package object

import (
	"errors"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"

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

var (
	ErrObservedGenerationNotFound = errors.New("observed generation not found")
	ErrRequeueIntervalNotFound    = errors.New("requeue interval not found")
)

// GetStatusObservedGeneration returns the status.observedGeneration of a given
// runtime object.
func GetStatusObservedGeneration(obj runtime.Object) (int64, error) {
	u, err := edgeunstructured.FromRuntime(obj)
	if err != nil {
		return 0, err
	}
	og, found, err := unstructured.NestedInt64(u.Object, "status", "observedGeneration")
	if err != nil {
		return 0, err
	}
	if !found {
		return 0, ErrObservedGenerationNotFound
	}
	return og, nil
}

// GetRequeueInterval returns the spec.interval of a given runtime object, if
// present.
func GetRequeueInterval(obj runtime.Object) (time.Duration, error) {
	period := time.Second
	u, err := edgeunstructured.FromRuntime(obj)
	if err != nil {
		return period, err
	}
	interval, found, err := unstructured.NestedString(u.Object, "spec", "interval")
	if err != nil {
		return period, err
	}
	if !found {
		return period, ErrRequeueIntervalNotFound
	}
	return time.ParseDuration(interval)
}

// GetConditions returns the list of conditions from an Unstructured object.
//
// NOTE: Due to the constraints of JSON-unmarshal, this operation is to be considered best effort.
// In more details:
//   - Errors during JSON-unmarshal are ignored and a empty collection list is returned.
//   - It's not possible to detect if the object has an empty condition list or if it does not implement conditions;
//     in both cases the operation returns an empty slice.
//   - If the object doesn't implement status conditions as defined in GitOps Toolkit API,
//     JSON-unmarshal matches incoming object keys to the keys; this can lead to to conditions values partially set.
func GetConditions(obj runtime.Object) []metav1.Condition {
	u, err := edgeunstructured.FromRuntime(obj)
	if err != nil {
		return nil
	}
	conditions := []metav1.Condition{}
	if err := edgeunstructured.UnmarshalField(u, &conditions, "status", "conditions"); err != nil {
		return nil
	}
	return conditions
}