//go:build linux && cgo && !agent

package db

import (
	"context"
	"database/sql"
	"fmt"
	"net/http"
	"time"

	"github.com/canonical/lxd/lxd/db/query"
	"github.com/canonical/lxd/shared/api"
	"github.com/canonical/lxd/shared/logger"
)

// InstanceBackup is a value object holding all db-related details about an instance backup.
type InstanceBackup struct {
	ID                   int
	InstanceID           int
	Name                 string
	CreationDate         time.Time
	ExpiryDate           time.Time
	InstanceOnly         bool
	OptimizedStorage     bool
	CompressionAlgorithm string
}

// StoragePoolVolumeBackup is a value object holding all db-related details about a storage volume backup.
type StoragePoolVolumeBackup struct {
	ID                   int
	VolumeID             int64
	Name                 string
	CreationDate         time.Time
	ExpiryDate           time.Time
	VolumeOnly           bool
	OptimizedStorage     bool
	CompressionAlgorithm string
}

// Returns the ID of the instance backup with the given name.
func (c *ClusterTx) getInstanceBackupID(ctx context.Context, name string) (int, error) {
	q := "SELECT id FROM instances_backups WHERE name=?"
	id := -1
	arg1 := []any{name}
	arg2 := []any{&id}

	err := dbQueryRowScan(ctx, c, q, arg1, arg2)
	if err == sql.ErrNoRows {
		return -1, api.StatusErrorf(http.StatusNotFound, "Instance backup not found")
	}

	return id, err
}

// GetInstanceBackup returns the backup with the given name.
func (c *ClusterTx) GetInstanceBackup(ctx context.Context, projectName string, name string) (InstanceBackup, error) {
	args := InstanceBackup{}
	args.Name = name

	instanceOnlyInt := -1
	optimizedStorageInt := -1
	q := `
SELECT instances_backups.id, instances_backups.instance_id,
       instances_backups.creation_date, instances_backups.expiry_date,
       instances_backups.container_only, instances_backups.optimized_storage
    FROM instances_backups
    JOIN instances ON instances.id=instances_backups.instance_id
    JOIN projects ON projects.id=instances.project_id
    WHERE projects.name=? AND instances_backups.name=?
`
	arg1 := []any{projectName, name}
	arg2 := []any{&args.ID, &args.InstanceID, &args.CreationDate,
		&args.ExpiryDate, &instanceOnlyInt, &optimizedStorageInt}

	err := dbQueryRowScan(ctx, c, q, arg1, arg2)
	if err != nil {
		if err == sql.ErrNoRows {
			return args, api.StatusErrorf(http.StatusNotFound, "Instance backup not found")
		}

		return args, err
	}

	if instanceOnlyInt == 1 {
		args.InstanceOnly = true
	}

	if optimizedStorageInt == 1 {
		args.OptimizedStorage = true
	}

	return args, nil
}

// GetInstanceBackupWithID returns the backup with the given ID.
func (c *ClusterTx) GetInstanceBackupWithID(ctx context.Context, backupID int) (InstanceBackup, error) {
	args := InstanceBackup{}
	args.ID = backupID

	instanceOnlyInt := -1
	optimizedStorageInt := -1
	q := `
SELECT instances_backups.name, instances_backups.instance_id,
       instances_backups.creation_date, instances_backups.expiry_date,
       instances_backups.container_only, instances_backups.optimized_storage
    FROM instances_backups
    JOIN instances ON instances.id=instances_backups.instance_id
    JOIN projects ON projects.id=instances.project_id
    WHERE instances_backups.id=?
`
	arg1 := []any{backupID}
	arg2 := []any{&args.Name, &args.InstanceID, &args.CreationDate,
		&args.ExpiryDate, &instanceOnlyInt, &optimizedStorageInt}

	err := dbQueryRowScan(ctx, c, q, arg1, arg2)
	if err != nil {
		if err == sql.ErrNoRows {
			return args, api.StatusErrorf(http.StatusNotFound, "Instance backup not found")
		}

		return args, err
	}

	if instanceOnlyInt == 1 {
		args.InstanceOnly = true
	}

	if optimizedStorageInt == 1 {
		args.OptimizedStorage = true
	}

	return args, nil
}

// GetInstanceBackups returns the names of all backups of the instance with the
// given name.
func (c *ClusterTx) GetInstanceBackups(ctx context.Context, projectName string, name string) ([]string, error) {
	var instanceBackupNames []string

	q := `SELECT instances_backups.name FROM instances_backups
JOIN instances ON instances_backups.instance_id=instances.id
JOIN projects ON projects.id=instances.project_id
WHERE projects.name=? AND instances.name=?`

	err := query.Scan(ctx, c.tx, q, func(scan func(dest ...any) error) error {
		var backupName string
		err := scan(&backupName)
		if err != nil {
			return err
		}

		instanceBackupNames = append(instanceBackupNames, backupName)

		return nil
	}, projectName, name)
	if err != nil {
		return nil, err
	}

	return instanceBackupNames, nil
}

// CreateInstanceBackup creates a new backup.
func (c *ClusterTx) CreateInstanceBackup(ctx context.Context, args InstanceBackup) error {
	_, err := c.getInstanceBackupID(ctx, args.Name)
	if err == nil {
		return api.StatusErrorf(http.StatusConflict, "Backup for instance %q already exists", args.Name)
	}

	instanceOnlyInt := 0
	if args.InstanceOnly {
		instanceOnlyInt = 1
	}

	optimizedStorageInt := 0
	if args.OptimizedStorage {
		optimizedStorageInt = 1
	}

	str := "INSERT INTO instances_backups (instance_id, name, creation_date, expiry_date, container_only, optimized_storage) VALUES (?, ?, ?, ?, ?, ?)"
	stmt, err := c.tx.Prepare(str)
	if err != nil {
		return err
	}

	defer func() { _ = stmt.Close() }()
	result, err := stmt.Exec(args.InstanceID, args.Name,
		args.CreationDate.Unix(), args.ExpiryDate.Unix(), instanceOnlyInt,
		optimizedStorageInt)
	if err != nil {
		return err
	}

	_, err = result.LastInsertId()
	if err != nil {
		return fmt.Errorf("Error inserting %q into database", args.Name)
	}

	return nil
}

// DeleteInstanceBackup removes the instance backup with the given name from the database.
func (c *ClusterTx) DeleteInstanceBackup(ctx context.Context, name string) error {
	id, err := c.getInstanceBackupID(ctx, name)
	if err != nil {
		return err
	}

	_, err = c.tx.ExecContext(ctx, "DELETE FROM instances_backups WHERE id=?", id)
	if err != nil {
		return err
	}

	return nil
}

// RenameInstanceBackup renames an instance backup from the given current name
// to the new one.
func (c *ClusterTx) RenameInstanceBackup(ctx context.Context, oldName, newName string) error {
	str := "UPDATE instances_backups SET name = ? WHERE name = ?"
	stmt, err := c.tx.PrepareContext(ctx, str)
	if err != nil {
		return err
	}

	defer func() { _ = stmt.Close() }()

	logger.Debug(
		"Calling SQL Query",
		logger.Ctx{
			"query":   "UPDATE instances_backups SET name = ? WHERE name = ?",
			"oldName": oldName,
			"newName": newName})
	_, err = stmt.ExecContext(ctx, newName, oldName)
	if err != nil {
		return err
	}

	return nil
}

// GetExpiredInstanceBackups returns a list of expired instance backups.
func (c *ClusterTx) GetExpiredInstanceBackups(ctx context.Context) ([]InstanceBackup, error) {
	var expiredInstanceBackups []InstanceBackup

	q := `SELECT instances_backups.name, instances_backups.expiry_date, instances_backups.instance_id FROM instances_backups`

	err := query.Scan(ctx, c.tx, q, func(scan func(dest ...any) error) error {
		var name string
		var expiryDate string
		var instanceID int

		err := scan(&name, &expiryDate, &instanceID)
		if err != nil {
			return err
		}

		var backupExpiry time.Time
		err = backupExpiry.UnmarshalText([]byte(expiryDate))
		if err != nil {
			return err
		}

		// Since zero time causes some issues due to timezones, we check the
		// unix timestamp instead of IsZero().
		if backupExpiry.Unix() <= 0 {
			// Backup doesn't expire
			return nil
		}

		// Backup has expired
		if time.Now().Unix()-backupExpiry.Unix() >= 0 {
			expiredInstanceBackups = append(expiredInstanceBackups, InstanceBackup{
				Name:       name,
				InstanceID: instanceID,
				ExpiryDate: backupExpiry,
			})
		}

		return nil
	})
	if err != nil {
		return nil, err
	}

	return expiredInstanceBackups, nil
}

// GetExpiredStorageVolumeBackups returns a list of expired storage volume backups.
func (c *ClusterTx) GetExpiredStorageVolumeBackups(ctx context.Context) ([]StoragePoolVolumeBackup, error) {
	var backups []StoragePoolVolumeBackup

	q := `SELECT storage_volumes_backups.name, storage_volumes_backups.expiry_date, storage_volumes_backups.storage_volume_id FROM storage_volumes_backups`

	err := query.Scan(ctx, c.Tx(), q, func(scan func(dest ...any) error) error {
		var b StoragePoolVolumeBackup
		var expiryTime sql.NullTime

		err := scan(&b.Name, &expiryTime, &b.VolumeID)
		if err != nil {
			return err
		}

		b.ExpiryDate = expiryTime.Time // Convert nulls to zero.

		// Since zero time causes some issues due to timezones, we check the
		// unix timestamp instead of IsZero().
		if b.ExpiryDate.Unix() <= 0 {
			// Backup doesn't expire
			return nil
		}

		// Backup has expired
		if time.Now().Unix()-b.ExpiryDate.Unix() >= 0 {
			backups = append(backups, b)
		}

		return nil
	})
	if err != nil {
		return nil, err
	}

	return backups, nil
}

// GetStoragePoolVolumeBackups returns a list of volume backups.
func (c *ClusterTx) GetStoragePoolVolumeBackups(ctx context.Context, projectName string, volumeName string, poolID int64) ([]StoragePoolVolumeBackup, error) {
	q := `
	SELECT
		backups.id,
		backups.storage_volume_id,
		backups.name,
		backups.creation_date,
		backups.expiry_date,
		backups.volume_only,
		backups.optimized_storage
	FROM storage_volumes_backups AS backups
	JOIN storage_volumes ON storage_volumes.id=backups.storage_volume_id
	JOIN projects ON projects.id=storage_volumes.project_id
	WHERE projects.name=? AND storage_volumes.name=? AND storage_volumes.storage_pool_id=?
	ORDER BY backups.id
	`

	var backups []StoragePoolVolumeBackup

	err := query.Scan(ctx, c.tx, q, func(scan func(dest ...any) error) error {
		var b StoragePoolVolumeBackup
		var expiryTime sql.NullTime

		err := scan(&b.ID, &b.VolumeID, &b.Name, &b.CreationDate, &expiryTime, &b.VolumeOnly, &b.OptimizedStorage)
		if err != nil {
			return err
		}

		b.ExpiryDate = expiryTime.Time // Convert nulls to zero.

		backups = append(backups, b)

		return nil
	}, projectName, volumeName, poolID)
	if err != nil {
		return nil, err
	}

	return backups, nil
}

// GetStoragePoolVolumeBackupsNames returns the names of all backups of the storage volume with the given name.
func (c *ClusterTx) GetStoragePoolVolumeBackupsNames(ctx context.Context, projectName string, volumeName string, poolID int64) ([]string, error) {
	var storagePoolVolumeBackupsNames []string

	q := `SELECT storage_volumes_backups.name FROM storage_volumes_backups
JOIN storage_volumes ON storage_volumes_backups.storage_volume_id=storage_volumes.id
JOIN projects ON projects.id=storage_volumes.project_id
WHERE projects.name=? AND storage_volumes.name=?
ORDER BY storage_volumes_backups.id`

	err := query.Scan(ctx, c.tx, q, func(scan func(dest ...any) error) error {
		var backupName string
		err := scan(&backupName)
		if err != nil {
			return err
		}

		storagePoolVolumeBackupsNames = append(storagePoolVolumeBackupsNames, backupName)

		return nil
	}, projectName, volumeName)
	if err != nil {
		return nil, err
	}

	return storagePoolVolumeBackupsNames, nil
}

// CreateStoragePoolVolumeBackup creates a new storage volume backup.
func (c *ClusterTx) CreateStoragePoolVolumeBackup(ctx context.Context, args StoragePoolVolumeBackup) error {
	_, err := c.getStoragePoolVolumeBackupID(ctx, args.Name)
	if err == nil {
		return api.StatusErrorf(http.StatusConflict, "Backup for storage volume %q already exists", args.Name)
	}

	volumeOnlyInt := 0
	if args.VolumeOnly {
		volumeOnlyInt = 1
	}

	optimizedStorageInt := 0
	if args.OptimizedStorage {
		optimizedStorageInt = 1
	}

	str := "INSERT INTO storage_volumes_backups (storage_volume_id, name, creation_date, expiry_date, volume_only, optimized_storage) VALUES (?, ?, ?, ?, ?, ?)"
	stmt, err := c.tx.Prepare(str)
	if err != nil {
		return err
	}

	defer func() { _ = stmt.Close() }()
	result, err := stmt.Exec(args.VolumeID, args.Name,
		args.CreationDate.Unix(), args.ExpiryDate.Unix(), volumeOnlyInt,
		optimizedStorageInt)
	if err != nil {
		return err
	}

	_, err = result.LastInsertId()
	if err != nil {
		return fmt.Errorf("Error inserting %q into database", args.Name)
	}

	return nil
}

// Returns the ID of the storage volume backup with the given name.
func (c *ClusterTx) getStoragePoolVolumeBackupID(ctx context.Context, name string) (int, error) {
	q := "SELECT id FROM storage_volumes_backups WHERE name=?"
	id := -1
	arg1 := []any{name}
	arg2 := []any{&id}

	err := dbQueryRowScan(ctx, c, q, arg1, arg2)
	if err == sql.ErrNoRows {
		return -1, api.StatusErrorf(http.StatusNotFound, "Storage volume backup not found")
	}

	return id, err
}

// DeleteStoragePoolVolumeBackup removes the storage volume backup with the given name from the database.
func (c *ClusterTx) DeleteStoragePoolVolumeBackup(ctx context.Context, name string) error {
	id, err := c.getStoragePoolVolumeBackupID(ctx, name)
	if err != nil {
		return err
	}

	_, err = c.tx.ExecContext(ctx, "DELETE FROM storage_volumes_backups WHERE id=?", id)
	if err != nil {
		return err
	}

	return nil
}

// GetStoragePoolVolumeBackup returns the volume backup with the given name.
func (c *ClusterTx) GetStoragePoolVolumeBackup(ctx context.Context, projectName string, poolName string, backupName string) (StoragePoolVolumeBackup, error) {
	args := StoragePoolVolumeBackup{}
	q := `
SELECT
	backups.id,
	backups.storage_volume_id,
	backups.name,
	backups.creation_date,
	backups.expiry_date,
	backups.volume_only,
	backups.optimized_storage
FROM storage_volumes_backups AS backups
JOIN storage_volumes ON storage_volumes.id=backups.storage_volume_id
JOIN projects ON projects.id=storage_volumes.project_id
WHERE projects.name=? AND backups.name=?
`
	arg1 := []any{projectName, backupName}
	outfmt := []any{&args.ID, &args.VolumeID, &args.Name, &args.CreationDate, &args.ExpiryDate, &args.VolumeOnly, &args.OptimizedStorage}

	err := dbQueryRowScan(ctx, c, q, arg1, outfmt)
	if err != nil {
		if err == sql.ErrNoRows {
			return args, api.StatusErrorf(http.StatusNotFound, "Storage volume backup not found")
		}

		return args, err
	}

	return args, nil
}

// GetStoragePoolVolumeBackupWithID returns the volume backup with the given ID.
func (c *ClusterTx) GetStoragePoolVolumeBackupWithID(ctx context.Context, backupID int) (StoragePoolVolumeBackup, error) {
	args := StoragePoolVolumeBackup{}
	q := `
SELECT
	backups.id,
	backups.storage_volume_id,
	backups.name,
	backups.creation_date,
	backups.expiry_date,
	backups.volume_only,
	backups.optimized_storage
FROM storage_volumes_backups AS backups
JOIN storage_volumes ON storage_volumes.id=backups.storage_volume_id
JOIN projects ON projects.id=storage_volumes.project_id
WHERE backups.id=?
`
	arg1 := []any{backupID}
	outfmt := []any{&args.ID, &args.VolumeID, &args.Name, &args.CreationDate, &args.ExpiryDate, &args.VolumeOnly, &args.OptimizedStorage}

	err := dbQueryRowScan(ctx, c, q, arg1, outfmt)
	if err != nil {
		if err == sql.ErrNoRows {
			return args, api.StatusErrorf(http.StatusNotFound, "Storage volume backup not found")
		}

		return args, err
	}

	return args, nil
}

// RenameVolumeBackup renames a volume backup from the given current name
// to the new one.
func (c *ClusterTx) RenameVolumeBackup(ctx context.Context, oldName, newName string) error {
	str := "UPDATE storage_volumes_backups SET name = ? WHERE name = ?"
	stmt, err := c.tx.Prepare(str)
	if err != nil {
		return err
	}

	defer func() { _ = stmt.Close() }()

	logger.Debug(
		"Calling SQL Query",
		logger.Ctx{
			"query":   "UPDATE storage_volumes_backups SET name = ? WHERE name = ?",
			"oldName": oldName,
			"newName": newName})
	_, err = stmt.Exec(newName, oldName)
	if err != nil {
		return err
	}

	return nil
}
