/*
Copyright © The ESO Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

// Package keyvault implements a provider for Azure Key Vault secrets, allowing
// External Secrets to read from and write to Azure Key Vault.
package keyvault

import (
	"context"
	"crypto/x509"
	b64 "encoding/base64"
	"encoding/json"
	"encoding/pem"
	"errors"
	"fmt"
	"maps"
	"os"
	"path"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	"github.com/Azure/azure-sdk-for-go/sdk/azcore"
	"github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/azcertificates"
	"github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/azkeys"
	"github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/azsecrets"
	"github.com/Azure/azure-sdk-for-go/services/keyvault/v7.0/keyvault"
	"github.com/Azure/go-autorest/autorest"
	"github.com/Azure/go-autorest/autorest/adal"
	"github.com/Azure/go-autorest/autorest/azure"
	kvauth "github.com/Azure/go-autorest/autorest/azure/auth"
	"github.com/Azure/go-autorest/autorest/date"
	"github.com/AzureAD/microsoft-authentication-library-for-go/apps/confidential"
	"github.com/aws/smithy-go/ptr"
	"github.com/lestrrat-go/jwx/v2/jwk"
	"github.com/tidwall/gjson"
	"golang.org/x/crypto/sha3"
	authv1 "k8s.io/api/authentication/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes"
	kcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"
	ctrlcfg "sigs.k8s.io/controller-runtime/pkg/client/config"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
	gopkcs12 "software.sslmate.com/src/go-pkcs12"

	esv1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1"
	"github.com/external-secrets/external-secrets/runtime/constants"
	"github.com/external-secrets/external-secrets/runtime/esutils"
	"github.com/external-secrets/external-secrets/runtime/esutils/metadata"
	"github.com/external-secrets/external-secrets/runtime/esutils/resolvers"
	"github.com/external-secrets/external-secrets/runtime/metrics"
)

const (
	defaultObjType = "secret"
	objectTypeCert = "cert"
	objectTypeKey  = "key"

	attributeExpires   = "attribute.expires"
	attributeCreated   = "attribute.created"
	attributeUpdated   = "attribute.updated"
	attributeNotBefore = "attribute.notBefore"

	// AzureDefaultAudience is the default audience used for Azure AD token exchange.
	AzureDefaultAudience = "api://AzureADTokenExchange"

	// AnnotationClientID is the annotation key for Azure Workload Identity client ID.
	AnnotationClientID = "azure.workload.identity/client-id"

	// AnnotationTenantID is the annotation key for Azure Workload Identity tenant ID.
	AnnotationTenantID = "azure.workload.identity/tenant-id"

	managerLabel = "external-secrets"
	managedBy    = "managed-by"

	errUnexpectedStoreSpec      = "unexpected store spec"
	errMissingAuthType          = "cannot initialize Azure Client: no valid authType was specified"
	errPropNotExist             = "property %s does not exist in key %s"
	errTagNotExist              = "tag %s does not exist"
	errUnknownObjectType        = "unknown Azure Keyvault object Type for %s"
	errUnmarshalJSONData        = "error unmarshalling json data: %w"
	errDataFromCert             = "cannot get use dataFrom to get certificate secret"
	errDataFromKey              = "cannot get use dataFrom to get key secret"
	errMissingTenant            = "missing tenantID in store config"
	errMissingClient            = "missing clientID: either serviceAccountRef or service account annotation '%s' is missing"
	errMissingSecretRef         = "missing secretRef in provider config"
	errMissingClientIDSecret    = "missing accessKeyID/secretAccessKey in store config"
	errInvalidClientCredentials = "both clientSecret and clientCredentials set"
	errMultipleClientID         = "multiple clientID found. Check secretRef and serviceAccountRef"
	errMultipleTenantID         = "multiple tenantID found. Check secretRef, 'spec.provider.azurekv.tenantId', and serviceAccountRef"

	errInvalidStore              = "invalid store"
	errInvalidStoreSpec          = "invalid store spec"
	errInvalidStoreProv          = "invalid store provider"
	errInvalidAzureProv          = "invalid azure keyvault provider"
	errInvalidSecRefClientID     = "invalid AuthSecretRef.ClientID: %w"
	errInvalidSecRefClientSecret = "invalid AuthSecretRef.ClientSecret: %w"
	errInvalidSARef              = "invalid ServiceAccountRef: %w"

	errMissingWorkloadEnvVars = "missing environment variables. AZURE_CLIENT_ID, AZURE_TENANT_ID and AZURE_FEDERATED_TOKEN_FILE must be set"
	errReadTokenFile          = "unable to read token file %s: %w"
)

// https://github.com/external-secrets/external-secrets/issues/644
var _ esv1.SecretsClient = &Azure{}
var _ esv1.Provider = &Azure{}

// SecretClient is an interface to keyvault.BaseClient.
type SecretClient interface {
	GetKey(ctx context.Context, vaultBaseURL string, keyName string, keyVersion string) (result keyvault.KeyBundle, err error)
	GetSecret(ctx context.Context, vaultBaseURL string, secretName string, secretVersion string) (result keyvault.SecretBundle, err error)
	GetSecretsComplete(ctx context.Context, vaultBaseURL string, maxresults *int32) (result keyvault.SecretListResultIterator, err error)
	GetCertificate(ctx context.Context, vaultBaseURL string, certificateName string, certificateVersion string) (result keyvault.CertificateBundle, err error)
	SetSecret(ctx context.Context, vaultBaseURL string, secretName string, parameters keyvault.SecretSetParameters) (result keyvault.SecretBundle, err error)
	ImportKey(ctx context.Context, vaultBaseURL string, keyName string, parameters keyvault.KeyImportParameters) (result keyvault.KeyBundle, err error)
	ImportCertificate(ctx context.Context, vaultBaseURL string, certificateName string, parameters keyvault.CertificateImportParameters) (result keyvault.CertificateBundle, err error)
	DeleteCertificate(ctx context.Context, vaultBaseURL string, certificateName string) (result keyvault.DeletedCertificateBundle, err error)
	DeleteKey(ctx context.Context, vaultBaseURL string, keyName string) (result keyvault.DeletedKeyBundle, err error)
	DeleteSecret(ctx context.Context, vaultBaseURL string, secretName string) (result keyvault.DeletedSecretBundle, err error)
}

// Azure implements the External Secrets provider for Azure Key Vault.
type Azure struct {
	crClient   client.Client
	kubeClient kcorev1.CoreV1Interface
	store      esv1.GenericStore
	provider   *esv1.AzureKVProvider
	namespace  string

	// Legacy go-autorest client
	baseClient SecretClient

	// New Azure SDK clients (used when UseAzureSDK is true)
	secretsClient *azsecrets.Client
	keysClient    *azkeys.Client
	certsClient   *azcertificates.Client
}

// PushSecretMetadataSpec defines metadata for pushing secrets to Azure Key Vault,
// including expiration date and tags.
type PushSecretMetadataSpec struct {
	ExpirationDate string            `json:"expirationDate,omitempty"`
	Tags           map[string]string `json:"tags,omitempty"`
}

// Capabilities return the provider supported capabilities (ReadOnly, WriteOnly, ReadWrite).
func (a *Azure) Capabilities() esv1.SecretStoreCapabilities {
	return esv1.SecretStoreReadWrite
}

// NewClient constructs a new secrets client based on the provided store.
func (a *Azure) NewClient(ctx context.Context, store esv1.GenericStore, kube client.Client, namespace string) (esv1.SecretsClient, error) {
	return newClient(ctx, store, kube, namespace)
}

func newClient(ctx context.Context, store esv1.GenericStore, kube client.Client, namespace string) (esv1.SecretsClient, error) {
	provider, err := getProvider(store)
	if err != nil {
		return nil, err
	}
	cfg, err := ctrlcfg.GetConfig()
	if err != nil {
		return nil, err
	}
	kubeClient, err := kubernetes.NewForConfig(cfg)
	if err != nil {
		return nil, err
	}
	az := &Azure{
		crClient:   kube,
		kubeClient: kubeClient.CoreV1(),
		store:      store,
		namespace:  namespace,
		provider:   provider,
	}

	// allow SecretStore controller validation to pass
	// when using referent namespace.
	if store.GetKind() == esv1.ClusterSecretStoreKind &&
		namespace == "" &&
		isReferentSpec(provider) {
		return az, nil
	}

	// Check if the new Azure SDK should be used
	if provider.UseAzureSDK != nil && *provider.UseAzureSDK {
		err = initializeNewAzureSDK(ctx, az)
	} else {
		err = initializeLegacyClient(ctx, az)
	}

	return az, err
}

// initializeLegacyClient sets up the Azure Key Vault client using the legacy go-autorest SDK.
func initializeLegacyClient(ctx context.Context, az *Azure) error {
	var authorizer autorest.Authorizer
	var err error

	switch *az.provider.AuthType {
	case esv1.AzureManagedIdentity:
		authorizer, err = az.authorizerForManagedIdentity()
	case esv1.AzureServicePrincipal:
		authorizer, err = az.authorizerForServicePrincipal(ctx)
	case esv1.AzureWorkloadIdentity:
		authorizer, err = az.authorizerForWorkloadIdentity(ctx, NewTokenProvider)
	default:
		return errors.New(errMissingAuthType)
	}

	if err != nil {
		return err
	}

	cl := keyvault.New()
	cl.Authorizer = authorizer
	az.baseClient = &cl

	return nil
}

// initializeNewAzureSDK sets up the Azure Key Vault client using the new azcore-based SDK.
func initializeNewAzureSDK(ctx context.Context, az *Azure) error {
	// Get cloud configuration
	cloudConfig, err := getCloudConfiguration(az.provider)
	if err != nil {
		return fmt.Errorf("failed to get cloud configuration: %w", err)
	}

	// Build credential based on auth type
	var credential azcore.TokenCredential

	switch *az.provider.AuthType {
	case esv1.AzureManagedIdentity:
		credential, err = buildManagedIdentityCredential(az, cloudConfig)
	case esv1.AzureServicePrincipal:
		credential, err = buildServicePrincipalCredential(ctx, az, cloudConfig)
	case esv1.AzureWorkloadIdentity:
		credential, err = buildWorkloadIdentityCredential(ctx, az, cloudConfig)
	default:
		return errors.New(errMissingAuthType)
	}

	if err != nil {
		return err
	}

	// Create Azure SDK clients and store them directly
	az.secretsClient, err = azsecrets.NewClient(*az.provider.VaultURL, credential, &azsecrets.ClientOptions{
		ClientOptions: azcore.ClientOptions{Cloud: cloudConfig},
	})
	if err != nil {
		return fmt.Errorf("failed to create secrets client: %w", err)
	}

	az.keysClient, err = azkeys.NewClient(*az.provider.VaultURL, credential, &azkeys.ClientOptions{
		ClientOptions: azcore.ClientOptions{Cloud: cloudConfig},
	})
	if err != nil {
		return fmt.Errorf("failed to create keys client: %w", err)
	}

	az.certsClient, err = azcertificates.NewClient(*az.provider.VaultURL, credential, &azcertificates.ClientOptions{
		ClientOptions: azcore.ClientOptions{Cloud: cloudConfig},
	})
	if err != nil {
		return fmt.Errorf("failed to create certificates client: %w", err)
	}

	return nil
}

// useNewSDK returns true if the new Azure SDK should be used.
func (a *Azure) useNewSDK() bool {
	return a.provider.UseAzureSDK != nil && *a.provider.UseAzureSDK
}

func getProvider(store esv1.GenericStore) (*esv1.AzureKVProvider, error) {
	spc := store.GetSpec()
	if spc == nil || spc.Provider.AzureKV == nil {
		return nil, errors.New(errUnexpectedStoreSpec)
	}

	return spc.Provider.AzureKV, nil
}

// ValidateStore validates the Azure Key Vault provider configuration.
func (a *Azure) ValidateStore(store esv1.GenericStore) (admission.Warnings, error) {
	if store == nil {
		return nil, errors.New(errInvalidStore)
	}
	spc := store.GetSpec()
	if spc == nil {
		return nil, errors.New(errInvalidStoreSpec)
	}
	if spc.Provider == nil {
		return nil, errors.New(errInvalidStoreProv)
	}
	p := spc.Provider.AzureKV
	if p == nil {
		return nil, errors.New(errInvalidAzureProv)
	}
	if p.AuthSecretRef != nil {
		if p.AuthSecretRef.ClientID != nil {
			if err := esutils.ValidateReferentSecretSelector(store, *p.AuthSecretRef.ClientID); err != nil {
				return nil, fmt.Errorf(errInvalidSecRefClientID, err)
			}
		}
		if p.AuthSecretRef.ClientSecret != nil {
			if err := esutils.ValidateReferentSecretSelector(store, *p.AuthSecretRef.ClientSecret); err != nil {
				return nil, fmt.Errorf(errInvalidSecRefClientSecret, err)
			}
		}
	}
	if p.ServiceAccountRef != nil {
		if err := esutils.ValidateReferentServiceAccountSelector(store, *p.ServiceAccountRef); err != nil {
			return nil, fmt.Errorf(errInvalidSARef, err)
		}
	}

	if p.CustomCloudConfig != nil {
		if !ptr.ToBool(p.UseAzureSDK) {
			return nil, errors.New("CustomCloudConfig requires UseAzureSDK to be set to true - the legacy SDK does not support custom clouds")
		}
		if p.CustomCloudConfig.ActiveDirectoryEndpoint == "" {
			return nil, errors.New("activeDirectoryEndpoint is required in CustomCloudConfig")
		}
	}

	if p.EnvironmentType == esv1.AzureEnvironmentAzureStackCloud && p.CustomCloudConfig == nil {
		return nil, errors.New("CustomCloudConfig is required when EnvironmentType is AzureStackCloud")
	}

	return nil, nil
}

func canDelete(tags map[string]*string, err error) (bool, error) {
	aerr := &autorest.DetailedError{}
	conv := errors.As(err, aerr)
	if err != nil && !conv {
		return false, fmt.Errorf("could not parse error: %w", err)
	}
	if conv && aerr.StatusCode != 404 { // Secret is already deleted, nothing to do.
		return false, fmt.Errorf("unexpected api error: %w", err)
	}
	if aerr.StatusCode == 404 {
		return false, nil
	}
	manager, ok := tags[managedBy]
	if !ok || manager == nil || *manager != managerLabel {
		return false, errors.New("not managed by external-secrets")
	}
	return true, nil
}

func (a *Azure) deleteKeyVaultKey(ctx context.Context, keyName string) error {
	value, err := a.baseClient.GetKey(ctx, *a.provider.VaultURL, keyName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetKey, err)
	ok, err := canDelete(value.Tags, err)
	if err != nil {
		return fmt.Errorf("error getting key %v: %w", keyName, err)
	}
	if ok {
		_, err = a.baseClient.DeleteKey(ctx, *a.provider.VaultURL, keyName)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVDeleteKey, err)
		if err != nil {
			return fmt.Errorf("error deleting key %v: %w", keyName, err)
		}
	}
	return nil
}

func (a *Azure) deleteKeyVaultSecret(ctx context.Context, secretName string) error {
	value, err := a.baseClient.GetSecret(ctx, *a.provider.VaultURL, secretName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
	ok, err := canDelete(value.Tags, err)
	if err != nil {
		return fmt.Errorf("error getting secret %v: %w", secretName, err)
	}
	if ok {
		_, err = a.baseClient.DeleteSecret(ctx, *a.provider.VaultURL, secretName)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVDeleteSecret, err)
		if err != nil {
			return fmt.Errorf("error deleting secret %v: %w", secretName, err)
		}
	}
	return nil
}

func (a *Azure) deleteKeyVaultCertificate(ctx context.Context, certName string) error {
	value, err := a.baseClient.GetCertificate(ctx, *a.provider.VaultURL, certName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetCertificate, err)
	ok, err := canDelete(value.Tags, err)
	if err != nil {
		return fmt.Errorf("error getting certificate %v: %w", certName, err)
	}
	if ok {
		_, err = a.baseClient.DeleteCertificate(ctx, *a.provider.VaultURL, certName)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVDeleteCertificate, err)
		if err != nil {
			return fmt.Errorf("error deleting certificate %v: %w", certName, err)
		}
	}
	return nil
}

// DeleteSecret deletes a secret from Azure Key Vault.
func (a *Azure) DeleteSecret(ctx context.Context, remoteRef esv1.PushSecretRemoteRef) error {
	objectType, secretName := getObjType(esv1.ExternalSecretDataRemoteRef{Key: remoteRef.GetRemoteKey()})
	switch objectType {
	case defaultObjType:
		if a.useNewSDK() {
			return a.deleteKeyVaultSecretWithNewSDK(ctx, secretName)
		}
		return a.deleteKeyVaultSecret(ctx, secretName)
	case objectTypeCert:
		if a.useNewSDK() {
			return a.deleteKeyVaultCertificateWithNewSDK(ctx, secretName)
		}
		return a.deleteKeyVaultCertificate(ctx, secretName)
	case objectTypeKey:
		if a.useNewSDK() {
			return a.deleteKeyVaultKeyWithNewSDK(ctx, secretName)
		}
		return a.deleteKeyVaultKey(ctx, secretName)
	default:
		return fmt.Errorf("secret type '%v' is not supported", objectType)
	}
}

// SecretExists checks if a secret exists in Azure Key Vault.
func (a *Azure) SecretExists(ctx context.Context, remoteRef esv1.PushSecretRemoteRef) (bool, error) {
	if a.useNewSDK() {
		return a.secretExistsWithNewSDK(ctx, remoteRef)
	}

	objectType, secretName := getObjType(esv1.ExternalSecretDataRemoteRef{Key: remoteRef.GetRemoteKey()})

	var err error
	switch objectType {
	case defaultObjType:
		_, err = a.baseClient.GetSecret(ctx, *a.provider.VaultURL, secretName, "")
	case objectTypeCert:
		_, err = a.baseClient.GetCertificate(ctx, *a.provider.VaultURL, secretName, "")
	case objectTypeKey:
		_, err = a.baseClient.GetKey(ctx, *a.provider.VaultURL, secretName, "")
	default:
		errMsg := fmt.Sprintf("secret type '%v' is not supported", objectType)
		return false, errors.New(errMsg)
	}

	err = parseError(err)
	if err != nil {
		if _, ok := errors.AsType[esv1.NoSecretError](err); ok {
			return false, nil
		}
		return false, err
	}

	return true, nil
}

func getCertificateFromValue(value []byte) (*x509.Certificate, error) {
	// 1st: try decode pkcs12
	_, localCert, err := gopkcs12.Decode(value, "")
	if err == nil {
		return localCert, nil
	}

	// 2nd: try decode pkcs12 with chain
	_, localCert, _, err = gopkcs12.DecodeChain(value, "")
	if err == nil {
		return localCert, nil
	}

	// 3rd: try DER
	localCert, err = x509.ParseCertificate(value)
	if err == nil {
		return localCert, nil
	}

	// 4th: parse PEM blocks
	for {
		block, rest := pem.Decode(value)
		value = rest
		if block == nil {
			break
		}
		cert, err := x509.ParseCertificate(block.Bytes)
		if err == nil {
			return cert, nil
		}
	}
	return nil, errors.New("could not parse certificate value as PKCS#12, DER or PEM")
}

func getKeyFromValue(value []byte) (any, error) {
	val := value
	pemBlock, _ := pem.Decode(value)
	// if a private key regular expression doesn't match, we should consider this key to be symmetric
	if pemBlock == nil {
		return val, nil
	}
	val = pemBlock.Bytes
	switch pemBlock.Type {
	case "PRIVATE KEY":
		return x509.ParsePKCS8PrivateKey(val)
	case "RSA PRIVATE KEY":
		return x509.ParsePKCS1PrivateKey(val)
	case "EC PRIVATE KEY":
		return x509.ParseECPrivateKey(val)
	default:
		return nil, fmt.Errorf("key type %v is not supported", pemBlock.Type)
	}
}

func canCreate(tags map[string]*string, err error) (bool, error) {
	aerr := &autorest.DetailedError{}
	conv := errors.As(err, aerr)
	if err != nil && !conv {
		return false, fmt.Errorf("could not parse error: %w", err)
	}
	if conv && aerr.StatusCode != 404 {
		return false, fmt.Errorf("unexpected api error: %w", err)
	}
	if err == nil {
		manager, ok := tags[managedBy]
		if !ok || manager == nil || *manager != managerLabel {
			return false, errors.New("not managed by external-secrets")
		}
	}
	return true, nil
}

func (a *Azure) setKeyVaultSecret(ctx context.Context, secretName string, value []byte, expires *date.UnixTime, tags map[string]string) error {
	secret, err := a.baseClient.GetSecret(ctx, *a.provider.VaultURL, secretName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
	ok, err := canCreate(secret.Tags, err)
	if err != nil {
		return fmt.Errorf("cannot get secret %v: %w", secretName, err)
	}
	if !ok {
		return nil
	}
	val := string(value)
	if secret.Value != nil && val == *secret.Value {
		if secret.Attributes != nil {
			if (secret.Attributes.Expires == nil && expires == nil) ||
				(secret.Attributes.Expires != nil && expires != nil && *secret.Attributes.Expires == *expires) {
				return nil
			}
		}
	}

	secretParams := keyvault.SecretSetParameters{
		Value: &val,
		Tags: map[string]*string{
			managedBy: new(managerLabel),
		},
		SecretAttributes: &keyvault.SecretAttributes{
			Enabled: new(true),
		},
	}

	for k, v := range tags {
		secretParams.Tags[k] = &v
	}

	if expires != nil {
		secretParams.SecretAttributes.Expires = expires
	}

	_, err = a.baseClient.SetSecret(ctx, *a.provider.VaultURL, secretName, secretParams)
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
	if err != nil {
		return fmt.Errorf("could not set secret %v: %w", secretName, err)
	}
	return nil
}

func (a *Azure) setKeyVaultCertificate(ctx context.Context, secretName string, value []byte, tags map[string]string) error {
	val := b64.StdEncoding.EncodeToString(value)
	localCert, err := getCertificateFromValue(value)
	if err != nil {
		return fmt.Errorf("value from secret is not a valid certificate: %w", err)
	}
	cert, err := a.baseClient.GetCertificate(ctx, *a.provider.VaultURL, secretName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetCertificate, err)
	ok, err := canCreate(cert.Tags, err)
	if err != nil {
		return fmt.Errorf("cannot get certificate %v: %w", secretName, err)
	}
	if !ok {
		return nil
	}
	b512 := sha3.Sum512(localCert.Raw)
	if cert.Cer != nil && b512 == sha3.Sum512(*cert.Cer) {
		return nil
	}
	params := keyvault.CertificateImportParameters{
		Base64EncodedCertificate: &val,
		Tags: map[string]*string{
			managedBy: new(managerLabel),
		},
	}

	for k, v := range tags {
		params.Tags[k] = &v
	}

	_, err = a.baseClient.ImportCertificate(ctx, *a.provider.VaultURL, secretName, params)
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVImportCertificate, err)
	if err != nil {
		return fmt.Errorf("could not import certificate %v: %w", secretName, err)
	}
	return nil
}
func equalKeys(newKey, oldKey keyvault.JSONWebKey) bool {
	// checks for everything except KeyID and KeyOps
	rsaCheck := newKey.E != nil && oldKey.E != nil && *newKey.E == *oldKey.E &&
		newKey.N != nil && oldKey.N != nil && *newKey.N == *oldKey.N

	symmetricCheck := newKey.Crv == oldKey.Crv &&
		newKey.T != nil && oldKey.T != nil && *newKey.T == *oldKey.T &&
		newKey.X != nil && oldKey.X != nil && *newKey.X == *oldKey.X &&
		newKey.Y != nil && oldKey.Y != nil && *newKey.Y == *oldKey.Y

	return newKey.Kty == oldKey.Kty && (rsaCheck || symmetricCheck)
}
func (a *Azure) setKeyVaultKey(ctx context.Context, secretName string, value []byte, tags map[string]string) error {
	key, err := getKeyFromValue(value)
	if err != nil {
		return fmt.Errorf("could not load private key %v: %w", secretName, err)
	}
	jwKey, err := jwk.FromRaw(key)
	if err != nil {
		return fmt.Errorf("failed to generate a JWK from secret %v content: %w", secretName, err)
	}
	buf, err := json.Marshal(jwKey)
	if err != nil {
		return fmt.Errorf("error parsing key: %w", err)
	}
	azkey := keyvault.JSONWebKey{}
	err = json.Unmarshal(buf, &azkey)
	if err != nil {
		return fmt.Errorf("error unmarshalling key: %w", err)
	}
	keyFromVault, err := a.baseClient.GetKey(ctx, *a.provider.VaultURL, secretName, "")
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetKey, err)
	ok, err := canCreate(keyFromVault.Tags, err)
	if err != nil {
		return fmt.Errorf("cannot get key %v: %w", secretName, err)
	}
	if !ok {
		return nil
	}
	if keyFromVault.Key != nil && equalKeys(azkey, *keyFromVault.Key) {
		return nil
	}
	params := keyvault.KeyImportParameters{
		Key:           &azkey,
		KeyAttributes: &keyvault.KeyAttributes{},
		Tags: map[string]*string{
			managedBy: new(managerLabel),
		},
	}

	for k, v := range tags {
		params.Tags[k] = &v
	}
	_, err = a.baseClient.ImportKey(ctx, *a.provider.VaultURL, secretName, params)
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVImportKey, err)
	if err != nil {
		return fmt.Errorf("could not import key %v: %w", secretName, err)
	}
	return nil
}

func getSecretKey(secret *corev1.Secret, data esv1.PushSecretData) ([]byte, error) {
	if data.GetSecretKey() != "" {
		return secret.Data[data.GetSecretKey()], nil
	}

	// Must convert secret values to string, otherwise data will be sent as base64 to Vault
	secretStringVal := make(map[string]string)
	for k, v := range secret.Data {
		secretStringVal[k] = string(v)
	}
	value, err := esutils.JSONMarshal(secretStringVal)
	if err != nil {
		return nil, fmt.Errorf("failed to serialize secret content as JSON: %w", err)
	}
	return value, nil
}

// PushSecret stores secrets into a Key vault instance.
func (a *Azure) PushSecret(ctx context.Context, secret *corev1.Secret, data esv1.PushSecretData) error {
	var (
		value   []byte
		err     error
		expires *date.UnixTime
		tags    map[string]string
	)

	if value, err = getSecretKey(secret, data); err != nil {
		return err
	}

	metadata, err := metadata.ParseMetadataParameters[PushSecretMetadataSpec](data.GetMetadata())
	if err != nil {
		return fmt.Errorf("failed to parse push secret metadata: %w", err)
	}

	if metadata != nil && metadata.Spec.ExpirationDate != "" {
		t, err := time.Parse(time.RFC3339, metadata.Spec.ExpirationDate)
		if err != nil {
			return fmt.Errorf("error parsing expiration date in metadata: %w. Expected format: YYYY-MM-DDTHH:MM:SSZ (RFC3339). Example: 2024-12-31T20:00:00Z", err)
		}
		unixTime := date.UnixTime(t)
		expires = &unixTime
	}

	if metadata != nil && metadata.Spec.Tags != nil {
		if _, exists := metadata.Spec.Tags[managedBy]; exists {
			return fmt.Errorf("error parsing tags in metadata: Cannot specify a '%s' tag", managedBy)
		}
		tags = metadata.Spec.Tags
	}

	objectType, secretName := getObjType(esv1.ExternalSecretDataRemoteRef{Key: data.GetRemoteKey()})
	switch objectType {
	case defaultObjType:
		if a.useNewSDK() {
			return a.setKeyVaultSecretWithNewSDK(ctx, secretName, value, nil, tags)
		}
		return a.setKeyVaultSecret(ctx, secretName, value, expires, tags)
	case objectTypeCert:
		if a.useNewSDK() {
			return a.setKeyVaultCertificateWithNewSDK(ctx, secretName, value, tags)
		}
		return a.setKeyVaultCertificate(ctx, secretName, value, tags)
	case objectTypeKey:
		if a.useNewSDK() {
			return a.setKeyVaultKeyWithNewSDK(ctx, secretName, value, tags)
		}
		return a.setKeyVaultKey(ctx, secretName, value, tags)
	default:
		return fmt.Errorf("secret type %v not supported", objectType)
	}
}

// GetAllSecrets implements store.Client.GetAllSecrets Interface.
// Retrieves a map[string][]byte with the secret names as key and the secret itself as the calue.
func (a *Azure) GetAllSecrets(ctx context.Context, ref esv1.ExternalSecretFind) (map[string][]byte, error) {
	if a.useNewSDK() {
		return a.getAllSecretsWithNewSDK(ctx, ref)
	}
	return a.getAllSecretsWithLegacySDK(ctx, ref)
}

func (a *Azure) getAllSecretsWithLegacySDK(ctx context.Context, ref esv1.ExternalSecretFind) (map[string][]byte, error) {
	basicClient := a.baseClient
	secretsMap := make(map[string][]byte)
	checkTags := len(ref.Tags) > 0
	checkName := ref.Name != nil && ref.Name.RegExp != ""

	secretListIter, err := basicClient.GetSecretsComplete(ctx, *a.provider.VaultURL, nil)
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecrets, err)
	err = parseError(err)
	if err != nil {
		return nil, err
	}

	for secretListIter.NotDone() {
		secret := secretListIter.Value()
		ok, secretName := isValidSecret(checkTags, checkName, ref, secret)
		if !ok {
			err = secretListIter.Next()
			if err != nil {
				return nil, err
			}
			continue
		}
		secretResp, err := basicClient.GetSecret(ctx, *a.provider.VaultURL, secretName, "")
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
		err = parseError(err)
		if err != nil {
			return nil, err
		}

		secretValue := *secretResp.Value
		secretsMap[secretName] = []byte(secretValue)

		err = secretListIter.Next()
		if err != nil {
			return nil, err
		}
	}
	return secretsMap, nil
}

// getSecretAllMetadata merges tags with time-based attributes into a single metadata map.
// resp must be a keyvault.SecretBundle, CertificateBundle, or KeyBundle.
func getSecretAllMetadata(resp any) map[string]*string {
	var tags map[string]*string
	var expires, created, updated, notBefore *date.UnixTime
	switch v := resp.(type) {
	case keyvault.SecretBundle:
		tags = maps.Clone(v.Tags)
		if v.Attributes != nil {
			expires, created, updated, notBefore = v.Attributes.Expires, v.Attributes.Created, v.Attributes.Updated, v.Attributes.NotBefore
		}
	case keyvault.CertificateBundle:
		tags = maps.Clone(v.Tags)
		if v.Attributes != nil {
			expires, created, updated, notBefore = v.Attributes.Expires, v.Attributes.Created, v.Attributes.Updated, v.Attributes.NotBefore
		}
	case keyvault.KeyBundle:
		tags = maps.Clone(v.Tags)
		if v.Attributes != nil {
			expires, created, updated, notBefore = v.Attributes.Expires, v.Attributes.Created, v.Attributes.Updated, v.Attributes.NotBefore
		}
	default:
		return nil
	}
	if tags == nil {
		tags = make(map[string]*string)
	}
	set := func(key string, v *date.UnixTime) {
		if v == nil {
			return
		}
		tags[key] = new(time.Time(*v).UTC().Format(time.RFC3339))
	}
	set(attributeExpires, expires)
	set(attributeCreated, created)
	set(attributeUpdated, updated)
	set(attributeNotBefore, notBefore)
	return tags
}

// Retrieves a tag value if specified and all tags in JSON format if not.
func getSecretTag(tags map[string]*string, property string) ([]byte, error) {
	if property == "" {
		secretTagsData := make(map[string]string)
		for k, v := range tags {
			if v == nil {
				continue
			}
			secretTagsData[k] = *v
		}
		return json.Marshal(secretTagsData)
	}
	if val, exist := tags[property]; exist {
		if val == nil {
			return nil, nil
		}

		return []byte(*val), nil
	}

	idx := strings.Index(property, ".")
	if idx < 0 {
		return nil, fmt.Errorf(errTagNotExist, property)
	}

	if idx > 0 {
		tagName := property[0:idx]
		if val, exist := tags[tagName]; exist {
			if val == nil {
				return nil, nil
			}
			key := strings.Replace(property, tagName+".", "", 1)
			return getProperty(*val, key, property)
		}
	}

	return nil, fmt.Errorf(errTagNotExist, property)
}

// Retrieves a property value if specified and the secret value if not.
func getProperty(secret, property, key string) ([]byte, error) {
	if property == "" {
		return []byte(secret), nil
	}
	res := gjson.Get(secret, property)
	if !res.Exists() {
		found := strings.Contains(property, ".")
		if !found {
			return nil, fmt.Errorf(errPropNotExist, property, key)
		}
		escaped := strings.ReplaceAll(property, ".", "\\.")
		jValue := gjson.Get(secret, escaped)
		if jValue.Exists() {
			return []byte(jValue.String()), nil
		}
		return nil, fmt.Errorf(errPropNotExist, property, key)
	}
	return []byte(res.String()), nil
}

func parseError(err error) error {
	aerr := autorest.DetailedError{}
	if errors.As(err, &aerr) && aerr.StatusCode == 404 {
		return esv1.NoSecretError{}
	}
	return err
}

// GetSecret implements store.Client.GetSecret Interface.
// Retrieves a secret/Key/Certificate/Tag with the secret name defined in ref.Name
// The Object Type is defined as a prefix in the ref.Name , if no prefix is defined , we assume a secret is required.
func (a *Azure) GetSecret(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) ([]byte, error) {
	if a.useNewSDK() {
		return a.getSecretWithNewSDK(ctx, ref)
	}
	return a.getSecretWithLegacySDK(ctx, ref)
}

// returns a SecretBundle with the tags values.
func (a *Azure) getSecretTags(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) (map[string]*string, error) {
	if a.useNewSDK() {
		return a.getSecretTagsWithNewSDK(ctx, ref)
	}
	return a.getSecretTagsWithLegacySDK(ctx, ref)
}

func (a *Azure) getSecretTagsWithLegacySDK(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) (map[string]*string, error) {
	_, secretName := getObjType(ref)
	secretResp, err := a.baseClient.GetSecret(ctx, *a.provider.VaultURL, secretName, ref.Version)
	metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
	err = parseError(err)
	if err != nil {
		return nil, err
	}

	secretTagsData := make(map[string]*string)

	for tagname, tagval := range secretResp.Tags {
		if tagval == nil {
			continue
		}
		name := secretName + "_" + tagname
		kv := make(map[string]string)
		err = json.Unmarshal([]byte(*tagval), &kv)
		// if the tagvalue is not in JSON format then we added to secretTagsData we added as it is
		if err != nil {
			secretTagsData[name] = tagval
		} else {
			for k, v := range kv {
				value := v
				secretTagsData[name+"_"+k] = &value
			}
		}
	}

	if secretResp.Attributes != nil {
		set := func(key string, v *date.UnixTime) {
			if v == nil {
				return
			}
			s := time.Time(*v).UTC().Format(time.RFC3339)
			secretTagsData[secretName+"_"+key] = &s
		}
		set(attributeExpires, secretResp.Attributes.Expires)
		set(attributeCreated, secretResp.Attributes.Created)
		set(attributeUpdated, secretResp.Attributes.Updated)
		set(attributeNotBefore, secretResp.Attributes.NotBefore)
	}

	return secretTagsData, nil
}

// GetSecretMap returns a map of secret values from Azure KeyVault by fetching the secret with
// the given name and parsing it as a JSON object. If MetadataPolicy is set to Fetch, it will
// return the secret tags instead.
func (a *Azure) GetSecretMap(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	objectType, secretName := getObjType(ref)

	switch objectType {
	case defaultObjType:
		data, err := a.GetSecret(ctx, ref)
		if err != nil {
			return nil, err
		}

		if ref.MetadataPolicy == esv1.ExternalSecretMetadataPolicyFetch {
			tags, _ := a.getSecretTags(ctx, ref)
			return getSecretMapProperties(tags, ref.Key, ref.Property), nil
		}

		return getSecretMapMap(data)

	case objectTypeCert:
		return nil, errors.New(errDataFromCert)
	case objectTypeKey:
		return nil, errors.New(errDataFromKey)
	}
	return nil, fmt.Errorf(errUnknownObjectType, secretName)
}

func getSecretMapMap(data []byte) (map[string][]byte, error) {
	kv := make(map[string]json.RawMessage)
	err := json.Unmarshal(data, &kv)
	if err != nil {
		return nil, fmt.Errorf(errUnmarshalJSONData, err)
	}

	secretData := make(map[string][]byte)
	for k, v := range kv {
		var strVal string
		err = json.Unmarshal(v, &strVal)
		if err == nil {
			secretData[k] = []byte(strVal)
		} else {
			secretData[k] = v
		}
	}
	return secretData, nil
}

func getSecretMapProperties(tags map[string]*string, key, property string) map[string][]byte {
	tagByteArray := make(map[string][]byte)
	if property != "" {
		keyPropertyName := key + "_" + property
		singleTag, _ := getSecretTag(tags, keyPropertyName)
		tagByteArray[keyPropertyName] = singleTag

		return tagByteArray
	}

	for k, v := range tags {
		tagByteArray[k] = []byte(*v)
	}

	return tagByteArray
}

func (a *Azure) authorizerForWorkloadIdentity(ctx context.Context, tokenProvider tokenProviderFunc) (autorest.Authorizer, error) {
	aadEndpoint := AadEndpointForType(a.provider.EnvironmentType)
	kvResource := kvResourceForProviderConfig(a.provider.EnvironmentType)
	// If no serviceAccountRef was provided
	// we expect certain env vars to be present.
	// They are set by the azure workload identity webhook
	// by adding the label `azure.workload.identity/use: "true"` to the external-secrets pod
	if a.provider.ServiceAccountRef == nil {
		clientID := os.Getenv("AZURE_CLIENT_ID")
		tenantID := os.Getenv("AZURE_TENANT_ID")
		tokenFilePath := os.Getenv("AZURE_FEDERATED_TOKEN_FILE")
		if clientID == "" || tenantID == "" || tokenFilePath == "" {
			return nil, errors.New(errMissingWorkloadEnvVars)
		}
		token, err := os.ReadFile(filepath.Clean(tokenFilePath))
		if err != nil {
			return nil, fmt.Errorf(errReadTokenFile, tokenFilePath, err)
		}
		tp, err := tokenProvider(ctx, string(token), clientID, tenantID, aadEndpoint, kvResource)
		if err != nil {
			return nil, err
		}
		return autorest.NewBearerAuthorizer(tp), nil
	}
	ns := a.namespace
	if a.store.GetKind() == esv1.ClusterSecretStoreKind && a.provider.ServiceAccountRef.Namespace != nil {
		ns = *a.provider.ServiceAccountRef.Namespace
	}
	var sa corev1.ServiceAccount
	err := a.crClient.Get(ctx, types.NamespacedName{
		Name:      a.provider.ServiceAccountRef.Name,
		Namespace: ns,
	}, &sa)
	if err != nil {
		return nil, err
	}
	// Extract clientID
	var clientID string
	// First check if AuthSecretRef is set and clientID can be fetched from there
	if a.provider.AuthSecretRef != nil {
		if a.provider.AuthSecretRef.ClientID == nil {
			return nil, errors.New(errMissingClientIDSecret)
		}
		clientID, err = resolvers.SecretKeyRef(
			ctx,
			a.crClient,
			a.store.GetKind(),
			a.namespace, a.provider.AuthSecretRef.ClientID)
		if err != nil {
			return nil, err
		}
	}
	// If AuthSecretRef is not set, use default (Service Account) implementation
	// Try to get clientID from Annotations
	if len(sa.ObjectMeta.Annotations) > 0 {
		if val, found := sa.ObjectMeta.Annotations[AnnotationClientID]; found {
			// If clientID is defined in both Annotations and AuthSecretRef, return an error
			if clientID != "" {
				return nil, errors.New(errMultipleClientID)
			}
			clientID = val
		}
	}
	// Return an error if clientID is still empty
	if clientID == "" {
		return nil, fmt.Errorf(errMissingClient, AnnotationClientID)
	}
	// Extract tenantID
	var tenantID string
	// First check if AuthSecretRef is set and tenantID can be fetched from there
	if a.provider.AuthSecretRef != nil {
		// We may want to set tenantID explicitly in the `spec.provider.azurekv` section of the SecretStore object
		// So that is okay if it is not there
		if a.provider.AuthSecretRef.TenantID != nil {
			tenantID, err = resolvers.SecretKeyRef(
				ctx,
				a.crClient,
				a.store.GetKind(),
				a.namespace, a.provider.AuthSecretRef.TenantID)
			if err != nil {
				return nil, err
			}
		}
	}
	// Check if spec.provider.azurekv.tenantID is set
	if tenantID == "" && a.provider.TenantID != nil {
		tenantID = *a.provider.TenantID
	}
	// Try to get tenantID from Annotations first. Default implementation.
	if len(sa.ObjectMeta.Annotations) > 0 {
		if val, found := sa.ObjectMeta.Annotations[AnnotationTenantID]; found {
			// If tenantID is defined in both Annotations and AuthSecretRef, return an error
			if tenantID != "" {
				return nil, errors.New(errMultipleTenantID)
			}
			tenantID = val
		}
	}
	// Fallback: use the AZURE_TENANT_ID env var which is set by the azure workload identity webhook
	// https://azure.github.io/azure-workload-identity/docs/topics/service-account-labels-and-annotations.html#service-account
	if tenantID == "" {
		tenantID = os.Getenv("AZURE_TENANT_ID")
	}
	// Return an error if tenantID is still empty
	if tenantID == "" {
		return nil, errors.New(errMissingTenant)
	}
	audiences := []string{AzureDefaultAudience}
	if len(a.provider.ServiceAccountRef.Audiences) > 0 {
		audiences = append(audiences, a.provider.ServiceAccountRef.Audiences...)
	}

	token, err := FetchSAToken(ctx, ns, a.provider.ServiceAccountRef.Name, audiences, a.kubeClient)
	if err != nil {
		return nil, err
	}

	tp, err := tokenProvider(ctx, token, clientID, tenantID, aadEndpoint, kvResource)
	if err != nil {
		return nil, err
	}
	return autorest.NewBearerAuthorizer(tp), nil
}

// FetchSAToken retrieves a service account token from Kubernetes with the specified audiences.
// It takes the service account namespace, name, audience list, and Kubernetes client interface.
// Returns the token string or an error if the token creation fails.
func FetchSAToken(ctx context.Context, ns, name string, audiences []string, kubeClient kcorev1.CoreV1Interface) (string, error) {
	token, err := kubeClient.ServiceAccounts(ns).CreateToken(ctx, name, &authv1.TokenRequest{
		Spec: authv1.TokenRequestSpec{
			Audiences: audiences,
		},
	}, metav1.CreateOptions{})
	if err != nil {
		return "", err
	}
	return token.Status.Token, nil
}

// tokenProvider satisfies the adal.OAuthTokenProvider interface.
type tokenProvider struct {
	accessToken string
}

type tokenProviderFunc func(ctx context.Context, token, clientID, tenantID, aadEndpoint, kvResource string) (adal.OAuthTokenProvider, error)

// NewTokenProvider creates a new Azure OAuth token provider for authentication.
func NewTokenProvider(ctx context.Context, token, clientID, tenantID, aadEndpoint, kvResource string) (adal.OAuthTokenProvider, error) {
	cred := confidential.NewCredFromAssertionCallback(func(_ context.Context, _ confidential.AssertionRequestOptions) (string, error) {
		return token, nil
	})

	cClient, err := confidential.New(fmt.Sprintf("%s%s", aadEndpoint, tenantID), clientID, cred)
	if err != nil {
		return nil, err
	}
	scope := kvResource
	// .default needs to be added to the scope
	if !strings.Contains(kvResource, ".default") {
		scope = fmt.Sprintf("%s/.default", kvResource)
	}
	authRes, err := cClient.AcquireTokenByCredential(ctx, []string{
		scope,
	})
	if err != nil {
		return nil, err
	}
	return &tokenProvider{
		accessToken: authRes.AccessToken,
	}, nil
}

func (t *tokenProvider) OAuthToken() string {
	return t.accessToken
}

func (a *Azure) authorizerForManagedIdentity() (autorest.Authorizer, error) {
	msiConfig := kvauth.NewMSIConfig()
	msiConfig.Resource = kvResourceForProviderConfig(a.provider.EnvironmentType)
	if a.provider.IdentityID != nil {
		msiConfig.ClientID = *a.provider.IdentityID
	}
	return msiConfig.Authorizer()
}

func (a *Azure) authorizerForServicePrincipal(ctx context.Context) (autorest.Authorizer, error) {
	if a.provider.TenantID == nil {
		return nil, errors.New(errMissingTenant)
	}
	if a.provider.AuthSecretRef == nil {
		return nil, errors.New(errMissingSecretRef)
	}
	if a.provider.AuthSecretRef.ClientID == nil || (a.provider.AuthSecretRef.ClientSecret == nil && a.provider.AuthSecretRef.ClientCertificate == nil) {
		return nil, errors.New(errMissingClientIDSecret)
	}
	if a.provider.AuthSecretRef.ClientSecret != nil && a.provider.AuthSecretRef.ClientCertificate != nil {
		return nil, errors.New(errInvalidClientCredentials)
	}

	return a.getAuthorizerFromCredentials(ctx)
}

func (a *Azure) getAuthorizerFromCredentials(ctx context.Context) (autorest.Authorizer, error) {
	clientID, err := resolvers.SecretKeyRef(
		ctx,
		a.crClient,
		a.store.GetKind(),
		a.namespace, a.provider.AuthSecretRef.ClientID,
	)

	if err != nil {
		return nil, err
	}

	if a.provider.AuthSecretRef.ClientSecret != nil {
		clientSecret, err := resolvers.SecretKeyRef(
			ctx,
			a.crClient,
			a.store.GetKind(),
			a.namespace, a.provider.AuthSecretRef.ClientSecret,
		)

		if err != nil {
			return nil, err
		}

		return getAuthorizerForClientSecret(
			clientID,
			clientSecret,
			*a.provider.TenantID,
			a.provider.EnvironmentType,
		)
	}

	clientCertificate, err := resolvers.SecretKeyRef(
		ctx,
		a.crClient,
		a.store.GetKind(),
		a.namespace, a.provider.AuthSecretRef.ClientCertificate,
	)

	if err != nil {
		return nil, err
	}

	return getAuthorizerForClientCertificate(
		clientID,
		[]byte(clientCertificate),
		*a.provider.TenantID,
		a.provider.EnvironmentType,
	)
}

func getAuthorizerForClientSecret(clientID, clientSecret, tenantID string, environmentType esv1.AzureEnvironmentType) (autorest.Authorizer, error) {
	clientCredentialsConfig := kvauth.NewClientCredentialsConfig(clientID, clientSecret, tenantID)
	clientCredentialsConfig.Resource = kvResourceForProviderConfig(environmentType)
	clientCredentialsConfig.AADEndpoint = AadEndpointForType(environmentType)
	return clientCredentialsConfig.Authorizer()
}

func getAuthorizerForClientCertificate(clientID string, certificateBytes []byte, tenantID string, environmentType esv1.AzureEnvironmentType) (autorest.Authorizer, error) {
	clientCertificateConfig := NewClientInMemoryCertificateConfig(clientID, certificateBytes, tenantID)
	clientCertificateConfig.Resource = kvResourceForProviderConfig(environmentType)
	clientCertificateConfig.AADEndpoint = AadEndpointForType(environmentType)
	return clientCertificateConfig.Authorizer()
}

// Close closes the Azure Key Vault provider.
func (a *Azure) Close(_ context.Context) error {
	return nil
}

// Validate validates the Azure Key Vault provider configuration.
func (a *Azure) Validate() (esv1.ValidationResult, error) {
	if a.store.GetKind() == esv1.ClusterSecretStoreKind && isReferentSpec(a.provider) {
		return esv1.ValidationResultUnknown, nil
	}
	return esv1.ValidationResultReady, nil
}

func isReferentSpec(prov *esv1.AzureKVProvider) bool {
	if prov.AuthSecretRef != nil &&
		((prov.AuthSecretRef.ClientID != nil &&
			prov.AuthSecretRef.ClientID.Namespace == nil) ||
			(prov.AuthSecretRef.ClientSecret != nil &&
				prov.AuthSecretRef.ClientSecret.Namespace == nil)) {
		return true
	}
	if prov.ServiceAccountRef != nil &&
		prov.ServiceAccountRef.Namespace == nil {
		return true
	}
	return false
}

// AadEndpointForType returns the Azure Active Directory endpoint for the specified Azure environment type.
func AadEndpointForType(t esv1.AzureEnvironmentType) string {
	switch t {
	case esv1.AzureEnvironmentPublicCloud:
		return azure.PublicCloud.ActiveDirectoryEndpoint
	case esv1.AzureEnvironmentChinaCloud:
		return azure.ChinaCloud.ActiveDirectoryEndpoint
	case esv1.AzureEnvironmentUSGovernmentCloud:
		return azure.USGovernmentCloud.ActiveDirectoryEndpoint
	case esv1.AzureEnvironmentGermanCloud:
		return azure.GermanCloud.ActiveDirectoryEndpoint
	case esv1.AzureEnvironmentAzureStackCloud:
		// Azure Stack Cloud requires custom configuration and new SDK
		// Return empty string to indicate it's not supported in old SDK
		return ""
	default:
		return azure.PublicCloud.ActiveDirectoryEndpoint
	}
}

// ServiceManagementEndpointForType returns the service management endpoint for the specified Azure environment type.
func ServiceManagementEndpointForType(t esv1.AzureEnvironmentType) string {
	switch t {
	case esv1.AzureEnvironmentPublicCloud:
		return azure.PublicCloud.ServiceManagementEndpoint
	case esv1.AzureEnvironmentChinaCloud:
		return azure.ChinaCloud.ServiceManagementEndpoint
	case esv1.AzureEnvironmentUSGovernmentCloud:
		return azure.USGovernmentCloud.ServiceManagementEndpoint
	case esv1.AzureEnvironmentGermanCloud:
		return azure.GermanCloud.ServiceManagementEndpoint
	case esv1.AzureEnvironmentAzureStackCloud:
		// Azure Stack Cloud requires custom configuration and new SDK
		// Return empty string to indicate it's not supported in old SDK
		return ""
	default:
		return azure.PublicCloud.ServiceManagementEndpoint
	}
}

func kvResourceForProviderConfig(t esv1.AzureEnvironmentType) string {
	var res string
	switch t {
	case esv1.AzureEnvironmentPublicCloud:
		res = azure.PublicCloud.KeyVaultEndpoint
	case esv1.AzureEnvironmentChinaCloud:
		res = azure.ChinaCloud.KeyVaultEndpoint
	case esv1.AzureEnvironmentUSGovernmentCloud:
		res = azure.USGovernmentCloud.KeyVaultEndpoint
	case esv1.AzureEnvironmentGermanCloud:
		res = azure.GermanCloud.KeyVaultEndpoint
	case esv1.AzureEnvironmentAzureStackCloud:
		// Azure Stack Cloud requires custom configuration and new SDK
		// Return empty string to indicate it's not supported in old SDK
		res = ""
	default:
		res = azure.PublicCloud.KeyVaultEndpoint
	}
	return strings.TrimSuffix(res, "/")
}

func getObjType(ref esv1.ExternalSecretDataRemoteRef) (string, string) {
	objectType := defaultObjType

	secretName := ref.Key
	nameSplitted := strings.Split(secretName, "/")

	if len(nameSplitted) > 1 {
		objectType = nameSplitted[0]
		secretName = nameSplitted[1]
		// TODO: later tokens can be used to read the secret tags
	}
	return objectType, secretName
}

func isValidSecret(checkTags, checkName bool, ref esv1.ExternalSecretFind, secret keyvault.SecretItem) (bool, string) {
	if secret.ID == nil || !*secret.Attributes.Enabled {
		return false, ""
	}

	if checkTags && !okByTags(ref, secret) {
		return false, ""
	}

	secretName := path.Base(*secret.ID)
	if checkName && !okByName(ref, secretName) {
		return false, ""
	}

	return true, secretName
}

func okByName(ref esv1.ExternalSecretFind, secretName string) bool {
	matches, _ := regexp.MatchString(ref.Name.RegExp, secretName)
	return matches
}

func okByTags(ref esv1.ExternalSecretFind, secret keyvault.SecretItem) bool {
	tagsFound := true
	for k, v := range ref.Tags {
		if val, ok := secret.Tags[k]; !ok || val == nil || *val != v {
			tagsFound = false
			break
		}
	}
	return tagsFound
}

// GetSecret implementation using legacy go-autorest SDK.
func (a *Azure) getSecretWithLegacySDK(ctx context.Context, ref esv1.ExternalSecretDataRemoteRef) ([]byte, error) {
	objectType, secretName := getObjType(ref)

	switch objectType {
	case defaultObjType:
		// returns a SecretBundle with the secret value
		// https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/services/keyvault/v7.0/keyvault#SecretBundle
		secretResp, err := a.baseClient.GetSecret(ctx, *a.provider.VaultURL, secretName, ref.Version)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetSecret, err)
		err = parseError(err)
		if err != nil {
			return nil, err
		}
		if ref.MetadataPolicy == esv1.ExternalSecretMetadataPolicyFetch {
			return getSecretTag(getSecretAllMetadata(secretResp), ref.Property)
		}
		return getProperty(*secretResp.Value, ref.Property, ref.Key)

	case objectTypeCert:
		// returns a CertBundle. We return CER contents of x509 certificate
		// see: https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/services/keyvault/v7.0/keyvault#CertificateBundle
		certResp, err := a.baseClient.GetCertificate(ctx, *a.provider.VaultURL, secretName, ref.Version)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetCertificate, err)
		err = parseError(err)
		if err != nil {
			return nil, err
		}
		if ref.MetadataPolicy == esv1.ExternalSecretMetadataPolicyFetch {
			return getSecretTag(getSecretAllMetadata(certResp), ref.Property)
		}
		return *certResp.Cer, nil

	case objectTypeKey:
		// returns a KeyBundle
		// https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/services/keyvault/v7.0/keyvault#KeyBundle
		keyResp, err := a.baseClient.GetKey(ctx, *a.provider.VaultURL, secretName, ref.Version)
		metrics.ObserveAPICall(constants.ProviderAzureKV, constants.CallAzureKVGetKey, err)
		err = parseError(err)
		if err != nil {
			return nil, err
		}
		if ref.MetadataPolicy == esv1.ExternalSecretMetadataPolicyFetch {
			return getSecretTag(getSecretAllMetadata(keyResp), ref.Property)
		}
		keyBytes, err := json.Marshal(keyResp.Key)
		if err != nil {
			return nil, fmt.Errorf("failed to marshal key: %w", err)
		}
		return getProperty(string(keyBytes), ref.Property, ref.Key)
	}

	return nil, fmt.Errorf(errUnknownObjectType, secretName)
}

// NewProvider creates a new Provider instance.
func NewProvider() esv1.Provider {
	return &Azure{}
}

// ProviderSpec returns the provider specification for registration.
func ProviderSpec() *esv1.SecretStoreProvider {
	return &esv1.SecretStoreProvider{
		AzureKV: &esv1.AzureKVProvider{},
	}
}

// MaintenanceStatus returns the maintenance status of the provider.
func MaintenanceStatus() esv1.MaintenanceStatus {
	return esv1.MaintenanceStatusMaintained
}