// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

package integration

import (
	"context"
	"crypto/x509"
	"encoding/pem"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	jwtpkg "gopkg.in/square/go-jose.v2/jwt"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	auth1alpha1 "go.pinniped.dev/generated/1.20/apis/concierge/authentication/v1alpha1"
	loginv1alpha1 "go.pinniped.dev/generated/1.20/apis/concierge/login/v1alpha1"
	"go.pinniped.dev/test/library"
)

func TestUnsuccessfulCredentialRequest(t *testing.T) {
	library.SkipUnlessIntegration(t)

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	response, err := makeRequest(ctx, t, validCredentialRequestSpecWithRealToken(t, corev1.TypedLocalObjectReference{
		APIGroup: &auth1alpha1.SchemeGroupVersion.Group,
		Kind:     "WebhookAuthenticator",
		Name:     "some-webhook-that-does-not-exist",
	}))
	require.NoError(t, err)
	require.Nil(t, response.Status.Credential)
	require.NotNil(t, response.Status.Message)
	require.Equal(t, "authentication failed", *response.Status.Message)
}

func TestSuccessfulCredentialRequest(t *testing.T) {
	env := library.IntegrationEnv(t).WithCapability(library.ClusterSigningKeyIsAvailable)

	ctx, cancel := context.WithTimeout(context.Background(), 6*time.Minute)
	defer cancel()

	tests := []struct {
		name          string
		authenticator func(context.Context, *testing.T) corev1.TypedLocalObjectReference
		token         func(t *testing.T) (token string, username string, groups []string)
	}{
		{
			name:          "webhook",
			authenticator: library.CreateTestWebhookAuthenticator,
			token: func(t *testing.T) (string, string, []string) {
				return library.IntegrationEnv(t).TestUser.Token, env.TestUser.ExpectedUsername, env.TestUser.ExpectedGroups
			},
		},
		{
			name:          "jwt authenticator",
			authenticator: library.CreateTestJWTAuthenticatorForCLIUpstream,
			token: func(t *testing.T) (string, string, []string) {
				pinnipedExe := library.PinnipedCLIPath(t)
				credOutput, _ := runPinnipedLoginOIDC(ctx, t, pinnipedExe)
				token := credOutput.Status.Token

				// By default, the JWTAuthenticator expects the username to be in the "username" claim and the
				// groups to be in the "groups" claim.
				// However, we are configuring Pinniped in the `CreateTestJWTAuthenticatorForCLIUpstream` method above
				// to read the username from the "sub" claim of the token instead.
				username, groups := getJWTSubAndGroupsClaims(t, token)

				return token, username, groups
			},
		},
	}
	for _, test := range tests {
		test := test
		t.Run(test.name, func(t *testing.T) {
			authenticator := test.authenticator(ctx, t)
			token, username, groups := test.token(t)

			var response *loginv1alpha1.TokenCredentialRequest
			successfulResponse := func() bool {
				var err error
				response, err = makeRequest(ctx, t, loginv1alpha1.TokenCredentialRequestSpec{
					Token:         token,
					Authenticator: authenticator,
				})
				require.NoError(t, err, "the request should never fail at the HTTP level")
				return response.Status.Credential != nil
			}
			assert.Eventually(t, successfulResponse, 10*time.Second, 500*time.Millisecond)
			require.NotNil(t, response)
			require.Emptyf(t, response.Status.Message, "value is: %q", safeDerefStringPtr(response.Status.Message))
			require.NotNil(t, response.Status.Credential)
			require.Empty(t, response.Spec)
			require.Empty(t, response.Status.Credential.Token)
			require.NotEmpty(t, response.Status.Credential.ClientCertificateData)
			require.Equal(t, username, getCommonName(t, response.Status.Credential.ClientCertificateData))
			require.ElementsMatch(t, groups, getOrganizations(t, response.Status.Credential.ClientCertificateData))
			require.NotEmpty(t, response.Status.Credential.ClientKeyData)
			require.NotNil(t, response.Status.Credential.ExpirationTimestamp)
			require.InDelta(t, 5*time.Minute, time.Until(response.Status.Credential.ExpirationTimestamp.Time), float64(time.Minute))

			// Create a client using the admin kubeconfig.
			adminClient := library.NewClientset(t)

			// Create a client using the certificate from the CredentialRequest.
			clientWithCertFromCredentialRequest := library.NewClientsetWithCertAndKey(
				t,
				response.Status.Credential.ClientCertificateData,
				response.Status.Credential.ClientKeyData,
			)

			t.Run(
				"access as user",
				library.AccessAsUserTest(ctx, adminClient, username, clientWithCertFromCredentialRequest),
			)
			for _, group := range groups {
				group := group
				t.Run(
					"access as group "+group,
					library.AccessAsGroupTest(ctx, adminClient, group, clientWithCertFromCredentialRequest),
				)
			}
		})
	}
}

func TestFailedCredentialRequestWhenTheRequestIsValidButTheTokenDoesNotAuthenticateTheUser(t *testing.T) {
	library.IntegrationEnv(t).WithCapability(library.ClusterSigningKeyIsAvailable)

	response, err := makeRequest(context.Background(), t, loginv1alpha1.TokenCredentialRequestSpec{Token: "not a good token"})

	require.NoError(t, err)

	require.Empty(t, response.Spec)
	require.Nil(t, response.Status.Credential)
	require.Equal(t, stringPtr("authentication failed"), response.Status.Message)
}

func TestCredentialRequest_ShouldFailWhenRequestDoesNotIncludeToken(t *testing.T) {
	library.IntegrationEnv(t).WithCapability(library.ClusterSigningKeyIsAvailable)

	response, err := makeRequest(context.Background(), t, loginv1alpha1.TokenCredentialRequestSpec{Token: ""})

	require.Error(t, err)
	statusError, isStatus := err.(*errors.StatusError)
	require.True(t, isStatus)

	require.Equal(t, 1, len(statusError.ErrStatus.Details.Causes))
	cause := statusError.ErrStatus.Details.Causes[0]
	require.Equal(t, metav1.CauseType("FieldValueRequired"), cause.Type)
	require.Equal(t, "Required value: token must be supplied", cause.Message)
	require.Equal(t, "spec.token.value", cause.Field)

	require.Empty(t, response.Spec)
	require.Nil(t, response.Status.Credential)
}

func TestCredentialRequest_OtherwiseValidRequestWithRealTokenShouldFailWhenTheClusterIsNotCapable(t *testing.T) {
	library.IntegrationEnv(t).WithoutCapability(library.ClusterSigningKeyIsAvailable)

	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()

	testWebhook := library.CreateTestWebhookAuthenticator(ctx, t)

	response, err := makeRequest(ctx, t, validCredentialRequestSpecWithRealToken(t, testWebhook))

	require.NoError(t, err)

	require.Empty(t, response.Spec)
	require.Nil(t, response.Status.Credential)
	require.Equal(t, stringPtr("authentication failed"), response.Status.Message)
}

func makeRequest(ctx context.Context, t *testing.T, spec loginv1alpha1.TokenCredentialRequestSpec) (*loginv1alpha1.TokenCredentialRequest, error) {
	t.Helper()
	env := library.IntegrationEnv(t)

	client := library.NewAnonymousConciergeClientset(t)

	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()

	return client.LoginV1alpha1().TokenCredentialRequests(env.ConciergeNamespace).Create(ctx, &loginv1alpha1.TokenCredentialRequest{
		TypeMeta:   metav1.TypeMeta{},
		ObjectMeta: metav1.ObjectMeta{Namespace: env.ConciergeNamespace},
		Spec:       spec,
	}, metav1.CreateOptions{})
}

func validCredentialRequestSpecWithRealToken(t *testing.T, authenticator corev1.TypedLocalObjectReference) loginv1alpha1.TokenCredentialRequestSpec {
	return loginv1alpha1.TokenCredentialRequestSpec{
		Token:         library.IntegrationEnv(t).TestUser.Token,
		Authenticator: authenticator,
	}
}

func stringPtr(s string) *string {
	return &s
}

func getCommonName(t *testing.T, certPEM string) string {
	t.Helper()

	pemBlock, _ := pem.Decode([]byte(certPEM))
	cert, err := x509.ParseCertificate(pemBlock.Bytes)
	require.NoError(t, err)

	return cert.Subject.CommonName
}

func getOrganizations(t *testing.T, certPEM string) []string {
	t.Helper()

	pemBlock, _ := pem.Decode([]byte(certPEM))
	cert, err := x509.ParseCertificate(pemBlock.Bytes)
	require.NoError(t, err)

	return cert.Subject.Organization
}

func safeDerefStringPtr(s *string) string {
	if s == nil {
		return "<nil>"
	}
	return *s
}

func getJWTSubAndGroupsClaims(t *testing.T, jwt string) (string, []string) {
	t.Helper()

	token, err := jwtpkg.ParseSigned(jwt)
	require.NoError(t, err)

	var claims struct {
		Sub    string   `json:"sub"`
		Groups []string `json:"groups"`
	}
	err = token.UnsafeClaimsWithoutVerification(&claims)
	require.NoError(t, err)

	return claims.Sub, claims.Groups
}