package tree

import (
	"encoding/hex"
	"fmt"
	"strings"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/ape/converter"
	aperequest "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/ape/request"
	core "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/container"
	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
	cnrSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/acl"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	apechain "git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/engine"
	commonschema "git.frostfs.info/TrueCloudLab/policy-engine/schema/common"
	nativeschema "git.frostfs.info/TrueCloudLab/policy-engine/schema/native"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
)

var subjectNotFoundErrorMessage = "subject not found"

func (s *Service) checkAPE(container *core.Container, cid cid.ID, operation acl.Op, role acl.Role, publicKey *keys.PublicKey) error {
	namespace := ""
	cntNamespace, hasNamespace := strings.CutSuffix(cnrSDK.ReadDomain(container.Value).Zone(), ".ns")
	if hasNamespace {
		namespace = cntNamespace
	}

	schemaMethod, err := converter.SchemaMethodFromACLOperation(operation)
	if err != nil {
		return apeErr(err)
	}
	schemaRole, err := converter.SchemaRoleFromACLRole(role)
	if err != nil {
		return apeErr(err)
	}
	reqProps := map[string]string{
		nativeschema.PropertyKeyActorPublicKey: hex.EncodeToString(publicKey.Bytes()),
		nativeschema.PropertyKeyActorRole:      schemaRole,
	}
	reqProps, err = s.fillWithUserClaimTags(reqProps, publicKey)
	if err != nil {
		return apeErr(err)
	}

	var resourceName string
	if namespace == "root" || namespace == "" {
		resourceName = fmt.Sprintf(nativeschema.ResourceFormatRootContainerObjects, cid.EncodeToString())
	} else {
		resourceName = fmt.Sprintf(nativeschema.ResourceFormatNamespaceContainerObjects, namespace, cid.EncodeToString())
	}

	request := aperequest.NewRequest(
		schemaMethod,
		aperequest.NewResource(resourceName, make(map[string]string)),
		reqProps,
	)

	rt := engine.NewRequestTargetExtended(namespace, cid.EncodeToString(), fmt.Sprintf("%s:%s", namespace, publicKey.Address()), nil)
	status, found, err := s.router.IsAllowed(apechain.Ingress, rt, request)
	if err != nil {
		return apeErr(err)
	}
	if found && status == apechain.Allow {
		return nil
	}
	err = fmt.Errorf("access to operation %s is denied by access policy engine: %s", schemaMethod, status.String())
	return apeErr(err)
}

func apeErr(err error) error {
	errAccessDenied := &apistatus.ObjectAccessDenied{}
	errAccessDenied.WriteReason(err.Error())
	return errAccessDenied
}

// fillWithUserClaimTags fills ape request properties with user claim tags getting them from frostfsid contract by actor public key.
func (s *Service) fillWithUserClaimTags(reqProps map[string]string, publicKey *keys.PublicKey) (map[string]string, error) {
	if reqProps == nil {
		reqProps = make(map[string]string)
	}
	subj, err := s.frostfsidSubjectProvider.GetSubject(publicKey.GetScriptHash())
	if err != nil {
		if !strings.Contains(err.Error(), subjectNotFoundErrorMessage) {
			return nil, fmt.Errorf("get subject error: %w", err)
		}
		return reqProps, nil
	}
	for k, v := range subj.KV {
		properyKey := fmt.Sprintf(commonschema.PropertyKeyFormatFrostFSIDUserClaim, k)
		reqProps[properyKey] = v
	}
	return reqProps, nil
}