package cluster

import "sort"

// SortRegions sorts regions. first by length those 3-character
// or shorter, and then by length. It's mostly aimed at
// supporting ISO-3166 order
func SortRegions(regions []string) []string {
	sort.Slice(regions, func(i, j int) bool {
		r1, r2 := regions[i], regions[j]
		return regionLess(r1, r2)
	})

	return regions
}

func regionLess(r1, r2 string) bool {
	switch {
	case len(r1) < 4:
		switch {
		case len(r1) < len(r2):
			return true
		case len(r1) > len(r2):
			return false
		default:
			return r1 < r2
		}
	case len(r2) < 4:
		return false
	default:
		return r1 < r2
	}
}

func (m *Cluster) sortRegions() {
	sort.Slice(m.Regions, func(i, j int) bool {
		r1 := m.Regions[i].Name
		r2 := m.Regions[j].Name
		return regionLess(r1, r2)
	})
}