import intersectLine from './intersect-line'

/*
 * Returns the point ({x, y}) at which the point argument intersects with the
 * node argument assuming that it has the shape specified by polygon.
 */
function intersectPolygon (node, polyPoints, point) {
  const x1 = node.x
  const y1 = node.y

  const intersections = []

  let minX = Number.POSITIVE_INFINITY
  let minY = Number.POSITIVE_INFINITY
  polyPoints.forEach(function (entry) {
    minX = Math.min(minX, entry.x)
    minY = Math.min(minY, entry.y)
  })

  const left = x1 - node.width / 2 - minX
  const top = y1 - node.height / 2 - minY

  for (let i = 0; i < polyPoints.length; i += 1) {
    const p1 = polyPoints[i]
    const p2 = polyPoints[i < polyPoints.length - 1 ? i + 1 : 0]
    const intersect = intersectLine(node, point,
      {x: left + p1.x, y: top + p1.y}, {x: left + p2.x, y: top + p2.y})
    if (intersect) {
      intersections.push(intersect)
    }
  }

  if (!intersections.length) {
    console.log('NO INTERSECTION FOUND, RETURN NODE CENTER', node)
    return node
  }

  if (intersections.length > 1) {
    // More intersections, find the one nearest to edge end point
    intersections.sort(function (p, q) {
      const pdx = p.x - point.x
      const pdy = p.y - point.y
      const distp = Math.sqrt(pdx * pdx + pdy * pdy)

      const qdx = q.x - point.x
      const qdy = q.y - point.y
      const distq = Math.sqrt(qdx * qdx + qdy * qdy)

      return (distp < distq) ? -1 : (distp === distq ? 0 : 1)
    })
  }
  return intersections[0]
}

export default intersectPolygon