import { Point } from './types'

export const line = ( x0: number, y0: number, x1: number, y1: number ) => {
  x0 = x0 | 0
  y0 = y0 | 0
  x1 = x1 | 0
  y1 = y1 | 0

  const line: Point[] = [ [ x0, y0 ] ]

  const dX = Math.abs( x1 - x0 )
  const dY = Math.abs( y1 - y0 )
  const sX = x0 < x1 ? 1 : -1
  const sY = y0 < y1 ? 1 : -1

  let err = dX - dY

  while ( x0 !== x1 || y0 !== y1 ) {
    const err2 = 2 * err

    if ( err2 > dY * -1 ) {
      err -= dY
      x0 += sX
    }

    if ( err2 < dX ) {
      err += dX
      y0 += sY
    }

    line.push( [ x0, y0 ] )
  }

  return line
}