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/**
 * Creative commons Attribution-NonCommercial license.
 *
 * http://creativecommons.org/licenses/by-nc/2.5/au/deed.en_GB
 *
 * NO WARRANTY IS GIVEN OR IMPLIED, USE AT YOUR OWN RISK.
 */
package base.task;

import base.jee.api.Settings;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class TaskManager {

	private static Map taskHandlers = new HashMap<>();

	/**
	 * Register that a task should be executed regularly at a specific interval.
	 *
	 * @param name Unique name identifying the task
	 * @param interval How frequently the task should be executed in seconds
	 * @param task The task that should be executed regularly
	 */
	public static void registerRegularTask(String name, int interval, Task task) {
		if(taskHandlers.containsKey(name)) {
			throw new IllegalStateException("Attempted to register a task named " + name + " when a task with this name already exists.");
		}

		RegularTaskHandler handler = new RegularTaskHandler(name, task, interval);
		taskHandlers.put(name, handler);
		handler.start();
	}

	/**
	 * Register that a task should be executed regularly at a specific interval.
	 *
	 * @param name Unique name identifying the task
	 * @param daysOfMonth Which days of the month this task will run (null/empty means every day)
	 * @param daysOfWeek Which days of the week this task will run (null/empty means every day)
	 * @param hoursOfDay Which hours of the day this task will run (null/empty means every hour)
	 * @param task The task that should be executed regularly
	 * @throws IOException
	 */
	public static void registerScheduledTask(String name, int[]daysOfMonth, int[] daysOfWeek, int[] hoursOfDay, Task task, Settings settings) throws IOException {
		if(taskHandlers.containsKey(name)) {
			throw new IllegalStateException("Attempted to register a task named " + name + " when a task with this name already exists.");
		}

		ScheduledTaskHandler handler = new ScheduledTaskHandler(name, task, daysOfMonth, daysOfWeek, hoursOfDay, settings);
		taskHandlers.put(name, handler);
		handler.start();
	}

	public static void unregisterRegularTask(String name) throws InterruptedException {
		TaskHandler handler = null;

		if(taskHandlers.containsKey(name)) {
			handler = taskHandlers.remove(name);
			handler.shutdown();
			handler.join();
		}


	}

	/**
	 * Called when either java process is being terminated, to clean up any Task's that are still
	 * scheduled to be executed.
	 */
	public static void shutdown() throws InterruptedException {
		for(TaskHandler handler : taskHandlers.values()) {
			handler.shutdown();
			handler.join();
		}
		taskHandlers.clear();
	}

}