package db

import (
	"context"
	"encoding/json"
	"fmt"
	"maps"
	"slices"
	"strconv"
	"strings"
	"sync"
	"time"

	log "github.com/sirupsen/logrus"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/version"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/utils/ptr"

	"github.com/argoproj/argo-cd/v3/common"
	appv1 "github.com/argoproj/argo-cd/v3/pkg/apis/application/v1alpha1"
	"github.com/argoproj/argo-cd/v3/util/settings"
)

const errCheckingInClusterEnabled = "%s: error checking if in-cluster is enabled: %v"

var (
	localCluster = appv1.Cluster{
		Name:            appv1.KubernetesInClusterName,
		Server:          appv1.KubernetesInternalAPIServerAddr,
		ConnectionState: appv1.ConnectionState{Status: appv1.ConnectionStatusSuccessful},
	}
	initLocalCluster sync.Once
)

func (db *db) getLocalCluster() *appv1.Cluster {
	initLocalCluster.Do(func() {
		info, err := db.kubeclientset.Discovery().ServerVersion()
		if err == nil {
			ver, verErr := version.ParseGeneric(info.GitVersion)
			if verErr == nil {
				//nolint:staticcheck
				localCluster.ServerVersion = ver.String()
			} else {
				log.Warnf("Failed to parse Kubernetes server version: %v", verErr)
			}
			//nolint:staticcheck
			localCluster.ConnectionState = appv1.ConnectionState{Status: appv1.ConnectionStatusSuccessful}
		} else {
			//nolint:staticcheck
			localCluster.ConnectionState = appv1.ConnectionState{
				Status:  appv1.ConnectionStatusFailed,
				Message: err.Error(),
			}
		}
	})
	cluster := localCluster.DeepCopy()
	now := metav1.Now()
	//nolint:staticcheck
	cluster.ConnectionState.ModifiedAt = &now
	return cluster
}

// ListClusters returns list of clusters
func (db *db) ListClusters(_ context.Context) (*appv1.ClusterList, error) {
	clusterSecrets, err := db.listSecretsByType(common.LabelValueSecretTypeCluster)
	if err != nil {
		return nil, err
	}
	clusterList := appv1.ClusterList{
		Items: make([]appv1.Cluster, 0),
	}
	inClusterEnabled, err := db.settingsMgr.IsInClusterEnabled()
	if err != nil {
		log.Warnf(errCheckingInClusterEnabled, "ListClusters", err)
	}
	hasInClusterCredentials := false
	for _, clusterSecret := range clusterSecrets {
		cluster, err := SecretToCluster(clusterSecret)
		if err != nil {
			log.Errorf("could not unmarshal cluster secret %s", clusterSecret.Name)
			continue
		}
		if cluster.Server == appv1.KubernetesInternalAPIServerAddr {
			if inClusterEnabled {
				hasInClusterCredentials = true
				clusterList.Items = append(clusterList.Items, *cluster)
			}
		} else {
			clusterList.Items = append(clusterList.Items, *cluster)
		}
	}
	if inClusterEnabled && !hasInClusterCredentials {
		clusterList.Items = append(clusterList.Items, *db.getLocalCluster())
	}
	return &clusterList, nil
}

// CreateCluster creates a cluster
func (db *db) CreateCluster(ctx context.Context, c *appv1.Cluster) (*appv1.Cluster, error) {
	if c.Server == appv1.KubernetesInternalAPIServerAddr {
		inClusterEnabled, err := db.settingsMgr.IsInClusterEnabled()
		if err != nil {
			log.Warnf(errCheckingInClusterEnabled, "CreateCluster", err)
		}
		if !inClusterEnabled {
			return nil, status.Errorf(codes.InvalidArgument, "cannot register cluster: in-cluster has been disabled")
		}
	}
	secName, err := URIToSecretName("cluster", c.Server)
	if err != nil {
		return nil, err
	}

	clusterSecret := &corev1.Secret{
		ObjectMeta: metav1.ObjectMeta{
			Name: secName,
		},
	}

	err = clusterToSecret(c, clusterSecret)
	if err != nil {
		return nil, err
	}

	clusterSecret, err = db.createSecret(ctx, clusterSecret)
	if err != nil {
		if apierrors.IsAlreadyExists(err) {
			return nil, status.Errorf(codes.AlreadyExists, "cluster %q already exists", c.Server)
		}
		return nil, err
	}

	cluster, err := SecretToCluster(clusterSecret)
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "could not unmarshal cluster secret %s", clusterSecret.Name)
	}
	return cluster, db.settingsMgr.ResyncInformers()
}

// ClusterEvent contains information about cluster event
type ClusterEvent struct {
	Type    watch.EventType
	Cluster *appv1.Cluster
}

func (db *db) WatchClusters(ctx context.Context,
	handleAddEvent func(cluster *appv1.Cluster),
	handleModEvent func(oldCluster *appv1.Cluster, newCluster *appv1.Cluster),
	handleDeleteEvent func(clusterServer string),
) error {
	inClusterEnabled, err := db.settingsMgr.IsInClusterEnabled()
	if err != nil {
		log.Warnf(errCheckingInClusterEnabled, "WatchClusters", err)
	}
	localCls := db.getLocalCluster()
	if inClusterEnabled {
		localCls, err = db.GetCluster(ctx, appv1.KubernetesInternalAPIServerAddr)
		if err != nil {
			return fmt.Errorf("could not get local cluster: %w", err)
		}
		handleAddEvent(localCls)
	}

	db.watchSecrets(
		ctx,
		common.LabelValueSecretTypeCluster,

		func(secret *corev1.Secret) {
			cluster, err := SecretToCluster(secret)
			if err != nil {
				log.Errorf("could not unmarshal cluster secret %s", secret.Name)
				return
			}
			if cluster.Server == appv1.KubernetesInternalAPIServerAddr {
				if inClusterEnabled {
					// change local cluster event to modified, since it cannot be added at runtime
					handleModEvent(localCls, cluster)
					localCls = cluster
				}
				return
			}
			handleAddEvent(cluster)
		},

		func(oldSecret *corev1.Secret, newSecret *corev1.Secret) {
			oldCluster, err := SecretToCluster(oldSecret)
			if err != nil {
				log.Errorf("could not unmarshal cluster secret %s", oldSecret.Name)
				return
			}
			newCluster, err := SecretToCluster(newSecret)
			if err != nil {
				log.Errorf("could not unmarshal cluster secret %s", newSecret.Name)
				return
			}
			if newCluster.Server == appv1.KubernetesInternalAPIServerAddr {
				localCls = newCluster
			}
			handleModEvent(oldCluster, newCluster)
		},

		func(secret *corev1.Secret) {
			if string(secret.Data["server"]) == appv1.KubernetesInternalAPIServerAddr && inClusterEnabled {
				// change local cluster event to modified, since it cannot be deleted at runtime, unless disabled.
				newLocalCls := db.getLocalCluster()
				handleModEvent(localCls, newLocalCls)
				localCls = newLocalCls
			} else {
				handleDeleteEvent(string(secret.Data["server"]))
			}
		},
	)

	return err
}

func (db *db) getClusterSecret(server string) (*corev1.Secret, error) {
	clusterSecrets, err := db.listSecretsByType(common.LabelValueSecretTypeCluster)
	if err != nil {
		return nil, err
	}
	srv := strings.TrimRight(server, "/")
	for _, clusterSecret := range clusterSecrets {
		if strings.TrimRight(string(clusterSecret.Data["server"]), "/") == srv {
			return clusterSecret, nil
		}
	}
	return nil, status.Errorf(codes.NotFound, "cluster %q not found", server)
}

// GetCluster returns a cluster from a query
func (db *db) GetCluster(_ context.Context, server string) (*appv1.Cluster, error) {
	informer, err := db.settingsMgr.GetClusterInformer()
	if err != nil {
		return nil, fmt.Errorf("failed to get cluster informer: %w", err)
	}
	if server == appv1.KubernetesInternalAPIServerAddr {
		inClusterEnabled, err := db.settingsMgr.IsInClusterEnabled()
		if err != nil {
			log.Warnf(errCheckingInClusterEnabled, "GetCluster", err)
		}
		if !inClusterEnabled {
			return nil, status.Errorf(codes.NotFound, "cluster %q is disabled", server)
		}

		// Check if there's a secret configured for the in-cluster address
		// If so, use that instead of the hardcoded local cluster
		cluster, err := informer.GetClusterByURL(server)
		if err == nil {
			return cluster, nil
		}

		// Fall back to the hardcoded local cluster if no secret is configured
		return db.getLocalCluster(), nil
	}

	cluster, err := informer.GetClusterByURL(server)
	if err != nil {
		return nil, status.Errorf(codes.NotFound, "cluster %q not found", server)
	}

	return cluster, nil
}

// GetProjectClusters return project scoped clusters by given project name
func (db *db) GetProjectClusters(_ context.Context, project string) ([]*appv1.Cluster, error) {
	informer, err := db.settingsMgr.GetSecretsInformer()
	if err != nil {
		return nil, fmt.Errorf("failed to get secrets informer: %w", err)
	}
	secrets, err := informer.GetIndexer().ByIndex(settings.ByProjectClusterIndexer, project)
	if err != nil {
		return nil, fmt.Errorf("failed to get index by project cluster indexer for project %q: %w", project, err)
	}
	var res []*appv1.Cluster
	for i := range secrets {
		cluster, err := SecretToCluster(secrets[i].(*corev1.Secret))
		if err != nil {
			return nil, fmt.Errorf("failed to convert secret to cluster: %w", err)
		}
		res = append(res, cluster)
	}
	return res, nil
}

func (db *db) GetClusterServersByName(_ context.Context, name string) ([]string, error) {
	informer, err := db.settingsMgr.GetClusterInformer()
	if err != nil {
		return nil, fmt.Errorf("failed to get cluster informer: %w", err)
	}
	servers, err := informer.GetClusterServersByName(name)
	if err != nil {
		return nil, err
	}

	// attempt to short circuit if the in-cluster name is not involved
	if name != appv1.KubernetesInClusterName && !slices.Contains(servers, appv1.KubernetesInternalAPIServerAddr) {
		return servers, nil
	}

	inClusterEnabled, err := db.settingsMgr.IsInClusterEnabled()
	if err != nil {
		log.Warnf(errCheckingInClusterEnabled, "GetClusterServersByName", err)
	}

	// Handle local cluster special case
	if len(servers) == 0 && name == appv1.KubernetesInClusterName && inClusterEnabled {
		return []string{appv1.KubernetesInternalAPIServerAddr}, nil
	}

	// Filter out disabled in-cluster
	if !inClusterEnabled {
		filtered := make([]string, 0, len(servers))
		for _, s := range servers {
			if s != appv1.KubernetesInternalAPIServerAddr {
				filtered = append(filtered, s)
			}
		}
		return filtered, nil
	}

	return servers, nil
}

// UpdateCluster updates a cluster
func (db *db) UpdateCluster(ctx context.Context, c *appv1.Cluster) (*appv1.Cluster, error) {
	clusterSecret, err := db.getClusterSecret(c.Server)
	if err != nil {
		if status.Code(err) == codes.NotFound {
			return db.CreateCluster(ctx, c)
		}
		return nil, err
	}
	if err := clusterToSecret(c, clusterSecret); err != nil {
		return nil, err
	}

	clusterSecret, err = db.kubeclientset.CoreV1().Secrets(db.ns).Update(ctx, clusterSecret, metav1.UpdateOptions{})
	if err != nil {
		return nil, err
	}
	cluster, err := SecretToCluster(clusterSecret)
	if err != nil {
		log.Errorf("could not unmarshal cluster secret %s", clusterSecret.Name)
		return nil, err
	}
	return cluster, db.settingsMgr.ResyncInformers()
}

// DeleteCluster deletes a cluster by name
func (db *db) DeleteCluster(ctx context.Context, server string) error {
	secret, err := db.getClusterSecret(server)
	if err != nil {
		return err
	}

	err = db.deleteSecret(ctx, secret)
	if err != nil {
		return err
	}

	return db.settingsMgr.ResyncInformers()
}

// clusterToSecret converts a cluster object to string data for serialization to a secret
func clusterToSecret(c *appv1.Cluster, secret *corev1.Secret) error {
	data := make(map[string][]byte)
	data["server"] = []byte(strings.TrimRight(c.Server, "/"))
	if c.Name == "" {
		data["name"] = []byte(c.Server)
	} else {
		data["name"] = []byte(c.Name)
	}
	if len(c.Namespaces) != 0 {
		data["namespaces"] = []byte(strings.Join(c.Namespaces, ","))
	}
	configBytes, err := json.Marshal(c.Config)
	if err != nil {
		return err
	}
	data["config"] = configBytes
	if c.Shard != nil {
		data["shard"] = []byte(strconv.Itoa(int(*c.Shard)))
	}
	if c.ClusterResources {
		data["clusterResources"] = []byte("true")
	}
	if c.Project != "" {
		data["project"] = []byte(c.Project)
	}
	secret.Data = data

	secret.Labels = c.Labels
	if c.Annotations != nil && c.Annotations[corev1.LastAppliedConfigAnnotation] != "" {
		return status.Errorf(codes.InvalidArgument, "annotation %s cannot be set", corev1.LastAppliedConfigAnnotation)
	}
	secret.Annotations = c.Annotations

	if secret.Annotations == nil {
		secret.Annotations = make(map[string]string)
	}

	if c.RefreshRequestedAt != nil {
		secret.Annotations[appv1.AnnotationKeyRefresh] = c.RefreshRequestedAt.Format(time.RFC3339)
	} else {
		delete(secret.Annotations, appv1.AnnotationKeyRefresh)
	}
	addSecretMetadata(secret, common.LabelValueSecretTypeCluster)
	return nil
}

// SecretToCluster converts a secret into a Cluster object
func SecretToCluster(s *corev1.Secret) (*appv1.Cluster, error) {
	var config appv1.ClusterConfig
	if len(s.Data["config"]) > 0 {
		err := json.Unmarshal(s.Data["config"], &config)
		if err != nil {
			return nil, fmt.Errorf("failed to unmarshal cluster config: %w", err)
		}
	}

	var namespaces []string
	for _, ns := range strings.Split(string(s.Data["namespaces"]), ",") {
		if ns = strings.TrimSpace(ns); ns != "" {
			namespaces = append(namespaces, ns)
		}
	}
	var refreshRequestedAt *metav1.Time
	if v, found := s.Annotations[appv1.AnnotationKeyRefresh]; found {
		requestedAt, err := time.Parse(time.RFC3339, v)
		if err != nil {
			log.Warnf("Error while parsing date in cluster secret '%s': %v", s.Name, err)
		} else {
			refreshRequestedAt = &metav1.Time{Time: requestedAt}
		}
	}
	var shard *int64
	if shardStr := s.Data["shard"]; shardStr != nil {
		if val, err := strconv.Atoi(string(shardStr)); err != nil {
			log.Warnf("Error while parsing shard in cluster secret '%s': %v", s.Name, err)
		} else {
			shard = ptr.To(int64(val))
		}
	}

	// copy labels and annotations excluding system ones
	labels := map[string]string{}
	if s.Labels != nil {
		labels = maps.Clone(s.Labels)
		delete(labels, common.LabelKeySecretType)
	}
	annotations := map[string]string{}
	if s.Annotations != nil {
		annotations = maps.Clone(s.Annotations)
		// delete system annotations
		delete(annotations, corev1.LastAppliedConfigAnnotation)
		delete(annotations, common.AnnotationKeyManagedBy)
	}

	cluster := appv1.Cluster{
		ID:                 string(s.UID),
		Server:             strings.TrimRight(string(s.Data["server"]), "/"),
		Name:               string(s.Data["name"]),
		Namespaces:         namespaces,
		ClusterResources:   string(s.Data["clusterResources"]) == "true",
		Config:             config,
		RefreshRequestedAt: refreshRequestedAt,
		Shard:              shard,
		Project:            string(s.Data["project"]),
		Labels:             labels,
		Annotations:        annotations,
	}
	return &cluster, nil
}
