package util

//  1. oldstring element is not in new  : abandon(delete)
//  2. new element is not in oldstring  : add(add)
func Difference(oldstring []string, newstring []string) map[string]string {
	var diff = make(map[string]string)

	// Loop two times, first to find oldstring strings not in newstring,
	// second loop to find newstring strings not in oldstring
	for i := 0; i < 2; i++ {
		for _, s1 := range oldstring {
			found := false
			for _, s2 := range newstring {
				if s1 == s2 {
					found = true
					break
				}
			}
			// String not found. We add it to return slice
			if !found && i == 0 {
				diff[s1] = "delete"
			}
			if !found && i != 0 {
				diff[s1] = "add"
			}
		}
		// Swap the slices, only if it was the first loop
		if i == 0 {
			oldstring, newstring = newstring, oldstring
		}
	}
	return diff
}