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]

		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
		}
	})
	return regions
}