package common

import (
	"context"
	"fmt"
	"time"

	"k8s.io/apimachinery/pkg/fields"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"

	"github.com/tidbcloud/infra-provider/regional-server/api/v1alpha1"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/controllers"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/controllers/internet/task"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/deploy"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/util"
)

// Guardian adds and removes the finalizer of the VPC.
type Guardian struct {
	*task.BaseTask
}

func NewGuardian(ctx *task.Context) *Guardian {
	return &Guardian{BaseTask: &task.BaseTask{Context: ctx}}
}

func (t *Guardian) Name() string {
	return "Guardian"
}

func (t *Guardian) Create(ctx context.Context) deploy.Result {
	t.BeginAt = util.Pointer(time.Now())
	// TODO: check region
	// Add finalizer
	if !controllerutil.ContainsFinalizer(t.Internet, v1alpha1.Finalizer) {
		controllerutil.AddFinalizer(t.Internet, v1alpha1.Finalizer)
		// Require immediate requeue without running other tasks
		return deploy.Panic(nil).WithRequeuAfter(0)
	}

	defer func() {
		if err := t.InternetRW.UpdateStatus(ctx, t.Internet); err != nil {
			t.Logger.Error(err, "failed to update internet status")
		}
	}()

	// Check internet phase
	switch phase := t.Internet.Status.Phase; phase {
	case "", v1alpha1.InternetPhasePending:
		active := t.waitVPCActive(ctx)
		if !active {
			t.Logger.Info("VPC is not active yet, waiting for it to be active")
			t.Internet.Status.Phase = v1alpha1.InternetPhasePending
			return deploy.Panic(nil).WithRequeuAfter(time.Second * 30)
		}
		t.Internet.Status.Phase = v1alpha1.InternetPhaseReadyForCreate
		return deploy.Panic(nil).WithRequeuAfter(0)
	case v1alpha1.InternetPhaseReadyForCreate, v1alpha1.InternetPhaseFailed:
		t.Internet.Status.Phase = v1alpha1.InternetPhaseCreating
	case v1alpha1.InternetPhaseCreating, v1alpha1.InternetPhaseActive, v1alpha1.InternetPhaseReadyForDelete:
	default:
		return deploy.Panic(fmt.Errorf("unexpected Internet phase during creation: %s", phase))
	}

	return deploy.Done()
}

func (t *Guardian) waitVPCActive(ctx context.Context) bool {
	if t.VPC.Status.Phase == v1alpha1.VPCPhaseActive {
		t.Internet.Status.VPCID = t.VPC.Status.VPC.VPCID
		return true
	}

	return false
}

func (t *Guardian) Delete(ctx context.Context) deploy.Result {
	if err := t.readyToDelete(ctx); err != nil {
		t.Internet.Status.Reason = err.Error()
		return deploy.Panic(err).WithRequeuAfter(30 * time.Second)
	}
	return deploy.Done()
}

func (t *Guardian) readyToDelete(ctx context.Context) error {
	relatedAppBoxList := &v1alpha1.APPBoxList{}
	listOpts := &client.ListOptions{
		FieldSelector: fields.OneTermEqualSelector(controllers.VPCNameField, t.Internet.Spec.VPCRef.Name),
		Namespace:     t.Internet.Namespace,
	}
	if err := t.APPBoxR.List(ctx, relatedAppBoxList, listOpts); err != nil {
		return err
	}
	if len(relatedAppBoxList.Items) != 0 {
		return fmt.Errorf("clusters to be deleted: %d", len(relatedAppBoxList.Items))
	}
	relatedVPCPeeringList := &v1alpha1.VPCPeeringList{}
	if err := t.VPCPeeringR.List(ctx, relatedVPCPeeringList, client.MatchingLabels{
		v1alpha1.VPCNameKey: t.Internet.Spec.VPCRef.Name,
	}, client.InNamespace(t.Internet.Namespace)); err != nil {
		return err
	}
	if len(relatedVPCPeeringList.Items) != 0 {
		return fmt.Errorf("vpcpeerings to be deleted: %d", len(relatedVPCPeeringList.Items))
	}
	return nil
}