/**

 * 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.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);

	}

}