/**
I wrote this code recently for a Word Puzzle game I created and this particular class is responsible for processing the touch events 
that occur when the user swipes on different words within the grid. It's suppose to detect the direction that the swipe took place in 
so that it can utilize the direction with determine the coordinates between the start and end event of the touch interaction so that 
it can highlight those letters. 
**/
class CoordinatesDirectionInteractor @Inject constructor() {
    private var swipeDirection: SwipeDirection? = null
    private var swipeType: SwipeType? = null

    fun detectSwipeDirection(startCoordinate: WordCoordinate, endCoordinate: WordCoordinate): Pair<SwipeDirection?, SwipeType?> {

        return when {
            areCoordinatesInSameRow(startCoordinate, endCoordinate) -> Pair(swipeDirection, swipeType)
            areCoordinatesInSameColumn(startCoordinate, endCoordinate) -> Pair(swipeDirection, swipeType)
            else -> {
                calculateDiagonalCoordinates(startCoordinate, endCoordinate)
                Pair(swipeDirection, swipeType)
            }
        }
    }

    private fun areCoordinatesInSameRow(startCoordinate: WordCoordinate, endCoordinate: WordCoordinate): Boolean {
        if (startCoordinate.y != endCoordinate.y) return false

        swipeType = Horizontal

        if (startCoordinate.x < endCoordinate.x) {
            swipeDirection = W.to(E)
        } else if (startCoordinate.x > endCoordinate.x) {
            swipeDirection = E.to(W)
        }

        return true
    }

    private fun areCoordinatesInSameColumn(startCoordinate: WordCoordinate, endCoordinate: WordCoordinate): Boolean {
        if (startCoordinate.x != endCoordinate.x)
            return false

        swipeType = Vertical

        if (startCoordinate.y < endCoordinate.y) {
            swipeDirection = N.to(S)
        } else if (startCoordinate.y > endCoordinate.y) {
            swipeDirection = S.to(N)
        }

        return true
    }

    private fun calculateDiagonalCoordinates(startCoordinate: WordCoordinate, endCoordinate: WordCoordinate): Boolean {

        val diffX = Math.abs(startCoordinate.x - endCoordinate.x)
        val diffY = Math.abs(startCoordinate.y - endCoordinate.y)

        if (diffX == diffY && diffX != 0) {
            swipeType = Diagonal

            if (startCoordinate.x > endCoordinate.x && startCoordinate.y < endCoordinate.y) {
                swipeDirection = NE.to(SW)
            }

            if (startCoordinate.x < endCoordinate.x && startCoordinate.y > endCoordinate.y) {
                swipeDirection = SW.to(NE)
            }

            if (startCoordinate.x < endCoordinate.x && startCoordinate.y < endCoordinate.y) {
                swipeDirection = NW.to(SE)
            }

            if (startCoordinate.x > endCoordinate.x && startCoordinate.y > endCoordinate.y) {
                swipeDirection = SE.to(NW)
            }
        }
        return true
    }

    fun Direction.to(value: Direction): SwipeDirection = SwipeDirection(this, value)
}