package main

import (
	"context"
	"fmt"
	"log"

	"github.com/gofrs/uuid"
	"google.golang.org/grpc/metadata"
	"gorm.io/gorm"
	"whiteboxsystems.nl/openkvpoc/kisservice/model"
	"whiteboxsystems.nl/openkvpoc/openkv"
	"whiteboxsystems.nl/openkvpoc/sharedmodel"
)

var errNotAuthorized = fmt.Errorf("Not Authorized")
var errInvalidService = fmt.Errorf("Invalid service")
var errActiveServiceConfig = fmt.Errorf("Service not activated")

type OpenKVServer struct {
	openkv.UnimplementedOpenKVServer
	data *gorm.DB
}

func (srv *OpenKVServer) LoadData(location string) error {
	var err error
	srv.data, err = model.GetDB(location)
	return err
}

func requireConnection(db *gorm.DB, ctx context.Context) (*sharedmodel.Connection, error) {
	md, ok := metadata.FromIncomingContext(ctx)
	if !ok {
		log.Printf("No metadata")
		return nil, errNotAuthorized
	}

	connection := &sharedmodel.Connection{}

	if a, ok := md["authorization"]; !ok {
		log.Printf("No token provided")
		return nil, errNotAuthorized
	} else {
		if err := db.Preload("AuthMethod").Raw(`
			SELECT conn.*
			FROM connections conn
			JOIN auth_configs a on conn.auth_config_id = a.id WHERE a.method = ? and a.raw = ?
		`, openkv.AuthMethod_APIToken, a[0]).Scan(connection).Error; err != nil {
			log.Printf("Invalid token; err: %v;", err)
			return nil, errNotAuthorized
		}
	}
	return connection, nil
}

func requireService(db *gorm.DB, conn *sharedmodel.Connection, serviceID string) (*sharedmodel.ServiceConfig, error) {
	service := &sharedmodel.Service{}
	if err := db.Where("service_id = ?", serviceID).First(service).Error; err != nil {
		return nil, errInvalidService
	}

	srvConfig := &sharedmodel.ServiceConfig{}

	if err := db.Where("connection_id = ? and enabled = ? and service_id = ?", conn.ID, true, service.ID).First(srvConfig).Error; err != nil {
		return nil, errActiveServiceConfig
	}

	return srvConfig, nil
}

func (srv *OpenKVServer) GetMetadata(
	ctx context.Context, in *openkv.GetMetadataRequest,
) (*openkv.GetMetadataResponse, error) {
	log.Printf("Got metadata request")

	services := []*openkv.ServiceDefinition{}
	presentServices := []sharedmodel.Service{}
	srv.data.Find(&presentServices)

	for _, service := range presentServices {
		services = append(services, &openkv.ServiceDefinition{
			Name:               service.Name,
			Description:        service.Description,
			Id:                 service.ServiceID,
			SubscriptionPolicy: service.SubscriptionPolicy,
			ConsentPolicy:      service.ConsentPolicy,
			FetchProtocols:     service.GetFetchProtocols(),
			PushProtocols:      service.GetPushProtocols(),
		})
	}

	resp := &openkv.GetMetadataResponse{
		Supplier: "Voorbeeld",
		System:   "Voorbeeld KIS",
		Services: services,
		Success:  true,
	}

	return resp, nil
}

func (srv *OpenKVServer) Register(
	ctx context.Context, in *openkv.RegisterRequest,
) (*openkv.RegisterResponse, error) {
	ref, _ := uuid.NewV4()
	psk, _ := uuid.NewV4()

	reg := &sharedmodel.Registration{
		Reference:               ref.String(),
		OrganisationId:          in.OrganisationId,
		OrganisationIdSystem:    in.OrganisationIdSystem,
		OrganisationDisplayName: in.OrganisationDisplayName,
		PSK:                     psk.String()[0:6],
		Status:                  sharedmodel.RegistrationStatusPending,
	}

	reg.SetAuthConfig(in.Auth)

	srv.data.Create(reg)

	resp := &openkv.RegisterResponse{
		Reference: ref.String(),
		Success:   true,
	}

	log.Printf("Got registration request from %v; ref: %v; PSK: %v", reg.OrganisationDisplayName, reg.Reference, reg.PSK)
	return resp, nil
}

func (srv *OpenKVServer) CompleteRegistration(
	ctx context.Context, in *openkv.CompleteRegistrationRequest,
) (*openkv.CompleteRegistrationResponse, error) {
	registration := &sharedmodel.Registration{}

	if err := srv.data.Preload("AuthConfig").Where("reference = ? and status = ?", in.Reference, sharedmodel.RegistrationStatusPending).First(registration).Error; err != nil {
		log.Printf("Invalid ref")
		return nil, errNotAuthorized
	}

	md, ok := metadata.FromIncomingContext(ctx)
	if !ok {
		log.Printf("No metadata")
		return nil, errNotAuthorized
	}

	// The keys within metadata.MD are normalized to lowercase.
	// See: https://godoc.org/google.golang.org/grpc/metadata#New
	if a, ok := md["authorization"]; !ok {
		log.Printf("No token provided")
		return nil, errNotAuthorized
	} else {
		if a[0] != registration.AuthConfig.Raw {
			log.Printf("Invalid token; eXpected: %v; got: %v", registration.AuthConfig.Raw, a[0])
			return nil, errNotAuthorized
		}
	}

	resp := &openkv.CompleteRegistrationResponse{}
	if in.RegistrationToken != registration.PSK {
		resp.Error = &openkv.Error{
			Code:    1,
			Message: "Invalid PSK",
		}

		return resp, nil
	}

	conn := &sharedmodel.Connection{
		OrganisationId:          registration.OrganisationId,
		OrganisationIdSystem:    registration.OrganisationIdSystem,
		OrganisationDisplayName: registration.OrganisationDisplayName,
		AuthConfig:              registration.AuthConfig.Clone(),
	}

	srv.data.Create(conn)

	registration.Status = sharedmodel.RegistrationStatusCompleted
	srv.data.Save(registration)

	resp.Success = true

	return resp, nil
}

func (srv *OpenKVServer) ConfigService(
	ctx context.Context, in *openkv.ConfigServiceRequest,
) (*openkv.ConfigServiceResponse, error) {
	conn, err := requireConnection(srv.data, ctx)

	if err != nil {
		return nil, err
	}

	service := &sharedmodel.Service{}
	if err := srv.data.Where("service_id = ?", in.Service).First(service).Error; err != nil {
		return nil, fmt.Errorf("Invalid service: %v", service.ServiceID)
	}

	cnf := &sharedmodel.ServiceConfig{}

	if err := srv.data.Where("connection_id = ? and service_id = ?", conn.ID, service.ID).First(cnf); err != nil {
		cnf.ConnectionID = conn.ID
		cnf.ServiceID = service.ID
	}

	log.Printf("Update service config %v for conn: %v", cnf.Service.Name, conn.ID)

	cnf.Enabled = in.Enabled

	// TODO actually init authdata
	cnf.PushProtocol = &sharedmodel.ProtocolConfig{
		Protocol:   in.Push.Protocol,
		AuthConfig: sharedmodel.NewAuthConfig(in.Push.Auth),
	}

	cnf.PushProtocol.SetConfig(in.Push.Config)
	cnf.PushProtocol.AuthConfig.Raw = "3333"

	cnf.FetchProtocol = &sharedmodel.ProtocolConfig{
		Protocol:   in.Fetch.Protocol,
		AuthConfig: sharedmodel.NewAuthConfig(in.Fetch.Auth),
	}

	cnf.FetchProtocol.SetConfig(in.Fetch.Config)
	cnf.FetchProtocol.AuthConfig.Raw = "3333"

	if cnf.ID == 0 {
		if err := srv.data.Create(cnf).Error; err != nil {
			return nil, err
		}
	} else {
		if err := srv.data.Save(cnf).Error; err != nil {
			return nil, err
		}
	}

	// If disabled unsubscribe all subscriptions
	if !cnf.Enabled {
		srv.data.Unscoped().Where("service_config_id = ?", cnf.ID).Delete(&sharedmodel.Subscription{})
	}

	resp := &openkv.ConfigServiceResponse{
		Success: true,
		Service: in.Service,
		Enabled: in.Enabled,
		Fetch: &openkv.ServiceConfig{
			Protocol: "https://hl7.nl/fhir",
			Auth: &openkv.AuthConfig{
				Method: openkv.AuthMethod_APIToken,
				Config: &openkv.AuthConfig_ApiTokenConfig{&openkv.APITokenConfig{Token: "3333"}},
			},
		},
	}
	return resp, nil
}

func (srv *OpenKVServer) UpdateSubscriptions(
	ctx context.Context, in *openkv.UpdateSubscriptionsRequest,
) (*openkv.UpdateSubscriptionsResponse, error) {
	conn, err := requireConnection(srv.data, ctx)

	if err != nil {
		return nil, err
	}

	serviceConfig, err := requireService(srv.data, conn, in.ServiceId)

	if err != nil {
		return nil, err
	}

	subscriptionErrors := []*openkv.SubscriptionError{}

	if err := srv.data.Transaction(func(tx *gorm.DB) error {
		for idx, sd := range in.SubscriptionData {
			subscription := &sharedmodel.Subscription{}
			err := srv.data.Where(
				"subject_external_id = ? and subject_external_id_system = ? and service_config_id = ?",
				sd.Subject.ExternalId,
				sd.Subject.ExternalIdSystem,
				serviceConfig.ID,
			).First(subscription).Error

			if err != nil && err != gorm.ErrRecordNotFound {
				return err
			} else if err != nil && sd.Subscribe {
				sub := &sharedmodel.Subscription{
					SubjectExternalId:       sd.Subject.ExternalId,
					SubjectExternalIdSystem: sd.Subject.ExternalIdSystem,
					SubjectName:             sd.Subject.Name,
					SubjectBirthdate:        sd.Subject.Birthdate,
					ServiceConfigID:         serviceConfig.ID,
				}
				// TODO check if it is valid metadata for the specified protocol
				sub.SetProtocolMeta(sd.ProtocolMeta)

				if err := srv.data.Create(sub).Error; err != nil {
					subscriptionErrors = append(subscriptionErrors, &openkv.SubscriptionError{
						Index: int32(idx),
						Error: &openkv.Error{
							Code:    openkv.ErrServiceException,
							Message: fmt.Sprintf("Subject with id: %v (%v) could not be persisted; %v", sd.Subject.ExternalId, sd.Subject.ExternalIdSystem, err),
						},
					})
				}

				log.Printf("add subscription: %v", sd.Subject.ExternalId)
				continue
			} else if err != nil && !sd.Subscribe {
				subscriptionErrors = append(subscriptionErrors, &openkv.SubscriptionError{
					Index: int32(idx),
					Error: &openkv.Error{
						Code:    openkv.ErrCodeAlreadySubscribed,
						Message: fmt.Sprintf("Subject with id: %v (%v) already unsubscribed", sd.Subject.ExternalId, sd.Subject.ExternalIdSystem),
					},
				})
				continue
			} else if !sd.Subscribe {
				if err := srv.data.Unscoped().Delete(subscription).Error; err != nil {
					subscriptionErrors = append(subscriptionErrors, &openkv.SubscriptionError{
						Index: int32(idx),
						Error: &openkv.Error{
							Code:    openkv.ErrServiceException,
							Message: fmt.Sprintf("Subject with id: %v (%v) could not be removed; %v", sd.Subject.ExternalId, sd.Subject.ExternalIdSystem, err)},
					})
				}
				log.Printf("delete subscription: %v", sd.Subject.ExternalId)
				continue
			}

			subscription.SubjectExternalId = sd.Subject.ExternalId
			subscription.SubjectExternalIdSystem = sd.Subject.ExternalIdSystem
			subscription.SubjectName = sd.Subject.Name
			subscription.SubjectBirthdate = sd.Subject.Birthdate
			subscription.SetProtocolMeta(sd.ProtocolMeta)

			if err := srv.data.Save(subscription).Error; err != nil {
				subscriptionErrors = append(subscriptionErrors, &openkv.SubscriptionError{
					Index: int32(idx),
					Error: &openkv.Error{
						Code:    openkv.ErrServiceException,
						Message: fmt.Sprintf("Subject with id: %v (%v) could not be updated; %v", sd.Subject.ExternalId, sd.Subject.ExternalIdSystem, err)},
				})
				continue
			}

			log.Printf("update subscription: %v", sd.Subject.ExternalId)
		}

		return nil
	}); err != nil {
		return nil, err
	}

	resp := &openkv.UpdateSubscriptionsResponse{
		Success: true,
		Errors:  subscriptionErrors,
	}

	return resp, nil
}

func (srv *OpenKVServer) ListSubscriptions(
	ctx context.Context, in *openkv.ListSubscriptionsRequest,
) (*openkv.ListSubscriptionsResponse, error) {
	conn, err := requireConnection(srv.data, ctx)

	if err != nil {
		return nil, err
	}

	serviceConfig, err := requireService(srv.data, conn, in.ServiceId)

	if err != nil {
		return nil, err
	}

	subscriptions := []*sharedmodel.Subscription{}

	srv.data.Where("service_config_id = ?", serviceConfig.ID).Find(&subscriptions)

	subs := []*openkv.SubscriptionData{}

	for _, s := range subscriptions {
		meta := map[string]string{}
		s.GetProtocolMeta(&meta)
		subs = append(subs, &openkv.SubscriptionData{
			Subject: &openkv.PatientMeta{
				ExternalId:       s.SubjectExternalId,
				ExternalIdSystem: s.SubjectExternalIdSystem,
				Name:             s.SubjectName,
				Birthdate:        s.SubjectBirthdate,
			},
			ProtocolMeta: meta,
		})
	}

	resp := &openkv.ListSubscriptionsResponse{
		Success:          true,
		SubscriptionData: subs,
	}

	return resp, nil
}

func NewServer() *OpenKVServer {
	return &OpenKVServer{}
}