package engine

import (
	"errors"

	"github.com/nspcc-dev/neofs-node/pkg/core/object"
	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/shard"
	objectSDK "github.com/nspcc-dev/neofs-sdk-go/object"
	"go.uber.org/zap"
)

// PutPrm groups the parameters of Put operation.
type PutPrm struct {
	obj *objectSDK.Object
}

// PutRes groups the resulting values of Put operation.
type PutRes struct{}

var errPutShard = errors.New("could not put object to any shard")

// WithObject is a Put option to set object to save.
//
// Option is required.
func (p *PutPrm) WithObject(obj *objectSDK.Object) {
	if p != nil {
		p.obj = obj
	}
}

// Put saves the object to local storage.
//
// Returns any error encountered that
// did not allow to completely save the object.
//
// Returns an error if executions are blocked (see BlockExecution).
//
// Returns an error of type apistatus.ObjectAlreadyRemoved if the object has been marked as removed.
func (e *StorageEngine) Put(prm PutPrm) (res PutRes, err error) {
	err = e.execIfNotBlocked(func() error {
		res, err = e.put(prm)
		return err
	})

	return
}

func (e *StorageEngine) put(prm PutPrm) (PutRes, error) {
	if e.metrics != nil {
		defer elapsed(e.metrics.AddPutDuration)()
	}

	addr := object.AddressOf(prm.obj)

	// In #1146 this check was parallelized, however, it became
	// much slower on fast machines for 4 shards.
	_, err := e.exists(addr)
	if err != nil {
		return PutRes{}, err
	}

	var existPrm shard.ExistsPrm
	existPrm.SetAddress(addr)

	finished := false

	e.iterateOverSortedShards(addr, func(ind int, sh hashedShard) (stop bool) {
		e.mtx.RLock()
		pool := e.shardPools[sh.ID().String()]
		e.mtx.RUnlock()

		exitCh := make(chan struct{})

		if err := pool.Submit(func() {
			defer close(exitCh)

			exists, err := sh.Exists(existPrm)
			if err != nil {
				return // this is not ErrAlreadyRemoved error so we can go to the next shard
			}

			if exists.Exists() {
				if ind != 0 {
					var toMoveItPrm shard.ToMoveItPrm
					toMoveItPrm.SetAddress(addr)

					_, err = sh.ToMoveIt(toMoveItPrm)
					if err != nil {
						e.log.Warn("could not mark object for shard relocation",
							zap.Stringer("shard", sh.ID()),
							zap.String("error", err.Error()),
						)
					}
				}

				finished = true

				return
			}

			var putPrm shard.PutPrm
			putPrm.SetObject(prm.obj)

			_, err = sh.Put(putPrm)
			if err != nil {
				e.log.Warn("could not put object in shard",
					zap.Stringer("shard", sh.ID()),
					zap.String("error", err.Error()),
				)

				return
			}

			finished = true
		}); err != nil {
			close(exitCh)
		}

		<-exitCh

		return finished
	})

	if !finished {
		err = errPutShard
	}

	return PutRes{}, err
}

// Put writes provided object to local storage.
func Put(storage *StorageEngine, obj *objectSDK.Object) error {
	var putPrm PutPrm
	putPrm.WithObject(obj)

	_, err := storage.Put(putPrm)

	return err
}