<?php
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *	   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * @package log4php
   */
  
  /**
   * A convenience class to convert property values to specific types.
   *
   * @version $Revision: 1374617 $ 
   * @package log4php
   * @subpackage helpers
   * @since 0.5
   */
  class LoggerOptionConverter {
  	
  	/** String values which are converted to boolean TRUE. */
  	private static $trueValues = array('1', 'true', 'yes', 'on');
  	
  	/** 
  	 * String values which are converted to boolean FALSE.
  	 * 
  	 * Note that an empty string must convert to false, because 
  	 * parse_ini_file() which is used for parsing configuration 
  	 * converts the value _false_ to an empty string.
  	 */
  	private static $falseValues = array('0', 'false', 'no', 'off', '');
  	
  	/**
  	 * Read a predefined var.
  	 *
  	 * It returns a value referenced by <var>$key</var> using this search criteria:
  	 * - if <var>$key</var> is a constant then return it. Else
  	 * - if <var>$key</var> is set in <var>$_ENV</var> then return it. Else
  	 * - return <var>$def</var>. 
  	 *
  	 * @param string $key The key to search for.
  	 * @param string $def The default value to return.
  	 * @return string	the string value of the system property, or the default
  	 *					value if there is no property with that key.
  	 */
  	public static function getSystemProperty($key, $def) {
  		if(defined($key)) {
  			return (string)constant($key);
  		} else if(isset($_SERVER[$key])) {
  			return (string)$_SERVER[$key];
  		} else if(isset($_ENV[$key])) {
  			return (string)$_ENV[$key];
  		} else {
  			return $def;
  		}
  	}
  
  	/** Converts $value to boolean, or throws an exception if not possible. */
  	public static function toBooleanEx($value) {
  		if (isset($value)) {
  			if (is_bool($value)) {
  				return $value;
  			}
  			$value = strtolower(trim($value));
  			if (in_array($value, self::$trueValues)) {
  				return true;
  			}
  			if (in_array($value, self::$falseValues)) {
  				return false;
  			}
  		}
  		
  		throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to boolean.");
  	}
  	
  	/** 
  	 * Converts $value to integer, or throws an exception if not possible. 
  	 * Floats cannot be converted to integer.
  	 */
  	public static function toIntegerEx($value) {
  		if (is_integer($value)) {
  			return $value;
  		}
  		if (is_numeric($value) && ($value == (integer) $value)) {
  			return (integer) $value;
  		}
  	
  		throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to integer.");
  	}
  	
  	/**
  	 * Converts $value to integer, or throws an exception if not possible.
  	 * Floats cannot be converted to integer.
  	 */
  	public static function toPositiveIntegerEx($value) {
  		if (is_integer($value) && $value > 0) {
  			return $value;
  		}
  		if (is_numeric($value) && ($value == (integer) $value) && $value > 0) {
  			return (integer) $value;
  		}
  	
  		throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to a positive integer.");
  	}
  
  	/** Converts the value to a level. Throws an exception if not possible. */
  	public static function toLevelEx($value) {
  		if ($value instanceof LoggerLevel) {
  			return $value;
  		}
  		$level = LoggerLevel::toLevel($value);
  		if ($level === null) {
  			throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to a logger level.");
  		}
  		return $level;
  	}
  
  	/**
  	 * Converts a value to a valid file size (integer).
  	 * 
  	 * Supports 'KB', 'MB' and 'GB' suffixes, where KB = 1024 B etc. 
  	 *
  	 * The final value will be rounded to the nearest integer.
  	 *
  	 * Examples:
  	 * - '100' => 100
  	 * - '100.12' => 100
  	 * - '100KB' => 102400
  	 * - '1.5MB' => 1572864
  	 * 
  	 * @param mixed $value File size (optionally with suffix).
  	 * @return integer Parsed file size.
  	 */
  	public static function toFileSizeEx($value) {
  		
  		if (empty($value)) {
  			throw new LoggerException("Empty value cannot be converted to a file size.");
  		}
  		
  		if (is_numeric($value)) {
  			return (integer) $value;
  		}
  		
  		if (!is_string($value)) {
  			throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to a file size.");
  		}
  		
  		$str = strtoupper(trim($value));
  		$count = preg_match('/^([0-9.]+)(KB|MB|GB)?$/', $str, $matches);
  		
  		if ($count > 0) {
  			$size = $matches[1];
  			$unit = $matches[2];
  			
  			switch($unit) {
  				case 'KB': $size *= pow(1024, 1); break;
  				case 'MB': $size *= pow(1024, 2); break;
  				case 'GB': $size *= pow(1024, 3); break;
  			}
  			
  			return (integer) $size;
  		}
  		
  		throw new LoggerException("Given value [$value] cannot be converted to a file size.");
  	}
  
  	/** 
  	 * Converts a value to string, or throws an exception if not possible. 
  	 * 
  	 * Objects can be converted to string if they implement the magic 
  	 * __toString() method.
  	 * 
  	 */
  	public static function toStringEx($value) {
  		if (is_string($value)) {
  			return $value;
  		}
  		if (is_numeric($value)) {
  			return (string) $value;
  		}
  		if (is_object($value) && method_exists($value, '__toString')) {
  			return (string) $value;
  		}
  	
  		throw new LoggerException("Given value [" . var_export($value, true) . "] cannot be converted to string.");
  	}
  	
  	/**
  	 * Performs value substitution for string options.
  	 * 
  	 * An option can contain PHP constants delimited by '${' and '}'.
  	 * 
  	 * E.g. for input string "some ${FOO} value", the method will attempt 
  	 * to substitute ${FOO} with the value of constant FOO if it exists.
  	 * 
  	 * Therefore, if FOO is a constant, and it has value "bar", the resulting 
  	 * string will be "some bar value". 
  	 * 
  	 * If the constant is not defined, it will be replaced by an empty string, 
  	 * and the resulting string will be "some  value". 
  	 * 
  	 * @param string $string String on which to perform substitution.
  	 * @return string
  	 */
  	public static function substConstants($string) {
  		preg_match_all('/\${([^}]+)}/', $string, $matches);
  		
  		foreach($matches[1] as $key => $match) {
  			$match = trim($match);
  			$search = $matches[0][$key];
  			$replacement = defined($match) ? constant($match) : '';
  			$string = str_replace($search, $replacement, $string);
  		}
  		return $string;
  	}
  }