package addonconfiguration

import (
	"context"

	"github.com/openshift/library-go/pkg/controller/factory"
	"github.com/openshift/library-go/pkg/operator/events"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/labels"
	utilerrors "k8s.io/apimachinery/pkg/util/errors"
	"k8s.io/client-go/tools/cache"
	"k8s.io/klog/v2"

	"open-cluster-management.io/addon-framework/pkg/index"
	addonv1alpha1 "open-cluster-management.io/api/addon/v1alpha1"
	addonv1alpha1client "open-cluster-management.io/api/client/addon/clientset/versioned"
	addoninformerv1alpha1 "open-cluster-management.io/api/client/addon/informers/externalversions/addon/v1alpha1"
	addonlisterv1alpha1 "open-cluster-management.io/api/client/addon/listers/addon/v1alpha1"
	clusterinformersv1beta1 "open-cluster-management.io/api/client/cluster/informers/externalversions/cluster/v1beta1"
	clusterlisterv1beta1 "open-cluster-management.io/api/client/cluster/listers/cluster/v1beta1"
	clusterv1beta1 "open-cluster-management.io/api/cluster/v1beta1"

	"open-cluster-management.io/ocm/pkg/common/patcher"
	"open-cluster-management.io/ocm/pkg/common/queue"
)

// addonConfigurationController is a controller to update configuration of mca with the following order
// 1. use configuration in mca spec if it is set
// 2. use configuration in install strategy
// 3. use configuration in the default configuration in cma
type addonConfigurationController struct {
	addonClient                  addonv1alpha1client.Interface
	clusterManagementAddonLister addonlisterv1alpha1.ClusterManagementAddOnLister
	managedClusterAddonIndexer   cache.Indexer
	addonFilterFunc              factory.EventFilterFunc
	placementLister              clusterlisterv1beta1.PlacementLister
	placementDecisionLister      clusterlisterv1beta1.PlacementDecisionLister

	reconcilers []addonConfigurationReconcile
}

type addonConfigurationReconcile interface {
	reconcile(ctx context.Context, cma *addonv1alpha1.ClusterManagementAddOn,
		graph *configurationGraph) (*addonv1alpha1.ClusterManagementAddOn, reconcileState, error)
}

type reconcileState int64

const (
	reconcileStop reconcileState = iota
	reconcileContinue
)

func NewAddonConfigurationController(
	addonClient addonv1alpha1client.Interface,
	addonInformers addoninformerv1alpha1.ManagedClusterAddOnInformer,
	clusterManagementAddonInformers addoninformerv1alpha1.ClusterManagementAddOnInformer,
	placementInformer clusterinformersv1beta1.PlacementInformer,
	placementDecisionInformer clusterinformersv1beta1.PlacementDecisionInformer,
	addonFilterFunc factory.EventFilterFunc,
	recorder events.Recorder,
) factory.Controller {
	c := &addonConfigurationController{
		addonClient:                  addonClient,
		clusterManagementAddonLister: clusterManagementAddonInformers.Lister(),
		managedClusterAddonIndexer:   addonInformers.Informer().GetIndexer(),
		placementLister:              placementInformer.Lister(),
		placementDecisionLister:      placementDecisionInformer.Lister(),
		addonFilterFunc:              addonFilterFunc,
	}

	c.reconcilers = []addonConfigurationReconcile{
		&managedClusterAddonConfigurationReconciler{
			addonClient: addonClient,
		},
		&clusterManagementAddonProgressingReconciler{
			patcher: patcher.NewPatcher[
				*addonv1alpha1.ClusterManagementAddOn, addonv1alpha1.ClusterManagementAddOnSpec, addonv1alpha1.ClusterManagementAddOnStatus](
				addonClient.AddonV1alpha1().ClusterManagementAddOns()),
		},
	}

	controllerFactory := factory.New().WithFilteredEventsInformersQueueKeysFunc(
		queue.QueueKeyByMetaNamespaceName,
		c.addonFilterFunc,
		clusterManagementAddonInformers.Informer()).
		WithInformersQueueKeysFunc(queue.QueueKeyByMetaNamespaceName, addonInformers.Informer()).
		WithInformersQueueKeysFunc(
			index.ClusterManagementAddonByPlacementDecisionQueueKey(clusterManagementAddonInformers), placementDecisionInformer.Informer()).
		WithInformersQueueKeysFunc(
			index.ClusterManagementAddonByPlacementQueueKey(clusterManagementAddonInformers), placementInformer.Informer())

	return controllerFactory.WithSync(c.sync).ToController("addon-configuration-controller", recorder)
}

func (c *addonConfigurationController) sync(ctx context.Context, syncCtx factory.SyncContext) error {
	key := syncCtx.QueueKey()
	_, addonName, err := cache.SplitMetaNamespaceKey(key)
	if err != nil {
		// ignore addon whose key is invalid
		return nil
	}

	klog.V(4).Infof("Reconciling addon %q", addonName)

	cma, err := c.clusterManagementAddonLister.Get(addonName)
	switch {
	case errors.IsNotFound(err):
		return nil
	case err != nil:
		return err
	}

	if !c.addonFilterFunc(cma) {
		return nil
	}

	cma = cma.DeepCopy()
	graph, err := c.buildConfigurationGraph(cma)
	if err != nil {
		return err
	}

	var state reconcileState
	var errs []error
	for _, reconciler := range c.reconcilers {
		cma, state, err = reconciler.reconcile(ctx, cma, graph)
		if err != nil {
			errs = append(errs, err)
		}
		if state == reconcileStop {
			break
		}
	}

	return utilerrors.NewAggregate(errs)
}

func (c *addonConfigurationController) buildConfigurationGraph(cma *addonv1alpha1.ClusterManagementAddOn) (*configurationGraph, error) {
	graph := newGraph(cma.Spec.SupportedConfigs, cma.Status.DefaultConfigReferences)
	addons, err := c.managedClusterAddonIndexer.ByIndex(index.ManagedClusterAddonByName, cma.Name)
	if err != nil {
		return graph, err
	}

	// add all existing addons to the default at first
	for _, addonObject := range addons {
		addon := addonObject.(*addonv1alpha1.ManagedClusterAddOn)
		graph.addAddonNode(addon)
	}

	if cma.Spec.InstallStrategy.Type == "" || cma.Spec.InstallStrategy.Type == addonv1alpha1.AddonInstallStrategyManual {
		return graph, nil
	}

	// check each install strategy in status
	var errs []error
	for _, installProgression := range cma.Status.InstallProgressions {
		clusters, err := c.getClustersByPlacement(installProgression.PlacementRef.Name, installProgression.PlacementRef.Namespace)
		if errors.IsNotFound(err) {
			klog.V(2).Infof("placement %s/%s is not found for addon %s", installProgression.PlacementRef.Namespace, installProgression.PlacementRef.Name, cma.Name)
			continue
		}
		if err != nil {
			errs = append(errs, err)
			continue
		}

		for _, installStrategy := range cma.Spec.InstallStrategy.Placements {
			if installStrategy.PlacementRef == installProgression.PlacementRef {
				graph.addPlacementNode(installStrategy, installProgression, clusters)

			}
		}
	}

	return graph, utilerrors.NewAggregate(errs)
}

func (c *addonConfigurationController) getClustersByPlacement(name, namespace string) ([]string, error) {
	var clusters []string
	if c.placementLister == nil || c.placementDecisionLister == nil {
		return clusters, nil
	}
	_, err := c.placementLister.Placements(namespace).Get(name)
	if err != nil {
		return clusters, err
	}

	decisionSelector := labels.SelectorFromSet(labels.Set{
		clusterv1beta1.PlacementLabel: name,
	})
	decisions, err := c.placementDecisionLister.PlacementDecisions(namespace).List(decisionSelector)
	if err != nil {
		return clusters, err
	}

	for _, d := range decisions {
		for _, sd := range d.Status.Decisions {
			clusters = append(clusters, sd.ClusterName)
		}
	}

	return clusters, nil
}