package robot

import "fmt"

const testVersion = 3

// Stuff added for step 1
const (
	N = iota
	E
	S
	W
	ErrDir
)

func Advance() {
	switch Step1Robot.Dir {
	case N:
		Step1Robot.Y++
	case E:
		Step1Robot.X++
	case S:
		Step1Robot.Y--
	case W:
		Step1Robot.X--
	}
}

func Left() {
	switch Step1Robot.Dir {
	case N:
		Step1Robot.Dir = W
	case E:
		Step1Robot.Dir = N
	case S:
		Step1Robot.Dir = E
	case W:
		Step1Robot.Dir = S
	}
}

func Right() {
	switch Step1Robot.Dir {
	case N:
		Step1Robot.Dir = E
	case E:
		Step1Robot.Dir = S
	case S:
		Step1Robot.Dir = W
	case W:
		Step1Robot.Dir = N
	}
}

func (d Dir) String() string {
	switch d {
	case N:
		return "N"
	case E:
		return "E"
	case S:
		return "S"
	default:
		return "W"
	}
}

// Stuff added for step 2
type Action byte

func StartRobot(cmd chan Command, act chan Action) {
	fmt.Println("Starting Robot")
	for {
		fmt.Println("Waiting for command")
		j, more := <-cmd
		fmt.Println("Received a Command:", j)
		if more {
			// Received a command, try to act in the room
			act <- Action(j)
		}
	}
	fmt.Println("Robot Done")
}

func Room(extent Rect, robot Step2Robot, act chan Action, rep chan Step2Robot) {
	fmt.Println("Starting Room")
	for {
		j, more := <-act
		if more {
			// Received an action, try to perform it
			if j == 'R' { // Turn Right
				switch robot.Dir {
				case N:
					robot.Dir = E
				case E:
					robot.Dir = S
				case S:
					robot.Dir = W
				case W:
					robot.Dir = N
				}
			} else if j == 'L' { // Turn Left
				switch robot.Dir {
				case N:
					robot.Dir = W
				case E:
					robot.Dir = N
				case S:
					robot.Dir = E
				case W:
					robot.Dir = S
				}
			} else if j == 'A' { // Advance
				switch robot.Dir {
				case N:
					if robot.Pos.Northing < extent.Max.Northing {
						robot.Pos.Northing++
					} else {
						fmt.Println("Hit North Wall")
					}
				case E:
					if robot.Pos.Easting < extent.Max.Easting {
						robot.Pos.Easting++
					} else {
						fmt.Println("Hit East Wall")
					}
				case S:
					if robot.Pos.Northing > extent.Min.Northing {
						robot.Pos.Northing--
					} else {
						fmt.Println("Hit South Wall")
					}
				case W:
					if robot.Pos.Easting > extent.Min.Easting {
						robot.Pos.Easting--
					} else {
						fmt.Println("Hit West Wall")
					}
				}
			}
		} else {
			// Done, report back
			rep <- robot
		}
	}
	close(rep)
	fmt.Println("Room Done")
}