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/*
 * Copyright (C) 2005, The Beangle Software.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 */

package org.beangle.commons.lang

import org.beangle.commons.lang.reflect.Reflections

import java.lang.reflect.Method

/** Create Enumeration value
  *
  * @since 3.1
  */
object Enums {

  /** Returns an optional enum constant for the given type, using {@link Enum# valueOf}. If the
    * constant does not exist, {@link Option# none} is returned. A common use case is for parsing
    * user input or falling back to a default enum constant. For example,
    * {@code Enums.get(Country.class, countryInput).getOrElse(Country.DEFAULT);}
    *
    * @since 3.1
    */
  def get[T <: _root_.scala.reflect.Enum](enumClass: Class[T], value: String): Option[T] = {
    try {
      val e = Reflections.getInstance[AnyRef](enumClass.getName)
      Some(enumClass.getMethod("valueOf", classOf[String]).invoke(e, value).asInstanceOf[T])
    } catch {
      case _: IllegalArgumentException => None
    }
  }

  def of[T <: _root_.scala.reflect.Enum](enumClass: Class[T], id: Int): Option[T] = {
    val e = Reflections.getInstance[AnyRef](enumClass.getName)
    toIdMaps(values(e)).get(id).asInstanceOf[Option[T]]
  }

  def id(e: AnyRef): Int = {
    findIndexMethod(e.getClass).invoke(e).asInstanceOf[Int]
  }

  def values(e: AnyRef): Array[AnyRef] = {
    e.getClass.getMethod("values").invoke(e).asInstanceOf[Array[AnyRef]]
  }

  def toIdMaps(vs: Array[AnyRef]): Map[Int, AnyRef] = {
    vs.map { v =>
      val idMethod = findIndexMethod(v.getClass)
      val o = idMethod.invoke(v).asInstanceOf[Number]
      (o.intValue(), v)
    }.toMap[Int, AnyRef]
  }

  def isEnum(clazz: Class[_]): Boolean = {
    classOf[_root_.scala.reflect.Enum].isAssignableFrom(clazz)
  }

  private def findIndexMethod(clazz: Class[_]): Method = {
    val method =
      try {
        clazz.getMethod("id")
      } catch {
        case _: Throwable => clazz.getMethod("ordinal")
      }
    method.setAccessible(true)
    method
  }

}