import tester.Tester;

// represents a road trip
class RoadTrip {
  String driver1;
  String driver2;
  ILoDirection directions;

  RoadTrip(String driver1, String driver2, ILoDirection directions) {
    this.driver1 = driver1;
    this.driver2 = driver2;
    this.directions = directions;
  }

}

// lists of directions
interface ILoDirection {
  
}

//an empty list of directions
class MtLoDirection implements ILoDirection {

}

//a non-empty list of directions
class ConsLoDirection implements ILoDirection {
  Direction first;
  ILoDirection rest;

  ConsLoDirection(Direction first, ILoDirection rest) {
    this.first = first;
    this.rest = rest;
  }

}

// represents a direction
class Direction {
  String description;
  int miles; // how many miles this instruction is

  Direction(String description, int miles) {
    this.description = description;
    this.miles = miles;
  }

  // is the distance left to go on this Direction less than this.miles?
  boolean needsSplitting(int distanceLeft) {
    return this.miles > distanceLeft;
  }

  // remove miles from this Direction's distance because it needs splitting
  Direction shrink(int milesToRemove) {
    return new Direction(this.description, this.miles - milesToRemove);
  }

  // how much a driver would have left on their part after driving this direction
  int distanceLeft(int leftToDrive) {
    return leftToDrive - this.miles;
  }
}

// represents a chunk of a road trip
class RoadTripChunk {
  String driver;
  ILoDirection directions;

  RoadTripChunk(String driver, ILoDirection directions) {
    this.driver = driver;
    this.directions = directions;
  }

  // Convenience constructor
  RoadTripChunk(String driver, Direction dir) {
    this.driver = driver;
    this.directions = new ConsLoDirection(dir, new MtLoDirection());
  }

  // does this chunk have the given driver?
  boolean hasDriver(String driver) {
    return this.driver.equals(driver);
  }

  // add direction to front of directions
  RoadTripChunk addDir(Direction dir) {
    return new RoadTripChunk(this.driver, new ConsLoDirection(dir, this.directions));
  }

}

//lists of road trip chunks
interface ILoRoadTripChunk {

  // add this direction driven by driver to the front of the list
  ILoRoadTripChunk addDirection(String driver, Direction dir);

}

//an empty list of road trip chunks
class MtLoRoadTripChunk implements ILoRoadTripChunk {

  // create non-empty road trip chunk list
  public ILoRoadTripChunk addDirection(String driver, Direction dir) {
    return new ConsLoRoadTripChunk(new RoadTripChunk(driver, dir), this);
  }

}

//a non-empty list of road trip chunks
class ConsLoRoadTripChunk implements ILoRoadTripChunk {
  RoadTripChunk first;
  ILoRoadTripChunk rest;

  ConsLoRoadTripChunk(RoadTripChunk first, ILoRoadTripChunk rest) {
    this.first = first;
    this.rest = rest;
  }

  // create add dir to first if driver matches, otherwise create new section
  public ILoRoadTripChunk addDirection(String driver, Direction dir) {
    if (first.hasDriver(driver)) {
      return new ConsLoRoadTripChunk(this.first.addDir(dir), this.rest);
    }
    else {
      return new ConsLoRoadTripChunk(new RoadTripChunk(driver, dir), this);
    }
  }

}