package chaos

import (
	"context"
	"fmt"
	"time"

	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/runtime"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/tools/record"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/builder"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/predicate"

	"github.com/go-logr/logr"
	eksv1alpha1 "github.com/tidbcloud/eks-provider/api/v1alpha1"
	cloudv1 "github.com/tidbcloud/infra-api/api/v1"
	"github.com/tidbcloud/infra-provider/pkg/consts"
	"github.com/tidbcloud/infra-provider/pkg/controllers/common"
	"github.com/tidbcloud/infra-provider/pkg/deploy"
	metricsctrl "github.com/tidbcloud/infra-provider/pkg/metrics/controller"
	"github.com/tidbcloud/infra-provider/pkg/procedure"

	"github.com/tidbcloud/chaos-provider/controllers/chaos/task"
	chaosCommon "github.com/tidbcloud/chaos-provider/controllers/chaos/task/common"
	"github.com/tidbcloud/chaos-provider/pkg/config"
)

type ChaosServerReconciler struct {
	Logger        logr.Logger
	EventRecorder record.EventRecorder
	Scheme        *runtime.Scheme
	client.Client
	Cache  client.Reader
	Config config.ChaosConfig
}

//+kubebuilder:rbac:groups=cloud.pingcap.com.infra.pingcap.com,resources=chaosservers,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=cloud.pingcap.com.infra.pingcap.com,resources=chaosservers/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=cloud.pingcap.com.infra.pingcap.com,resources=chaosservers/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.
func (r *ChaosServerReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := r.Logger.WithValues("object", req.NamespacedName)
	log.Info("Reconciling ChaosServer")
	start := time.Now()
	defer func() {
		metricsctrl.ReconcileDuration.
			WithLabelValues("chaos_server").Observe(time.Since(start).Seconds())
		log.Info("Finish ChaosServer reconcile", "take", time.Since(start))
	}()

	var chaosServer eksv1alpha1.ChaosServer
	if err := r.Cache.Get(ctx, req.NamespacedName, &chaosServer); err != nil {
		if apierrors.IsNotFound(err) {
			log.Info("ChaosServer not found", "chaos server", req.NamespacedName)
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get chaos server %s: %v", req.NamespacedName, err)
	}

	var network cloudv1.Network
	networkKey := types.NamespacedName{Namespace: req.Namespace, Name: chaosServer.Spec.NetworkName}
	if err := r.Cache.Get(ctx, networkKey, &network); err != nil {
		if apierrors.IsNotFound(err) {
			log.Info("Network not found", "network", chaosServer.Spec.NetworkName)
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get network %s: %v", chaosServer.Spec.NetworkName, err)
	}

	providerType := network.Spec.Provider
	if providerType != consts.ProviderTypeEKS && providerType != consts.ProviderTypeGKE {
		return ctrl.Result{}, nil
	}

	c, err := (&task.Context{
		Local:       r.Client,
		Config:      r.Config,
		ChaosServer: &chaosServer,
		Network:     &network,
		Logger:      log,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to create a new context: %v", err)
	}

	err = c.SetRemoteClient(ctx)
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to set remote client: %v", err)
	}

	tasks := r.buildTaskGroup(c)
	d := deploy.NewDeployer(tasks, nil, log)

	var res ctrl.Result
	if chaosServer.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, c, d.Deploy(ctx))
	} else {
		res, err = r.updateDelete(ctx, c, d.Destroy(ctx))
	}

	if err == nil {
		r.EventRecorder.Event(&chaosServer, corev1.EventTypeNormal, "ReconcileSuccess", "")
	} else {
		r.EventRecorder.Event(&chaosServer, corev1.EventTypeWarning, "ReconcileFail", err.Error())
	}

	return res, nil
}

func (r *ChaosServerReconciler) buildTaskGroup(c *task.Context) []deploy.Task {
	return []deploy.Task{
		chaosCommon.NewGuardian(c),
		chaosCommon.NewNamespace(c),
		chaosCommon.NewCRD(c),
		task.NewChaosMesh(c),
	}
}

func (r *ChaosServerReconciler) updateCreate(ctx context.Context, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	var condition eksv1alpha1.Condition
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		t.Logger.Info("mark chaos server become ready when creating chaos server",
			"sinceCreate", t.ChaosServer.CreationTimestamp.Time)
		condition = eksv1alpha1.Condition{
			Type:   eksv1alpha1.ConditionReady,
			Status: corev1.ConditionTrue,
		}
	}
	if err != nil {
		condition = eksv1alpha1.Condition{
			Type:    eksv1alpha1.ConditionReady,
			Status:  corev1.ConditionFalse,
			Reason:  err.Error(),
			Message: "failed to exec apply chaos server tasks",
		}
	}

	if !procedure.ConditionEqual(t.ChaosServer.Status.Conditions.GetCondition(condition.Type), condition) {
		condition.LastTransitionTime = metav1.Now()
		t.ChaosServer.Status.Conditions.SetCondition(condition)
	}

	if err := r.update(ctx, t.Local, t.ChaosServer); err != nil {
		return res, err
	}

	return res, err
}

func (r *ChaosServerReconciler) updateDelete(ctx context.Context, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		controllerutil.RemoveFinalizer(t.ChaosServer, task.Finalizer)
	}

	if err := r.update(ctx, t.Local, t.ChaosServer); err != nil {
		return res, err
	}

	return res, nil
}

func (r *ChaosServerReconciler) update(ctx context.Context, cli client.Client, chaosServer *eksv1alpha1.ChaosServer) error {
	chaosServerStatus := chaosServer.Status.DeepCopy()
	if err := cli.Update(ctx, chaosServer); err != nil {
		return err
	}

	if err := cli.Get(ctx, types.NamespacedName{Name: chaosServer.Name, Namespace: chaosServer.Namespace}, chaosServer); err != nil {
		return err
	}
	chaosServer.Status = *chaosServerStatus

	return cli.Status().Update(ctx, chaosServer)

}

func (r *ChaosServerReconciler) SetupWithManager(mgr ctrl.Manager, pds ...predicate.Predicate) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&eksv1alpha1.ChaosServer{}, builder.WithPredicates(pds...)).
		WithOptions(controller.Options{RateLimiter: common.DefaultRateLimiter(), MaxConcurrentReconciles: 10}).
		Complete(r)
}