package checker

import (
	"net"
	"testing"
)

func TestReverseNameToIP(t *testing.T) {
	cases := []struct {
		name string
		in   string
		want string // empty = expect nil
	}{
		{"ipv4 ok", "4.3.2.1.in-addr.arpa.", "1.2.3.4"},
		{"ipv4 no trailing dot", "4.3.2.1.in-addr.arpa", "1.2.3.4"},
		{"ipv4 uppercase suffix", "4.3.2.1.IN-ADDR.ARPA.", "1.2.3.4"},
		{"ipv4 too few labels", "3.2.1.in-addr.arpa.", ""},
		{"ipv4 too many labels", "5.4.3.2.1.in-addr.arpa.", ""},
		{"ipv4 non-numeric label", "a.3.2.1.in-addr.arpa.", ""},
		{"ipv4 octet out of range", "256.3.2.1.in-addr.arpa.", ""},

		{
			"ipv6 ok",
			"1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.",
			"2001:db8::1",
		},
		{"ipv6 too few nibbles", "0.0.8.b.d.0.ip6.arpa.", ""},
		{
			"ipv6 multi-char label",
			"00.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.",
			"",
		},

		{"not arpa", "example.com.", ""},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := reverseNameToIP(tc.in)
			if tc.want == "" {
				if got != nil {
					t.Fatalf("expected nil, got %v", got)
				}
				return
			}
			if got == nil {
				t.Fatalf("expected %s, got nil", tc.want)
			}
			want := net.ParseIP(tc.want)
			if !got.Equal(want) {
				t.Fatalf("expected %s, got %s", want, got)
			}
		})
	}
}

func TestIsReverseArpa(t *testing.T) {
	cases := map[string]bool{
		"4.3.2.1.in-addr.arpa.": true,
		"4.3.2.1.in-addr.arpa":  true,
		"1.0.0.0.ip6.arpa.":     true,
		"IN-ADDR.ARPA.":         false, // bare apex, no leading label
		"example.com.":          false,
		"":                      false,
	}
	for in, want := range cases {
		if got := isReverseArpa(in); got != want {
			t.Errorf("isReverseArpa(%q) = %v, want %v", in, got, want)
		}
	}
}

func TestLowerFQDN(t *testing.T) {
	cases := map[string]string{
		"Example.COM":  "example.com.",
		"example.com.": "example.com.",
		"":             ".",
	}
	for in, want := range cases {
		if got := lowerFQDN(in); got != want {
			t.Errorf("lowerFQDN(%q) = %q, want %q", in, got, want)
		}
	}
}

func TestHostPort(t *testing.T) {
	cases := []struct {
		host, port, want string
	}{
		{"1.2.3.4", "53", "1.2.3.4:53"},
		{"ns1.example.com.", "53", "ns1.example.com:53"},
		{"2001:db8::1", "53", "[2001:db8::1]:53"},
	}
	for _, tc := range cases {
		if got := hostPort(tc.host, tc.port); got != tc.want {
			t.Errorf("hostPort(%q,%q) = %q, want %q", tc.host, tc.port, got, tc.want)
		}
	}
}

func TestRcodeText(t *testing.T) {
	if got := rcodeText(0); got != "NOERROR" {
		t.Errorf("rcodeText(0) = %q, want NOERROR", got)
	}
	if got := rcodeText(3); got != "NXDOMAIN" {
		t.Errorf("rcodeText(3) = %q, want NXDOMAIN", got)
	}
	if got := rcodeText(999); got != "RCODE(999)" {
		t.Errorf("rcodeText(999) = %q, want RCODE(999)", got)
	}
}