import tester.*;

class Person {
    String dest;   // where the person wants to go
    double height; // person's height in inches
    Person(String dest, double height) {
        this.dest = dest;
        this.height = height;
    }
    boolean isDest(String place) {
        return this.dest.equals(place);
    }
    boolean isShorter(double h) {
        return this.height <= h; 
    }
}

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 place;
    Escape(String place) {
        this.place = place;
    }
    public IPath escapePath(Person player) {
        if (player.isDest(this.place))
            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 Room {
    IDoor left;
    IDoor right;
    Room(IDoor left, IDoor right) {
        this.left = left;
        this.right = right;
    }
    IPath escapePath(Person player) {
        IPath rpath = this.right.escapePath(player);
        IPath lpath = this.left.escapePath(player);
        if (rpath.isOk())
            return new Right(rpath);
        else if (lpath.isOk())
            return new Left(lpath);
        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 mars = new Escape("mars");
    IDoor venus = new Escape("venus");
    Room planetsRoom = new Room(mars, venus);
    IDoor planets = new Into(planetsRoom);
    Room slcOrSpaceRoom = new Room(new Escape("Salt Lake City"), planets);
    IDoor slcOrSpace = new Into(slcOrSpaceRoom);
    Fail fail = new Fail();
    Success success = new Success();
    Person joe = new Person("junk", 80.0);
    Person martian = new Person("mars", 45.0);
    Person venutian = new Person("venus", 60.0);
    Person tallVenutian = new Person("venus", 61.0);
    Person matthias = new Person("Salt Lake City", 70.0);
    IDoor fiveFoot = new Short(planetsRoom, 60.0);

    void tests(Tester t) {
        t.checkExpect(mars.escapePath(joe), fail);
        t.checkExpect(mars.escapePath(martian), success);
        t.checkExpect(planets.escapePath(joe), fail);
        t.checkExpect(planets.escapePath(venutian), new Right(success));
        t.checkExpect(slcOrSpace.escapePath(matthias), new Left(success));
        t.checkExpect(slcOrSpace.escapePath(martian), new Right(new Left(success)));
        t.checkExpect(fiveFoot.escapePath(martian), new Left(success));
        t.checkExpect(fiveFoot.escapePath(venutian), new Right(success));
        t.checkExpect(fiveFoot.escapePath(tallVenutian), fail);
        
        t.checkExpect(planetsRoom.escapePath(joe), fail);
        t.checkExpect(planetsRoom.escapePath(martian), new Left(success));

        t.checkExpect(joe.isDest("mars"), false);
        t.checkExpect(joe.isDest("junk"), true);
        t.checkExpect(joe.isShorter(70.0), false);
        t.checkExpect(joe.isShorter(90.0), true);
        t.checkExpect(joe.isShorter(80.0), true);        
    }
}