package checker

import (
	"reflect"
	"testing"
)

func TestJoinSubdomain(t *testing.T) {
	cases := []struct {
		sub, origin, want string
	}{
		{"", "example.com", "example.com."},
		{"@", "example.com", "example.com."},
		{"www", "example.com", "www.example.com."},
		{"www.", "example.com.", "www.example.com."},
		{"www.example.com", "example.com", "www.example.com."},
		{"example.com", "example.com", "example.com."},
	}
	for _, c := range cases {
		got := joinSubdomain(c.sub, c.origin)
		if got != c.want {
			t.Errorf("joinSubdomain(%q,%q) = %q, want %q", c.sub, c.origin, got, c.want)
		}
	}
}

func TestResolvers_Explicit(t *testing.T) {
	got := resolvers("1.1.1.1, 8.8.8.8:5353 ,")
	want := []string{"1.1.1.1:53", "8.8.8.8:5353"}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("got %v, want %v", got, want)
	}
}

func TestResolvers_FallbackList(t *testing.T) {
	// We don't trust /etc/resolv.conf to be absent in all CI environments,
	// but the empty-input path must always return at least one resolver.
	got := resolvers("")
	if len(got) == 0 {
		t.Fatal("expected at least one resolver")
	}
}

func TestMaxAnswerRecords_Constant(t *testing.T) {
	// Sanity check: don't silently lower the cap to something useless
	// without updating tests / behaviour.
	if maxAnswerRecords < 8 {
		t.Errorf("maxAnswerRecords=%d is suspiciously low", maxAnswerRecords)
	}
}