/*

 *   SONEWS News Server

 *   see AUTHORS for the list of contributors

 *

 *   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 org.sonews.daemon;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Properties;

import org.sonews.util.AbstractConfig;

/**

 * Manages the bootstrap configuration. It MUST contain all config values

 * that are needed to establish a database connection.

 * For further configuration values use the Config class instead as that class

 * stores its values within the database.

 * @author Christian Lins

 * @since sonews/0.5.0

 */

public final class BootstrapConfig extends AbstractConfig

{

  /** Key constant. If value is "true" every I/O is written to logfile 

   * (which is a lot!) 

   */

  public static final String DEBUG              = "sonews.debug";

  /** Key constant. Value is classname of the JDBC driver */

  public static final String STORAGE_DBMSDRIVER = "sonews.storage.dbmsdriver";

  /** Key constant. Value is JDBC connect String to the database. */

  public static final String STORAGE_DATABASE   = "sonews.storage.database";

  /** Key constant. Value is the username for the DBMS. */

  public static final String STORAGE_USER       = "sonews.storage.user";

  /** Key constant. Value is the password for the DBMS. */

  public static final String STORAGE_PASSWORD   = "sonews.storage.password";

  /** Key constant. Value is the name of the host which is allowed to use the

   *  XDAEMON command; default: "localhost" */

  public static final String XDAEMON_HOST       = "sonews.xdaemon.host";

  /** The config key for the filename of the logfile */

  public static final String LOGFILE = "sonews.log";

  /** The filename of the config file that is loaded on startup */

  public static volatile String FILE               = "sonews.conf";

  private static final Properties defaultConfig = new Properties();

  private static BootstrapConfig instance = null;

  static

  {

    // Set some default values

    defaultConfig.setProperty(STORAGE_DATABASE, "jdbc:mysql://localhost/sonews");

    defaultConfig.setProperty(STORAGE_DBMSDRIVER, "com.mysql.jdbc.Driver");

    defaultConfig.setProperty(STORAGE_USER, "sonews_user");

    defaultConfig.setProperty(STORAGE_PASSWORD, "mysecret");

    defaultConfig.setProperty(DEBUG, "false");

  }

  /**

   * Note: this method is not thread-safe

   * @return A Config instance

   */

  public static synchronized BootstrapConfig getInstance()

  {

    if(instance == null)

    {

      instance = new BootstrapConfig();

    }

    return instance;

  }

  // Every config instance is initialized with the default values.

  private final Properties settings = (Properties)defaultConfig.clone();

  /**

   * Config is a singelton class with only one instance at time.

   * So the constructor is private to prevent the creation of more

   * then one Config instance.

   * @see Config.getInstance() to retrieve an instance of Config

   */

  private BootstrapConfig()

  {

    try

    {

      // Load settings from file

      load();

    }

    catch(IOException ex)

    {

      ex.printStackTrace();

    }

  }

  /**

   * Loads the configuration from the config file. By default this is done

   * by the (private) constructor but it can be useful to reload the config

   * by invoking this method.

   * @throws IOException

   */

  public void load() 

    throws IOException

  {

    FileInputStream in = null;

    try

    {

      in = new FileInputStream(FILE);

      settings.load(in);

    }

    catch (FileNotFoundException e)

    {

      // MUST NOT use Log otherwise endless loop

      System.err.println(e.getMessage());

      save();

    }

    finally

    {

      if(in != null)

        in.close();

    }

  }

  /**

   * Saves this Config to the config file. By default this is done

   * at program end.

   * @throws FileNotFoundException

   * @throws IOException

   */

  public void save() throws FileNotFoundException, IOException

  {

    FileOutputStream out = null;

    try

    {

      out = new FileOutputStream(FILE);

      settings.store(out, "SONEWS Config File");

      out.flush();

    }

    catch(IOException ex)

    {

      throw ex;

    }

    finally

    {

      if(out != null)

        out.close();

    }

  }

  /**

   * Returns the value that is stored within this config

   * identified by the given key. If the key cannot be found

   * the default value is returned.

   * @param key Key to identify the value.

   * @param def The default value that is returned if the key

   * is not found in this Config.

   * @return

   */

  public String get(String key, String def)

  {

    return settings.getProperty(key, def);

  }

  /**

   * Sets the value for a given key.

   * @param key

   * @param value

   */

  public void set(final String key, final String value)

  {

    settings.setProperty(key, value);

  }

}