package ie.dcu.auto.automator;

import ie.dcu.auto.AutomationData;

import java.lang.reflect.*;
import java.util.*;

/**
 * Creates automator instances.
 * 
 * @author Kevin McGuinness
 */
public class AutomatorFactory {
	
	public static final String STRATEGY1 = "Strategy 1 (Deterministic)";
	public static final String STRATEGY2 = "Strategy 2 (Probabilistic)";
	public static final String STRATEGY3 = "Strategy 3 (Probabilistic)";
	public static final String STRATEGY4 = "Strategy 4 (Probabilistic)";
	
	private final Map<String, Class<? extends Automator>> automators;
	private static AutomatorFactory instance;
	
	private AutomatorFactory() {
		automators = new HashMap<String, Class<? extends Automator>>();
		automators.put(STRATEGY1, DeterministicAutomator.class);
		automators.put(STRATEGY2, NonDeterministicAutomator1.class);
		automators.put(STRATEGY3, NonDeterministicAutomator2.class);
		automators.put(STRATEGY4, NonDeterministicAutomator3.class);
	}
	
	public Automator createAutomator(String strategy, AutomationData data) {
		
		try {
			Class<? extends Automator> clazz = automators.get(strategy);
			if (clazz != null) {
				Constructor<? extends Automator> ctor = 
					clazz.getConstructor(AutomationData.class);
				return ctor.newInstance(data);
			} else {
				throw new IllegalArgumentException(
					"no such strategy: " + strategy);
			}
			
		} catch (SecurityException e) {
			throw new RuntimeException(e);
		} catch (NoSuchMethodException e) {
			throw new RuntimeException(e);
		} catch (InstantiationException e) {
			throw new RuntimeException(e);
		} catch (IllegalAccessException e) {
			throw new RuntimeException(e);
		} catch (InvocationTargetException e) {
			throw new RuntimeException(e);
		}
	}
	
	public boolean hasAutomator(String strategy) {
		return automators.containsKey(strategy);
	}
	
	public Set<String> getAvailableStrategies() {
		return Collections.unmodifiableSet(automators.keySet());
	}	
	
	public boolean isNonDeterministic(String strategy) {
		if (hasAutomator(strategy)) {
			Class<? extends Automator> clazz = automators.get(strategy);
			try {
				Method method = clazz.getMethod("isNonDeterministic");
				return (Boolean) method.invoke(null);

			} catch (SecurityException e) {
				return false;
			} catch (NoSuchMethodException e) {
				return false;
			} catch (IllegalAccessException e) {
				throw new RuntimeException(e);
			} catch (InvocationTargetException e) {
				throw new RuntimeException(e);
			}
		}
		return false;
	}
	
	public static AutomatorFactory getInstance() {
		if (instance == null) {
			instance = new AutomatorFactory();
		}
		return instance;
	}
}