/*
Copyright 2024 The Ceph-CSI 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

    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.
*/

package group

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/ceph/go-ceph/rados"

	"github.com/ceph/ceph-csi/internal/journal"
	"github.com/ceph/ceph-csi/internal/util"
	"github.com/ceph/ceph-csi/internal/util/log"
)

type commonVolumeGroup struct {
	// id is a unique value for this volume group in the Ceph cluster, it
	// is used to find the group in the journal.
	id string

	// requestName is passed by the caller when a group is created.
	requestName string

	// name is used in RBD API calls as the name of this object
	name string

	// creationTime is the time the group was created
	creationTime *time.Time

	clusterID  string
	objectUUID string

	credentials *util.Credentials

	// temporary connection attributes
	conn  *util.ClusterConnection
	ioctx *rados.IOContext

	// required details to perform operations on the group
	monitors  string
	pool      string
	namespace string

	// csiDriver is the CSI drivername that is required to connect the journal
	csiDriver string
	// use getJournal() to make sure the journal is connected
	journal journal.VolumeGroupJournal
}

func (cvg *commonVolumeGroup) initCommonVolumeGroup(
	ctx context.Context,
	id string,
	csiDriver string,
	creds *util.Credentials,
) error {
	csiID := util.CSIIdentifier{}
	err := csiID.DecomposeCSIID(id)
	if err != nil {
		return fmt.Errorf("failed to decompose volume group id %q: %w", id, err)
	}

	mons, err := util.Mons(util.CsiConfigFile, csiID.ClusterID)
	if err != nil {
		return fmt.Errorf("failed to get MONs for cluster id %q: %w", csiID.ClusterID, err)
	}

	namespace, err := util.GetRBDRadosNamespace(util.CsiConfigFile, csiID.ClusterID)
	if err != nil {
		return fmt.Errorf("failed to get RADOS namespace for cluster id %q: %w", csiID.ClusterID, err)
	}

	pool, err := util.GetPoolName(mons, creds, csiID.LocationID)
	if err != nil {
		return fmt.Errorf("failed to get pool for volume group id %q: %w", id, err)
	}

	cvg.csiDriver = csiDriver
	cvg.credentials = creds
	cvg.id = id
	cvg.clusterID = csiID.ClusterID
	cvg.objectUUID = csiID.ObjectUUID
	cvg.monitors = mons
	cvg.pool = pool
	cvg.namespace = namespace

	log.DebugLog(ctx, "object for volume group %q has been initialized", cvg.id)

	return nil
}

func (cvg *commonVolumeGroup) Destroy(ctx context.Context) {
	if cvg.ioctx != nil {
		cvg.ioctx.Destroy()
		cvg.ioctx = nil
	}

	if cvg.conn != nil {
		cvg.conn.Destroy()
		cvg.conn = nil
	}

	if cvg.credentials != nil {
		// credentials should only be removed with DeleteCredentials()
		// by the caller that allocated them
		cvg.credentials = nil
	}

	if cvg.journal != nil {
		cvg.journal.Destroy()
		cvg.journal = nil
	}
}

// getVolumeGroupAttributes fetches the attributes from the journal, sets some
// of the common values for the VolumeGroup and returns the attributes struct
// for further consumption (like checking the VolumeMap).
func (cvg *commonVolumeGroup) getVolumeGroupAttributes(ctx context.Context) (*journal.VolumeGroupAttributes, error) {
	j, err := cvg.getJournal(ctx)
	if err != nil {
		return nil, err
	}

	attrs, err := j.GetVolumeGroupAttributes(ctx, cvg.pool, cvg.objectUUID)
	if err != nil {
		if !errors.Is(err, util.ErrKeyNotFound) && !errors.Is(err, util.ErrPoolNotFound) {
			return nil, fmt.Errorf("failed to get attributes for volume group id %q: %w", cvg.id, err)
		}

		attrs = &journal.VolumeGroupAttributes{}
	}

	if attrs.GroupName == "" {
		log.ErrorLog(ctx, "volume group with id %v not found", cvg.id)

		return nil, ErrRBDGroupNotFound
	}

	cvg.requestName = attrs.RequestName
	cvg.name = attrs.GroupName
	cvg.creationTime = attrs.CreationTime

	return attrs, nil
}

// String returns the image-spec (pool/{namespace}/{name}) format of the group.
func (cvg *commonVolumeGroup) String() string {
	if cvg.namespace != "" && cvg.pool != "" && cvg.name != "" {
		return fmt.Sprintf("%s/%s/%s", cvg.pool, cvg.namespace, cvg.name)
	}

	if cvg.name != "" && cvg.pool != "" {
		return fmt.Sprintf("%s/%s", cvg.pool, cvg.name)
	}

	return fmt.Sprintf("<unidentified group %v>", *cvg)
}

// GetID returns the CSI-Addons VolumeGroupId of the VolumeGroup.
func (cvg *commonVolumeGroup) GetID(ctx context.Context) (string, error) {
	if cvg.id == "" {
		return "", errors.New("BUG: ID is not set")
	}

	return cvg.id, nil
}

// GetName returns the name in the backend storage for the VolumeGroup.
func (cvg *commonVolumeGroup) GetName(ctx context.Context) (string, error) {
	if cvg.name == "" {
		return "", errors.New("BUG: name is not set")
	}

	return cvg.name, nil
}

// GetRequestName returns the requestName of the VolumeGroup.
func (cvg *commonVolumeGroup) GetRequestName(ctx context.Context) (string, error) {
	if cvg.requestName == "" {
		return "", errors.New("BUG: requestName is not set")
	}

	return cvg.requestName, nil
}

// GetPool returns the name of the pool that holds the VolumeGroup.
func (cvg *commonVolumeGroup) GetPool(ctx context.Context) (string, error) {
	if cvg.pool == "" {
		return "", errors.New("BUG: pool is not set")
	}

	return cvg.pool, nil
}

// GetClusterID returns the name of the pool that holds the VolumeGroup.
func (cvg *commonVolumeGroup) GetClusterID(ctx context.Context) (string, error) {
	if cvg.clusterID == "" {
		return "", errors.New("BUG: clusterID is not set")
	}

	return cvg.clusterID, nil
}

// getConnection returns the ClusterConnection for the volume group if it
// exists, otherwise it will open a new one.
// Destroy should be used to close the ClusterConnection.
func (cvg *commonVolumeGroup) getConnection(ctx context.Context) (*util.ClusterConnection, error) {
	if cvg.conn != nil {
		return cvg.conn, nil
	}

	if cvg.credentials == nil {
		log.DebugLog(ctx, "missing credentials for common volume group %q: %s", cvg, util.CallStack())

		return nil, errors.New("can not connect to cluster without credentials")
	}

	conn := &util.ClusterConnection{}
	err := conn.Connect(cvg.monitors, cvg.credentials)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to MONs %q: %w", cvg.monitors, err)
	}

	cvg.conn = conn
	log.DebugLog(ctx, "connection established for volume group %q", cvg.id)

	return conn, nil
}

func (cvg *commonVolumeGroup) getJournal(ctx context.Context) (journal.VolumeGroupJournal, error) {
	if cvg.journal != nil {
		return cvg.journal, nil
	}

	if cvg.credentials == nil {
		log.DebugLog(ctx, "missing credentials for common volume group %q: %s", cvg, util.CallStack())

		return nil, errors.New("can not connect the journal without credentials")
	}

	journalConfig := journal.NewCSIVolumeGroupJournalWithNamespace(cvg.csiDriver, cvg.namespace)

	j, err := journalConfig.Connect(cvg.monitors, cvg.namespace, cvg.credentials)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to journal: %w", err)
	}

	cvg.journal = j

	return j, nil
}

// GetIOContext returns the IOContext for the volume group if it exists,
// otherwise it will allocate a new one.
// Destroy should be used to free the IOContext.
func (cvg *commonVolumeGroup) GetIOContext(ctx context.Context) (*rados.IOContext, error) {
	if cvg.ioctx != nil {
		return cvg.ioctx, nil
	}

	conn, err := cvg.getConnection(ctx)
	if err != nil {
		return nil, fmt.Errorf("%w: failed to connect: %w", ErrRBDGroupNotConnected, err)
	}

	ioctx, err := conn.GetIoctx(cvg.pool)
	if err != nil {
		return nil, fmt.Errorf("%w: failed to get IOContext: %w", ErrRBDGroupNotConnected, err)
	}

	if cvg.namespace != "" {
		ioctx.SetNamespace(cvg.namespace)
	}

	cvg.ioctx = ioctx
	log.DebugLog(ctx, "iocontext created for volume group %q in pool %q", cvg.id, cvg.pool)

	return ioctx, nil
}

// Delete removes the volume group from the journal.
func (cvg *commonVolumeGroup) Delete(ctx context.Context) error {
	name, err := cvg.GetName(ctx)
	if err != nil {
		return fmt.Errorf("failed to get name for volume group %q: %w", cvg, err)
	}

	reqName, err := cvg.GetRequestName(ctx)
	if err != nil {
		return fmt.Errorf("failed to get request name for volume group %q: %w", cvg, err)
	}

	pool, err := cvg.GetPool(ctx)
	if err != nil {
		return fmt.Errorf("failed to get pool for volume group %q: %w", cvg, err)
	}

	j, err := cvg.getJournal(ctx)
	if err != nil {
		return err
	}

	err = j.UndoReservation(ctx, pool, name, reqName)
	if err != nil /* TODO? !errors.Is(..., err) */ {
		return fmt.Errorf("failed to undo the reservation for volume group %q: %w", cvg, err)
	}

	return nil
}

// GetCreationTime fetches the creation time of the volume group from the
// journal and returns it.
func (cvg *commonVolumeGroup) GetCreationTime(ctx context.Context) (*time.Time, error) {
	if cvg.creationTime == nil {
		// getVolumeGroupAttributes sets .creationTime (and a few other attributes)
		_, err := cvg.getVolumeGroupAttributes(ctx)
		if err != nil {
			return nil, fmt.Errorf("failed to get volume attributes for id %q: %w", cvg, err)
		}
	}

	return cvg.creationTime, nil
}