func PackingIterator[T any]()

in internal/utils.go [58:115]
49 lines of code
10 McCabe index (conditional complexity)

func PackingIterator[T any](itr iter.Seq[T], targetWeight int64, lookback int, weightFunc func(T) int64, largestBinFirst bool) iter.Seq[[]T] {
	bins := make([]Bin[T], 0)
	findBin := func(weight int64) *Bin[T] {
		for i := range bins {
			if bins[i].CanAdd(weight) {
				return &bins[i]
			}
		}

		return nil
	}

	removeBin := func() Bin[T] {
		if largestBinFirst {
			maxBin := slices.MaxFunc(bins, func(a, b Bin[T]) int {
				return cmp.Compare(a.Weight(), b.Weight())
			})
			i := slices.IndexFunc(bins, func(e Bin[T]) bool {
				return e.Weight() == maxBin.Weight()
			})

			bins = slices.Delete(bins, i, i+1)

			return maxBin
		}

		var out Bin[T]
		out, bins = bins[0], bins[1:]

		return out
	}

	return func(yield func([]T) bool) {
		for item := range itr {
			w := weightFunc(item)
			bin := findBin(w)
			if bin != nil {
				bin.Add(item, w)
			} else {
				bin := Bin[T]{targetWeight: targetWeight}
				bin.Add(item, w)
				bins = append(bins, bin)

				if len(bins) > lookback {
					if !yield(removeBin().items) {
						return
					}
				}
			}
		}

		for len(bins) > 0 {
			if !yield(removeBin().items) {
				return
			}
		}
	}
}