package chaos

import (
	"context"
	"fmt"
	"time"

	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"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/chaos-provider/controllers/chaos/task"
	chaosCommon "github.com/tidbcloud/chaos-provider/controllers/chaos/task/common"
	"github.com/tidbcloud/chaos-provider/pkg/config"
)

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

	var chaosWorkflow eksv1alpha1.ChaosWorkflow
	if err := r.Cache.Get(ctx, req.NamespacedName, &chaosWorkflow); err != nil {
		if apierrors.IsNotFound(err) {
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get chaos workflow %s: %v", req.NamespacedName, err)
	}

	var network cloudv1.Network
	networkKey := types.NamespacedName{Namespace: req.Namespace, Name: chaosWorkflow.Spec.NetworkName}
	if err := r.Cache.Get(ctx, networkKey, &network); err != nil {
		if apierrors.IsNotFound(err) {
			log.Info("Network not found", "network", chaosWorkflow.Spec.NetworkName)
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get network %s: %v", chaosWorkflow.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,
		ChaosWorkflow: &chaosWorkflow,
		Network:       &network,
		Logger:        log,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to 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 chaosWorkflow.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(&chaosWorkflow, corev1.EventTypeNormal, "ReconcileSuccess", "")
	} else {
		r.EventRecorder.Event(&chaosWorkflow, corev1.EventTypeWarning, "ReconcileFail", err.Error())
	}
	return res, err
}

func (r *ChaosWorkflowReconciler) buildTaskGroup(c *task.Context) []deploy.Task {
	return []deploy.Task{
		chaosCommon.NewGuardian(c),
		task.NewChaosWorkflowTask(c),
	}
}

// SetupWithManager sets up the controller with the Manager.
func (r *ChaosWorkflowReconciler) SetupWithManager(mgr ctrl.Manager, p ...predicate.Predicate) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&eksv1alpha1.ChaosWorkflow{}, builder.WithPredicates(p...)).
		WithOptions(controller.Options{RateLimiter: common.DefaultRateLimiter(), MaxConcurrentReconciles: 10}).
		Complete(r)
}

func (r *ChaosWorkflowReconciler) updateCreate(ctx context.Context, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, _ := deploy.MinRequeue(results)
	// Because ChaosWorkflow doesn't have a specific status definition yet, even if there is no err, we will not
	// update its status here. Its status will be set to `AllAccomplished` only when all ChaosWorkflowNodes' status are
	// finished.
	if err := r.update(ctx, t.Local, t.ChaosWorkflow); err != nil {
		return res, err
	}
	return res, err
}

func (r *ChaosWorkflowReconciler) 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.ChaosWorkflow, task.Finalizer)
	}
	if err := r.update(ctx, t.Local, t.ChaosWorkflow); err != nil {
		return res, err
	}

	return res, nil
}

func (r *ChaosWorkflowReconciler) update(ctx context.Context, cli client.Client, chaosWorkflow *eksv1alpha1.ChaosWorkflow) error {
	chaosWorkflowStatus := chaosWorkflow.Status.DeepCopy()
	if err := cli.Update(ctx, chaosWorkflow); err != nil {
		return err
	}

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

	return cli.Status().Update(ctx, chaosWorkflow)
}