package gke

import (
	"context"
	"fmt"
	"strings"

	"golang.org/x/mod/semver"
	"k8s.io/utils/pointer"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"

	eksv1alpha1 "github.com/tidbcloud/eks-provider/api/v1alpha1"
	"github.com/tidbcloud/eks-provider/controllers/cluster/task"
	"github.com/tidbcloud/eks-provider/controllers/cluster/task/utils/annotator"
	cloudv1 "github.com/tidbcloud/infra-api/api/v1"
	"github.com/tidbcloud/infra-provider/pkg/cloud/gcp"
	"github.com/tidbcloud/infra-provider/pkg/deploy"
	"github.com/tidbcloud/infra-provider/pkg/util"
)

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

	GCPCli gcp.Client
}

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

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

func (t *Guardian) Create(ctx context.Context) deploy.Result {
	// TODO: remove this check?
	// prevent reconciling objects from different regions
	if t.EnvProvider.GetRegion() != t.Config.Network.Region {
		return deploy.Panic(nil)
	}
	// ignore resource that doesn't belong to this region
	if !util.ContainsRegionLabel(t.Cluster) {
		if t.LegacyNetwork != nil {
			if ok, err := util.CheckNetworkRegion(t.Config.Network.Region, t.LegacyNetwork); err != nil {
				return deploy.Panic(err)
			} else if !ok {
				return deploy.Panic(nil)
			}
		}

		// TODO: add region label in webhook
		// ensure the object contains the region label
		if !util.EnsureRegion(t.Cluster, t.EnvProvider.GetRegion()) {
			return deploy.Panic(nil).WithRequeuAfter(0)
		}
	}

	annotator.AnnotateCluster(t.Config.Override, t.Cluster)
	if !controllerutil.ContainsFinalizer(t.Cluster, task.Finalizer) {
		controllerutil.AddFinalizer(t.Cluster, task.Finalizer)
		// Require immediate requeue without running other tasks
		return deploy.Panic(nil).WithRequeuAfter(0)
	}
	if t.Cluster.Status.Phase == "" {
		t.Cluster.Status.Phase = cloudv1.ClusterPhasePending

	}
	switch phase := t.Cluster.Status.Phase; phase {
	case cloudv1.ClusterPhasePending:
		abort, err := t.setNodeVersion(ctx)
		if err != nil {
			return deploy.Panic(fmt.Errorf("node version is failed to set: %v", err))
		}
		if abort {
			return deploy.Panic(nil).WithRequeuAfter(0)
		}

		if err := t.readyToCreate(ctx); err != nil {
			return deploy.Panic(fmt.Errorf("cluster is not ready to create: %v", err))
		}
		t.Cluster.Status.Phase = cloudv1.ClusterPhaseCreating
	case cloudv1.ClusterPhaseCreating, cloudv1.ClusterPhaseRunning,
		cloudv1.ClusterPhaseUnavailable, cloudv1.ClusterPhaseScaling,
		cloudv1.ClusterPhaseUpgrading, cloudv1.ClusterPhaseSuspend:
		if err := t.initClusterSpec(); err != nil {
			return deploy.Panic(err)
		}
	default:
		return deploy.Panic(fmt.Errorf("unexpected cluster phase during creation: %s", phase))
	}
	return deploy.Done()
}

func (t *Guardian) readyToCreate(ctx context.Context) error {
	if t.LegacyNetwork != nil {
		if phase := t.LegacyNetwork.Status.Phase; phase != cloudv1.NetworkPhaseNormal {
			return fmt.Errorf("network phase not ready: %s", phase)
		}
	}
	return nil
}

func (t *Guardian) Delete(ctx context.Context) deploy.Result {
	switch phase := t.Cluster.Status.Phase; phase {
	case cloudv1.ClusterPhaseCreating, cloudv1.ClusterPhaseRunning, "":
		t.Cluster.Status.Phase = cloudv1.ClusterPhasePendingDelete
		// Require immediate requeue without running other tasks
		return deploy.Panic(nil).WithRequeuAfter(0)
	case cloudv1.ClusterPhasePendingDelete:
		err := t.readyToDelete(ctx)
		if err != nil {
			return deploy.Panic(fmt.Errorf("cluster is not ready to delete: %v", err))
		}
		t.Cluster.Status.Phase = cloudv1.ClusterPhaseDeleting
	case cloudv1.ClusterPhaseDeleting:
	default:
		return deploy.Panic(fmt.Errorf("unexpected cluster phase during deletion: %s", phase))
	}
	return deploy.Done()
}

func (t *Guardian) readyToDelete(ctx context.Context) error {
	return nil
}

func (t *Guardian) initClusterSpec() error {
	if t.GKEClusterSpec.ComponentPCAARN == nil {
		t.GKEClusterSpec.ComponentPCAARN = pointer.String(t.AcctInfoGetter.GetComponentPCAARN())
	}

	if t.LegacyNetwork != nil {
		networkStatus, err := eksv1alpha1.GKENetworkStatusFromNetwork(t.LegacyNetwork)
		if err != nil {
			return err
		}
		// TODO: check whether it's necessary for NEW cluster ctrl
		t.GKEClusterSpec.BackupStorage = cloudv1.StorageInfo{
			StorageType: cloudv1.StorageTypeGCP,
			Region:      t.EnvProvider.GetRegion(),
			Bucket:      networkStatus.BucketName,
		}
	}

	return nil
}

func (t *Guardian) setNodeVersion(ctx context.Context) (abort bool, _ error) {
	// node version has been set, just return
	if t.CommonK8sClusterStatus.NodeVersion != "" {
		return false, nil
	}

	c, err := t.GCPCli.ClusterManager().GetCluster(ctx, t.EnvProvider.GetAccount(), t.EnvProvider.GetRegion(), t.EnvProvider.GetClusterName())
	if err != nil {
		return true, err
	}

	// x.y.z-gke.xxx
	masterVersion := c.GetCurrentMasterVersion()
	version := semver.MajorMinor("v" + masterVersion)
	t.Logger.Info("set node version", "version", version, "master version", masterVersion)
	t.CommonK8sClusterStatus.NodeVersion = strings.TrimPrefix(version, "v")

	return true, nil
}