package instance

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

	barmanBackup "github.com/cloudnative-pg/barman-cloud/pkg/backup"
	barmanCapabilities "github.com/cloudnative-pg/barman-cloud/pkg/capabilities"
	barmanCredentials "github.com/cloudnative-pg/barman-cloud/pkg/credentials"
	cnpgv1 "github.com/cloudnative-pg/cloudnative-pg/api/v1"
	"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"
	"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/metadata"
)

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

// This is an implementation of the barman executor
// that always instruct the barman library to use the
// "--name" option for backups. We don't support old
// Barman versions that do not implement that option.
type barmanCloudExecutor struct{}

func (barmanCloudExecutor) ShouldForceLegacyBackup() bool {
	return false
}

// 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,
	_ *backup.BackupRequest,
) (*backup.BackupResult, error) {
	contextLogger := log.FromContext(ctx)

	contextLogger.Info("Starting backup")

	var cluster cnpgv1.Cluster
	if err := b.Client.Get(ctx, b.ClusterObjectKey, &cluster); err != nil {
		return nil, err
	}

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

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

	capabilities, err := barmanCapabilities.CurrentCapabilities()
	if err != nil {
		contextLogger.Error(err, "while getting capabilities")
		return nil, err
	}
	backupCmd := barmanBackup.NewBackupCommand(
		&objectStore.Spec.Configuration,
		capabilities,
	)

	// 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.EnvSetBackupCloudCredentials(
		ctx,
		b.Client,
		objectStore.Namespace,
		&objectStore.Spec.Configuration,
		common.MergeEnv(osEnvironment, caBundleEnvironment))
	if err != nil {
		contextLogger.Error(err, "while setting backup cloud credentials")
		return nil, err
	}

	serverName := cluster.Name
	for _, plugin := range cluster.Spec.Plugins {
		if plugin.IsEnabled() && plugin.Name == metadata.PluginName {
			if pluginServerName, ok := plugin.Parameters["serverName"]; ok {
				serverName = pluginServerName
			}
		}
	}

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

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

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

	contextLogger.Info("Backup completed", "backup", executedBackupInfo.ID)
	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: map[string]string{
			"timeline":    strconv.Itoa(executedBackupInfo.TimeLine),
			"version":     metadata.Data.Version,
			"name":        metadata.Data.Name,
			"displayName": metadata.Data.DisplayName,
		},
	}, nil
}