package nodepatcher

import (
	"context"
	"fmt"
	"slices"
	"strings"

	"maps"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"k8s.io/apimachinery/pkg/util/validation"

	"edge-infra.dev/pkg/edge/api/graph/model"
	"edge-infra.dev/pkg/edge/capabilities"
	"edge-infra.dev/pkg/k8s/runtime/controller/reconcile"
	"edge-infra.dev/pkg/sds/controlplaneguardian/identifier"
	v1ien "edge-infra.dev/pkg/sds/ien/k8s/apis/v1"
	"edge-infra.dev/pkg/sds/ien/k8s/controllers/nodeagent/config"
	nodemeta "edge-infra.dev/pkg/sds/ien/node"
)

type NodePatcher struct{}

// Updates the host node with labels and ownerReferences generated from the IEN Spec
func (nodePatcherPlugin NodePatcher) Reconcile(ctx context.Context, ienode *v1ien.IENode, conf config.Config) (reconcile.Result, error) {
	node, err := conf.GetHostNode(ctx)
	if err != nil {
		return reconcile.ResultRequeue, err
	}

	idf, err := identifier.FromClient(ctx, conf.GetClient())
	if client.IgnoreNotFound(err) != nil {
		return reconcile.ResultRequeue, err
	}

	nodeUpdated := node.DeepCopy()
	if err := setNodeLabels(nodeUpdated, ienode, idf); err != nil {
		return reconcile.ResultRequeue, err
	}
	setNodeOwnerReferences(nodeUpdated, ienode, idf)

	if err := conf.GetClient().Patch(ctx, nodeUpdated, client.StrategicMergeFrom(node)); err != nil {
		return reconcile.ResultRequeue, err
	}
	return reconcile.ResultSuccess, nil
}

// Sets the labels on the hostsystem node from the IEN Spec
func setNodeLabels(node *corev1.Node, ienode *v1ien.IENode, idf *identifier.ControlPlaneIdentifier) error {
	labels := node.GetLabels()
	if err := validateCustomNodeLabels(ienode); err != nil {
		return err
	}
	// delete custom and edge capability labels so only the current custom labels on the ienode cr
	// are applied to the node https://github.com/ncr-swt-retail/edge-roadmap/issues/9425
	maps.DeleteFunc(labels, func(key string, _ string) bool {
		edgeCap := slices.ContainsFunc(capabilities.EdgeAutomatedCapabilityLabels, func(edgeLabel *model.LabelInput) bool {
			return edgeLabel != nil && edgeLabel.Key == key
		})
		return strings.HasPrefix(key, v1ien.CustomNodePrefix) || edgeCap
	})
	maps.Copy(labels, ienode.CustomLabels())
	addNodeLabels(ienode, labels, idf)
	node.SetLabels(labels)
	return nil
}

// Validate the custom labels on the hostsystem node from the IEN Spec
func validateCustomNodeLabels(ienode *v1ien.IENode) error {
	customLabels := ienode.CustomLabels()
	for key, value := range customLabels {
		keyErrs := validation.IsQualifiedName(key)
		if len(keyErrs) > 0 {
			return fmt.Errorf("Invalid label key %s: %s", key, strings.Join(keyErrs, "; "))
		}
		valueErrs := validation.IsValidLabelValue(value)
		if len(valueErrs) > 0 {
			return fmt.Errorf("Invalid label value %s: %s", value, strings.Join(valueErrs, "; "))
		}
	}
	return nil
}

// Creates the node labels from the IEN spec to apply to the host node
func addNodeLabels(ienode *v1ien.IENode, labels map[string]string, idf *identifier.ControlPlaneIdentifier) {
	if ienode.GetName() != "" {
		labels[nodemeta.HostnameLabel] = ienode.GetName()
	}
	if string(ienode.Spec.Class) != "" {
		labels[nodemeta.ClassLabel] = string(ienode.Spec.Class)
	}
	if ienode.Spec.Lane != "" {
		labels[nodemeta.LaneLabel] = ienode.Spec.Lane
	}

	role := getRole(ienode, idf)

	if role != "" {
		labels[nodemeta.RoleLabel] = role
	}
	// ensures the control plane nodes are marked
	if role == string(v1ien.ControlPlane) {
		labels[nodemeta.ControlPlaneLabel] = ""
		delete(labels, nodemeta.WorkerClassLabel)
	}
	if role == string(v1ien.Worker) {
		labels[nodemeta.WorkerClassLabel] = string(ienode.Spec.Class)
		delete(labels, nodemeta.ControlPlaneLabel)
	}
}

// getRole returns the role of the IENode based on the identifier. If the
// identifier is nil, the role is taken from the IENode spec.
func getRole(ienode *v1ien.IENode, idf *identifier.ControlPlaneIdentifier) string {
	if idf == nil || idf.ControlPlane == "" {
		return string(ienode.Spec.Role)
	}
	if idf.ControlPlane == ienode.GetName() {
		return string(v1ien.ControlPlane)
	}
	return string(v1ien.Worker)
}

// Sets the ownerRefernces on k8s node to be owned by the IENode document. This only applies to worker nodes.
func setNodeOwnerReferences(node *corev1.Node, ienode *v1ien.IENode, idf *identifier.ControlPlaneIdentifier) {
	if getRole(ienode, idf) == string(v1ien.Worker) {
		node.SetOwnerReferences([]metav1.OwnerReference{createOwnerReferenceToIEN(ienode)})
		return
	}
	// remove old owner references on existing control plane nodes
	ownerReferences := []metav1.OwnerReference{}
	for _, or := range node.ObjectMeta.OwnerReferences {
		if or.Kind == v1ien.IENodeGVK.Kind && or.Name == ienode.Name {
			continue
		}
		ownerReferences = append(ownerReferences, or)
	}
	node.OwnerReferences = ownerReferences
}

func createOwnerReferenceToIEN(ienode *v1ien.IENode) metav1.OwnerReference {
	return metav1.OwnerReference{
		APIVersion: ienode.APIVersion,
		Kind:       ienode.Kind,
		Name:       ienode.GetName(),
		UID:        ienode.GetUID(),
	}
}