package net.bmahe.genetics4j.gp.spec.mutation;
   
   import java.util.Optional;
   
   import org.apache.commons.lang3.Validate;
   import org.immutables.value.Value;
   
   import net.bmahe.genetics4j.core.spec.mutation.MutationPolicy;
   
  /**
   * Ensure no tree will have a greater depth than allowed
   * <p>
   * By default it will use the depth as specified in the Program definition, but
   * that can be overriden
   *
   */
  @Value.Immutable
  public interface TrimTree extends MutationPolicy {
  
  	/**
  	 * Override the max depth to enforce
  	 * 
  	 * @return
  	 */
  	@Value.Parameter
  	@Value.Default
  	public default Optional<Integer> maxDepth() {
  		return Optional.empty();
  	}
  
  	@Value.Check
  	default void check() {
  		maxDepth().ifPresent(maxDepth -> Validate.isTrue(maxDepth > 0));
  	}
  
  	/**
  	 * Build a TrimTree enforcing a specific max depth
  	 * 
  	 * @param maxDepth
  	 * @return
  	 */
  	public static TrimTree of(final int maxDepth) {
  		return ImmutableTrimTree.of(Optional.of(maxDepth));
  	}
  
  	/**
  	 * Build a TrimTree using the default max depth as specified in the Program
  	 * 
  	 * @return
  	 */
  	public static TrimTree build() {
  		return ImmutableTrimTree.builder().build();
  	}
  }