package getsvc

import (
	"context"
	"errors"

	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"go.uber.org/zap"
)

func (r *request) assemble(ctx context.Context) {
	if !r.canAssemble() {
		r.log.Debug(logs.GetCanNotAssembleTheObject)
		return
	}

	// Any access tokens are not expected to be used in the assembly process:
	//  - there is no requirement to specify child objects in session/bearer
	//    token for `GET`/`GETRANGE`/`RANGEHASH` requests in the API protocol,
	//    and, therefore, their missing in the original request should not be
	//    considered as error; on the other hand, without session for every child
	//    object, it is impossible to attach bearer token in the new generated
	//    requests correctly because the token has not been issued for that node's
	//    key;
	//  - the assembly process is expected to be handled on a container node
	//    only since the requests forwarding mechanism presentation; such the
	//    node should have enough rights for getting any child object by design.
	r.prm.common.ForgetTokens()

	// Do not use forwarding during assembly stage.
	// Request forwarding closure inherited in produced
	// `execCtx` so it should be disabled there.
	r.disableForwarding()

	r.log.Debug(logs.GetTryingToAssembleTheObject)

	assembler := newAssembler(r.address(), r.splitInfo(), r.ctxRange(), r)

	r.log.Debug(logs.GetAssemblingSplittedObject,
		zap.Stringer("address", r.address()),
		zap.Uint64("range_offset", r.ctxRange().GetOffset()),
		zap.Uint64("range_length", r.ctxRange().GetLength()),
	)
	defer r.log.Debug(logs.GetAssemblingSplittedObjectCompleted,
		zap.Stringer("address", r.address()),
		zap.Uint64("range_offset", r.ctxRange().GetOffset()),
		zap.Uint64("range_length", r.ctxRange().GetLength()),
	)

	obj, err := assembler.Assemble(ctx, r.prm.objWriter)
	if err != nil {
		r.log.Warn(logs.GetFailedToAssembleSplittedObject,
			zap.Error(err),
			zap.Stringer("address", r.address()),
			zap.Uint64("range_offset", r.ctxRange().GetOffset()),
			zap.Uint64("range_length", r.ctxRange().GetLength()),
		)
	}

	var errSplitInfo *objectSDK.SplitInfoError
	var errRemovedRemote *apistatus.ObjectAlreadyRemoved
	var errOutOfRangeRemote *apistatus.ObjectOutOfRange
	var errRemovedLocal apistatus.ObjectAlreadyRemoved
	var errOutOfRangeLocal apistatus.ObjectOutOfRange

	switch {
	default:
		r.status = statusUndefined
		r.err = err
	case err == nil:
		r.status = statusOK
		r.err = nil
		r.collectedObject = obj
	case errors.As(err, &errRemovedRemote):
		r.status = statusINHUMED
		r.err = errRemovedRemote
	case errors.As(err, &errRemovedLocal):
		r.status = statusINHUMED
		r.err = errRemovedLocal
	case errors.As(err, &errSplitInfo):
		r.status = statusVIRTUAL
		r.err = errSplitInfo
	case errors.As(err, &errOutOfRangeRemote):
		r.status = statusOutOfRange
		r.err = errOutOfRangeRemote
	case errors.As(err, &errOutOfRangeLocal):
		r.status = statusOutOfRange
		r.err = errOutOfRangeLocal
	}
}

func equalAddresses(a, b oid.Address) bool {
	return a.Container().Equals(b.Container()) && a.Object().Equals(b.Object())
}

func (r *request) HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object, error) {
	w := NewSimpleObjectWriter()

	p := RequestParameters{}
	p.common = p.common.WithLocalOnly(false)
	p.addr.SetContainer(r.containerID())
	p.addr.SetObject(id)
	p.head = true
	p.SetHeaderWriter(w)

	if err := r.getObjectWithIndependentRequest(ctx, p); err != nil {
		return nil, err
	}

	return w.Object(), nil
}

func (r *request) GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range) (*objectSDK.Object, error) {
	w := NewSimpleObjectWriter()

	p := r.prm
	p.common = p.common.WithLocalOnly(false)
	p.objWriter = w
	p.rng = rng

	p.addr.SetContainer(r.containerID())
	p.addr.SetObject(id)

	if err := r.getObjectWithIndependentRequest(ctx, p); err != nil {
		return nil, err
	}
	return w.Object(), nil
}

func (r *request) getObjectWithIndependentRequest(ctx context.Context, prm RequestParameters) error {
	detachedExecutor := &request{
		keyStore:                 r.keyStore,
		traverserGenerator:       r.traverserGenerator,
		remoteStorageConstructor: r.remoteStorageConstructor,
		epochSource:              r.epochSource,
		localStorage:             r.localStorage,

		prm:       prm,
		infoSplit: objectSDK.NewSplitInfo(),
		log:       r.log,
	}

	detachedExecutor.execute(ctx)

	return detachedExecutor.statusError.err
}