package org.bukkit;

import com.google.common.collect.ImmutableMap;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Map;

/**
 * This designates the warning state for a specific item.
 * <p>
 * When the server settings dictate 'default' warnings, warnings are printed
 * if the {@link #value()} is true.
 */
@Target({ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Warning
{

	/**
	 * This represents the states that server verbose for warnings may be.
	 */
	public enum WarningState
	{

		/**
		 * Indicates all warnings should be printed for deprecated items.
		 */
		ON,
		/**
		 * Indicates no warnings should be printed for deprecated items.
		 */
		OFF,
		/**
		 * Indicates each warning would default to the configured {@link
		 * Warning} annotation, or always if annotation not found.
		 */
		DEFAULT;

		private static final Map<String, WarningState> values = ImmutableMap.<String, WarningState>builder()
				.put("off", OFF)
				.put("false", OFF)
				.put("f", OFF)
				.put("no", OFF)
				.put("n", OFF)
				.put("on", ON)
				.put("true", ON)
				.put("t", ON)
				.put("yes", ON)
				.put("y", ON)
				.put("", DEFAULT)
				.put("d", DEFAULT)
				.put("default", DEFAULT)
				.build();

		/**
		 * This method checks the provided warning should be printed for this
		 * state
		 *
		 * @param warning The warning annotation added to a deprecated item
		 * @return <ul>
		 * <li>ON is always True
		 * <li>OFF is always false
		 * <li>DEFAULT is false if and only if annotation is not null and
		 * specifies false for {@link Warning#value()}, true otherwise.
		 * </ul>
		 */
		public boolean printFor(Warning warning)
		{
			if(this == DEFAULT)
			{
				return warning == null || warning.value();
			}
			return this == ON;
		}

		/**
		 * This method returns the corresponding warning state for the given
		 * string value.
		 *
		 * @param value The string value to check
		 * @return {@link #DEFAULT} if not found, or the respective
		 * WarningState
		 */
		public static WarningState value(final String value)
		{
			if(value == null)
			{
				return DEFAULT;
			}
			WarningState state = values.get(value.toLowerCase());
			if(state == null)
			{
				return DEFAULT;
			}
			return state;
		}
	}

	/**
	 * This sets if the deprecation warnings when registering events gets
	 * printed when the setting is in the default state.
	 *
	 * @return false normally, or true to encourage warning printout
	 */
	boolean value() default false;

	/**
	 * This can provide detailed information on why the event is deprecated.
	 *
	 * @return The reason an event is deprecated
	 */
	String reason() default "";
}