/*
Copyright 2024.

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 controller

import (
	"context"
	"fmt"

	awsclient "github.com/kkb0318/irsa-manager/internal/aws"
	"github.com/kkb0318/irsa-manager/internal/handler"
	"github.com/kkb0318/irsa-manager/internal/issuer"
	"github.com/kkb0318/irsa-manager/internal/kubernetes"
	"github.com/kkb0318/irsa-manager/internal/manifests"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	ctrllog "sigs.k8s.io/controller-runtime/pkg/log"

	irsav1alpha1 "github.com/kkb0318/irsa-manager/api/v1alpha1"
)

// IRSAReconciler reconciles a IRSA object
type IRSAReconciler struct {
	client.Client
	Scheme    *runtime.Scheme
	AwsClient awsclient.AwsClient
}

//+kubebuilder:rbac:groups=irsa.kkb0318.github.io,resources=irsas,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=irsa.kkb0318.github.io,resources=irsas/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=irsa.kkb0318.github.io,resources=irsas/finalizers,verbs=update
//+kubebuilder:rbac:groups=irsa.kkb0318.github.io,resources=irsasetups,verbs=get;list
//+kubebuilder:rbac:groups="",resources=serviceaccounts,verbs=get;list;watch;create;update;patch;delete

// 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 IRSA 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@v0.16.3/pkg/reconcile
func (r *IRSAReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := ctrllog.FromContext(ctx)
	obj := &irsav1alpha1.IRSA{}
	if err := r.Get(ctx, req.NamespacedName, obj); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}
	if r.AwsClient == nil {
		awsClient, err := awsclient.NewAwsClientFactory(ctx)
		if err != nil {
			return ctrl.Result{}, err
		}
		r.AwsClient = awsClient
	}
	kubeClient, err := kubernetes.NewKubernetesClient(r.Client, kubernetes.Owner{Field: "irsa-manager"})
	if err != nil {
		return ctrl.Result{}, err
	}
	if !controllerutil.ContainsFinalizer(obj, irsamanagerFinalizer) {
		controllerutil.AddFinalizer(obj, irsamanagerFinalizer)
		if err := r.Update(ctx, obj); err != nil {
			log.Error(err, "Failed to update custom resource to add finalizer")
			return ctrl.Result{}, err
		}
		return ctrl.Result{Requeue: true}, nil
	}

	defer func() {
		if err := r.Get(ctx, req.NamespacedName, &irsav1alpha1.IRSA{}); err != nil {
			return
		}
		statusHandler := handler.NewStatusHandler(kubeClient)
		if err := statusHandler.Patch(ctx, obj); err != nil {
			return
		}
	}()

	if !obj.DeletionTimestamp.IsZero() {
		err = r.reconcileDelete(ctx, obj, kubeClient)
		if err != nil {
			return ctrl.Result{}, err
		}
		controllerutil.RemoveFinalizer(obj, irsamanagerFinalizer)
		err = r.Update(ctx, obj)
		if err == nil {
			log.Info("successfully deleted")
		}
		return ctrl.Result{}, err
	}

	if err := r.reconcile(ctx, obj, kubeClient); err != nil {
		return ctrl.Result{}, err
	}

	log.Info("successfully reconciled")
	return ctrl.Result{}, nil
}

func (r *IRSAReconciler) reconcileDelete(ctx context.Context, obj *irsav1alpha1.IRSA, kubeClient *kubernetes.KubernetesClient) error {
	if !obj.Spec.Cleanup {
		return nil
	}
	serviceAccount := obj.Spec.ServiceAccount
	kubeHandler := handler.NewKubernetesHandler(kubeClient)
	roleManager := awsclient.RoleManager{
		RoleName: obj.Spec.IamRole.Name,
		Policies: obj.Spec.IamPolicies,
	}
	err := r.AwsClient.IamClient().DeleteIRSARole(
		ctx,
		roleManager,
	)
	if err != nil {
		return err
	}
	for _, ns := range serviceAccount.Namespaces {
		sa := manifests.NewServiceAccountBuilder().Build(types.NamespacedName{
			Name:      serviceAccount.Name,
			Namespace: ns,
		})
		kubeHandler.Append(sa)

	}
	err = kubeHandler.DeleteAll(ctx)
	if err != nil {
		return err
	}
	return nil
}

func (r *IRSAReconciler) reconcile(ctx context.Context, obj *irsav1alpha1.IRSA, kubeClient *kubernetes.KubernetesClient) error {
	list, err := kubeClient.List(ctx, irsav1alpha1.GroupVersion.WithKind(irsav1alpha1.IRSASetupKind))
	if err != nil {
		return err
	}
	if len(list.Items) != 1 {
		return fmt.Errorf("there should be exactly one IRSASetup item")
	}
	irsaSetup := &irsav1alpha1.IRSASetup{}
	err = runtime.DefaultUnstructuredConverter.FromUnstructured(list.Items[0].Object, irsaSetup)
	if err != nil {
		return fmt.Errorf("error converting to IRSASetup for %s: %v", list.Items[0].GetName(), err)
	}

	serviceAccount := obj.Spec.ServiceAccount
	accountId, err := r.AwsClient.StsClient().GetAccountId()
	if err != nil {
		return err
	}
	roleManager := awsclient.RoleManager{
		RoleName:       obj.Spec.IamRole.Name,
		ServiceAccount: serviceAccount,
		Policies:       obj.Spec.IamPolicies,
		AccountId:      accountId,
	}
	issuerMeta, err := issuer.NewS3IssuerMeta(&irsaSetup.Spec.Discovery.S3)
	if err != nil {
		return err
	}
	err = r.AwsClient.IamClient().CreateIRSARole(
		ctx,
		issuerMeta,
		roleManager,
	)
	if err != nil {
		return err
	}
	kubeHandler := handler.NewKubernetesHandler(kubeClient)

	for _, ns := range serviceAccount.Namespaces {
		sa := manifests.NewServiceAccountBuilder().WithIRSAAnnotation(roleManager).Build(types.NamespacedName{
			Name:      serviceAccount.Name,
			Namespace: ns,
		})
		kubeHandler.Append(sa)
	}
	return kubeHandler.ApplyAll(ctx)
}

// SetupWithManager sets up the controller with the Manager.
func (r *IRSAReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&irsav1alpha1.IRSA{}).
		Complete(r)
}