/*
Copyright 2019 The KubeSphere Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package user

import (
	"context"
	"fmt"
	"reflect"
	"time"

	"github.com/go-logr/logr"
	rbacv1 "k8s.io/api/rbac/v1"
	"k8s.io/apimachinery/pkg/types"
	typesv1beta1 "kubesphere.io/api/types/v1beta1"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"

	authoptions "kubesphere.io/kubesphere/pkg/apiserver/authentication/options"

	"k8s.io/apimachinery/pkg/util/validation"

	utilwait "k8s.io/apimachinery/pkg/util/wait"

	"golang.org/x/crypto/bcrypt"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/client-go/kubernetes/scheme"
	"k8s.io/client-go/tools/record"
	"k8s.io/klog"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"

	iamv1alpha2 "kubesphere.io/api/iam/v1alpha2"

	"kubesphere.io/kubesphere/pkg/constants"
	modelsdevops "kubesphere.io/kubesphere/pkg/models/devops"
	"kubesphere.io/kubesphere/pkg/models/kubeconfig"
	"kubesphere.io/kubesphere/pkg/simple/client/devops"
	ldapclient "kubesphere.io/kubesphere/pkg/simple/client/ldap"
	"kubesphere.io/kubesphere/pkg/utils/sliceutil"
)

const (
	// SuccessSynced is used as part of the Event 'reason' when a Foo is synced
	successSynced = "Synced"
	failedSynced  = "FailedSync"
	// is synced successfully
	messageResourceSynced = "User synced successfully"
	controllerName        = "user-controller"
	// user finalizer
	finalizer       = "finalizers.kubesphere.io/users"
	interval        = time.Second
	timeout         = 15 * time.Second
	syncFailMessage = "Failed to sync: %s"
)

// Reconciler reconciles a WorkspaceRole object
type Reconciler struct {
	client.Client
	KubeconfigClient        kubeconfig.Interface
	MultiClusterEnabled     bool
	DevopsClient            devops.Interface
	LdapClient              ldapclient.Interface
	AuthenticationOptions   *authoptions.AuthenticationOptions
	Logger                  logr.Logger
	Scheme                  *runtime.Scheme
	Recorder                record.EventRecorder
	MaxConcurrentReconciles int
}

func (r *Reconciler) SetupWithManager(mgr ctrl.Manager) error {
	if r.Client == nil {
		r.Client = mgr.GetClient()
	}
	if r.Logger == nil {
		r.Logger = ctrl.Log.WithName("controllers").WithName(controllerName)
	}
	if r.Scheme == nil {
		r.Scheme = mgr.GetScheme()
	}
	if r.Recorder == nil {
		r.Recorder = mgr.GetEventRecorderFor(controllerName)
	}
	if r.MaxConcurrentReconciles <= 0 {
		r.MaxConcurrentReconciles = 1
	}
	return ctrl.NewControllerManagedBy(mgr).
		Named(controllerName).
		WithOptions(controller.Options{
			MaxConcurrentReconciles: r.MaxConcurrentReconciles,
		}).
		For(&iamv1alpha2.User{}).
		Complete(r)
}

func (r *Reconciler) Reconcile(ctx context.Context, req reconcile.Request) (reconcile.Result, error) {
	logger := r.Logger.WithValues("user", req.NamespacedName)
	rootCtx := context.Background()
	user := &iamv1alpha2.User{}
	err := r.Get(rootCtx, req.NamespacedName, user)
	if err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	if user.ObjectMeta.DeletionTimestamp.IsZero() {
		// The object is not being deleted, so if it does not have our finalizer,
		// then lets add the finalizer and update the object.
		if !sliceutil.HasString(user.Finalizers, finalizer) {
			user.ObjectMeta.Finalizers = append(user.ObjectMeta.Finalizers, finalizer)
			if err = r.Update(context.Background(), user, &client.UpdateOptions{}); err != nil {
				logger.Error(err, "failed to update user")
				return ctrl.Result{}, err
			}
		}
	} else {
		// The object is being deleted
		if sliceutil.HasString(user.ObjectMeta.Finalizers, finalizer) {
			// we do not need to delete the user from ldapServer when ldapClient is nil
			if r.LdapClient != nil {
				if err = r.waitForDeleteFromLDAP(user.Name); err != nil {
					// ignore timeout error
					r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				}
			}

			if err = r.deleteRoleBindings(ctx, user); err != nil {
				r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				return ctrl.Result{}, err
			}

			if err = r.deleteGroupBindings(ctx, user); err != nil {
				r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				return ctrl.Result{}, err
			}

			if r.DevopsClient != nil {
				// unassign jenkins role, unassign multiple times is allowed
				if err = r.waitForUnassignDevOpsAdminRole(user); err != nil {
					// ignore timeout error
					r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				}
			}

			if err = r.deleteLoginRecords(ctx, user); err != nil {
				r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				return ctrl.Result{}, err
			}

			// remove our finalizer from the list and update it.
			user.Finalizers = sliceutil.RemoveString(user.ObjectMeta.Finalizers, func(item string) bool {
				return item == finalizer
			})

			if err = r.Update(context.Background(), user, &client.UpdateOptions{}); err != nil {
				klog.Error(err)
				r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
				return ctrl.Result{}, err
			}
		}

		// Our finalizer has finished, so the reconciler can do nothing.
		return ctrl.Result{}, err
	}

	// synchronization through kubefed-controller when multi cluster is enabled
	if r.MultiClusterEnabled {
		if err = r.multiClusterSync(ctx, user); err != nil {
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
			return ctrl.Result{}, err
		}
	}

	// we do not need to sync ldap info when ldapClient is nil
	if r.LdapClient != nil {
		// ignore errors if timeout
		if err = r.waitForSyncToLDAP(user); err != nil {
			// ignore timeout error
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
		}
	}

	// update user status if not managed by kubefed
	managedByKubefed := user.Labels[constants.KubefedManagedLabel] == "true"
	if !managedByKubefed {
		if user, err = r.encryptPassword(user); err != nil {
			klog.Error(err)
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
			return ctrl.Result{}, err
		}
		if user, err = r.syncUserStatus(ctx, user); err != nil {
			klog.Error(err)
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
			return ctrl.Result{}, err
		}
	}

	if r.KubeconfigClient != nil {
		// ensure user KubeconfigClient configmap is created
		if err = r.KubeconfigClient.CreateKubeConfig(user); err != nil {
			klog.Error(err)
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
			return ctrl.Result{}, err
		}
	}

	if r.DevopsClient != nil {
		// assign jenkins role after user create, assign multiple times is allowed
		// used as logged-in users can do anything
		if err = r.waitForAssignDevOpsAdminRole(user); err != nil {
			// ignore timeout error
			r.Recorder.Event(user, corev1.EventTypeWarning, failedSynced, fmt.Sprintf(syncFailMessage, err))
		}
	}

	r.Recorder.Event(user, corev1.EventTypeNormal, successSynced, messageResourceSynced)

	// block user for AuthenticateRateLimiterDuration duration, after that put it back to the queue to unblock
	if user.Status.State != nil && *user.Status.State == iamv1alpha2.UserAuthLimitExceeded {
		return ctrl.Result{Requeue: true, RequeueAfter: r.AuthenticationOptions.AuthenticateRateLimiterDuration}, nil
	}

	return ctrl.Result{}, nil
}

func (r *Reconciler) encryptPassword(user *iamv1alpha2.User) (*iamv1alpha2.User, error) {
	// password is not empty and not encrypted
	if user.Spec.EncryptedPassword != "" && !isEncrypted(user.Spec.EncryptedPassword) {
		password, err := encrypt(user.Spec.EncryptedPassword)
		if err != nil {
			klog.Error(err)
			return nil, err
		}
		user = user.DeepCopy()
		user.Spec.EncryptedPassword = password
		if user.Annotations == nil {
			user.Annotations = make(map[string]string)
		}
		user.Annotations[iamv1alpha2.LastPasswordChangeTimeAnnotation] = time.Now().UTC().Format(time.RFC3339)
		// ensure plain text password won't be kept anywhere
		delete(user.Annotations, corev1.LastAppliedConfigAnnotation)
		err = r.Update(context.Background(), user, &client.UpdateOptions{})
		if err != nil {
			return nil, err
		}
		return user, nil
	}
	return user, nil
}

func (r *Reconciler) ensureNotControlledByKubefed(user *iamv1alpha2.User) error {
	if user.Labels[constants.KubefedManagedLabel] != "false" {
		if user.Labels == nil {
			user.Labels = make(map[string]string, 0)
		}
		user = user.DeepCopy()
		user.Labels[constants.KubefedManagedLabel] = "false"
		err := r.Update(context.Background(), user, &client.UpdateOptions{})
		if err != nil {
			klog.Error(err)
		}
	}
	return nil
}

func (r *Reconciler) multiClusterSync(ctx context.Context, user *iamv1alpha2.User) error {
	if err := r.ensureNotControlledByKubefed(user); err != nil {
		klog.Error(err)
		return err
	}

	federatedUser := &typesv1beta1.FederatedUser{}
	err := r.Get(ctx, types.NamespacedName{Name: user.Name}, federatedUser)
	if err != nil {
		return err
	}

	if !reflect.DeepEqual(federatedUser.Spec.Template.Spec, user.Spec) ||
		!reflect.DeepEqual(federatedUser.Spec.Template.Status, user.Status) ||
		!reflect.DeepEqual(federatedUser.Spec.Template.Labels, user.Labels) {

		federatedUser.Spec.Template.Labels = user.Labels
		federatedUser.Spec.Template.Spec = user.Spec
		federatedUser.Spec.Template.Status = user.Status
		return r.Update(ctx, federatedUser, &client.UpdateOptions{})
	}

	return nil
}

func (r *Reconciler) createFederatedUser(ctx context.Context, user *iamv1alpha2.User) error {
	federatedUser := &typesv1beta1.FederatedUser{
		TypeMeta: metav1.TypeMeta{
			Kind:       iamv1alpha2.FedUserKind,
			APIVersion: iamv1alpha2.FedUserResource.Group + "/" + iamv1alpha2.FedUserResource.Version,
		},
		ObjectMeta: metav1.ObjectMeta{
			Name: user.Name,
		},
		Spec: typesv1beta1.FederatedUserSpec{
			Template: typesv1beta1.UserTemplate{
				ObjectMeta: metav1.ObjectMeta{
					Labels: user.Labels,
				},
				Spec:   user.Spec,
				Status: user.Status,
			},
			Placement: typesv1beta1.GenericPlacementFields{
				ClusterSelector: &metav1.LabelSelector{},
			},
		},
	}

	// must bind user lifecycle
	err := controllerutil.SetControllerReference(user, federatedUser, scheme.Scheme)
	if err != nil {
		return err
	}

	err = r.Create(ctx, federatedUser, &client.CreateOptions{})
	if err != nil {
		if errors.IsAlreadyExists(err) {
			return nil
		}
		return err
	}

	return nil
}

func (r *Reconciler) waitForAssignDevOpsAdminRole(user *iamv1alpha2.User) error {
	err := utilwait.PollImmediate(interval, timeout, func() (done bool, err error) {
		if err := r.DevopsClient.AssignGlobalRole(modelsdevops.JenkinsAdminRoleName, user.Name); err != nil {
			klog.Error(err)
			return false, err
		}
		return true, nil
	})
	return err
}

func (r *Reconciler) waitForUnassignDevOpsAdminRole(user *iamv1alpha2.User) error {
	err := utilwait.PollImmediate(interval, timeout, func() (done bool, err error) {
		if err := r.DevopsClient.UnAssignGlobalRole(modelsdevops.JenkinsAdminRoleName, user.Name); err != nil {
			return false, err
		}
		return true, nil
	})
	return err
}

func (r *Reconciler) waitForSyncToLDAP(user *iamv1alpha2.User) error {
	if isEncrypted(user.Spec.EncryptedPassword) {
		return nil
	}
	err := utilwait.PollImmediate(interval, timeout, func() (done bool, err error) {
		_, err = r.LdapClient.Get(user.Name)
		if err != nil {
			if err == ldapclient.ErrUserNotExists {
				err = r.LdapClient.Create(user)
				if err != nil {
					klog.Error(err)
					return false, err
				}
				return true, nil
			}
			klog.Error(err)
			return false, err
		}
		err = r.LdapClient.Update(user)
		if err != nil {
			klog.Error(err)
			return false, err
		}
		return true, nil
	})
	return err
}

func (r *Reconciler) waitForDeleteFromLDAP(username string) error {
	err := utilwait.PollImmediate(interval, timeout, func() (done bool, err error) {
		err = r.LdapClient.Delete(username)
		if err != nil && err != ldapclient.ErrUserNotExists {
			klog.Error(err)
			return false, err
		}
		return true, nil
	})
	return err
}

func (r *Reconciler) deleteGroupBindings(ctx context.Context, user *iamv1alpha2.User) error {
	// groupBindings that created by kubeshpere will be deleted directly.
	groupBindings := &iamv1alpha2.GroupBinding{}
	return r.Client.DeleteAllOf(ctx, groupBindings, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
}

func (r *Reconciler) deleteRoleBindings(ctx context.Context, user *iamv1alpha2.User) error {
	if len(user.Name) > validation.LabelValueMaxLength {
		// ignore invalid label value error
		return nil
	}

	globalRoleBinding := &iamv1alpha2.GlobalRoleBinding{}
	err := r.Client.DeleteAllOf(ctx, globalRoleBinding, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
	if err != nil {
		return err
	}

	workspaceRoleBinding := &iamv1alpha2.WorkspaceRoleBinding{}
	err = r.Client.DeleteAllOf(ctx, workspaceRoleBinding, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
	if err != nil {
		return err
	}

	clusterRoleBinding := &rbacv1.ClusterRoleBinding{}
	err = r.Client.DeleteAllOf(ctx, clusterRoleBinding, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
	if err != nil {
		return err
	}

	roleBinding := &rbacv1.RoleBinding{}
	err = r.Client.DeleteAllOf(ctx, roleBinding, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
	if err != nil {
		return err
	}

	return nil
}

func (r *Reconciler) deleteLoginRecords(ctx context.Context, user *iamv1alpha2.User) error {
	loginRecord := &iamv1alpha2.LoginRecord{}
	return r.Client.DeleteAllOf(ctx, loginRecord, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
}

// syncUserStatus will reconcile user state based on user login records
func (r *Reconciler) syncUserStatus(ctx context.Context, user *iamv1alpha2.User) (*iamv1alpha2.User, error) {
	if user.Spec.EncryptedPassword == "" {
		if user.Labels[iamv1alpha2.IdentifyProviderLabel] != "" {
			// mapped user from other identity provider always active until disabled
			if user.Status.State == nil || *user.Status.State != iamv1alpha2.UserActive {
				expected := user.DeepCopy()
				active := iamv1alpha2.UserActive
				expected.Status = iamv1alpha2.UserStatus{
					State:              &active,
					LastTransitionTime: &metav1.Time{Time: time.Now()},
				}
				err := r.Update(ctx, expected, &client.UpdateOptions{})
				if err != nil {
					return nil, err
				}
				return expected, nil
			}
		} else {
			// becomes disabled after setting a blank password
			if user.Status.State == nil || *user.Status.State != iamv1alpha2.UserDisabled {
				expected := user.DeepCopy()
				disabled := iamv1alpha2.UserDisabled
				expected.Status = iamv1alpha2.UserStatus{
					State:              &disabled,
					LastTransitionTime: &metav1.Time{Time: time.Now()},
				}
				err := r.Update(ctx, expected, &client.UpdateOptions{})
				if err != nil {
					return nil, err
				}
				return expected, nil
			}
		}
		return user, nil
	}

	// becomes active after password encrypted
	if isEncrypted(user.Spec.EncryptedPassword) {
		if user.Status.State == nil || *user.Status.State == iamv1alpha2.UserDisabled {
			expected := user.DeepCopy()
			active := iamv1alpha2.UserActive
			expected.Status = iamv1alpha2.UserStatus{
				State:              &active,
				LastTransitionTime: &metav1.Time{Time: time.Now()},
			}
			err := r.Update(ctx, expected, &client.UpdateOptions{})
			if err != nil {
				return nil, err
			}
			return expected, nil
		}
	}

	// blocked user, check if need to unblock user
	if user.Status.State != nil && *user.Status.State == iamv1alpha2.UserAuthLimitExceeded {
		if user.Status.LastTransitionTime != nil &&
			user.Status.LastTransitionTime.Add(r.AuthenticationOptions.AuthenticateRateLimiterDuration).Before(time.Now()) {
			expected := user.DeepCopy()
			// unblock user
			active := iamv1alpha2.UserActive
			expected.Status = iamv1alpha2.UserStatus{
				State:              &active,
				LastTransitionTime: &metav1.Time{Time: time.Now()},
			}
			err := r.Update(ctx, expected, &client.UpdateOptions{})
			if err != nil {
				return nil, err
			}
			return expected, nil
		}
	}

	records := &iamv1alpha2.LoginRecordList{}
	// normal user, check user's login records see if we need to block
	err := r.List(ctx, records, client.MatchingLabels{iamv1alpha2.UserReferenceLabel: user.Name})
	if err != nil {
		klog.Error(err)
		return nil, err
	}

	// count failed login attempts during last AuthenticateRateLimiterDuration
	now := time.Now()
	failedLoginAttempts := 0
	for _, loginRecord := range records.Items {
		if !loginRecord.Spec.Success &&
			loginRecord.CreationTimestamp.Add(r.AuthenticationOptions.AuthenticateRateLimiterDuration).After(now) {
			failedLoginAttempts++
		}
	}

	// block user if failed login attempts exceeds maximum tries setting
	if failedLoginAttempts >= r.AuthenticationOptions.AuthenticateRateLimiterMaxTries {
		expected := user.DeepCopy()
		limitExceed := iamv1alpha2.UserAuthLimitExceeded
		expected.Status = iamv1alpha2.UserStatus{
			State:              &limitExceed,
			Reason:             fmt.Sprintf("Failed login attempts exceed %d in last %s", failedLoginAttempts, r.AuthenticationOptions.AuthenticateRateLimiterDuration),
			LastTransitionTime: &metav1.Time{Time: time.Now()},
		}

		err = r.Update(context.Background(), expected, &client.UpdateOptions{})
		if err != nil {
			return nil, err
		}
		return expected, nil
	}

	return user, nil
}

func encrypt(password string) (string, error) {
	bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	return string(bytes), err
}

// isEncrypted returns whether the given password is encrypted
func isEncrypted(password string) bool {
	// bcrypt.Cost returns the hashing cost used to create the given hashed
	cost, _ := bcrypt.Cost([]byte(password))
	// cost > 0 means the password has been encrypted
	return cost > 0
}