/*
Copyright © contributors to CloudNativePG, established as
CloudNativePG a Series of LF Projects, LLC.

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.

SPDX-License-Identifier: Apache-2.0
*/

package instance

import (
	"context"
	"fmt"
	"os"
	"time"

	barmanBackup "github.com/cloudnative-pg/barman-cloud/pkg/backup"
	barmanCommand "github.com/cloudnative-pg/barman-cloud/pkg/command"
	barmanCredentials "github.com/cloudnative-pg/barman-cloud/pkg/credentials"
	"github.com/cloudnative-pg/cloudnative-pg/pkg/postgres"
	"github.com/cloudnative-pg/cnpg-i/pkg/backup"
	"github.com/cloudnative-pg/machinery/pkg/fileutils"
	"github.com/cloudnative-pg/machinery/pkg/log"
	pgTime "github.com/cloudnative-pg/machinery/pkg/postgres/time"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/util/retry"
	"sigs.k8s.io/controller-runtime/pkg/client"

	barmancloudv1 "github.com/cloudnative-pg/plugin-barman-cloud/api/v1"
	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/common"
	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/operator/config"
)

// BackupServiceImplementation is the implementation
// of the Backup CNPG capability
type BackupServiceImplementation struct {
	Client       client.Client
	InstanceName string
	backup.UnimplementedBackupServer
}

// GetCapabilities implements the BackupService interface
func (b BackupServiceImplementation) GetCapabilities(
	_ context.Context, _ *backup.BackupCapabilitiesRequest,
) (*backup.BackupCapabilitiesResult, error) {
	return &backup.BackupCapabilitiesResult{
		Capabilities: []*backup.BackupCapability{
			{
				Type: &backup.BackupCapability_Rpc{
					Rpc: &backup.BackupCapability_RPC{
						Type: backup.BackupCapability_RPC_TYPE_BACKUP,
					},
				},
			},
		},
	}, nil
}

// Backup implements the Backup interface
func (b BackupServiceImplementation) Backup(
	ctx context.Context,
	request *backup.BackupRequest,
) (*backup.BackupResult, error) {
	contextLogger := log.FromContext(ctx)

	contextLogger.Info("Starting backup")

	configuration, err := config.NewFromClusterJSON(request.ClusterDefinition)
	if err != nil {
		return nil, err
	}

	var objectStore barmancloudv1.ObjectStore
	if err := b.Client.Get(ctx, configuration.GetBarmanObjectKey(), &objectStore); err != nil {
		contextLogger.Error(err, "while getting object store", "key", configuration.GetRecoveryBarmanObjectKey())
		return nil, err
	}

	if err := fileutils.EnsureDirectoryExists(postgres.BackupTemporaryDirectory); err != nil {
		contextLogger.Error(err, "Cannot create backup temporary directory", "err", err)
		return nil, err
	}

	backupCmd := barmanBackup.NewBackupCommand(&objectStore.Spec.Configuration)

	// We need to connect to PostgreSQL and to do that we need
	// PGHOST (and the like) to be available
	osEnvironment := os.Environ()
	caBundleEnvironment := common.GetRestoreCABundleEnv(&objectStore.Spec.Configuration)
	env, err := barmanCredentials.EnvSetCloudCredentialsAndCertificates(
		ctx,
		b.Client,
		objectStore.Namespace,
		&objectStore.Spec.Configuration,
		common.MergeEnv(osEnvironment, caBundleEnvironment),
		common.BuildCertificateFilePath(objectStore.Name),
	)
	if err != nil {
		contextLogger.Error(err, "while setting backup cloud credentials")
		return nil, err
	}

	backupName := fmt.Sprintf("backup-%v", pgTime.ToCompactISO8601(time.Now()))

	if err = backupCmd.Take(
		ctx,
		backupName,
		configuration.ServerName,
		env,
		postgres.BackupTemporaryDirectory,
	); err != nil {
		contextLogger.Error(err, "while taking backup")

		if failureHandlerError := b.handleBackupError(ctx, configuration); failureHandlerError != nil {
			contextLogger.Error(
				failureHandlerError,
				"Error while handling backup failure, skipping. "+
					"BarmanObjectStore object may be not up to date.")
		}
		return nil, err
	}

	executedBackupInfo, err := backupCmd.GetExecutedBackupInfo(
		ctx,
		backupName,
		configuration.ServerName,
		env)
	if err != nil {
		contextLogger.Error(err, "while getting executed backup info")
		return nil, err
	}

	contextLogger.Info("Backup completed", "backup", executedBackupInfo.ID)

	// Refresh the recovery window
	contextLogger.Info(
		"Refreshing the recovery window",
		"backupName", executedBackupInfo.BackupName,
	)
	backupList, err := barmanCommand.GetBackupList(
		ctx,
		&objectStore.Spec.Configuration,
		configuration.ServerName,
		env,
	)
	if err != nil {
		contextLogger.Error(err, "while reading the backup list")
		return nil, err
	}

	if err := updateRecoveryWindow(
		ctx,
		b.Client,
		backupList,
		&objectStore,
		configuration.ServerName,
	); err != nil {
		contextLogger.Error(
			err,
			"Error while updating the recovery window in the ObjectStore status stanza. Skipping.",
			"backupName", executedBackupInfo.BackupName,
		)
	} else {
		contextLogger.Debug(
			"backupName", executedBackupInfo.BackupName,
			"Updated the recovery window in the ObjectStore status stanza",
			"serverRecoveryWindow", objectStore.Status.ServerRecoveryWindow,
		)
	}

	return &backup.BackupResult{
		BackupId:   executedBackupInfo.ID,
		BackupName: executedBackupInfo.BackupName,
		StartedAt:  metav1.Time{Time: executedBackupInfo.BeginTime}.Unix(),
		StoppedAt:  metav1.Time{Time: executedBackupInfo.EndTime}.Unix(),
		BeginWal:   executedBackupInfo.BeginWal,
		EndWal:     executedBackupInfo.EndWal,
		BeginLsn:   executedBackupInfo.BeginLSN,
		EndLsn:     executedBackupInfo.EndLSN,
		InstanceId: b.InstanceName,
		Online:     true,
		Metadata:   newBackupResultMetadata(configuration.Cluster.ObjectMeta.UID, executedBackupInfo.TimeLine).toMap(),
	}, nil
}

func (b BackupServiceImplementation) handleBackupError(ctx context.Context, cfg *config.PluginConfiguration) error {
	return retry.RetryOnConflict(
		retry.DefaultBackoff,
		func() error {
			return setLastFailedBackupTime(
				ctx,
				b.Client,
				cfg.GetBarmanObjectKey(),
				cfg.ServerName,
				time.Now(),
			)
		},
	)
}