//
// DISCLAIMER
//
// Copyright 2016-2022 ArangoDB GmbH, Cologne, Germany
//
// 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
//
// http://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.
//
// Copyright holder is ArangoDB GmbH, Cologne, Germany
//

package replication

import (
	"context"
	"net"
	"strconv"

	"github.com/arangodb/kube-arangodb/pkg/util/errors"

	certificates "github.com/arangodb-helper/go-certificates"
	"github.com/arangodb/arangosync-client/client"
	"github.com/arangodb/arangosync-client/tasks"
	meta "k8s.io/apimachinery/pkg/apis/meta/v1"

	api "github.com/arangodb/kube-arangodb/pkg/apis/replication/v1"
	"github.com/arangodb/kube-arangodb/pkg/apis/shared"
	"github.com/arangodb/kube-arangodb/pkg/util/k8sutil"
	"github.com/rs/zerolog/log"
)

// createSyncMasterClient creates an arangosync client for the given endpoint.
func (dr *DeploymentReplication) createSyncMasterClient(epSpec api.EndpointSpec) (client.API, error) {
	// Endpoint
	source, err := dr.createArangoSyncEndpoint(epSpec)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	// Authentication
	secrets := dr.deps.Client.Kubernetes().CoreV1().Secrets(dr.apiObject.GetNamespace())
	insecureSkipVerify := true
	tlsAuth := tasks.TLSAuthentication{}
	clientAuthKeyfileSecretName, userSecretName, authJWTSecretName, tlsCASecretName, err := dr.getEndpointSecretNames(epSpec)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	username := ""
	password := ""
	jwtSecret := ""
	if userSecretName != "" {
		var err error
		username, password, err = k8sutil.GetBasicAuthSecret(secrets, userSecretName)
		if err != nil {
			return nil, errors.WithStack(err)
		}
	} else if authJWTSecretName != "" {
		var err error
		jwtSecret, err = k8sutil.GetTokenSecret(context.TODO(), secrets, authJWTSecretName)
		if err != nil {
			return nil, errors.WithStack(err)
		}
	} else if clientAuthKeyfileSecretName != "" {
		keyFileContent, err := k8sutil.GetTLSKeyfileSecret(secrets, clientAuthKeyfileSecretName)
		if err != nil {
			return nil, errors.WithStack(err)
		}
		kf, err := certificates.NewKeyfile(keyFileContent)
		if err != nil {
			return nil, errors.WithStack(err)
		}
		tlsAuth.TLSClientAuthentication = tasks.TLSClientAuthentication{
			ClientCertificate: kf.EncodeCertificates(),
			ClientKey:         kf.EncodePrivateKey(),
		}
	}
	if tlsCASecretName != "" {
		caCert, err := k8sutil.GetCACertficateSecret(context.TODO(), secrets, tlsCASecretName)
		if err != nil {
			return nil, errors.WithStack(err)
		}
		tlsAuth.CACertificate = caCert
	}
	auth := client.NewAuthentication(tlsAuth, jwtSecret)
	auth.Username = username
	auth.Password = password

	// Create client
	// TODO: Change logger in clientset
	c, err := dr.clientCache.GetClient(log.Logger, source, auth, insecureSkipVerify)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	return c, nil
}

// createArangoSyncEndpoint creates the endpoints for the given spec.
func (dr *DeploymentReplication) createArangoSyncEndpoint(epSpec api.EndpointSpec) (client.Endpoint, error) {
	if epSpec.HasDeploymentName() {
		deploymentName := epSpec.GetDeploymentName()
		depls := dr.deps.Client.Arango().DatabaseV1().ArangoDeployments(dr.apiObject.GetNamespace())
		depl, err := depls.Get(context.Background(), deploymentName, meta.GetOptions{})
		if err != nil {
			dr.log.Err(err).Str("deployment", deploymentName).Debug("Failed to get deployment")
			return nil, errors.WithStack(err)
		}
		dnsName := k8sutil.CreateSyncMasterClientServiceDNSNameWithDomain(depl, depl.Spec.ClusterDomain)
		return client.Endpoint{"https://" + net.JoinHostPort(dnsName, strconv.Itoa(shared.ArangoSyncMasterPort))}, nil
	}
	return client.Endpoint(epSpec.MasterEndpoint), nil
}

// createArangoSyncTLSAuthentication creates the authentication needed to authenticate
// the destination syncmaster at the source syncmaster.
func (dr *DeploymentReplication) createArangoSyncTLSAuthentication(spec api.DeploymentReplicationSpec) (client.TLSAuthentication, error) {
	// Fetch secret names of source
	clientAuthKeyfileSecretName, _, _, tlsCASecretName, err := dr.getEndpointSecretNames(spec.Source)
	if err != nil {
		return client.TLSAuthentication{}, errors.WithStack(err)
	}

	// Fetch keyfile
	secrets := dr.deps.Client.Kubernetes().CoreV1().Secrets(dr.apiObject.GetNamespace())
	keyFileContent, err := k8sutil.GetTLSKeyfileSecret(secrets, clientAuthKeyfileSecretName)
	if err != nil {
		return client.TLSAuthentication{}, errors.WithStack(err)
	}
	kf, err := certificates.NewKeyfile(keyFileContent)
	if err != nil {
		return client.TLSAuthentication{}, errors.WithStack(err)
	}

	// Fetch TLS CA certificate for source
	caCert, err := k8sutil.GetCACertficateSecret(context.TODO(), secrets, tlsCASecretName)
	if err != nil {
		return client.TLSAuthentication{}, errors.WithStack(err)
	}

	// Create authentication
	result := client.TLSAuthentication{
		TLSClientAuthentication: tasks.TLSClientAuthentication{
			ClientCertificate: kf.EncodeCertificates(),
			ClientKey:         kf.EncodePrivateKey(),
		},
		CACertificate: caCert,
	}
	return result, nil
}

// getEndpointSecretNames returns the names of secrets that hold the:
// - client authentication certificate keyfile,
// - user (basic auth) secret,
// - JWT secret name,
// - TLS ca.crt
func (dr *DeploymentReplication) getEndpointSecretNames(epSpec api.EndpointSpec) (clientAuthCertKeyfileSecretName, userSecretName, jwtSecretName, tlsCASecretName string, err error) {
	clientAuthCertKeyfileSecretName = epSpec.Authentication.GetKeyfileSecretName()
	userSecretName = epSpec.Authentication.GetUserSecretName()
	if epSpec.HasDeploymentName() {
		deploymentName := epSpec.GetDeploymentName()
		depls := dr.deps.Client.Arango().DatabaseV1().ArangoDeployments(dr.apiObject.GetNamespace())
		depl, err := depls.Get(context.Background(), deploymentName, meta.GetOptions{})
		if err != nil {
			dr.log.Err(err).Str("deployment", deploymentName).Debug("Failed to get deployment")
			return "", "", "", "", errors.WithStack(err)
		}
		return clientAuthCertKeyfileSecretName, userSecretName, depl.Spec.Sync.Authentication.GetJWTSecretName(), depl.Spec.Sync.TLS.GetCASecretName(), nil
	}
	return clientAuthCertKeyfileSecretName, userSecretName, "", epSpec.TLS.GetCASecretName(), nil
}