T> collection, String name) {

 		for (T element : notNull(collection)) {

 			if (element != null && equalz(element.getName(), name)) {

 				return element;

 			}

 		}

 		return null;

 	}

 	/**

 	 * Copy file from Java resources to file system.

 	 */

 	public static void installResource(String resourceName, File target) throws IOException {

 		try (BufferedReader reader = new BufferedReader(new InputStreamReader(Functions.class.getClassLoader().getResourceAsStream(resourceName)))) {

 			try (PrintWriter writer = new PrintWriter(target)) {

 				while (true) {

 					String line = reader.readLine();

 					if (line == null) {

 						break;

 					} else {

 						writer.println(line);

 					}

 				}

 			}

 		}

 	}

 	public static String rpad(String s, int n) {

 		if (n > 0) {

 			return String.format("%1$-" + n + "s", s);

 		} else {

 			return s;

 		}

 	}

 	public static String lpad(String s, int n) {

 		if (n > 0) {

 			return String.format("%1$" + n + "s", s);

 		} else {

 			return s;

 		}

 	}

 	public static String repeat(char ch, int count) {

 		char[] array = new char[count];

 		Arrays.fill(array, ch);

 		return new String(array);

 	}

 	private final static char[] HEX_ALPHABET = "0123456789abcdef".toCharArray();

 	public static String toHex(byte[] bytes) {

 		char[] hexChars = new char[bytes.length * 2];

 		for (int j = 0; j < bytes.length; j++) {

 			int v = bytes[j] & 0xFF;

 			hexChars[j * 2] = HEX_ALPHABET[v >>> 4];

 			hexChars[j * 2 + 1] = HEX_ALPHABET[v & 0x0F];

 		}

 		return new String(hexChars);

 	}

 	public static String readString(InputStream in) throws IOException {

 		try (BufferedReader br = new BufferedReader(new InputStreamReader(in))) {

 			StringBuilder result = new StringBuilder();

 			for (String line = br.readLine(); line != null; line = br.readLine()) {

 				result.append(line);

 				result.append('\n');

 			}

 			return result.toString();

 		}

 	}

 }