# frozen_string_literal: true

# Ruby module to wrap robot moves features
module ToyRobotCli
  # Ruby class to handle Robot moves on square table top
  class Robot
    # Valid directions what robot can be faced
    VALID_DIRECTIONS = %w[NORTH EAST SOUTH WEST].freeze

    # Initialize a new Robot instance.
    def initialize
      @position = nil
      @direction = nil
    end

    # Place the robot on the table at the specified coordinates and facing direction.
    # Example:
    #   >> robot = ToyRobotCli::Robot.new
    #   => #<ToyRobotCli::Robot:0x000000... @direction=nil, @position=nil>
    #   >> robot.place(0, 0, "SOUTH")
    #   => 2
    #
    # Arguments:
    #   coordinate_x: (Integer) - The X-coordinate of the robot's position.
    #   coordinate_y: (Integer) - The Y-coordinate of the robot's position.
    #   facing: (String) - The direction the robot is facing (NORTH, EAST, SOUTH, WEST).

    def place(coordinate_x, coordinate_y, facing)
      return unless valid_position?(coordinate_x, coordinate_y) && VALID_DIRECTIONS.include?(facing)

      @position = Matrix[[coordinate_x], [coordinate_y]]
      @direction = VALID_DIRECTIONS.index(facing)
    end

    # Move the robot one unit forward in the current direction.
    def move
      return unless placed?

      new_position = @position + direction_vector
      @position = new_position if valid_position?(new_position[0, 0], new_position[1, 0])
    end

    # Rotate the robot 90 degrees to the left.
    def left
      return unless placed?

      @direction = (@direction - 1) % VALID_DIRECTIONS.length
    end

    # Rotate the robot 90 degrees to the right.
    def right
      return unless placed?

      @direction = (@direction + 1) % VALID_DIRECTIONS.length
    end

    # Report the current position and direction of the robot.
    # Example:
    #   >> robot = ToyRobotCli::Robot.new
    #   => #<ToyRobotCli::Robot:0x000000... @direction=nil, @position=nil>
    #   >> robot.place(0, 0, "SOUTH")
    #   => 2
    #   >> robot.report
    #   => "0,0,SOUTH"
    #
    # Returns:
    #   (String) - The current position and direction of the robot in the format "X,Y,FACING".
    def report
      return unless placed?

      coordinate_x, coordinate_y = @position.to_a.flatten
      "#{coordinate_x},#{coordinate_y},#{VALID_DIRECTIONS[@direction]}"
    end

    private

    # Check if the specified position is valid within the table boundaries.
    def valid_position?(coordinate_x, coordinate_y)
      (0..4).cover?(coordinate_x) && (0..4).cover?(coordinate_y)
    end

    # Check if the robot is placed on the table.
    def placed?
      !@position.nil? && !@direction.nil?
    end

    # Calculate the direction vector based on the current direction.
    def direction_vector
      direction = Matrix[[0], [0]]
      update_direction(direction)
      direction
    end

    # Update the direction vector based on the current direction.
    def update_direction(direction)
      case @direction
      when 0
        direction[1, 0] = -1
      when 1
        direction[0, 0] = 1
      when 2
        direction[1, 0] = 1
      when 3
        direction[0, 0] = -1
      end
    end
  end
end