package reconcile

import (
	"errors"
	"fmt"

	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"

	edgeunstructured "edge-infra.dev/pkg/k8s/unstructured"
)

const (
	// ReconcileRequestAnnotation is the annotation used for triggering a
	// reconciliation outside of a defined schedule. The value is interpreted as
	// a token, and any change in value SHOULD trigger a reconciliation.
	ReconcileRequestAnnotation string = "reconcile.f8n.ncr.com/requestedAt"
)

var ErrLastHandledReconcileAtNotFound = errors.New("last handled reconcile at not found")

// RequestStatus is a struct to embed in a status type, so that all types using the mechanism have the same
// field. Use it like this:
//
//		type FooStatus struct {
//	 		reconcile.RequestStatus `json:",inline"`
//	 		// other status fields...
//		}
type RequestStatus struct {
	// LastHandledReconcileAt holds the value of the most recent
	// reconcile request value, so a change of the annotation value
	// can be detected.
	// +optional
	LastHandledReconcileAt string `json:"lastHandledReconcileAt,omitempty"`
}

// GetStatusLastHandledReconcileAt returns the status.lastHandledReconcileAt
// value of a given runtime object, if present.
func GetStatusLastHandledReconcileAt(obj runtime.Object) (string, error) {
	u, err := edgeunstructured.FromRuntime(obj)
	if err != nil {
		return "", err
	}
	ra, found, err := unstructured.NestedString(u.Object, "status", "lastHandledReconcileAt")
	if err != nil {
		return "", err
	}
	if !found {
		return "", fmt.Errorf("%w", ErrLastHandledReconcileAtNotFound)
	}
	return ra, nil
}

// SetStatusLastHandledReconcileAt sets the status.lastHandledReconcileAt value
// of a given runtime object.
func SetStatusLastHandledReconcileAt(obj runtime.Object, val string) error {
	u, err := edgeunstructured.FromRuntime(obj)
	if err != nil {
		return err
	}
	if err := unstructured.SetNestedField(u.Object, val, "status", "lastHandledReconcileAt"); err != nil {
		return err
	}
	return runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, obj)
}

// GetAnnotation returns a value for the reconciliation request annotation,
// which can be used to detect changes; and, a boolean indicating whether the
// annotation was set.
func GetAnnotation(annotations map[string]string) (string, bool) {
	requestedAt, ok := annotations[ReconcileRequestAnnotation]
	return requestedAt, ok
}