package cluster

import (
	"context"
	"fmt"
	"net/url"
	"time"

	"github.com/argoproj/gitops-engine/pkg/utils/kube"
	log "github.com/sirupsen/logrus"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/client-go/kubernetes"

	"github.com/argoproj/argo-cd/v2/common"
	"github.com/argoproj/argo-cd/v2/pkg/apiclient/cluster"
	appv1 "github.com/argoproj/argo-cd/v2/pkg/apis/application/v1alpha1"
	servercache "github.com/argoproj/argo-cd/v2/server/cache"
	"github.com/argoproj/argo-cd/v2/util/argo"
	"github.com/argoproj/argo-cd/v2/util/clusterauth"
	"github.com/argoproj/argo-cd/v2/util/db"
	"github.com/argoproj/argo-cd/v2/util/rbac"
)

// Server provides a Cluster service
type Server struct {
	db      db.ArgoDB
	enf     *rbac.Enforcer
	cache   *servercache.Cache
	kubectl kube.Kubectl
}

// NewServer returns a new instance of the Cluster service
func NewServer(db db.ArgoDB, enf *rbac.Enforcer, cache *servercache.Cache, kubectl kube.Kubectl) *Server {
	return &Server{
		db:      db,
		enf:     enf,
		cache:   cache,
		kubectl: kubectl,
	}
}

func CreateClusterRBACObject(project string, server string) string {
	if project != "" {
		return project + "/" + server
	}
	return server
}

// List returns list of clusters
func (s *Server) List(ctx context.Context, q *cluster.ClusterQuery) (*appv1.ClusterList, error) {
	clusterList, err := s.db.ListClusters(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to list clusters: %w", err)
	}

	filteredItems := clusterList.Items

	// Filter clusters by id
	if filteredItems, err = filterClustersById(filteredItems, q.Id); err != nil {
		return nil, fmt.Errorf("error filtering clusters by id: %w", err)
	}

	// Filter clusters by name
	filteredItems = filterClustersByName(filteredItems, q.Name)

	// Filter clusters by server
	filteredItems = filterClustersByServer(filteredItems, q.Server)

	items := make([]appv1.Cluster, 0)
	for _, clust := range filteredItems {
		if s.enf.Enforce(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionGet, CreateClusterRBACObject(clust.Project, clust.Server)) {
			items = append(items, clust)
		}
	}
	err = kube.RunAllAsync(len(items), func(i int) error {
		items[i] = *s.toAPIResponse(&items[i])
		return nil
	})
	if err != nil {
		return nil, fmt.Errorf("error running async cluster responses: %w", err)
	}

	cl := *clusterList
	cl.Items = items

	return &cl, nil
}

func filterClustersById(clusters []appv1.Cluster, id *cluster.ClusterID) ([]appv1.Cluster, error) {
	if id == nil {
		return clusters, nil
	}

	var items []appv1.Cluster

	switch id.Type {
	case "name":
		items = filterClustersByName(clusters, id.Value)
	case "name_escaped":
		nameUnescaped, err := url.QueryUnescape(id.Value)
		if err != nil {
			return nil, fmt.Errorf("failed to unescape cluster name: %w", err)
		}
		items = filterClustersByName(clusters, nameUnescaped)
	default:
		items = filterClustersByServer(clusters, id.Value)
	}

	return items, nil
}

func filterClustersByName(clusters []appv1.Cluster, name string) []appv1.Cluster {
	if name == "" {
		return clusters
	}
	items := make([]appv1.Cluster, 0)
	for i := 0; i < len(clusters); i++ {
		if clusters[i].Name == name {
			items = append(items, clusters[i])
			return items
		}
	}
	return items
}

func filterClustersByServer(clusters []appv1.Cluster, server string) []appv1.Cluster {
	if server == "" {
		return clusters
	}
	items := make([]appv1.Cluster, 0)
	for i := 0; i < len(clusters); i++ {
		if clusters[i].Server == server {
			items = append(items, clusters[i])
			return items
		}
	}
	return items
}

// Create creates a cluster
func (s *Server) Create(ctx context.Context, q *cluster.ClusterCreateRequest) (*appv1.Cluster, error) {
	if err := s.enf.EnforceErr(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionCreate, CreateClusterRBACObject(q.Cluster.Project, q.Cluster.Server)); err != nil {
		return nil, fmt.Errorf("permission denied while creating cluster: %w", err)
	}
	c := q.Cluster
	clusterRESTConfig, err := c.RESTConfig()
	if err != nil {
		return nil, fmt.Errorf("error getting REST config: %w", err)
	}

	serverVersion, err := s.kubectl.GetServerVersion(clusterRESTConfig)
	if err != nil {
		return nil, fmt.Errorf("error getting server version: %w", err)
	}

	clust, err := s.db.CreateCluster(ctx, c)
	if err != nil {
		if status.Convert(err).Code() == codes.AlreadyExists {
			// act idempotent if existing spec matches new spec
			existing, getErr := s.db.GetCluster(ctx, c.Server)
			if getErr != nil {
				return nil, status.Errorf(codes.Internal, "unable to check existing cluster details: %v", getErr)
			}

			if existing.Equals(c) {
				clust = existing
			} else if q.Upsert {
				return s.Update(ctx, &cluster.ClusterUpdateRequest{Cluster: c})
			} else {
				return nil, status.Error(codes.InvalidArgument, argo.GenerateSpecIsDifferentErrorMessage("cluster", existing, c))
			}
		} else {
			return nil, fmt.Errorf("error creating cluster: %w", err)
		}
	}

	err = s.cache.SetClusterInfo(c.Server, &appv1.ClusterInfo{
		ServerVersion: serverVersion,
		ConnectionState: appv1.ConnectionState{
			Status:     appv1.ConnectionStatusSuccessful,
			ModifiedAt: &metav1.Time{Time: time.Now()},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("error setting cluster info in cache: %w", err)
	}
	return s.toAPIResponse(clust), err
}

// Get returns a cluster from a query
func (s *Server) Get(ctx context.Context, q *cluster.ClusterQuery) (*appv1.Cluster, error) {
	c, err := s.getClusterAndVerifyAccess(ctx, q, rbac.ActionGet)
	if err != nil {
		return nil, fmt.Errorf("error verifying access to update cluster: %w", err)
	}

	return s.toAPIResponse(c), nil
}

func (s *Server) getClusterWith403IfNotExist(ctx context.Context, q *cluster.ClusterQuery) (*appv1.Cluster, error) {
	repo, err := s.getCluster(ctx, q)
	if err != nil || repo == nil {
		return nil, common.PermissionDeniedAPIError
	}
	return repo, nil
}

func (s *Server) getClusterAndVerifyAccess(ctx context.Context, q *cluster.ClusterQuery, action string) (*appv1.Cluster, error) {
	c, err := s.getClusterWith403IfNotExist(ctx, q)
	if err != nil {
		return nil, fmt.Errorf("failed to get cluster with permissions check: %w", err)
	}

	// verify that user can do the specified action inside project where cluster is located
	if !s.enf.Enforce(ctx.Value("claims"), rbac.ResourceClusters, action, CreateClusterRBACObject(c.Project, c.Server)) {
		log.WithField("cluster", q.Server).Warnf("encountered permissions issue while processing request: %v", err)
		return nil, common.PermissionDeniedAPIError
	}

	return c, nil
}

func (s *Server) getCluster(ctx context.Context, q *cluster.ClusterQuery) (*appv1.Cluster, error) {
	if q.Id != nil {
		q.Server = ""
		q.Name = ""
		switch q.Id.Type {
		case "name":
			q.Name = q.Id.Value
		case "name_escaped":
			nameUnescaped, err := url.QueryUnescape(q.Id.Value)
			if err != nil {
				return nil, fmt.Errorf("failed to unescape cluster name: %w", err)
			}
			q.Name = nameUnescaped
		default:
			q.Server = q.Id.Value
		}
	}

	if q.Server != "" {
		c, err := s.db.GetCluster(ctx, q.Server)
		if err != nil {
			return nil, fmt.Errorf("failed to get cluster by server: %w", err)
		}
		return c, nil
	}

	// we only get the name when we specify Name in ApplicationDestination and next
	// we want to find the server in order to populate ApplicationDestination.Server
	if q.Name != "" {
		clusterList, err := s.db.ListClusters(ctx)
		if err != nil {
			return nil, fmt.Errorf("failed to list clusters: %w", err)
		}
		for _, c := range clusterList.Items {
			if c.Name == q.Name {
				return &c, nil
			}
		}
	}

	return nil, nil
}

var clusterFieldsByPath = map[string]func(updated *appv1.Cluster, existing *appv1.Cluster){
	"name": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Name = existing.Name
	},
	"namespaces": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Namespaces = existing.Namespaces
	},
	"config": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Config = existing.Config
	},
	"shard": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Shard = existing.Shard
	},
	"clusterResources": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.ClusterResources = existing.ClusterResources
	},
	"labels": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Labels = existing.Labels
	},
	"annotations": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Annotations = existing.Annotations
	},
	"project": func(updated *appv1.Cluster, existing *appv1.Cluster) {
		updated.Project = existing.Project
	},
}

// Update updates a cluster
func (s *Server) Update(ctx context.Context, q *cluster.ClusterUpdateRequest) (*appv1.Cluster, error) {
	c, err := s.getClusterAndVerifyAccess(ctx, &cluster.ClusterQuery{
		Server: q.Cluster.Server,
		Name:   q.Cluster.Name,
		Id:     q.Id,
	}, rbac.ActionUpdate)
	if err != nil {
		return nil, fmt.Errorf("failed to verify access for updating cluster: %w", err)
	}

	if len(q.UpdatedFields) == 0 || sets.NewString(q.UpdatedFields...).Has("project") {
		// verify that user can do update inside project where cluster will be located
		if !s.enf.Enforce(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionUpdate, CreateClusterRBACObject(q.Cluster.Project, c.Server)) {
			return nil, common.PermissionDeniedAPIError
		}
	}

	if len(q.UpdatedFields) != 0 {
		for _, path := range q.UpdatedFields {
			if updater, ok := clusterFieldsByPath[path]; ok {
				updater(c, q.Cluster)
			}
		}
		q.Cluster = c
	}
	clusterRESTConfig, err := q.Cluster.RESTConfig()
	if err != nil {
		return nil, fmt.Errorf("failed to get REST config for cluster: %w", err)
	}

	// Test the token we just created before persisting it
	serverVersion, err := s.kubectl.GetServerVersion(clusterRESTConfig)
	if err != nil {
		return nil, fmt.Errorf("failed to get server version: %w", err)
	}

	clust, err := s.db.UpdateCluster(ctx, q.Cluster)
	if err != nil {
		return nil, fmt.Errorf("failed to update cluster in database: %w", err)
	}
	err = s.cache.SetClusterInfo(clust.Server, &appv1.ClusterInfo{
		ServerVersion: serverVersion,
		ConnectionState: appv1.ConnectionState{
			Status:     appv1.ConnectionStatusSuccessful,
			ModifiedAt: &metav1.Time{Time: time.Now()},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to set cluster info in cache: %w", err)
	}
	return s.toAPIResponse(clust), nil
}

// Delete deletes a cluster by server/name
func (s *Server) Delete(ctx context.Context, q *cluster.ClusterQuery) (*cluster.ClusterResponse, error) {
	c, err := s.getClusterWith403IfNotExist(ctx, q)
	if err != nil {
		return nil, fmt.Errorf("failed to get cluster with permissions check: %w", err)
	}

	if q.Name != "" {
		servers, err := s.db.GetClusterServersByName(ctx, q.Name)
		if err != nil {
			log.WithField("cluster", q.Name).Warnf("failed to get cluster servers by name: %v", err)
			return nil, common.PermissionDeniedAPIError
		}
		for _, server := range servers {
			if err := enforceAndDelete(s, ctx, server, c.Project); err != nil {
				return nil, fmt.Errorf("failed to enforce and delete cluster server: %w", err)
			}
		}
	} else {
		if err := enforceAndDelete(s, ctx, q.Server, c.Project); err != nil {
			return nil, fmt.Errorf("failed to enforce and delete cluster server: %w", err)
		}
	}

	return &cluster.ClusterResponse{}, nil
}

func enforceAndDelete(s *Server, ctx context.Context, server, project string) error {
	if err := s.enf.EnforceErr(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionDelete, CreateClusterRBACObject(project, server)); err != nil {
		log.WithField("cluster", server).Warnf("encountered permissions issue while processing request: %v", err)
		return common.PermissionDeniedAPIError
	}
	return s.db.DeleteCluster(ctx, server)
}

// RotateAuth rotates the bearer token used for a cluster
func (s *Server) RotateAuth(ctx context.Context, q *cluster.ClusterQuery) (*cluster.ClusterResponse, error) {
	clust, err := s.getClusterWith403IfNotExist(ctx, q)
	if err != nil {
		return nil, fmt.Errorf("failed to get cluster with permissions check: %w", err)
	}

	var servers []string
	if q.Name != "" {
		servers, err = s.db.GetClusterServersByName(ctx, q.Name)
		if err != nil {
			log.WithField("cluster", q.Name).Warnf("failed to get cluster servers by name: %v", err)
			return nil, common.PermissionDeniedAPIError
		}
		for _, server := range servers {
			if err := s.enf.EnforceErr(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionUpdate, CreateClusterRBACObject(clust.Project, server)); err != nil {
				log.WithField("cluster", server).Warnf("encountered permissions issue while processing request: %v", err)
				return nil, common.PermissionDeniedAPIError
			}
		}
	} else {
		if err := s.enf.EnforceErr(ctx.Value("claims"), rbac.ResourceClusters, rbac.ActionUpdate, CreateClusterRBACObject(clust.Project, q.Server)); err != nil {
			log.WithField("cluster", q.Server).Warnf("encountered permissions issue while processing request: %v", err)
			return nil, common.PermissionDeniedAPIError
		}
		servers = append(servers, q.Server)
	}

	for _, server := range servers {
		logCtx := log.WithField("cluster", server)
		logCtx.Info("Rotating auth")
		restCfg, err := clust.RESTConfig()
		if err != nil {
			return nil, fmt.Errorf("failed to get REST config for cluster: %w", err)
		}
		if restCfg.BearerToken == "" {
			return nil, status.Errorf(codes.InvalidArgument, "Cluster '%s' does not use bearer token authentication", server)
		}

		claims, err := clusterauth.ParseServiceAccountToken(restCfg.BearerToken)
		if err != nil {
			return nil, fmt.Errorf("failed to parse service account token: %w", err)
		}
		kubeclientset, err := kubernetes.NewForConfig(restCfg)
		if err != nil {
			return nil, fmt.Errorf("failed to create Kubernetes clientset: %w", err)
		}
		newSecret, err := clusterauth.GenerateNewClusterManagerSecret(kubeclientset, claims)
		if err != nil {
			return nil, fmt.Errorf("failed to generate new cluster manager secret: %w", err)
		}
		// we are using token auth, make sure we don't store client-cert information
		clust.Config.KeyData = nil
		clust.Config.CertData = nil
		clust.Config.BearerToken = string(newSecret.Data["token"])

		clusterRESTConfig, err := clust.RESTConfig()
		if err != nil {
			return nil, fmt.Errorf("failed to get REST config for cluster: %w", err)
		}
		// Test the token we just created before persisting it
		serverVersion, err := s.kubectl.GetServerVersion(clusterRESTConfig)
		if err != nil {
			return nil, fmt.Errorf("failed to get server version: %w", err)
		}
		_, err = s.db.UpdateCluster(ctx, clust)
		if err != nil {
			return nil, fmt.Errorf("failed to update cluster in database: %w", err)
		}
		err = s.cache.SetClusterInfo(clust.Server, &appv1.ClusterInfo{
			ServerVersion: serverVersion,
			ConnectionState: appv1.ConnectionState{
				Status:     appv1.ConnectionStatusSuccessful,
				ModifiedAt: &metav1.Time{Time: time.Now()},
			},
		})
		if err != nil {
			return nil, fmt.Errorf("failed to set cluster info in cache: %w", err)
		}
		err = clusterauth.RotateServiceAccountSecrets(kubeclientset, claims, newSecret)
		if err != nil {
			return nil, fmt.Errorf("failed to rotate service account secrets: %w", err)
		}
		logCtx.Infof("Rotated auth (old: %s, new: %s)", claims.SecretName, newSecret.Name)
	}
	return &cluster.ClusterResponse{}, nil
}

func (s *Server) toAPIResponse(clust *appv1.Cluster) *appv1.Cluster {
	clust = clust.Sanitized()
	_ = s.cache.GetClusterInfo(clust.Server, &clust.Info)
	// populate deprecated fields for backward compatibility
	// nolint:staticcheck
	clust.ServerVersion = clust.Info.ServerVersion
	// nolint:staticcheck
	clust.ConnectionState = clust.Info.ConnectionState
	return clust
}

// InvalidateCache invalidates cluster cache
func (s *Server) InvalidateCache(ctx context.Context, q *cluster.ClusterQuery) (*appv1.Cluster, error) {
	cls, err := s.getClusterAndVerifyAccess(ctx, q, rbac.ActionUpdate)
	if err != nil {
		return nil, fmt.Errorf("failed to verify access for cluster: %w", err)
	}
	now := metav1.Now()
	cls.RefreshRequestedAt = &now
	cls, err = s.db.UpdateCluster(ctx, cls)
	if err != nil {
		return nil, fmt.Errorf("failed to update cluster in database: %w", err)
	}
	return s.toAPIResponse(cls), nil
}
