alessandro_toy_robot.rb

COMANDS = [:place, :move, :left, :right, :report]
DIRECTIONS = [:north, :east, :south, :west]
TABLETOP_MAX_WIDTH = 4
TABLETOP_MAX_HEIGHT = 4

@x, @y, @position = [0,0, :north]

def place(params)
  args = params.split(",")
  position_x = args[0].to_i
  @x = position_x > TABLETOP_MAX_WIDTH ? TABLETOP_MAX_WIDTH : position_x
  position_y = args[1].to_i
  @y = position_y > TABLETOP_MAX_HEIGHT ? TABLETOP_MAX_HEIGHT : position_y
  @position = to_sym(args[2])
end

def move
  case @position
  when :north # Move to up
    @y -= @y > 0 ? 1 : 0
  when :east # Move to right
    @x += @x < TABLETOP_MAX_WIDTH ? 1 : 0
  when :south # Move to down
    @y += @y < TABLETOP_MAX_HEIGHT ? 1 : 0
  when :west # Move to left
    @x -= @x > 0 ? 1 : 0
  end
end

def left
  # Rotate the robot 90 degrees
  @position = DIRECTIONS[DIRECTIONS.index(@position) - 1]
end

def right
  # Rotate the robot 90 degrees
  @position = DIRECTIONS[DIRECTIONS.index(@position) + 1] || DIRECTIONS[0]
end

def report
  p "#{@x},#{@y},#{@position.upcase}"
end

def to_sym(value)
  value.downcase.to_sym
end

def is_not_valid_comand(action)
  p "#{action} is not a valid command"
end

def robot_is_not_placed
  p "Robot is not placed"
end

robot_placed = false
while (input = $stdin.gets.chomp) do
  action, params = input.split
  robot_placed = true if to_sym(action) == :place
  if robot_placed && COMANDS.include?(to_sym(action))
    params ? send(to_sym(action), params) : send(to_sym(action))
  else
    break if to_sym(action) == :quit
    robot_placed ? is_not_valid_comand(action) : robot_is_not_placed
  end
end