package getsvc

import (
	"context"
	"crypto/ecdsa"
	"errors"

	coreclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine"
	internalclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/internal/client"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/bearer"
	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	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/session"
)

type epochSource interface {
	Epoch() (uint64, error)
}

type traverserGenerator interface {
	GenerateTraverser(cid.ID, *oid.ID, uint64) (*placement.Traverser, error)
}

type keyStorage interface {
	GetKey(info *util.SessionInfo) (*ecdsa.PrivateKey, error)
}

type localStorageEngine interface {
	Head(ctx context.Context, p engine.HeadPrm) (engine.HeadRes, error)
	GetRange(ctx context.Context, p engine.RngPrm) (engine.RngRes, error)
	Get(ctx context.Context, p engine.GetPrm) (engine.GetRes, error)
}

type clientConstructor interface {
	Get(coreclient.NodeInfo) (coreclient.MultiAddressClient, error)
}

type remoteStorageConstructor interface {
	Get(coreclient.NodeInfo) (remoteStorage, error)
}

type multiclientRemoteStorageConstructor struct {
	clientConstructor clientConstructor
}

func (c *multiclientRemoteStorageConstructor) Get(info coreclient.NodeInfo) (remoteStorage, error) {
	clt, err := c.clientConstructor.Get(info)
	if err != nil {
		return nil, err
	}

	return &multiaddressRemoteStorage{
		client: clt,
	}, nil
}

type localStorage interface {
	Head(ctx context.Context, address oid.Address, isRaw bool) (*objectSDK.Object, error)
	Range(ctx context.Context, address oid.Address, rng *objectSDK.Range) (*objectSDK.Object, error)
	Get(ctx context.Context, address oid.Address) (*objectSDK.Object, error)
}

type engineLocalStorage struct {
	engine localStorageEngine
}

func (s *engineLocalStorage) Head(ctx context.Context, address oid.Address, isRaw bool) (*objectSDK.Object, error) {
	var headPrm engine.HeadPrm
	headPrm.WithAddress(address)
	headPrm.WithRaw(isRaw)

	r, err := s.engine.Head(ctx, headPrm)
	if err != nil {
		return nil, err
	}

	return r.Header(), nil
}

func (s *engineLocalStorage) Range(ctx context.Context, address oid.Address, rng *objectSDK.Range) (*objectSDK.Object, error) {
	var getRange engine.RngPrm
	getRange.WithAddress(address)
	getRange.WithPayloadRange(rng)

	r, err := s.engine.GetRange(ctx, getRange)
	if err != nil {
		return nil, err
	}

	return r.Object(), nil
}

func (s *engineLocalStorage) Get(ctx context.Context, address oid.Address) (*objectSDK.Object, error) {
	var getPrm engine.GetPrm
	getPrm.WithAddress(address)

	r, err := s.engine.Get(ctx, getPrm)
	if err != nil {
		return nil, err
	}

	return r.Object(), nil
}

type RemoteRequestParams struct {
	Epoch        uint64
	TTL          uint32
	PrivateKey   *ecdsa.PrivateKey
	SessionToken *session.Object
	BearerToken  *bearer.Token
	XHeaders     []string
	IsRaw        bool
}

type remoteStorage interface {
	Get(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error)
	Head(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error)
	Range(ctx context.Context, address oid.Address, rng *objectSDK.Range, requestParams RemoteRequestParams) (*objectSDK.Object, error)

	ForwardRequest(ctx context.Context, info coreclient.NodeInfo, forwarder RequestForwarder) (*objectSDK.Object, error)
}

type multiaddressRemoteStorage struct {
	client coreclient.MultiAddressClient
}

func (s *multiaddressRemoteStorage) ForwardRequest(ctx context.Context, info coreclient.NodeInfo, forwarder RequestForwarder) (*objectSDK.Object, error) {
	return forwarder(ctx, info, s.client)
}

func (s *multiaddressRemoteStorage) Range(ctx context.Context, address oid.Address, rng *objectSDK.Range, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
	var prm internalclient.PayloadRangePrm

	prm.SetClient(s.client)
	prm.SetTTL(requestParams.TTL)
	prm.SetNetmapEpoch(requestParams.Epoch)
	prm.SetAddress(address)
	prm.SetPrivateKey(requestParams.PrivateKey)
	prm.SetSessionToken(requestParams.SessionToken)
	prm.SetBearerToken(requestParams.BearerToken)
	prm.SetXHeaders(requestParams.XHeaders)
	prm.SetRange(rng)
	if requestParams.IsRaw {
		prm.SetRawFlag()
	}

	res, err := internalclient.PayloadRange(ctx, prm)
	if err != nil {
		var errAccessDenied *apistatus.ObjectAccessDenied
		if errors.As(err, &errAccessDenied) {
			obj, err := s.Get(ctx, address, requestParams)
			if err != nil {
				return nil, err
			}

			payload := obj.Payload()
			from := rng.GetOffset()
			to := from + rng.GetLength()

			if pLen := uint64(len(payload)); to < from || pLen < from || pLen < to {
				return nil, new(apistatus.ObjectOutOfRange)
			}

			return s.payloadOnlyObject(payload[from:to]), nil
		}
		return nil, err
	}

	return s.payloadOnlyObject(res.PayloadRange()), nil
}

func (s *multiaddressRemoteStorage) Head(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
	var prm internalclient.HeadObjectPrm

	prm.SetClient(s.client)
	prm.SetTTL(requestParams.TTL)
	prm.SetNetmapEpoch(requestParams.Epoch)
	prm.SetAddress(address)
	prm.SetPrivateKey(requestParams.PrivateKey)
	prm.SetSessionToken(requestParams.SessionToken)
	prm.SetBearerToken(requestParams.BearerToken)
	prm.SetXHeaders(requestParams.XHeaders)

	if requestParams.IsRaw {
		prm.SetRawFlag()
	}

	res, err := internalclient.HeadObject(ctx, prm)
	if err != nil {
		return nil, err
	}

	return res.Header(), nil
}

func (s *multiaddressRemoteStorage) Get(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
	var prm internalclient.GetObjectPrm

	prm.SetClient(s.client)
	prm.SetTTL(requestParams.TTL)
	prm.SetNetmapEpoch(requestParams.Epoch)
	prm.SetAddress(address)
	prm.SetPrivateKey(requestParams.PrivateKey)
	prm.SetSessionToken(requestParams.SessionToken)
	prm.SetBearerToken(requestParams.BearerToken)
	prm.SetXHeaders(requestParams.XHeaders)

	if requestParams.IsRaw {
		prm.SetRawFlag()
	}

	res, err := internalclient.GetObject(ctx, prm)
	if err != nil {
		return nil, err
	}

	return res.Object(), nil
}

func (s *multiaddressRemoteStorage) payloadOnlyObject(payload []byte) *objectSDK.Object {
	obj := objectSDK.New()
	obj.SetPayload(payload)

	return obj
}

type RangeHashRes struct {
	hashes [][]byte
}

func (r *RangeHashRes) Hashes() [][]byte {
	return r.hashes
}