v1alpha1

type Feature struct {
	Status            FeatureStatus `json:"status,omitempty"`
	metav1.ObjectMeta `json:"metadata,omitempty"`
	Spec              FeatureSpec `json:"spec,omitempty"`
	metav1.TypeMeta   `json:",inline"`
}

type FeatureGate struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	// Spec is the specification for gating features.
	Spec FeatureGateSpec `json:"spec,omitempty"`
	// Status reports activation state and availability of features in the system.
	Status FeatureGateStatus `json:"status,omitempty"`
}

type FeatureGateList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []FeatureGate `json:"items"`
}

type FeatureGateSpec struct {
	// NamespaceSelector is a selector to specify namespaces for which this feature gate applies.
	// Use an empty LabelSelector to match all namespaces.
	NamespaceSelector metav1.LabelSelector `json:"namespaceSelector"`
	// Features is a slice of FeatureReference to gate features.
	// The Feature resource specified may or may not be present in the system. If the Feature is present, the
	// FeatureGate controller and webhook sets the specified activation state only if the Feature is discoverable and
	// its immutability constraint is satisfied. If the Feature is not present, the activation intent is applied when
	// the Feature resource appears in the system. The actual activation state of the Feature is reported in the status.
	// +listType=map
	// +listMapKey=name
	Features []FeatureReference `json:"features,omitempty"`
}

type FeatureGateStatus struct {
	// Namespaces lists the existing namespaces for which this feature gate applies. This is obtained from listing all
	// namespaces and applying the NamespaceSelector specified in spec.
	Namespaces []string `json:"namespaces,omitempty"`
	// ActivatedFeatures lists the discovered features that are activated for the namespaces specified in the spec.
	// This can include features that are not explicitly gated in the spec, but are already available in the system as
	// Feature resources.
	ActivatedFeatures []string `json:"activatedFeatures,omitempty"`
	// DeactivatedFeatures lists the discovered features that are deactivated for the namespaces specified in the spec.
	// This can include features that are not explicitly gated in the spec, but are already available in the system as
	// Feature resources.
	DeactivatedFeatures []string `json:"deactivatedFeatures,omitempty"`
	// UnavailableFeatures lists the features that are gated in the spec, but are not available in the system as
	// Feature resources.
	UnavailableFeatures []string `json:"unavailableFeatures,omitempty"`
}

type FeatureList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []Feature `json:"items"`
}

type FeatureReference struct {
	// Name is the name of the Feature resource, which represents a feature the system offers.
	// +kubebuilder:validation:Required
	Name string `json:"name"`
	// Activate indicates the activation intent for the feature.
	Activate bool `json:"activate,omitempty"`
}

type FeatureSpec struct {
	// Description of the feature.
	Description string `json:"description,omitempty"`
	// Immutable indicates this feature cannot be toggled once set
	// If set at creation time, this state will persist for the life of the cluster
	Immutable bool `json:"immutable"`
	// Discoverable indicates if clients should include consider the Feature available for their use
	// Allowing clients to control discoverability is one of the ways the API allows gradual rollout of functionality
	Discoverable bool `json:"discoverable"`
	// Activated defines the default state of the features activation
	Activated bool `json:"activated"`
	// Maturity indicates maturity level of this feature.
	// Maturity levels are Dev, Alpha, Beta, GA and Deprecated.
	// +kubebuilder:validation:Enum=dev;alpha;beta;ga;deprecated
	// - dev: the default for new resources, represents local dev. intended to be hidden and deactivated
	// - alpha: the first milestone meant for limited wider consumption, discoverable and defaults to deactivated
	// - beta: greater visibility for proven designs, discoverable and defaults to activated
	// - ga: intended to be part of the mainline codebase, non-optional
	// - deprecated: destined for future removal
	Maturity string `json:"maturity"`
}

type FeatureStatus struct{}