/*
Copyright 2022 Gravitational, Inc.

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 resources

import (
	"context"
	"fmt"

	"github.com/gravitational/trace"
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	kclient "sigs.k8s.io/controller-runtime/pkg/client"

	"github.com/gravitational/teleport/api/types"
	resourcesv2 "github.com/gravitational/teleport/operator/apis/resources/v2"
	"github.com/gravitational/teleport/operator/sidecar"
)

// UserReconciler reconciles a TeleportUser object
type UserReconciler struct {
	kclient.Client
	Scheme                 *runtime.Scheme
	TeleportClientAccessor sidecar.ClientAccessor
}

//+kubebuilder:rbac:groups=resources.teleport.dev,resources=users,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=resources.teleport.dev,resources=users/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=resources.teleport.dev,resources=users/finalizers,verbs=update

// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the cluster closer to the desired state.
// TODO(user): Modify the Reconcile function to compare the state specified by
// the TeleportUser object against the actual cluster state, and then
// perform operations to make the cluster state reflect the state specified by
// the user.
//
// For more details, check Reconcile and its Result here:
// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.11.0/pkg/reconcile
func (r *UserReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	return ResourceBaseReconciler{
		Client:         r.Client,
		DeleteExternal: r.Delete,
		UpsertExternal: r.Upsert,
	}.Do(ctx, req, &resourcesv2.TeleportUser{})
}

// SetupWithManager sets up the controller with the Manager.
func (r *UserReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&resourcesv2.TeleportUser{}).
		Complete(r)
}

func (r *UserReconciler) Delete(ctx context.Context, obj kclient.Object) error {
	teleportClient, err := r.TeleportClientAccessor(ctx)
	if err != nil {
		return trace.Wrap(err)
	}
	return teleportClient.DeleteUser(ctx, obj.GetName())
}

func (r *UserReconciler) Upsert(ctx context.Context, obj kclient.Object) error {
	k8sResource, ok := obj.(*resourcesv2.TeleportUser)
	if !ok {
		return fmt.Errorf("failed to convert Object into resource object: %T", obj)
	}
	teleportResource := k8sResource.ToTeleport()

	teleportClient, err := r.TeleportClientAccessor(ctx)
	if err != nil {
		return trace.Wrap(err)
	}

	existingResource, err := teleportClient.GetUser(teleportResource.GetName(), false)
	if err != nil && !trace.IsNotFound(err) {
		return trace.Wrap(err)
	}

	exists := !trace.IsNotFound(err)

	newCondition, err := checkOwnership(existingResource)
	// Setting the condition before returning a potential ownership error
	meta.SetStatusCondition(&k8sResource.Status.Conditions, newCondition)
	if err != nil {
		silentUpdateStatus(ctx, r.Client, k8sResource)
		return trace.Wrap(err)
	}

	r.addTeleportResourceOrigin(teleportResource)

	if !exists {
		err = teleportClient.CreateUser(ctx, teleportResource)
	} else {
		// We don't want to lose the "created_by" data populated on creation
		teleportResource.SetCreatedBy(existingResource.GetCreatedBy())
		err = teleportClient.UpdateUser(ctx, teleportResource)
	}
	// If an error happens we want to put it in status.conditions before returning.
	newReconciliationCondition := getReconciliationConditionFromError(err)
	meta.SetStatusCondition(&k8sResource.Status.Conditions, newReconciliationCondition)
	if err != nil {
		silentUpdateStatus(ctx, r.Client, k8sResource)
		return trace.Wrap(err)
	}

	// We update the status conditions on exit
	return trace.Wrap(r.Status().Update(ctx, k8sResource))
}

func (r *UserReconciler) addTeleportResourceOrigin(resource types.User) {
	metadata := resource.GetMetadata()
	if metadata.Labels == nil {
		metadata.Labels = make(map[string]string)
	}
	metadata.Labels[types.OriginLabel] = types.OriginKubernetes
	resource.SetMetadata(metadata)
}