package de.fhdw.wtf.persistence.utils;
   
   import java.util.HashMap;
   import java.util.MissingResourceException;
   
   /**
    * This class is a singleton that is used to create a PropertiesReader class that stores the connection properties to
    * the oracle database.
    * 
   * @author HFW413hy
   *
   */
  public class PropertiesReaderFactory {
  	
  	private static PropertiesReaderFactory _instance = null;
  	
  	/**
  	 * Returns the instance of this singleton.
  	 * 
  	 * @return The instance of this singleton.
  	 */
  	public static synchronized PropertiesReaderFactory getInstance() {
  		if (_instance == null) {
  			_instance = new PropertiesReaderFactory();
  		}
  		return _instance;
  	}
  	
  	/**
  	 * Creates a PropertiesReaderFile-Object that will be returned.
  	 * 
  	 * @param file
  	 * @return The PropertiesReaderFile-Object
  	 */
  	public PropertiesReader getPropertiesReaderFile(final String file) {
  		final PropertiesReader reader = new PropertiesReaderFile();
  		try {
  			reader.initialize(file);
  			return reader;
  		} catch (final MissingResourceException e) {
  			return this.getPropertiesReaderOracle();
  		}
  	}
  	
  	/**
  	 * Returns a new PropertiesReader that stores the Oracle connection properties. At first, it searches for a file
  	 * "oracle.properties" in the current directory. If there is no file that could be read, it tries to read the
  	 * "oracle.properties" from the current namespace. If there is not file, it will return a PropertiesReader that
  	 * contains default information.
  	 * 
  	 * @return The PropertiesReader that contains connection properties to the oracle database.
  	 */
  	public PropertiesReader getPropertiesReaderOracle() {
  		PropertiesReader reader;
  		
  		// Try to read the local file from the current directory
  		// --------------------------------------------------
  		reader = new PropertiesReaderFile();
  		try {
  			reader.initialize("oracle.properties");
  			return reader;
  		} catch (final MissingResourceException e) {
  			// Continue if this happens... file is not here
  		}
  		
  		// Try to read the ressource file from the current package
  		// --------------------------------------------------
  		reader = new PropertiesReaderRessource();
  		try {
  			reader.initialize("oracle");
  			return reader;
  		} catch (final MissingResourceException e) {
  			// Continue if this happens... file is not here
  		}
  		
  		// Now, the default reader with default params
  		// --------------------------------------------------
  		reader = new PropertiesReader() {
  			private final HashMap<String, String> propValues = new HashMap<>();
  			
  			@Override
  			public void initialize(final String propFile) throws MissingResourceException {
  				this.propValues.put("sid", "XE");
  				this.propValues.put("schema", "meta");
  				this.propValues.put("username", "meta");
  				this.propValues.put("password", "meta");
  				this.propValues.put("hostname", "localhost");
  				this.propValues.put("port", "1521");
  			}
  			
  			@Override
  			public String getProperty(final String key) {
  				if (!this.propValues.containsKey(key)) {
  					return "";
  				}
  				return this.propValues.get(key);
  			}
  		};
  		reader.initialize("");
 		return reader;
 	}
 }