package kubernetes

import (
	"context"
	"strings"
	"testing"

	"github.com/coredns/coredns/plugin/pkg/dnstest"
	"github.com/coredns/coredns/plugin/test"
	api "k8s.io/api/core/v1"
	meta "k8s.io/apimachinery/pkg/apis/meta/v1"

	"github.com/miekg/dns"
)

func TestKubernetesXFR(t *testing.T) {
	k := New([]string{"cluster.local."})
	k.APIConn = &APIConnServeTest{}
	k.TransferTo = []string{"127.0.0.1"}

	ctx := context.TODO()
	w := dnstest.NewMultiRecorder(&test.ResponseWriter{})
	dnsmsg := &dns.Msg{}
	dnsmsg.SetAxfr(k.Zones[0])

	_, err := k.ServeDNS(ctx, w, dnsmsg)
	if err != nil {
		t.Error(err)
	}

	if len(w.Msgs) == 0 {
		t.Logf("%+v\n", w)
		t.Error("Did not get back a zone response")
	}

	// Ensure xfr starts with SOA
	if w.Msgs[0].Answer[0].Header().Rrtype != dns.TypeSOA {
		t.Error("Invalid XFR, does not start with SOA record")
	}

	// Ensure xfr starts with SOA
	// Last message is empty, so we need to go back one further
	if w.Msgs[len(w.Msgs)-2].Answer[len(w.Msgs[len(w.Msgs)-2].Answer)-1].Header().Rrtype != dns.TypeSOA {
		t.Error("Invalid XFR, does not end with SOA record")
	}

	testRRs := []dns.RR{}
	for _, tc := range dnsTestCases {
		if tc.Rcode != dns.RcodeSuccess {
			continue
		}

		for _, ans := range tc.Answer {
			// Exclude wildcard searches
			if strings.Contains(ans.Header().Name, "*") {
				continue
			}

			// Exclude TXT records
			if ans.Header().Rrtype == dns.TypeTXT {
				continue
			}
			testRRs = append(testRRs, ans)
		}
	}

	gotRRs := []dns.RR{}
	for _, resp := range w.Msgs {
		for _, ans := range resp.Answer {
			// Skip SOA records since these
			// test cases do not exist
			if ans.Header().Rrtype == dns.TypeSOA {
				continue
			}

			gotRRs = append(gotRRs, ans)
		}

	}

	diff := difference(testRRs, gotRRs)
	if len(diff) != 0 {
		t.Errorf("Got back %d records that do not exist in test cases, should be 0:", len(diff))
		for _, rec := range diff {
			t.Errorf("%+v", rec)
		}
	}

	diff = difference(gotRRs, testRRs)
	if len(diff) != 0 {
		t.Errorf("Found %d records we're missing tham test cases, should be 0:", len(diff))
		for _, rec := range diff {
			t.Errorf("%+v", rec)
		}
	}

}

// difference shows what we're missing when comparing two RR slices
func difference(testRRs []dns.RR, gotRRs []dns.RR) []dns.RR {
	expectedRRs := map[string]bool{}
	for _, rr := range testRRs {
		expectedRRs[rr.String()] = true
	}

	foundRRs := []dns.RR{}
	for _, rr := range gotRRs {
		if _, ok := expectedRRs[rr.String()]; !ok {
			foundRRs = append(foundRRs, rr)
		}
	}
	return foundRRs
}

func TestEndpointsEquivalent(t *testing.T) {
	epA := api.Endpoints{
		ObjectMeta: meta.ObjectMeta{ResourceVersion: "1230"},
		Subsets: []api.EndpointSubset{{
			Addresses:         []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			NotReadyAddresses: []api.EndpointAddress{{IP: "1.2.3.5", Hostname: "foobar"}},
		}},
	}
	epB := api.Endpoints{
		ObjectMeta: meta.ObjectMeta{ResourceVersion: "1234"},
		Subsets: []api.EndpointSubset{{
			Addresses:         []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			NotReadyAddresses: []api.EndpointAddress{{IP: "1.1.1.1", Hostname: "foobar"}},
		}},
	}
	epC := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.5", Hostname: "foo"}},
		}},
	}
	epD := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.5", Hostname: "foo"}},
		},
			{
				Addresses: []api.EndpointAddress{{IP: "1.2.2.2", Hostname: "foofoo"}},
			}},
	}
	epE := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.5", Hostname: "foo"}, {IP: "1.1.1.1"}},
		}},
	}
	epF := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foofoo"}},
		}},
	}
	epG := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			Ports:     []api.EndpointPort{{Name: "http", Port: 80, Protocol: "TCP"}},
		}},
	}
	epH := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			Ports:     []api.EndpointPort{{Name: "newportname", Port: 80, Protocol: "TCP"}},
		}},
	}
	epI := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			Ports:     []api.EndpointPort{{Name: "http", Port: 8080, Protocol: "TCP"}},
		}},
	}
	epJ := api.Endpoints{
		Subsets: []api.EndpointSubset{{
			Addresses: []api.EndpointAddress{{IP: "1.2.3.4", Hostname: "foo"}},
			Ports:     []api.EndpointPort{{Name: "http", Port: 80, Protocol: "UDP"}},
		}},
	}

	tests := []struct {
		equiv bool
		a     *api.Endpoints
		b     *api.Endpoints
	}{
		{true, &epA, &epB},
		{false, &epA, &epC},
		{false, &epA, &epD},
		{false, &epA, &epE},
		{false, &epA, &epF},
		{false, &epF, &epG},
		{false, &epG, &epH},
		{false, &epG, &epI},
		{false, &epG, &epJ},
	}

	for i, tc := range tests {
		if tc.equiv && !endpointsEquivalent(tc.a, tc.b) {
			t.Errorf("Test %d: expected endpoints to be equivalent and they are not.", i)
		}
		if !tc.equiv && endpointsEquivalent(tc.a, tc.b) {
			t.Errorf("Test %d: expected endpoints to be seen as different but they were not.", i)
		}
	}
}
