import tester.*;

class Person {
  String dest;
  double height;
  String key;
  Person(String dest, double height, String key) {
    this.dest = dest;
    this.height = height;
    this.key = key;
  }
	
  // to determine whether the person wants to get to `target'
  boolean isDest(String target) {
    return this.dest.equals(target);
  }
	
  // to determine whether the person is shorter than `n' feet
  boolean isShorter(double n) {
    return this.height < n;
  }
	
  boolean hasKey(String wanted) {
    return this.key.equals(wanted);
  }
}

interface IDoor {
  IPath escapePath(Person player);
}

class Into implements IDoor {
  Room next;
  Into(Room next) {
    this.next = next;
  }

  public IPath escapePath(Person player) {
    return this.next.escapePath(player);
  }
}

class Escape implements IDoor {
  String name;
  Escape(String name) {
    this.name = name;
  }

  public IPath escapePath(Person player) {
    if (player.isDest(this.name))
      return new Success();
    else
      return new Fail();
  }
}

class Short implements IDoor {
  Room next;
  double height;
  Short(Room next, double height) {
    this.next = next;
    this.height = height;
  }
	
  public IPath escapePath(Person player) {
    if (player.isShorter(this.height))
      return this.next.escapePath(player);
    else
      return new Fail();
  }
}

class Locked implements IDoor {
  Room next;
  String key;
  Locked(Room next, String key) {
    this.next = next;
    this.key = key;
  }
	
  public IPath escapePath(Person player) {
    if (player.hasKey(this.key))
      return this.next.escapePath(player);
    else
      return new Fail();
  }
}

class Room {
  IDoor left;
  IDoor right;
  Room(IDoor left, IDoor right) {
    this.left = left;
    this.right = right;
  }

  // determines how you can reach "dest" through this
  // room
  IPath escapePath(Person player) {
    IPath p1 = this.left.escapePath(player);
    if (p1.isOk())
      return new Left(p1);
    else {
      IPath p2 = this.right.escapePath(player);
      if (p2.isOk())
        return new Right(p2);
      else
        return new Fail();
    }
  }
}

interface IPath {
  boolean isOk();
}

class Fail implements IPath {
  Fail() { }
  public boolean isOk() { return false; }
}

class Success implements IPath {
  Success() { }
  public boolean isOk() { return true; }
}

class Right implements IPath {
  IPath rest;
  Right(IPath rest) { this.rest = rest; }
  public boolean isOk() { return true; }
}

class Left implements IPath {
  IPath rest;
  Left(IPath rest) { this.rest = rest; }
  public boolean isOk() { return true; }
}

class Examples{
  IDoor toAlaska = new Escape("Alaska");
  IDoor toNorthPole = new Escape("North Pole");
  Room northRoom = new Room(toAlaska, toNorthPole);
  IDoor toRoom = new Into(northRoom);
  Short littleGate = new Short(northRoom, 5.0);
  Locked redDoor = new Locked(northRoom, "red");

  IDoor meadow = new Escape("meadow");
  IDoor street = new Escape("street");
  Room ms = new Room(meadow, street);
  Room planets = new Room(new Escape("mars"),new Escape("venus"));
  Room maze = new Room(new Into(ms), new Into(planets));
	
  Person annie = new Person("Alaska", 5.1, "red");
  Person sandra = new Person("Alaska", 4.8, "green");
  Person joe = new Person("Arizona", 5.0, "blue");
  Person santa = new Person("North Pole", 5.6, "orange");
  Person elmo = new Person("street", 2.0, "yellow");

  void tests(Tester t) {
    t.checkExpect(redDoor.escapePath(annie), new Left(new Success()));
    t.checkExpect(redDoor.escapePath(sandra), new Fail());
    t.checkExpect(redDoor.escapePath(elmo), new Fail());
		
    t.checkExpect(littleGate.escapePath(annie), new Fail());
    t.checkExpect(littleGate.escapePath(sandra), new Left(new Success()));
    t.checkExpect(littleGate.escapePath(elmo), new Fail());
    t.checkExpect(toRoom.escapePath(annie), new Left(new Success()));
    t.checkExpect(toRoom.escapePath(joe), new Fail());
    t.checkExpect(toRoom.escapePath(santa), new Right(new Success()));
    t.checkExpect(new Into(maze).escapePath(elmo), new Left(new Right(new Success())));
    t.checkExpect(annie.isShorter(6.0), true);
    t.checkExpect(annie.isShorter(5.0), false);
    t.checkExpect(annie.isShorter(5.1), false);
    t.checkExpect(annie.isDest("Alaska"), true);
    t.checkExpect(annie.isDest("Arizona"), false);
    t.checkExpect(annie.hasKey("red"), true);
    t.checkExpect(annie.hasKey("blue"), false);
  }
}