package kubernetes

import (
	"net"
	"slices"
	"strings"
	"testing"
	"time"

	"github.com/coredns/caddy"
	"github.com/coredns/coredns/core/dnsserver"
	"github.com/coredns/coredns/plugin/pkg/fall"

	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
)

var defaultStartupTimeout = time.Second * 5

func TestKubernetesParse(t *testing.T) {
	tests := []struct {
		input                          string // Corefile data as string
		shouldErr                      bool   // true if test case is expected to produce an error.
		expectedErrContent             string // substring from the expected error. Empty for positive cases.
		expectedZoneCount              int    // expected count of defined zones.
		expectedNSCount                int    // expected count of namespaces.
		expectedLabelSelector          string // expected label selector value
		expectedNamespaceLabelSelector string // expected namespace label selector value
		expectedPodMode                string
		expectedFallthrough            fall.F
		expectedStartupTimeout         time.Duration
	}{
		// positive
		{
			`kubernetes coredns.local`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local test.local`,
			false,
			"",
			2,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	endpoint http://localhost:9090 http://localhost:9091
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	namespaces demo
}`,
			false,
			"",
			1,
			1,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	namespaces demo test
}`,
			false,
			"",
			1,
			2,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    labels environment=prod
}`,
			false,
			"",
			1,
			0,
			"environment=prod",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    labels environment in (production, staging, qa),application=nginx
}`,
			false,
			"",
			1,
			0,
			"application=nginx,environment in (production,qa,staging)",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    namespace_labels istio-injection=enabled
}`,
			false,
			"",
			1,
			0,
			"",
			"istio-injection=enabled",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    namespaces foo bar
    namespace_labels istio-injection=enabled
}`,
			true,
			"Error during parsing: namespaces and namespace_labels cannot both be set",
			-1,
			0,
			"",
			"istio-injection=enabled",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local test.local {
	endpoint http://localhost:8080
	namespaces demo test
    labels environment in (production, staging, qa),application=nginx
    fallthrough
}`,
			false,
			"",
			2,
			2,
			"application=nginx,environment in (production,qa,staging)",
			"",
			podModeDisabled,
			fall.Root,
			defaultStartupTimeout,
		},
		// negative
		{
			`kubernetes coredns.local {
    endpoint
}`,
			true,
			"rong argument count or unexpected line ending",
			-1,
			-1,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	namespaces
}`,
			true,
			"rong argument count or unexpected line ending",
			-1,
			-1,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    labels
}`,
			true,
			"rong argument count or unexpected line ending",
			-1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
    labels environment in (production, qa
}`,
			true,
			"unable to parse label selector",
			-1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		// pods disabled
		{
			`kubernetes coredns.local {
	pods disabled
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		// pods insecure
		{
			`kubernetes coredns.local {
	pods insecure
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeInsecure,
			fall.Zero,
			defaultStartupTimeout,
		},
		// pods verified
		{
			`kubernetes coredns.local {
	pods verified
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeVerified,
			fall.Zero,
			defaultStartupTimeout,
		},
		// pods invalid
		{
			`kubernetes coredns.local {
	pods giant_seed
}`,
			true,
			"rong value for pods",
			-1,
			0,
			"",
			"",
			podModeVerified,
			fall.Zero,
			defaultStartupTimeout,
		},
		// fallthrough with zones
		{
			`kubernetes coredns.local {
	fallthrough ip6.arpa inaddr.arpa foo.com
}`,
			false,
			"rong argument count",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.F{Zones: []string{"ip6.arpa.", "inaddr.arpa.", "foo.com."}},
			defaultStartupTimeout,
		},
		// More than one Kubernetes not allowed
		{
			`kubernetes coredns.local
kubernetes cluster.local`,
			true,
			"this plugin",
			-1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	kubeconfig
}`,
			true,
			"Wrong argument count or unexpected line ending after",
			-1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	kubeconfig file context extraarg
}`,
			true,
			"Wrong argument count or unexpected line ending after",
			-1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	kubeconfig file
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
	kubeconfig file context
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			defaultStartupTimeout,
		},
		{
			`kubernetes coredns.local {
        kubeconfig file context
        startup_timeout 1s
}`,
			false,
			"",
			1,
			0,
			"",
			"",
			podModeDisabled,
			fall.Zero,
			time.Second * 1,
		},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8sController, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error, but did not find error for input '%s'. Error was: '%v'", i, test.input, err)
		}

		if err != nil {
			if !test.shouldErr {
				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
				continue
			}

			if test.shouldErr && (len(test.expectedErrContent) < 1) {
				t.Fatalf("Test %d: Test marked as expecting an error, but no expectedErrContent provided for input '%s'. Error was: '%v'", i, test.input, err)
			}

			if test.shouldErr && (test.expectedZoneCount >= 0) {
				t.Errorf("Test %d: Test marked as expecting an error, but provides value for expectedZoneCount!=-1 for input '%s'. Error was: '%v'", i, test.input, err)
			}

			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
			}
			continue
		}

		// No error was raised, so validate initialization of k8sController
		//     Zones
		foundZoneCount := len(k8sController.Zones)
		if foundZoneCount != test.expectedZoneCount {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with %d zones, instead found %d zones: '%v' for input '%s'", i, test.expectedZoneCount, foundZoneCount, k8sController.Zones, test.input)
		}

		//    Namespaces
		foundNSCount := len(k8sController.Namespaces)
		if foundNSCount != test.expectedNSCount {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with %d namespaces. Instead found %d namespaces: '%v' for input '%s'", i, test.expectedNSCount, foundNSCount, k8sController.Namespaces, test.input)
		}

		//    Labels
		if k8sController.opts.labelSelector != nil {
			foundLabelSelectorString := meta.FormatLabelSelector(k8sController.opts.labelSelector)
			if foundLabelSelectorString != test.expectedLabelSelector {
				t.Errorf("Test %d: Expected kubernetes controller to be initialized with label selector '%s'. Instead found selector '%s' for input '%s'", i, test.expectedLabelSelector, foundLabelSelectorString, test.input)
			}
		}
		//    Pods
		foundPodMode := k8sController.podMode
		if foundPodMode != test.expectedPodMode {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with pod mode '%s'. Instead found pod mode '%s' for input '%s'", i, test.expectedPodMode, foundPodMode, test.input)
		}

		// fallthrough
		if !k8sController.Fall.Equal(test.expectedFallthrough) {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with fallthrough '%v'. Instead found fallthrough '%v' for input '%s'", i, test.expectedFallthrough, k8sController.Fall, test.input)
		}

		// startupTimeout
		if k8sController.startupTimeout.String() != test.expectedStartupTimeout.String() {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with startupTimeout '%v'. Instead found startupTimeout '%v' for input '%s'", i, test.expectedStartupTimeout, k8sController.startupTimeout, test.input)
		}
	}
}

func TestKubernetesParseEndpointPodNames(t *testing.T) {
	tests := []struct {
		input                string // Corefile data as string
		shouldErr            bool   // true if test case is expected to produce an error.
		expectedErrContent   string // substring from the expected error. Empty for positive cases.
		expectedEndpointMode bool
	}{
		// valid endpoints mode
		{
			`kubernetes coredns.local {
	endpoint_pod_names
}`,
			false,
			"",
			true,
		},
		// endpoints invalid
		{
			`kubernetes coredns.local {
	endpoint_pod_names giant_seed
}`,
			true,
			"rong argument count or unexpected",
			false,
		},
		// endpoint not set
		{
			`kubernetes coredns.local {
}`,
			false,
			"",
			false,
		},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8sController, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error, but did not find error for input '%s'. Error was: '%v'", i, test.input, err)
		}

		if err != nil {
			if !test.shouldErr {
				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
				continue
			}

			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
			}
			continue
		}

		// Endpoints
		foundEndpointNameMode := k8sController.endpointNameMode
		if foundEndpointNameMode != test.expectedEndpointMode {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with endpoints mode '%v'. Instead found endpoints mode '%v' for input '%s'", i, test.expectedEndpointMode, foundEndpointNameMode, test.input)
		}
	}
}

func TestKubernetesParseNoEndpoints(t *testing.T) {
	tests := []struct {
		input                 string // Corefile data as string
		shouldErr             bool   // true if test case is expected to produce an error.
		expectedErrContent    string // substring from the expected error. Empty for positive cases.
		expectedEndpointsInit bool
	}{
		// valid
		{
			`kubernetes coredns.local {
	noendpoints
}`,
			false,
			"",
			false,
		},
		// invalid
		{
			`kubernetes coredns.local {
	noendpoints ixnay on the endpointsay
}`,
			true,
			"rong argument count or unexpected",
			true,
		},
		// not set
		{
			`kubernetes coredns.local {
}`,
			false,
			"",
			true,
		},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8sController, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error, but did not find error for input '%s'. Error was: '%v'", i, test.input, err)
		}

		if err != nil {
			if !test.shouldErr {
				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
				continue
			}

			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
			}
			continue
		}

		foundEndpointsInit := k8sController.opts.initEndpointsCache
		if foundEndpointsInit != test.expectedEndpointsInit {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with endpoints watch '%v'. Instead found endpoints watch '%v' for input '%s'", i, test.expectedEndpointsInit, foundEndpointsInit, test.input)
		}
	}
}

func TestKubernetesParseIgnoreEmptyService(t *testing.T) {
	tests := []struct {
		input                 string // Corefile data as string
		shouldErr             bool   // true if test case is expected to produce an error.
		expectedErrContent    string // substring from the expected error. Empty for positive cases.
		expectedEndpointsInit bool
	}{
		// valid
		{
			`kubernetes coredns.local {
	ignore empty_service
}`,
			false,
			"",
			true,
		},
		// invalid
		{
			`kubernetes coredns.local {
	ignore ixnay on the endpointsay
}`,
			true,
			"unable to parse ignore value",
			false,
		},
		{
			`kubernetes coredns.local {
	ignore empty_service ixnay on the endpointsay
}`,
			false,
			"",
			true,
		},
		// not set
		{
			`kubernetes coredns.local {
}`,
			false,
			"",
			false,
		},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8sController, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error, but did not find error for input '%s'. Error was: '%v'", i, test.input, err)
		}

		if err != nil {
			if !test.shouldErr {
				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
				continue
			}

			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
			}
			continue
		}

		foundIgnoreEmptyService := k8sController.opts.ignoreEmptyService
		if foundIgnoreEmptyService != test.expectedEndpointsInit {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with ignore empty_service '%v'. Instead found ignore empty_service watch '%v' for input '%s'", i, test.expectedEndpointsInit, foundIgnoreEmptyService, test.input)
		}
	}
}

func TestKubernetesParseMulticluster(t *testing.T) {
	tests := []struct {
		input                     string // Corefile data as string
		shouldErr                 bool   // true if test case is expected to produce an error.
		expectedErrContent        string // substring from the expected error. Empty for positive cases.
		expectedMulticlusterZones []string
	}{
		// valid
		{
			`kubernetes coredns.local clusterset.local {
	multicluster clusterset.local
}`,
			false,
			"",
			[]string{"clusterset.local."},
		},
		// invalid
		{
			`kubernetes coredns.local {
	multicluster clusterset.local
}`,
			true,
			"Error during parsing: is not authoritative for the multicluster zone clusterset.local.",
			[]string{"clusterset.local."},
		},
		{
			`kubernetes coredns.local clusterset.local {
	multicluster clusterset.local test.local
}`,
			true,
			"Error during parsing: is not authoritative for the multicluster zone test.local.",
			[]string{"clusterset.local.", "test.local."},
		},
		// not set
		{
			`kubernetes coredns.local {
	multicluster
}`,
			false,
			"",
			[]string{},
		},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8sController, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error, but did not find error for input '%s'. Error was: '%v'", i, test.input, err)
		}

		if err != nil {
			if !test.shouldErr {
				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
				continue
			}

			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
			}
			continue
		}

		foundMulticlusterZones := k8sController.opts.multiclusterZones
		if !slices.Equal(foundMulticlusterZones, test.expectedMulticlusterZones) {
			t.Errorf("Test %d: Expected kubernetes controller to be initialized with multicluster '%v'. Instead found multicluster '%v' for input '%s'", i, test.expectedMulticlusterZones, foundMulticlusterZones, test.input)
		}
	}
}

func TestKubernetesParseAPIRateLimiting(t *testing.T) {
	tests := []struct {
		input              string
		shouldErr          bool
		expectedErrContent string
		expectedQPS        float32
		expectedBurst      int
		expectedMaxInf     int
	}{
		{
			`kubernetes coredns.local {
	apiserver_qps 50.0
	apiserver_burst 100
	apiserver_max_inflight 25
}`,
			false, "", 50.0, 100, 25,
		},
		{
			`kubernetes coredns.local {
	apiserver_qps -10
}`, true, "apiserver_qps must be >= 0", 0, 0, 0},
		{
			`kubernetes coredns.local {
	apiserver_burst -5
}`, true, "apiserver_burst must be >= 0", 0, 0, 0},
		{
			`kubernetes coredns.local {
	apiserver_max_inflight -1
}`, true, "apiserver_max_inflight must be >= 0", 0, 0, 0},
	}

	for i, test := range tests {
		c := caddy.NewTestController("dns", test.input)
		k8s, err := kubernetesParse(c)

		if test.shouldErr && err == nil {
			t.Errorf("Test %d: Expected error but got none for input '%s'", i, test.input)
			continue
		}
		if !test.shouldErr && err != nil {
			t.Errorf("Test %d: Expected no error but got: %v", i, err)
			continue
		}
		if err != nil {
			if !strings.Contains(err.Error(), test.expectedErrContent) {
				t.Errorf("Test %d: Expected error to contain '%s', got: %v", i, test.expectedErrContent, err)
			}
			continue
		}

		if k8s.apiQPS != test.expectedQPS {
			t.Errorf("Test %d: Expected apiQPS=%v, got %v", i, test.expectedQPS, k8s.apiQPS)
		}
		if k8s.apiBurst != test.expectedBurst {
			t.Errorf("Test %d: Expected apiBurst=%v, got %v", i, test.expectedBurst, k8s.apiBurst)
		}
		if k8s.apiMaxInflight != test.expectedMaxInf {
			t.Errorf("Test %d: Expected apiMaxInflight=%v, got %v", i, test.expectedMaxInf, k8s.apiMaxInflight)
		}
	}
}

func TestBoundIPs(t *testing.T) {
	tests := []struct {
		name        string
		listenHosts []string
		expectIP    net.IP
	}{
		{"nil ListenHosts", nil, nil},
		{"empty slice ListenHosts", []string{}, nil},
		{"single empty string", []string{""}, nil},
		{"valid CIDR address", []string{"192.168.1.1/24"}, net.ParseIP("192.168.1.1")},
		{"loopback filtered", []string{"127.0.0.1/8"}, nil},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			c := caddy.NewTestController("dns", "kubernetes cluster.local")
			cfg := dnsserver.GetConfig(c)
			cfg.ListenHosts = tc.listenHosts

			ips := boundIPs(c)

			if tc.expectIP == nil {
				return
			}
			for _, ip := range ips {
				if ip.Equal(tc.expectIP) {
					return
				}
			}
			t.Errorf("expected %v in result, got %v", tc.expectIP, ips)
		})
	}
}
