package dnsname

import (
	"strings"
	"testing"
)

func TestValidateExternalFQDN(t *testing.T) {
	// Four maximal labels + three dots = 255 chars, over the 253 limit.
	overlongName := strings.Repeat("a", 63) + "." + strings.Repeat("b", 63) + "." +
		strings.Repeat("c", 63) + "." + strings.Repeat("d", 63)

	tests := []struct {
		name          string
		domain        string
		operatorRoots []string
		wantErr       bool
	}{
		{"valid external domain", "wiki.example.org", []string{"example.test"}, false},
		{"valid deep external domain", "a.b.wiki.example.org", []string{"example.test"}, false},
		{"shape check only with no operator roots", "wiki.example.org", nil, false},
		{"empty root entry ignored", "wiki.example.org", []string{""}, false},
		{"punycode label accepted", "xn--53h.example.org", nil, false},
		{"similar suffix is not under an operator root", "notexample.test", []string{"example.test"}, false},
		{"clear of every operator root", "wiki.example.org", []string{"example.test", "other.test"}, false},
		{"single label rejected", "intranet", nil, true},
		{"empty rejected", "", nil, true},
		{"operator root itself rejected", "example.test", []string{"example.test"}, true},
		{"name under an operator root rejected", "foo.example.test", []string{"example.test"}, true},
		{"deep name under an operator root rejected", "a.b.example.test", []string{"example.test"}, true},
		{"name under a later operator root rejected", "a.other.test", []string{"example.test", "other.test"}, true},
		{"uppercase rejected — caller must normalize", "Wiki.Example.org", nil, true},
		{"label over 63 chars rejected", strings.Repeat("a", 64) + ".example.org", nil, true},
		{"total over 253 chars rejected", overlongName, nil, true},
		{"leading hyphen rejected", "-wiki.example.org", nil, true},
		{"empty label rejected", "wiki..example.org", nil, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := ValidateExternalFQDN(tt.domain, tt.operatorRoots)
			if tt.wantErr && got == "" {
				t.Errorf("ValidateExternalFQDN(%q, %v) = no error, want error", tt.domain, tt.operatorRoots)
			}
			if !tt.wantErr && got != "" {
				t.Errorf("ValidateExternalFQDN(%q, %v) = %q, want no error", tt.domain, tt.operatorRoots, got)
			}
		})
	}
}