package world

import "edgaru089.ml/go/gl01/internal/util/itype"

// CastViewRay
func (w *World) CastViewRay(from, dir itype.Vec3d, maxlen float64) (ok bool, blockcoord itype.Vec3i, face itype.Direction, where itype.Vec3d, dist float64) {

	bfrom := from.Floor()
	bfromdir := itype.Direction(-1)
	for bfrom.ToFloat64().Addv(0.5, 0.5, 0.5).Add(from.Negative()).Length() < maxlen {
		for todir := itype.Direction(0); todir < 6; todir++ {
			if todir == bfromdir {
				continue
			}

			bto := bfrom.Add(itype.DirectionVeci[todir])
			block := w.Block(bto)

			if block.Id != 0 {
				outbox := itype.Boxd{
					OffX:  float64(bto[0]),
					OffY:  float64(bto[1]),
					OffZ:  float64(bto[2]),
					SizeX: 1,
					SizeY: 1,
					SizeZ: 1,
				}
				var outface itype.Direction
				if ok, outface, _, _ = outbox.IntersectRay(from, dir, maxlen); ok {
					app := block.Appearance(bto)
					for _, lb := range app.Lookbox {
						if ok, face, where, dist = lb.IntersectRay(from, dir, maxlen); ok {
							blockcoord = bto
							return
						}
					}
				}

				bfromdir = outface.Opposite()
				bfrom = bto
				break
			}
		}
	}

	ok = false
	return
}