package internal

import (
	"context"
	"fmt"
	"math/rand"
	"sync"

	meta "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/metabase"
	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/transformer"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"golang.org/x/sync/errgroup"
)

type EpochState struct{}

func (s EpochState) CurrentEpoch() uint64 {
	return 0
}

func PopulateWithObjects(
	ctx context.Context,
	db *meta.DB,
	group *errgroup.Group,
	count uint,
	factory func() *objectSDK.Object,
) {
	digits := "0123456789"

	for i := uint(0); i < count; i++ {
		obj := factory()

		id := []byte(fmt.Sprintf(
			"%c/%c/%c",
			digits[rand.Int()%len(digits)],
			digits[rand.Int()%len(digits)],
			digits[rand.Int()%len(digits)],
		))

		prm := meta.PutPrm{}
		prm.SetObject(obj)
		prm.SetStorageID(id)

		group.Go(func() error {
			if _, err := db.Put(ctx, prm); err != nil {
				return fmt.Errorf("couldn't put an object: %w", err)
			}
			return nil
		})
	}
}

func PopulateWithBigObjects(
	ctx context.Context,
	db *meta.DB,
	group *errgroup.Group,
	count uint,
	factory func() *objectSDK.Object,
) {
	for i := uint(0); i < count; i++ {
		group.Go(func() error {
			if err := populateWithBigObject(ctx, db, factory); err != nil {
				return fmt.Errorf("couldn't put a big object: %w", err)
			}
			return nil
		})
	}
}

func populateWithBigObject(
	ctx context.Context,
	db *meta.DB,
	factory func() *objectSDK.Object,
) error {
	t := &target{db: db}

	pk, _ := keys.NewPrivateKey()
	p := transformer.NewPayloadSizeLimiter(transformer.Params{
		Key:            &pk.PrivateKey,
		NextTargetInit: func() transformer.ObjectWriter { return t },
		NetworkState:   EpochState{},
		MaxSize:        10,
	})

	obj := factory()
	payload := make([]byte, 30)

	err := p.WriteHeader(ctx, obj)
	if err != nil {
		return err
	}

	_, err = p.Write(ctx, payload)
	if err != nil {
		return err
	}

	_, err = p.Close(ctx)
	if err != nil {
		return err
	}

	return nil
}

type target struct {
	db *meta.DB
}

func (t *target) WriteObject(ctx context.Context, obj *objectSDK.Object) error {
	prm := meta.PutPrm{}
	prm.SetObject(obj)

	_, err := t.db.Put(ctx, prm)
	return err
}

func PopulateGraveyard(
	ctx context.Context,
	db *meta.DB,
	group *errgroup.Group,
	workBufferSize int,
	count uint,
	factory func() *objectSDK.Object,
) {
	ts := factory()
	ts.SetType(objectSDK.TypeTombstone)

	prm := meta.PutPrm{}
	prm.SetObject(ts)

	group.Go(func() error {
		if _, err := db.Put(ctx, prm); err != nil {
			return fmt.Errorf("couldn't put a tombstone object: %w", err)
		}
		return nil
	})

	cID, _ := ts.ContainerID()
	oID, _ := ts.ID()

	var tsAddr oid.Address

	tsAddr.SetContainer(cID)
	tsAddr.SetObject(oID)

	addrs := make(chan oid.Address, workBufferSize)

	go func() {
		defer close(addrs)

		wg := &sync.WaitGroup{}
		wg.Add(int(count))

		for i := uint(0); i < count; i++ {
			obj := factory()

			prm := meta.PutPrm{}
			prm.SetObject(obj)

			group.Go(func() error {
				defer wg.Done()

				if _, err := db.Put(ctx, prm); err != nil {
					return fmt.Errorf("couldn't put an object: %w", err)
				}

				cID, _ := obj.ContainerID()
				oID, _ := obj.ID()

				var addr oid.Address
				addr.SetContainer(cID)
				addr.SetObject(oID)

				addrs <- addr
				return nil
			})
		}
		wg.Wait()
	}()

	go func() {
		for addr := range addrs {
			prm := meta.InhumePrm{}
			prm.SetAddresses(addr)
			prm.SetTombstoneAddress(tsAddr)

			group.Go(func() error {
				if _, err := db.Inhume(ctx, prm); err != nil {
					return fmt.Errorf("couldn't inhume an object: %w", err)
				}
				return nil
			})
		}
	}()
}

func PopulateLocked(
	ctx context.Context,
	db *meta.DB,
	group *errgroup.Group,
	workBufferSize int,
	count uint,
	factory func() *objectSDK.Object,
) {
	locker := factory()
	locker.SetType(objectSDK.TypeLock)

	prm := meta.PutPrm{}
	prm.SetObject(locker)

	group.Go(func() error {
		if _, err := db.Put(ctx, prm); err != nil {
			return fmt.Errorf("couldn't put a locker object: %w", err)
		}
		return nil
	})

	ids := make(chan oid.ID, workBufferSize)

	go func() {
		defer close(ids)

		wg := &sync.WaitGroup{}
		wg.Add(int(count))

		for i := uint(0); i < count; i++ {
			defer wg.Done()

			obj := factory()

			prm := meta.PutPrm{}
			prm.SetObject(obj)

			group.Go(func() error {
				if _, err := db.Put(ctx, prm); err != nil {
					return fmt.Errorf("couldn't put an object: %w", err)
				}

				id, _ := obj.ID()
				ids <- id
				return nil
			})
		}
		wg.Wait()
	}()

	go func() {
		for id := range ids {
			lockerCID, _ := locker.ContainerID()
			lockerOID, _ := locker.ID()

			group.Go(func() error {
				if err := db.Lock(ctx, lockerCID, lockerOID, []oid.ID{id}); err != nil {
					return fmt.Errorf("couldn't lock an object: %w", err)
				}
				return nil
			})
		}
	}()
}