import type { Grid } from 'pathfinding'
import type { Position, XYPosition } from '@vue-flow/core'

type Direction = 'top' | 'bottom' | 'left' | 'right'

export const getNextPointFromPosition = (point: XYPosition, position: Direction): XYPosition => {
  switch (position) {
    case 'top':
      return { x: point.x, y: point.y - 1 }
    case 'bottom':
      return { x: point.x, y: point.y + 1 }
    case 'left':
      return { x: point.x - 1, y: point.y }
    case 'right':
      return { x: point.x + 1, y: point.y }
  }
}

/**
 * Guarantee that the path is walkable, even if the point is inside a non
 * walkable area, by adding a walkable path in the direction of the point's
 * Position.
 */
export const guaranteeWalkablePath = (grid: Grid, point: XYPosition, position: Position) => {
  let node = grid.getNodeAt(point.x, point.y)
  while (!node.walkable) {
    grid.setWalkableAt(node.x, node.y, true)
    const next = getNextPointFromPosition(node, position)
    node = grid.getNodeAt(next.x, next.y)
  }
}