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package io.ebean.config;

import java.util.Properties;

public class PropertiesWrapper {

  protected final Properties properties;

  protected final String prefix;

  protected final String serverName;

  private final ClassLoadConfig classLoadConfig;

  /**
   * Construct with a prefix, serverName and properties.
   */
  public PropertiesWrapper(String prefix, String serverName, Properties properties, ClassLoadConfig classLoadConfig) {
    this.serverName = serverName;
    this.prefix = prefix;
    this.properties = properties;
    this.classLoadConfig = classLoadConfig;
  }

  /**
   * Construct without prefix of serverName.
   */
  public PropertiesWrapper(Properties properties, ClassLoadConfig classLoadConfig) {
    this(null, null, properties, classLoadConfig);
  }

  /**
   * Return the serverName (optional).
   */
  public String getServerName() {
    return serverName;
  }

  /**
   * Get a property with no default value.
   */
  public String get(String key) {
    return get(key, null);
  }

  /**
   * Get a property with a default value.
   * 
   * This performs a search using the prefix and server name (if supplied) to search for the property
   * value in order based on:
   * 
{@code
   *   prefix.serverName.key
   *   prefix.key
   *   key
   * }
   * 
   */
  public String get(String key, String defaultValue) {

    String value = null;
    if (serverName != null && prefix != null) {
      value = internalGet(prefix + "." + serverName + "." + key);
    }
    if (value == null && prefix != null) {
      value = internalGet(prefix + "." + key);
    }
    if (value == null) {
      value = internalGet(key);
    }
    return value == null ? defaultValue : value;
  }

  private String internalGet(String key) {
    return properties.getProperty(key);
  }

  /**
   * Return a double property value.
   */
  public double getDouble(String key, double defaultValue) {

    String value = get(key, String.valueOf(defaultValue));
    return Double.parseDouble(value);
  }

  /**
   * Return an int property value.
   */
  public int getInt(String key, int defaultValue) {

    String value = get(key, String.valueOf(defaultValue));
    return Integer.parseInt(value);
  }

  /**
   * Return a long property value.
   */
  public long getLong(String key, long defaultValue) {

    String value = get(key, String.valueOf(defaultValue));
    return Long.parseLong(value);
  }

  /**
   * Return a boolean property value.
   */
  public boolean getBoolean(String key, boolean defaultValue) {

    String value = get(key, String.valueOf(defaultValue));
    return Boolean.parseBoolean(value);
  }

  /**
   * Return a Enum property value.
   */
  public > T getEnum(Class enumType, String key, T defaultValue) {
    String level = get(key, null);
    return (level == null) ? defaultValue : Enum.valueOf(enumType, level.toUpperCase());
  }

  /**
   * Return the instance to use (can be null) for the given plugin.
   *
   * @param pluginType the type of plugin
   * @param key        properties key
   * @param instance   existing instance
   */
  public  T createInstance(Class pluginType, String key, T instance) {

    if (instance != null) {
      return instance;
    }
    String classname = get(key, null);
    return createInstance(pluginType, classname);
  }

  /**
   * Return the instance to use (can be null) for the given plugin.
   *
   * @param pluginType the type of plugin
   * @param classname  the implementation class as per properties
   */
  @SuppressWarnings("unchecked")
  public  T createInstance(Class pluginType, String classname) {
    return classname == null ? null : (T) classLoadConfig.newInstance(classname);
  }
}