// Copyright (c) Mainflux
// SPDX-License-Identifier: Apache-2.0

package grpc

import (
	"context"

	kitgrpc "github.com/go-kit/kit/transport/grpc"
	mainflux "github.com/mainflux/mainflux"
	"github.com/mainflux/mainflux/auth"
	"github.com/mainflux/mainflux/internal/apiutil"
	"github.com/mainflux/mainflux/pkg/errors"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

var _ mainflux.AuthServiceServer = (*grpcServer)(nil)

type grpcServer struct {
	mainflux.UnimplementedAuthServiceServer
	issue           kitgrpc.Handler
	login           kitgrpc.Handler
	refresh         kitgrpc.Handler
	identify        kitgrpc.Handler
	authorize       kitgrpc.Handler
	addPolicy       kitgrpc.Handler
	deletePolicy    kitgrpc.Handler
	listObjects     kitgrpc.Handler
	listAllObjects  kitgrpc.Handler
	countObjects    kitgrpc.Handler
	listSubjects    kitgrpc.Handler
	listAllSubjects kitgrpc.Handler
	countSubjects   kitgrpc.Handler
}

// NewServer returns new AuthServiceServer instance.
func NewServer(svc auth.Service) mainflux.AuthServiceServer {
	return &grpcServer{
		issue: kitgrpc.NewServer(
			(issueEndpoint(svc)),
			decodeIssueRequest,
			encodeIssueResponse,
		),
		login: kitgrpc.NewServer(
			(loginEndpoint(svc)),
			decodeLoginRequest,
			encodeIssueResponse,
		),
		refresh: kitgrpc.NewServer(
			(refreshEndpoint(svc)),
			decodeRefreshRequest,
			encodeIssueResponse,
		),
		identify: kitgrpc.NewServer(
			(identifyEndpoint(svc)),
			decodeIdentifyRequest,
			encodeIdentifyResponse,
		),
		authorize: kitgrpc.NewServer(
			(authorizeEndpoint(svc)),
			decodeAuthorizeRequest,
			encodeAuthorizeResponse,
		),
		addPolicy: kitgrpc.NewServer(
			(addPolicyEndpoint(svc)),
			decodeAddPolicyRequest,
			encodeAddPolicyResponse,
		),
		deletePolicy: kitgrpc.NewServer(
			(deletePolicyEndpoint(svc)),
			decodeDeletePolicyRequest,
			encodeDeletePolicyResponse,
		),
		listObjects: kitgrpc.NewServer(
			(listObjectsEndpoint(svc)),
			decodeListObjectsRequest,
			encodeListObjectsResponse,
		),
		listAllObjects: kitgrpc.NewServer(
			(listAllObjectsEndpoint(svc)),
			decodeListObjectsRequest,
			encodeListObjectsResponse,
		),
		countObjects: kitgrpc.NewServer(
			(countObjectsEndpoint(svc)),
			decodeCountObjectsRequest,
			encodeCountObjectsResponse,
		),
		listSubjects: kitgrpc.NewServer(
			(listSubjectsEndpoint(svc)),
			decodeListSubjectsRequest,
			encodeListSubjectsResponse,
		),
		listAllSubjects: kitgrpc.NewServer(
			(listAllSubjectsEndpoint(svc)),
			decodeListSubjectsRequest,
			encodeListSubjectsResponse,
		),
		countSubjects: kitgrpc.NewServer(
			(countSubjectsEndpoint(svc)),
			decodeCountSubjectsRequest,
			encodeCountSubjectsResponse,
		),
	}
}

func (s *grpcServer) Issue(ctx context.Context, req *mainflux.IssueReq) (*mainflux.Token, error) {
	_, res, err := s.issue.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.Token), nil
}

func (s *grpcServer) Login(ctx context.Context, req *mainflux.LoginReq) (*mainflux.Token, error) {
	_, res, err := s.login.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.Token), nil
}

func (s *grpcServer) Refresh(ctx context.Context, req *mainflux.RefreshReq) (*mainflux.Token, error) {
	_, res, err := s.refresh.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.Token), nil
}

func (s *grpcServer) Identify(ctx context.Context, token *mainflux.IdentityReq) (*mainflux.IdentityRes, error) {
	_, res, err := s.identify.ServeGRPC(ctx, token)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.IdentityRes), nil
}

func (s *grpcServer) Authorize(ctx context.Context, req *mainflux.AuthorizeReq) (*mainflux.AuthorizeRes, error) {
	_, res, err := s.authorize.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.AuthorizeRes), nil
}

func (s *grpcServer) AddPolicy(ctx context.Context, req *mainflux.AddPolicyReq) (*mainflux.AddPolicyRes, error) {
	_, res, err := s.addPolicy.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.AddPolicyRes), nil
}

func (s *grpcServer) DeletePolicy(ctx context.Context, req *mainflux.DeletePolicyReq) (*mainflux.DeletePolicyRes, error) {
	_, res, err := s.deletePolicy.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.DeletePolicyRes), nil
}

func (s *grpcServer) ListObjects(ctx context.Context, req *mainflux.ListObjectsReq) (*mainflux.ListObjectsRes, error) {
	_, res, err := s.listObjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.ListObjectsRes), nil
}

func (s *grpcServer) ListAllObjects(ctx context.Context, req *mainflux.ListObjectsReq) (*mainflux.ListObjectsRes, error) {
	_, res, err := s.listAllObjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.ListObjectsRes), nil
}

func (s *grpcServer) CountObjects(ctx context.Context, req *mainflux.CountObjectsReq) (*mainflux.CountObjectsRes, error) {
	_, res, err := s.countObjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.CountObjectsRes), nil
}

func (s *grpcServer) ListSubjects(ctx context.Context, req *mainflux.ListSubjectsReq) (*mainflux.ListSubjectsRes, error) {
	_, res, err := s.listSubjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.ListSubjectsRes), nil
}

func (s *grpcServer) ListAllSubjects(ctx context.Context, req *mainflux.ListSubjectsReq) (*mainflux.ListSubjectsRes, error) {
	_, res, err := s.listAllSubjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.ListSubjectsRes), nil
}

func (s *grpcServer) CountSubjects(ctx context.Context, req *mainflux.CountSubjectsReq) (*mainflux.CountSubjectsRes, error) {
	_, res, err := s.countSubjects.ServeGRPC(ctx, req)
	if err != nil {
		return nil, encodeError(err)
	}
	return res.(*mainflux.CountSubjectsRes), nil
}

func decodeIssueRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.IssueReq)
	return issueReq{id: req.GetId(), keyType: auth.KeyType(req.GetType())}, nil
}

func decodeLoginRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.LoginReq)
	return issueReq{id: req.GetId(), keyType: auth.AccessKey}, nil
}

func decodeRefreshRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.RefreshReq)
	return refreshReq{value: req.GetValue()}, nil
}

func encodeIssueResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(issueRes)

	return &mainflux.Token{
		AccessToken:  res.accessToken,
		RefreshToken: &res.refreshToken,
		AccessType:   res.accessType,
	}, nil
}

func decodeIdentifyRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.IdentityReq)
	return identityReq{token: req.GetToken()}, nil
}

func encodeIdentifyResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(identityRes)
	return &mainflux.IdentityRes{Id: res.id}, nil
}

func decodeAuthorizeRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.AuthorizeReq)
	return authReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		SubjectKind: req.GetSubjectKind(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(),
	}, nil
}

func encodeAuthorizeResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(authorizeRes)
	return &mainflux.AuthorizeRes{Authorized: res.authorized, Id: res.id}, nil
}

func decodeAddPolicyRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.AddPolicyReq)
	return policyReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(),
	}, nil
}

func encodeAddPolicyResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(addPolicyRes)
	return &mainflux.AddPolicyRes{Authorized: res.authorized}, nil
}

func decodeDeletePolicyRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.DeletePolicyReq)
	return policyReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(),
	}, nil
}

func encodeDeletePolicyResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(deletePolicyRes)
	return &mainflux.DeletePolicyRes{Deleted: res.deleted}, nil
}

func decodeListObjectsRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.ListObjectsReq)
	return listObjectsReq{
		Namespace:     req.GetNamespace(),
		SubjectType:   req.GetSubjectType(),
		Subject:       req.GetSubject(),
		Relation:      req.GetRelation(),
		Permission:    req.GetPermission(),
		ObjectType:    req.GetObjectType(),
		Object:        req.GetObject(),
		NextPageToken: req.GetNextPageToken(),
		Limit:         req.GetLimit(),
	}, nil
}

func encodeListObjectsResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(listObjectsRes)
	return &mainflux.ListObjectsRes{Policies: res.policies}, nil
}

func decodeCountObjectsRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.CountObjectsReq)
	return countObjectsReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(),
	}, nil
}

func encodeCountObjectsResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(countObjectsRes)
	return &mainflux.CountObjectsRes{Count: int64(res.count)}, nil
}

func decodeListSubjectsRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.ListSubjectsReq)
	return listSubjectsReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(), NextPageToken: req.GetNextPageToken(), Limit: req.GetLimit(),
	}, nil
}

func encodeListSubjectsResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(listSubjectsRes)
	return &mainflux.ListSubjectsRes{Policies: res.policies}, nil
}

func decodeCountSubjectsRequest(_ context.Context, grpcReq interface{}) (interface{}, error) {
	req := grpcReq.(*mainflux.CountSubjectsReq)
	return countSubjectsReq{
		Namespace:   req.GetNamespace(),
		SubjectType: req.GetSubjectType(),
		Subject:     req.GetSubject(),
		Relation:    req.GetRelation(),
		Permission:  req.GetPermission(),
		ObjectType:  req.GetObjectType(),
		Object:      req.GetObject(),
	}, nil
}

func encodeCountSubjectsResponse(_ context.Context, grpcRes interface{}) (interface{}, error) {
	res := grpcRes.(countObjectsRes)
	return &mainflux.CountObjectsRes{Count: int64(res.count)}, nil
}

func encodeError(err error) error {
	switch {
	case errors.Contains(err, nil):
		return nil
	case errors.Contains(err, errors.ErrMalformedEntity),
		err == apiutil.ErrInvalidAuthKey,
		err == apiutil.ErrMissingID,
		err == apiutil.ErrMissingMemberType,
		err == apiutil.ErrMissingPolicySub,
		err == apiutil.ErrMissingPolicyObj,
		err == apiutil.ErrMalformedPolicyAct:
		return status.Error(codes.InvalidArgument, err.Error())
	case errors.Contains(err, errors.ErrAuthentication),
		errors.Contains(err, auth.ErrKeyExpired),
		err == apiutil.ErrMissingEmail,
		err == apiutil.ErrBearerToken:
		return status.Error(codes.Unauthenticated, err.Error())
	case errors.Contains(err, errors.ErrAuthorization):
		return status.Error(codes.PermissionDenied, err.Error())
	default:
		return status.Error(codes.Internal, err.Error())
	}
}