package manager

import (
	"context"
	"fmt"
	"time"

	log "github.com/sirupsen/logrus"

	"github.com/netbirdio/netbird/management/internals/modules/reverseproxy"
	"github.com/netbirdio/netbird/management/internals/modules/reverseproxy/sessionkey"
	nbgrpc "github.com/netbirdio/netbird/management/internals/shared/grpc"
	"github.com/netbirdio/netbird/management/server/account"
	"github.com/netbirdio/netbird/management/server/activity"
	"github.com/netbirdio/netbird/management/server/permissions"
	"github.com/netbirdio/netbird/management/server/permissions/modules"
	"github.com/netbirdio/netbird/management/server/permissions/operations"
	"github.com/netbirdio/netbird/management/server/store"
	"github.com/netbirdio/netbird/shared/management/status"
)

const unknownHostPlaceholder = "unknown"

// ClusterDeriver derives the proxy cluster from a domain.
type ClusterDeriver interface {
	DeriveClusterFromDomain(ctx context.Context, domain string) (string, error)
}

type managerImpl struct {
	store              store.Store
	accountManager     account.Manager
	permissionsManager permissions.Manager
	proxyGRPCServer    *nbgrpc.ProxyServiceServer
	tokenStore         *nbgrpc.OneTimeTokenStore
	clusterDeriver     ClusterDeriver
}

// NewManager creates a new service manager.
func NewManager(store store.Store, accountManager account.Manager, permissionsManager permissions.Manager, proxyGRPCServer *nbgrpc.ProxyServiceServer, tokenStore *nbgrpc.OneTimeTokenStore, clusterDeriver ClusterDeriver) reverseproxy.Manager {
	return &managerImpl{
		store:              store,
		accountManager:     accountManager,
		permissionsManager: permissionsManager,
		proxyGRPCServer:    proxyGRPCServer,
		tokenStore:         tokenStore,
		clusterDeriver:     clusterDeriver,
	}
}

func (m *managerImpl) GetAllServices(ctx context.Context, accountID, userID string) ([]*reverseproxy.Service, error) {
	ok, err := m.permissionsManager.ValidateUserPermissions(ctx, accountID, userID, modules.Services, operations.Read)
	if err != nil {
		return nil, status.NewPermissionValidationError(err)
	}
	if !ok {
		return nil, status.NewPermissionDeniedError()
	}

	services, err := m.store.GetAccountServices(ctx, store.LockingStrengthNone, accountID)
	if err != nil {
		return nil, fmt.Errorf("failed to get services: %w", err)
	}

	for _, service := range services {
		err = m.replaceHostByLookup(ctx, accountID, service)
		if err != nil {
			return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
		}
	}

	return services, nil
}

func (m *managerImpl) replaceHostByLookup(ctx context.Context, accountID string, service *reverseproxy.Service) error {
	for _, target := range service.Targets {
		switch target.TargetType {
		case reverseproxy.TargetTypePeer:
			peer, err := m.store.GetPeerByID(ctx, store.LockingStrengthNone, accountID, target.TargetId)
			if err != nil {
				log.WithContext(ctx).Warnf("failed to get peer by id %s for service %s: %v", target.TargetId, service.ID, err)
				target.Host = unknownHostPlaceholder
				continue
			}
			target.Host = peer.IP.String()
		case reverseproxy.TargetTypeHost:
			resource, err := m.store.GetNetworkResourceByID(ctx, store.LockingStrengthNone, accountID, target.TargetId)
			if err != nil {
				log.WithContext(ctx).Warnf("failed to get resource by id %s for service %s: %v", target.TargetId, service.ID, err)
				target.Host = unknownHostPlaceholder
				continue
			}
			target.Host = resource.Prefix.Addr().String()
		case reverseproxy.TargetTypeDomain:
			resource, err := m.store.GetNetworkResourceByID(ctx, store.LockingStrengthNone, accountID, target.TargetId)
			if err != nil {
				log.WithContext(ctx).Warnf("failed to get resource by id %s for service %s: %v", target.TargetId, service.ID, err)
				target.Host = unknownHostPlaceholder
				continue
			}
			target.Host = resource.Domain
		case reverseproxy.TargetTypeSubnet:
			// For subnets we do not do any lookups on the resource
		default:
			return fmt.Errorf("unknown target type: %s", target.TargetType)
		}
	}
	return nil
}

func (m *managerImpl) GetService(ctx context.Context, accountID, userID, serviceID string) (*reverseproxy.Service, error) {
	ok, err := m.permissionsManager.ValidateUserPermissions(ctx, accountID, userID, modules.Services, operations.Read)
	if err != nil {
		return nil, status.NewPermissionValidationError(err)
	}
	if !ok {
		return nil, status.NewPermissionDeniedError()
	}

	service, err := m.store.GetServiceByID(ctx, store.LockingStrengthNone, accountID, serviceID)
	if err != nil {
		return nil, fmt.Errorf("failed to get service: %w", err)
	}

	err = m.replaceHostByLookup(ctx, accountID, service)
	if err != nil {
		return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
	}
	return service, nil
}

func (m *managerImpl) CreateService(ctx context.Context, accountID, userID string, service *reverseproxy.Service) (*reverseproxy.Service, error) {
	ok, err := m.permissionsManager.ValidateUserPermissions(ctx, accountID, userID, modules.Services, operations.Create)
	if err != nil {
		return nil, status.NewPermissionValidationError(err)
	}
	if !ok {
		return nil, status.NewPermissionDeniedError()
	}

	var proxyCluster string
	if m.clusterDeriver != nil {
		proxyCluster, err = m.clusterDeriver.DeriveClusterFromDomain(ctx, service.Domain)
		if err != nil {
			log.WithError(err).Warnf("could not derive cluster from domain %s, updates will broadcast to all proxy servers", service.Domain)
		}
	}

	service.AccountID = accountID
	service.ProxyCluster = proxyCluster
	service.InitNewRecord()
	err = service.Auth.HashSecrets()
	if err != nil {
		return nil, fmt.Errorf("hash secrets: %w", err)
	}

	// Generate session JWT signing keys
	keyPair, err := sessionkey.GenerateKeyPair()
	if err != nil {
		return nil, fmt.Errorf("generate session keys: %w", err)
	}
	service.SessionPrivateKey = keyPair.PrivateKey
	service.SessionPublicKey = keyPair.PublicKey

	err = m.store.ExecuteInTransaction(ctx, func(transaction store.Store) error {
		// Check for duplicate domain
		existingService, err := transaction.GetServiceByDomain(ctx, accountID, service.Domain)
		if err != nil {
			if sErr, ok := status.FromError(err); !ok || sErr.Type() != status.NotFound {
				return fmt.Errorf("failed to check existing service: %w", err)
			}
		}
		if existingService != nil {
			return status.Errorf(status.AlreadyExists, "service with domain %s already exists", service.Domain)
		}

		if err = validateTargetReferences(ctx, transaction, accountID, service.Targets); err != nil {
			return err
		}

		if err = transaction.CreateService(ctx, service); err != nil {
			return fmt.Errorf("failed to create service: %w", err)
		}

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

	token, err := m.tokenStore.GenerateToken(accountID, service.ID, 5*time.Minute)
	if err != nil {
		return nil, fmt.Errorf("failed to generate authentication token: %w", err)
	}

	m.accountManager.StoreEvent(ctx, userID, service.ID, accountID, activity.ServiceCreated, service.EventMeta())

	err = m.replaceHostByLookup(ctx, accountID, service)
	if err != nil {
		return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
	}

	m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Create, token, m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)

	m.accountManager.UpdateAccountPeers(ctx, accountID)

	return service, nil
}

func (m *managerImpl) UpdateService(ctx context.Context, accountID, userID string, service *reverseproxy.Service) (*reverseproxy.Service, error) {
	ok, err := m.permissionsManager.ValidateUserPermissions(ctx, accountID, userID, modules.Services, operations.Update)
	if err != nil {
		return nil, status.NewPermissionValidationError(err)
	}
	if !ok {
		return nil, status.NewPermissionDeniedError()
	}

	var oldCluster string
	var domainChanged bool
	var serviceEnabledChanged bool

	err = service.Auth.HashSecrets()
	if err != nil {
		return nil, fmt.Errorf("hash secrets: %w", err)
	}

	err = m.store.ExecuteInTransaction(ctx, func(transaction store.Store) error {
		existingService, err := transaction.GetServiceByID(ctx, store.LockingStrengthUpdate, accountID, service.ID)
		if err != nil {
			return err
		}

		oldCluster = existingService.ProxyCluster

		if existingService.Domain != service.Domain {
			domainChanged = true
			conflictService, err := transaction.GetServiceByDomain(ctx, accountID, service.Domain)
			if err != nil {
				if sErr, ok := status.FromError(err); !ok || sErr.Type() != status.NotFound {
					return fmt.Errorf("check existing service: %w", err)
				}
			}
			if conflictService != nil && conflictService.ID != service.ID {
				return status.Errorf(status.AlreadyExists, "service with domain %s already exists", service.Domain)
			}

			if m.clusterDeriver != nil {
				newCluster, err := m.clusterDeriver.DeriveClusterFromDomain(ctx, service.Domain)
				if err != nil {
					log.WithError(err).Warnf("could not derive cluster from domain %s", service.Domain)
				}
				service.ProxyCluster = newCluster
			}
		} else {
			service.ProxyCluster = existingService.ProxyCluster
		}

		if service.Auth.PasswordAuth != nil && service.Auth.PasswordAuth.Enabled &&
			existingService.Auth.PasswordAuth != nil && existingService.Auth.PasswordAuth.Enabled &&
			service.Auth.PasswordAuth.Password == "" {
			service.Auth.PasswordAuth = existingService.Auth.PasswordAuth
		}

		if service.Auth.PinAuth != nil && service.Auth.PinAuth.Enabled &&
			existingService.Auth.PinAuth != nil && existingService.Auth.PinAuth.Enabled &&
			service.Auth.PinAuth.Pin == "" {
			service.Auth.PinAuth = existingService.Auth.PinAuth
		}

		service.Meta = existingService.Meta
		service.SessionPrivateKey = existingService.SessionPrivateKey
		service.SessionPublicKey = existingService.SessionPublicKey
		serviceEnabledChanged = existingService.Enabled != service.Enabled

		if err = validateTargetReferences(ctx, transaction, accountID, service.Targets); err != nil {
			return err
		}

		if err = transaction.UpdateService(ctx, service); err != nil {
			return fmt.Errorf("update service: %w", err)
		}

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

	m.accountManager.StoreEvent(ctx, userID, service.ID, accountID, activity.ServiceUpdated, service.EventMeta())

	err = m.replaceHostByLookup(ctx, accountID, service)
	if err != nil {
		return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
	}

	token, err := m.tokenStore.GenerateToken(accountID, service.ID, 5*time.Minute)
	if err != nil {
		return nil, fmt.Errorf("failed to generate authentication token: %w", err)
	}

	switch {
	case domainChanged && oldCluster != service.ProxyCluster:
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Delete, "", m.proxyGRPCServer.GetOIDCValidationConfig()), oldCluster)
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Create, token, m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)
	case !service.Enabled && serviceEnabledChanged:
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Delete, "", m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)
	case service.Enabled && serviceEnabledChanged:
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Create, token, m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)
	default:
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Update, "", m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)

	}
	m.accountManager.UpdateAccountPeers(ctx, accountID)

	return service, nil
}

// validateTargetReferences checks that all target IDs reference existing peers or resources in the account.
func validateTargetReferences(ctx context.Context, transaction store.Store, accountID string, targets []*reverseproxy.Target) error {
	for _, target := range targets {
		switch target.TargetType {
		case reverseproxy.TargetTypePeer:
			if _, err := transaction.GetPeerByID(ctx, store.LockingStrengthShare, accountID, target.TargetId); err != nil {
				if sErr, ok := status.FromError(err); ok && sErr.Type() == status.NotFound {
					return status.Errorf(status.InvalidArgument, "peer target %q not found in account", target.TargetId)
				}
				return fmt.Errorf("look up peer target %q: %w", target.TargetId, err)
			}
		case reverseproxy.TargetTypeHost, reverseproxy.TargetTypeSubnet, reverseproxy.TargetTypeDomain:
			if _, err := transaction.GetNetworkResourceByID(ctx, store.LockingStrengthShare, accountID, target.TargetId); err != nil {
				if sErr, ok := status.FromError(err); ok && sErr.Type() == status.NotFound {
					return status.Errorf(status.InvalidArgument, "resource target %q not found in account", target.TargetId)
				}
				return fmt.Errorf("look up resource target %q: %w", target.TargetId, err)
			}
		}
	}
	return nil
}

func (m *managerImpl) DeleteService(ctx context.Context, accountID, userID, serviceID string) error {
	ok, err := m.permissionsManager.ValidateUserPermissions(ctx, accountID, userID, modules.Services, operations.Delete)
	if err != nil {
		return status.NewPermissionValidationError(err)
	}
	if !ok {
		return status.NewPermissionDeniedError()
	}

	var service *reverseproxy.Service
	err = m.store.ExecuteInTransaction(ctx, func(transaction store.Store) error {
		var err error
		service, err = transaction.GetServiceByID(ctx, store.LockingStrengthUpdate, accountID, serviceID)
		if err != nil {
			return err
		}

		if err = transaction.DeleteService(ctx, accountID, serviceID); err != nil {
			return fmt.Errorf("failed to delete service: %w", err)
		}

		return nil
	})
	if err != nil {
		return err
	}

	m.accountManager.StoreEvent(ctx, userID, serviceID, accountID, activity.ServiceDeleted, service.EventMeta())

	m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Delete, "", m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)

	m.accountManager.UpdateAccountPeers(ctx, accountID)

	return nil
}

// SetCertificateIssuedAt sets the certificate issued timestamp to the current time.
// Call this when receiving a gRPC notification that the certificate was issued.
func (m *managerImpl) SetCertificateIssuedAt(ctx context.Context, accountID, serviceID string) error {
	return m.store.ExecuteInTransaction(ctx, func(transaction store.Store) error {
		service, err := transaction.GetServiceByID(ctx, store.LockingStrengthUpdate, accountID, serviceID)
		if err != nil {
			return fmt.Errorf("failed to get service: %w", err)
		}

		service.Meta.CertificateIssuedAt = time.Now()

		if err = transaction.UpdateService(ctx, service); err != nil {
			return fmt.Errorf("failed to update service certificate timestamp: %w", err)
		}

		return nil
	})
}

// SetStatus updates the status of the service (e.g., "active", "tunnel_not_created", etc.)
func (m *managerImpl) SetStatus(ctx context.Context, accountID, serviceID string, status reverseproxy.ProxyStatus) error {
	return m.store.ExecuteInTransaction(ctx, func(transaction store.Store) error {
		service, err := transaction.GetServiceByID(ctx, store.LockingStrengthUpdate, accountID, serviceID)
		if err != nil {
			return fmt.Errorf("failed to get service: %w", err)
		}

		service.Meta.Status = string(status)

		if err = transaction.UpdateService(ctx, service); err != nil {
			return fmt.Errorf("failed to update service status: %w", err)
		}

		return nil
	})
}

func (m *managerImpl) ReloadService(ctx context.Context, accountID, serviceID string) error {
	service, err := m.store.GetServiceByID(ctx, store.LockingStrengthNone, accountID, serviceID)
	if err != nil {
		return fmt.Errorf("failed to get service: %w", err)
	}

	err = m.replaceHostByLookup(ctx, accountID, service)
	if err != nil {
		return fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
	}

	m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Update, "", m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)

	m.accountManager.UpdateAccountPeers(ctx, accountID)

	return nil
}

func (m *managerImpl) ReloadAllServicesForAccount(ctx context.Context, accountID string) error {
	services, err := m.store.GetAccountServices(ctx, store.LockingStrengthNone, accountID)
	if err != nil {
		return fmt.Errorf("failed to get services: %w", err)
	}

	for _, service := range services {
		err = m.replaceHostByLookup(ctx, accountID, service)
		if err != nil {
			return fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
		}
		m.proxyGRPCServer.SendServiceUpdateToCluster(service.ToProtoMapping(reverseproxy.Update, "", m.proxyGRPCServer.GetOIDCValidationConfig()), service.ProxyCluster)
	}

	m.accountManager.UpdateAccountPeers(ctx, accountID)

	return nil
}

func (m *managerImpl) GetGlobalServices(ctx context.Context) ([]*reverseproxy.Service, error) {
	services, err := m.store.GetServices(ctx, store.LockingStrengthNone)
	if err != nil {
		return nil, fmt.Errorf("failed to get services: %w", err)
	}

	for _, service := range services {
		err = m.replaceHostByLookup(ctx, service.AccountID, service)
		if err != nil {
			return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
		}
	}

	return services, nil
}

func (m *managerImpl) GetServiceByID(ctx context.Context, accountID, serviceID string) (*reverseproxy.Service, error) {
	service, err := m.store.GetServiceByID(ctx, store.LockingStrengthNone, accountID, serviceID)
	if err != nil {
		return nil, fmt.Errorf("failed to get service: %w", err)
	}

	err = m.replaceHostByLookup(ctx, accountID, service)
	if err != nil {
		return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
	}

	return service, nil
}

func (m *managerImpl) GetAccountServices(ctx context.Context, accountID string) ([]*reverseproxy.Service, error) {
	services, err := m.store.GetAccountServices(ctx, store.LockingStrengthNone, accountID)
	if err != nil {
		return nil, fmt.Errorf("failed to get services: %w", err)
	}

	for _, service := range services {
		err = m.replaceHostByLookup(ctx, accountID, service)
		if err != nil {
			return nil, fmt.Errorf("failed to replace host by lookup for service %s: %w", service.ID, err)
		}
	}

	return services, nil
}

func (m *managerImpl) GetServiceIDByTargetID(ctx context.Context, accountID string, resourceID string) (string, error) {
	target, err := m.store.GetServiceTargetByTargetID(ctx, store.LockingStrengthNone, accountID, resourceID)
	if err != nil {
		if s, ok := status.FromError(err); ok && s.Type() == status.NotFound {
			return "", nil
		}
		return "", fmt.Errorf("failed to get service target by resource ID: %w", err)
	}

	if target == nil {
		return "", nil
	}

	return target.ServiceID, nil
}