package shard

import (
	"context"
	"fmt"

	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
	meta "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/metabase"
	tracingPkg "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/tracing"
	"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
	"go.uber.org/zap"
)

// DeletePrm groups the parameters of Delete operation.
type DeletePrm struct {
	addr []oid.Address
}

// DeleteRes groups the resulting values of Delete operation.
type DeleteRes struct {
	deleted uint64
}

// SetAddresses is a Delete option to set the addresses of the objects to delete.
//
// Option is required.
func (p *DeletePrm) SetAddresses(addr ...oid.Address) {
	p.addr = append(p.addr, addr...)
}

// Delete removes data from the shard's metaBase and// blobStor.
func (s *Shard) Delete(ctx context.Context, prm DeletePrm) (DeleteRes, error) {
	ctx, span := tracing.StartSpanFromContext(ctx, "Shard.Delete",
		trace.WithAttributes(
			attribute.String("shard_id", s.ID().String()),
			attribute.Int("addr_count", len(prm.addr)),
		))
	defer span.End()

	s.m.RLock()
	defer s.m.RUnlock()

	return s.delete(ctx, prm, false)
}

func (s *Shard) delete(ctx context.Context, prm DeletePrm, skipFailed bool) (DeleteRes, error) {
	if s.info.Mode.ReadOnly() {
		return DeleteRes{}, ErrReadOnlyMode
	} else if s.info.Mode.NoMetabase() {
		return DeleteRes{}, ErrDegradedMode
	}

	result := DeleteRes{}
	for _, addr := range prm.addr {
		select {
		case <-ctx.Done():
			return result, ctx.Err()
		default:
		}

		if err := s.validateWritecacheDoesntContainObject(ctx, addr); err != nil {
			if skipFailed {
				continue
			}
			return result, err
		}

		if err := s.deleteFromBlobstor(ctx, addr); err != nil {
			if skipFailed {
				continue
			}
			return result, err
		}

		if err := s.deleteFromMetabase(ctx, addr); err != nil {
			if skipFailed {
				continue
			}
			return result, err
		}
		result.deleted++
	}

	return result, nil
}

func (s *Shard) validateWritecacheDoesntContainObject(ctx context.Context, addr oid.Address) error {
	if !s.hasWriteCache() {
		return nil
	}
	_, err := s.writeCache.Head(ctx, addr)
	if err == nil {
		s.log.Warn(ctx, logs.ObjectRemovalFailureExistsInWritecache, zap.Stringer("object_address", addr))
		return fmt.Errorf("object %s must be flushed from writecache", addr)
	}
	if client.IsErrObjectNotFound(err) {
		return nil
	}
	return err
}

func (s *Shard) deleteFromBlobstor(ctx context.Context, addr oid.Address) error {
	var sPrm meta.StorageIDPrm
	sPrm.SetAddress(addr)

	res, err := s.metaBase.StorageID(ctx, sPrm)
	if err != nil {
		s.log.Debug(ctx, logs.StorageIDRetrievalFailure,
			zap.Stringer("object", addr),
			zap.String("error", err.Error()),
			zap.String("trace_id", tracingPkg.GetTraceID(ctx)))
		return err
	}
	storageID := res.StorageID()
	if storageID == nil {
		// if storageID is nil it means:
		// 1. there is no such object
		// 2. object stored by writecache: should not happen, as `validateWritecacheDoesntContainObject` called before `deleteFromBlobstor`
		return nil
	}

	var delPrm common.DeletePrm
	delPrm.Address = addr
	delPrm.StorageID = storageID

	_, err = s.blobStor.Delete(ctx, delPrm)
	if err != nil && !client.IsErrObjectNotFound(err) {
		s.log.Debug(ctx, logs.ObjectRemovalFailureBlobStor,
			zap.Stringer("object_address", addr),
			zap.String("error", err.Error()),
			zap.String("trace_id", tracingPkg.GetTraceID(ctx)))
		return err
	}
	return nil
}

func (s *Shard) deleteFromMetabase(ctx context.Context, addr oid.Address) error {
	var delPrm meta.DeletePrm
	delPrm.SetAddresses(addr)

	res, err := s.metaBase.Delete(ctx, delPrm)
	if err != nil {
		return err
	}
	s.decObjectCounterBy(physical, res.PhyCount())
	s.decObjectCounterBy(logical, res.LogicCount())
	s.decObjectCounterBy(user, res.UserCount())
	s.decContainerObjectCounter(res.RemovedByCnrID())
	s.addToContainerSize(addr.Container().EncodeToString(), -int64(res.LogicSize()))
	s.addToPayloadSize(-int64(res.PhySize()))

	return nil
}