package org.junit.runners;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import java.util.List;

import org.junit.internal.builders.AllDefaultPossibilitiesBuilder;

import org.junit.runner.Description;

import org.junit.runner.Runner;

import org.junit.runner.notification.RunNotifier;

import org.junit.runners.model.InitializationError;

import org.junit.runners.model.RunnerBuilder;

/**

 * Using <code>Suite</code> as a runner allows you to manually

 * build a suite containing tests from many classes. It is the JUnit 4 equivalent of the JUnit 3.8.x

 * static {@link junit.framework.Test} <code>suite()</code> method. To use it, annotate a class

 * with <code>@RunWith(Suite.class)</code> and <code>@SuiteClasses(TestClass1.class, ...)</code>.

 * When you run this class, it will run all the tests in all the suite classes.

 */

public class Suite extends ParentRunner<Runner> {

	/**

	 * The <code>SuiteClasses</code> annotation specifies the classes to be run when a class

	 * annotated with <code>@RunWith(Suite.class)</code> is run.

	 */

	@Retention(RetentionPolicy.RUNTIME)

	@Target(ElementType.TYPE)

	public @interface SuiteClasses {

		/**

		 * @return the classes to be run

		 */

		public Class<?>[] value();

	}

	private static Class<?>[] getAnnotatedClasses(Class<?> klass) throws InitializationError {

		SuiteClasses annotation= klass.getAnnotation(SuiteClasses.class);

		if (annotation == null)

			throw new InitializationError(String.format("class '%s' must have a SuiteClasses annotation", klass.getName()));

		return annotation.value();

	}

	private final List<Runner> fRunners;

	/**

	 * Called reflectively on classes annotated with <code>@RunWith(Suite.class)</code>

	 * 

	 * @param klass the root class

	 * @param builder builds runners for classes in the suite

	 * @throws InitializationError

	 */

	public Suite(Class<?> klass, RunnerBuilder builder) throws InitializationError {

		this(builder, klass, getAnnotatedClasses(klass));

	}

	/**

	 * Call this when there is no single root class (for example, multiple class names

	 * passed on the command line to {@link org.junit.runner.JUnitCore}

	 * 

	 * @param builder builds runners for classes in the suite

	 * @param classes the classes in the suite

	 * @throws InitializationError 

	 */

	public Suite(RunnerBuilder builder, Class<?>[] classes) throws InitializationError {

		this(null, builder.runners(null, classes));

	}

	/**

	 * Call this when the default builder is good enough. Left in for compatibility with JUnit 4.4.

	 * @param klass the root of the suite

	 * @param suiteClasses the classes in the suite

	 * @throws InitializationError

	 */

	protected Suite(Class<?> klass, Class<?>[] suiteClasses) throws InitializationError {

		this(new AllDefaultPossibilitiesBuilder(true), klass, suiteClasses);

	}

	/**

	 * Called by this class and subclasses once the classes making up the suite have been determined

	 * 

	 * @param builder builds runners for classes in the suite

	 * @param klass the root of the suite

	 * @param suiteClasses the classes in the suite

	 * @throws InitializationError

	 */

	protected Suite(RunnerBuilder builder, Class<?> klass, Class<?>[] suiteClasses) throws InitializationError {

		this(klass, builder.runners(klass, suiteClasses));

	}

	/**

	 * Called by this class and subclasses once the runners making up the suite have been determined

	 * 

	 * @param klass root of the suite

	 * @param runners for each class in the suite, a {@link Runner}

	 * @throws InitializationError 

	 */

	protected Suite(Class<?> klass, List<Runner> runners) throws InitializationError {

		super(klass);

		fRunners = runners;

	}

	@Override

	protected List<Runner> getChildren() {

		return fRunners;

	}

	@Override

	protected Description describeChild(Runner child) {

		return child.getDescription();

	}

	@Override

	protected void runChild(Runner runner, final RunNotifier notifier) {

		runner.run(notifier);

	}

}