package dnsname

import (
	"net/netip"
	"strings"
	"testing"
)

func TestOwner(t *testing.T) {
	zone := "example.com."
	cases := []struct{ in, want string }{
		{"", "example.com."},
		{"@", "example.com."},
		{"www", "www.example.com."},
		{"WWW", "www.example.com."},
		{"www.example.com", "www.example.com."},
		{"www.example.com.", "www.example.com."},
		{"example.com", "example.com."},
		{"a.b", "a.b.example.com."},
		{"other.org.", "other.org."},
		{"_acme-challenge.www", "_acme-challenge.www.example.com."},
		{"bücher", "xn--bcher-kva.example.com."},
	}
	for _, c := range cases {
		got, err := Owner(c.in, zone)
		if err != nil || got != c.want {
			t.Errorf("Owner(%q) = %q, %v; want %q", c.in, got, err, c.want)
		}
	}
	// Not fooled by a zone name that's a suffix of a label.
	got, _ := Owner("myexample.com", zone)
	if got != "myexample.com.example.com." {
		t.Errorf("Owner(myexample.com) = %q", got)
	}
}

func TestRelative(t *testing.T) {
	cases := []struct{ name, zone, want string }{
		{"example.com.", "example.com.", "@"},
		{"www.example.com.", "example.com.", "www"},
		{"a.b.example.com.", "example.com.", "a.b"},
		{"other.org.", "example.com.", "other.org."},
		{"x.", ".", "x."},
	}
	for _, c := range cases {
		if got := Relative(c.name, c.zone); got != c.want {
			t.Errorf("Relative(%q,%q) = %q want %q", c.name, c.zone, got, c.want)
		}
	}
}

func TestCheckOwner(t *testing.T) {
	ok := []string{".", "example.com.", "*.example.com.", "_dmarc.example.com.", "0/26.2.0.192.in-addr.arpa.", "a-b.c."}
	for _, n := range ok {
		if err := CheckOwner(n); err != nil {
			t.Errorf("CheckOwner(%q) = %v", n, err)
		}
	}
	bad := []string{"a..b.", "x.*.example.com.", "foo*.example.com.", "Upper.example.com.", "sp ace.com.", "example.com"}
	for _, n := range bad {
		if err := CheckOwner(n); err == nil {
			t.Errorf("CheckOwner(%q) succeeded, want error", n)
		}
	}
	long := ""
	for i := 0; i < 64; i++ {
		long += "a"
	}
	if CheckOwner(long+".com.") == nil {
		t.Error("64 octet label accepted")
	}
	if CheckZoneName("*.example.com.") == nil {
		t.Error("wildcard zone accepted")
	}
}

func TestIsHostname(t *testing.T) {
	cases := []struct {
		name     string
		wildcard bool
		want     bool
	}{
		{"www.example.com.", false, true},
		{"1host.example.com.", false, true},
		{"foo_bar.example.com.", false, false},
		{"-x.example.com.", false, false},
		{"x-.example.com.", false, false},
		{"*.example.com.", true, true},
		{"*.example.com.", false, false},
		{".", false, false},
		{"a.b.", false, true},
	}
	for _, c := range cases {
		if got := IsHostname(c.name, c.wildcard); got != c.want {
			t.Errorf("IsHostname(%q,%v) = %v", c.name, c.wildcard, got)
		}
	}
}

func TestMailbox(t *testing.T) {
	mb, err := MailboxFromEmail("first.last@example.com")
	if err != nil || mb != `first\.last.example.com.` {
		t.Fatalf("MailboxFromEmail = %q %v", mb, err)
	}
	if !IsMailbox(mb) {
		t.Error("IsMailbox false for escaped local part")
	}
	if got := EmailFromMailbox(mb); got != "first.last@example.com" {
		t.Errorf("EmailFromMailbox = %q", got)
	}
	if mb, _ := MailboxFromEmail("hostmaster.example.com."); mb != "hostmaster.example.com." {
		t.Errorf("domain form changed: %q", mb)
	}
	if IsMailbox("hostmaster.bad_domain.com.") {
		t.Error("bad domain part accepted")
	}
}

func TestReverse(t *testing.T) {
	a := netip.MustParseAddr("192.0.2.10")
	if got := ReverseName(a); got != "10.2.0.192.in-addr.arpa." {
		t.Errorf("ReverseName v4 = %q", got)
	}
	a6 := netip.MustParseAddr("2001:db8::1")
	r6 := ReverseName(a6)
	if r6 != "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." {
		t.Errorf("ReverseName v6 = %q", r6)
	}
	for _, name := range []string{"10.2.0.192.in-addr.arpa.", r6} {
		back, ok := AddrFromReverse(name)
		if !ok {
			t.Errorf("AddrFromReverse(%q) failed", name)
			continue
		}
		if ReverseName(back) != name {
			t.Errorf("round trip %q -> %v", name, back)
		}
	}
	z, err := ReverseZone(netip.MustParsePrefix("192.168.1.0/24"))
	if err != nil || z != "1.168.192.in-addr.arpa." {
		t.Errorf("ReverseZone /24 = %q %v", z, err)
	}
	z, err = ReverseZone(netip.MustParsePrefix("10.0.0.0/8"))
	if err != nil || z != "10.in-addr.arpa." {
		t.Errorf("ReverseZone /8 = %q %v", z, err)
	}
	if _, err := ReverseZone(netip.MustParsePrefix("192.168.1.0/26")); err == nil {
		t.Error("ReverseZone /26 accepted")
	}
	z, err = ReverseZone(netip.MustParsePrefix("2001:db8::/32"))
	if err != nil || z != "8.b.d.0.1.0.0.2.ip6.arpa." {
		t.Errorf("ReverseZone v6 = %q %v", z, err)
	}
	if !IsReverse("1.168.192.in-addr.arpa.") || IsReverse("example.com.") {
		t.Error("IsReverse")
	}
}

func TestMisc(t *testing.T) {
	if Parent("www.example.com.") != "example.com." || Parent("com.") != "." || Parent(".") != "" {
		t.Error("Parent")
	}
	if CountLabels(".") != 0 || CountLabels("a.b.c.") != 3 {
		t.Error("CountLabels")
	}
	if BestZone("a.lab.example.com.", []string{"example.com.", "lab.example.com.", "other.com."}) != "lab.example.com." {
		t.Error("BestZone")
	}
	if FileSafe("0/26.2.0.192.in-addr.arpa.") != "0%2f26.2.0.192.in-addr.arpa" || FileSafe(".") != "root" {
		t.Errorf("FileSafe = %q", FileSafe("0/26.2.0.192.in-addr.arpa."))
	}
	if !IsSubdomain("a.example.com.", "example.com.") || IsSubdomain("aexample.com.", "example.com.") || !IsSubdomain("x.", ".") {
		t.Error("IsSubdomain")
	}
}

func TestOwnerAddressInReverseZone(t *testing.T) {
	for _, tc := range []struct{ in, zone, want string }{
		{"10.10.0.20", "0.10.10.in-addr.arpa.", "20.0.10.10.in-addr.arpa."},
		{"20", "0.10.10.in-addr.arpa.", "20.0.10.10.in-addr.arpa."},
		{"2001:db8::1", "8.b.d.0.1.0.0.2.ip6.arpa.", "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."},
		{"10.10.0.20", "adbraun.lol.", "10.10.0.20.adbraun.lol."}, // not special in forward zones
	} {
		if got, err := Owner(tc.in, tc.zone); err != nil || got != tc.want {
			t.Errorf("Owner(%q, %q) = %q, %v; want %q", tc.in, tc.zone, got, err, tc.want)
		}
	}
}

func TestReverseZones(t *testing.T) {
	cases := []struct {
		prefix string
		want   string // zones joined by spaces, or "error"
	}{
		{"10.0.10.0/24", "10.0.10.in-addr.arpa."},
		{"10.0.10.100/32", "100.10.0.10.in-addr.arpa."},
		{"10.0.8.0/22", "8.0.10.in-addr.arpa. 9.0.10.in-addr.arpa. 10.0.10.in-addr.arpa. 11.0.10.in-addr.arpa."},
		{"10.0.9.0/22", "8.0.10.in-addr.arpa. 9.0.10.in-addr.arpa. 10.0.10.in-addr.arpa. 11.0.10.in-addr.arpa."},
		{"172.16.0.0/12", "16.172.in-addr.arpa. 17.172.in-addr.arpa. 18.172.in-addr.arpa. 19.172.in-addr.arpa. 20.172.in-addr.arpa. 21.172.in-addr.arpa. 22.172.in-addr.arpa. 23.172.in-addr.arpa. 24.172.in-addr.arpa. 25.172.in-addr.arpa. 26.172.in-addr.arpa. 27.172.in-addr.arpa. 28.172.in-addr.arpa. 29.172.in-addr.arpa. 30.172.in-addr.arpa. 31.172.in-addr.arpa."},
		{"10.0.0.0/17", "error"}, // 128 zones
		{"10.0.10.64/26", "error"},
		{"10.0.0.0/7", "error"},
		{"2001:db8::/47", "0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa. 1.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa."},
		{"2001:db8::1/128", "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."},
	}
	for _, c := range cases {
		zones, err := ReverseZones(netip.MustParsePrefix(c.prefix))
		got := strings.Join(zones, " ")
		if err != nil {
			got = "error"
		}
		if got != c.want {
			t.Errorf("ReverseZones(%s) = %s (%v), want %s", c.prefix, got, err, c.want)
		}
	}
	if _, err := ReverseZone(netip.MustParsePrefix("10.0.8.0/22")); err == nil || !strings.Contains(err.Error(), "spans 4 reverse zones") {
		t.Errorf("ReverseZone /22: %v", err)
	}
}