// enumerated/PostOffice9.java
// TIJ4 Chapter Enumerated, Exercise 9, page 1041
// Modify class PostOffice so that it uses an EnumMap.

/* My solution to one of the exercises in 
* Thinking in Java 4th Edition (by Bruce Eckel).
* It compiles and runs correctly using JDK 1.6.0
* @author Greg Gordon
* @author www.greggordon.org
* June, 2008
*/

import java.util.*;
import net.mindview.util.*;
import static net.mindview.util.Print.*;

class Mail {
	// The NO's lower the probability of random selection:
	enum GeneralDelivery { YES, NO1, NO2, NO3, NO4, NO5 }
	enum Scannability { UNSCANNABLE, YES1, YES2, YES3, YES4 }
	enum Readability { ILLEGIBLE, YES1, YES2, YES3, YES4 }
	enum Address { INCORRECT, OK1, OK2, OK3, OK4, OK5, OK6 }
	enum ReturnAddress { MISSING, OK1, OK2, OK3, OK4, OK5 }
	GeneralDelivery generalDelivery;
	Scannability scannability;
	Readability readability;
	Address address;
	ReturnAddress returnAddress;
	static long counter = 0;
	long id = counter++;
	public String toString() { return "Mail " + id; }
	public String details() {
		return toString() +
			", General Delivery: " + generalDelivery +
			", Address Scannability: " + scannability + 
			", Address Readability: " + readability + 
			", Address Address: " + address +
			", Return address: " + returnAddress;
	} 
	// Generate test Mail:
	public static Mail randomMail() {
		Mail m = new Mail();
		m.generalDelivery = Enums.random(GeneralDelivery.class);
		m.scannability = Enums.random(Scannability.class);
		m.readability = Enums.random(Readability.class);
		m.address = Enums.random(Address.class);
		m.returnAddress = Enums.random(ReturnAddress.class);	
		return m;
	}
	public static Iterable<Mail> generator(final int count) {
		return new Iterable<Mail>() {
			int n = count;
			public Iterator<Mail> iterator() {
				return new Iterator<Mail>() {
					public boolean hasNext() { return n-- > 0; }
					public Mail next() { return randomMail(); }
					public void remove() { // not implemented
						throw new UnsupportedOperationException();
					}	
				};
			}
		};
	}
}

interface Handler { abstract boolean handle(Mail m); } // Command design pattern

public class PostOffice9 {
	enum MailHandler { GENERAL_DELIVERY, MACHINE_SCAN, VISUAL_INSPECTION, RETURN_TO_SENDER }
	public static void handle(Mail m, EnumMap<MailHandler,Handler> em) {	
		for(Map.Entry<MailHandler,Handler> e : em.entrySet()) {
			if(e.getValue().handle(m)) return; 							
		}
		print(m + " is a dead letter");		
	}	
	public static void main(String[] args) {
		EnumMap<MailHandler,Handler> em = new EnumMap<MailHandler,Handler>(MailHandler.class);
		em.put(MailHandler.GENERAL_DELIVERY, new Handler() {
			public boolean handle(Mail m) {
				switch(m.generalDelivery) {
					case YES:
						print("Using general delivery for " + m);
						return true;
					default: return false;
				}
			}
		});
		em.put(MailHandler.MACHINE_SCAN, new Handler() {
			public boolean handle(Mail m) {
				switch(m.scannability) {
					case UNSCANNABLE: return false;
					default:
						switch(m.address) {
							case INCORRECT: return false;
							default:
								print("Delivering " + m + " automatically");
								return true;
						}
				}
			}	
		});
		em.put(MailHandler.VISUAL_INSPECTION, new Handler() {
			public boolean handle(Mail m) {
				switch(m.readability) {
					case ILLEGIBLE: return false;
					default:
						switch(m.address) {
							case INCORRECT: return false;
							default:
								print("Delivering " + m + " normally");
								return true;
						}
				}
			}
		});
		em.put(MailHandler.RETURN_TO_SENDER, new Handler() {
			public boolean handle(Mail m) {
				switch(m.returnAddress) {
					case MISSING: return false;
					default:
						print("Return " + m + " to sender");
						return true;
				}
			}
		});
		for(Mail mail : Mail.generator(10)) {
			print(mail.details());
			handle(mail, em);
			print("*****");	
		}
	}
}