package com.nilhcem.fakesmtp.core;
   
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.util.Properties;
   import org.apache.commons.io.IOUtils;
  import org.slf4j.LoggerFactory;
  
  /**
   * Contains and returns some project-specific configuration variables.
   *
   * @author Nilhcem
   * @since 1.0
   */
  public enum Configuration {
  	INSTANCE;
  
  	private static final String CONFIG_FILE = "/configuration.properties";
  	private static final String USER_CONFIG_FILE = ".fakeSMTP.properties";
  	private final Properties config = new Properties();
  
  	/**
  	 * Opens the "{@code configuration.properties}" file and maps data.
  	 */
  	Configuration() {
  		InputStream in = getClass().getResourceAsStream(CONFIG_FILE);
  		try {
  			// Load defaults settings
  			config.load(in);
  			in.close();
  			// and override them from user settings
  			loadFromUserProfile();
  		} catch (IOException e) {
  			LoggerFactory.getLogger(Configuration.class).error("", e);
  		}
  	}
  
  	/**
  	 * Returns the value of a specific entry from the "{@code configuration.properties}" file.
  	 *
  	 * @param key a string representing the key from a key/value couple.
  	 * @return the value of the key, or an empty string if the key was not found.
  	 */
  	public String get(String key) {
  		if (config.containsKey(key)) {
  			return config.getProperty(key);
  		}
  		return "";
  	}
  
  	/**
  	 * Sets the value of a specific entry.
  	 *
  	 * @param key a string representing the key from a key/value couple.
  	 * @param value the value of the key.
  	 */
  	public void set(String key, String value) {
  		config.setProperty(key, value);
  	}
  
  	/**
  	 * Saves configuration to file.
  	 *
  	 * @param file file to save configuration.
  	 * @throws IOException
  	 */
  	public void saveToFile(File file) throws IOException {
  		FileOutputStream fos = new FileOutputStream(file);
  		try {
  			config.store(fos, "Last user settings");
  		} finally {
  			IOUtils.closeQuietly(fos);
  		}
  	}
  
  	/**
  	 * Saves configuration to the {@code .fakesmtp.properties} file in user profile directory.
  	 * Calls {@link Configuration#saveToFile(java.io.File)}.
  	 *
  	 * @throws IOException
  	 */
  	public void saveToUserProfile() throws IOException {
  		saveToFile(new File(System.getProperty("user.home"), USER_CONFIG_FILE));
  	}
  
  	/**
  	 * Loads configuration from file.
  	 *
  	 * @param file file to load configuration.
  	 * @return INSTANCE.
  	 * @throws IOException
  	 */
  	public Configuration loadFromFile(File file) throws IOException {
  		if (file.exists() && file.canRead()) {
  			FileInputStream fis = new FileInputStream(file);
  			try {
 				config.load(fis);
 			} finally {
 				IOUtils.closeQuietly(fis);
 			}
 		}
 		return INSTANCE;
 	}
 
 	/**
 	 * Loads configuration from the .fakesmtp.properties file in user profile directory.
 	 * Calls {@link Configuration#loadFromFile(java.io.File)}.
 	 *
 	 * @return INSTANCE.
 	 * @throws IOException
 	 */
 	public Configuration loadFromUserProfile() throws IOException {
 		return loadFromFile(new File(System.getProperty("user.home"), USER_CONFIG_FILE));
 	}
 }