/// <summary>
/// Entry point for the Mars Rover processor
/// </summary>
/// <param name="text"></param>
/// <returns></returns>
public string Process(string text)
{
var result = new List<string>();
try
{
// Parse file content to a list of string (ignore LineFeed character)
var fileContent =
new List<string>(text.Split(Environment.NewLine.ToCharArray(), StringSplitOptions.RemoveEmptyEntries));
// Validate general content: plateau, number of lines ...
ValidatePlateauInformation(fileContent);
var plateauCoordinate = fileContent[0].Split(' ');
// Construct the plateau coordinates
var thePlateau = new Coodinate { X = Convert.ToInt32(plateauCoordinate[0]), Y = Convert.ToInt32(plateauCoordinate[1]) };
// Process all rovers. If there's an error with a rover, it will be reported in the output then keep processing the next rover
for (int lineNo = 1; lineNo < fileContent.Count; lineNo += 2)
{
result.Add(ProccessRoverMovement(thePlateau, fileContent, lineNo));
}
}
catch (InputFormatException inputFormatException)
{
result.Add(inputFormatException.Message);
}
return string.Join(Environment.NewLine, result.ToArray());
}
/// <summary>
/// Ensure the rover's location doesn't fall out of the plateau
/// </summary>
/// <param name="plateauCoordinate"></param>
public void ValidateLocation(Coodinate plateauCoordinate)
{
if ((plateauCoordinate.X < CurrentLocation.X) || (CurrentLocation.X < 0)
|| (plateauCoordinate.Y < CurrentLocation.Y) || (plateauCoordinate.Y < 0))
{
throw new RoverLocationException("Rover location is out of the plateau");
}
}
/// <summary>
/// Contruct the rover object
/// All information are already validated, so the construction is straightforward
/// </summary>
/// <param name="roverInformation"></param>
/// <returns></returns>
private Rover InitializeRover(string roverInformation)
{
var roverLocationInput = roverInformation.Split(' ');
// Extract the initial location
var roverLocation = new Coodinate { X = Convert.ToInt32(roverLocationInput[0]), Y = Convert.ToInt32(roverLocationInput[1]) };
var stateFactory = new DirectionFactory();
var direction = stateFactory.InitializeAllCardinalPoints();
// Extract the initial direction
var roverFirstDirection = stateFactory.GetDirection(direction, roverLocationInput[2]);
if (roverFirstDirection == null) return null;
return new Rover { CurrentDirection = roverFirstDirection, CurrentLocation = roverLocation };
}
/// <summary>
/// Walk through each command and change the rover's location and direction accordingly
/// </summary>
/// <param name="thePlateau"></param>
/// <param name="fileContent"></param>
/// <param name="lineNo"></param>
/// <returns></returns>
private string ProccessRoverMovement(Coodinate thePlateau, List<string> fileContent, int lineNo)
{
try
{
// Ensure all provided information for a rover is correct
ValidateRoverInformation(fileContent, lineNo);
// Construct a rover
var theRover = InitializeRover(fileContent[lineNo]);
if (theRover == null)
{
throw new InputFormatException("Cannot initialize the rover");
}
// Ensure the rover doesn't fall out of plateau
theRover.ValidateLocation(thePlateau);
// Get the movement commands
var roverMovementCommands = fileContent[lineNo + 1].ToCharArray();
foreach (var movement in roverMovementCommands)
{
switch (movement)
{
case 'L':
theRover.TurnLeft();
break;
case 'R':
theRover.TurnRight();
break;
case 'M':
theRover.MoveForward();
break;
}
}
// Ensure the rover doesn't fall out of plateau
theRover.ValidateLocation(thePlateau);
return string.Format("{0} {1} {2}", theRover.CurrentLocation.X, theRover.CurrentLocation.Y, theRover.CurrentDirection.Name);
}
catch (RoverLocationException roverLocationException)
{
return roverLocationException.Message;
}
}
public void MoveForward()
{
CurrentLocation = CurrentDirection.MoveForward(CurrentLocation);
}
