const GroupName = "coordination.k8s.io"

var (
	// SchemeBuilder points to a list of functions added to Scheme.
	SchemeBuilder = runtime.NewSchemeBuilder(addKnownTypes)
	// AddToScheme applies all the stored functions to the scheme.
	AddToScheme = SchemeBuilder.AddToScheme
)

var SchemeGroupVersion = schema.GroupVersion{Group: GroupName, Version: runtime.APIVersionInternal}

type CoordinatedLeaseStrategy string

const (
	// OldestEmulationVersion picks the oldest LeaseCandidate, where "oldest" is defined as follows
	// 1) Select the candidate(s) with the lowest emulation version
	// 2) If multiple candidates have the same emulation version, select the candidate(s) with the lowest binary version. (Note that binary version must be greater or equal to emulation version)
	// 3) If multiple candidates have the same binary version, select the candidate with the oldest creationTimestamp.
	// If a candidate does not specify the emulationVersion and binaryVersion fields, it will not be considered a candidate for the lease.
	OldestEmulationVersion CoordinatedLeaseStrategy = "OldestEmulationVersion"
)

type Lease struct {
	metav1.TypeMeta
	// +optional
	metav1.ObjectMeta

	// spec contains the specification of the Lease.
	// +optional
	Spec LeaseSpec
}

type LeaseCandidate struct {
	metav1.TypeMeta
	// +optional
	metav1.ObjectMeta
	Spec LeaseCandidateSpec
}

type LeaseCandidateList struct {
	metav1.TypeMeta
	// +optional
	metav1.ListMeta

	// items is a list of schema objects.
	Items []LeaseCandidate
}

type LeaseCandidateSpec struct {
	// LeaseName is the name of the lease for which this candidate is contending.
	// The limits on this field are the same as on Lease.name. Multiple lease candidates
	// may reference the same Lease.name.
	// This field is immutable.
	// +required
	LeaseName string
	// PingTime is the last time that the server has requested the LeaseCandidate
	// to renew. It is only done during leader election to check if any
	// LeaseCandidates have become ineligible. When PingTime is updated, the
	// LeaseCandidate will respond by updating RenewTime.
	// +optional
	PingTime *metav1.MicroTime
	// RenewTime is the time that the LeaseCandidate was last updated. Any time
	// a Lease needs to do leader election, the PingTime field is updated to
	// signal to the LeaseCandidate that they should update the RenewTime. The
	// PingTime field is also updated regularly and LeaseCandidates must update
	// RenewTime to prevent garbage collection for still active LeaseCandidates.
	// Old LeaseCandidate objects are periodically garbage collected.
	// +optional
	RenewTime *metav1.MicroTime
	// BinaryVersion is the binary version. It must be in a semver format without leading `v`.
	// This field is required.
	// +required
	BinaryVersion string
	// EmulationVersion is the emulation version. It must be in a semver format without leading `v`.
	// EmulationVersion must be less than or equal to BinaryVersion.
	// This field is required when strategy is "OldestEmulationVersion"
	// +optional
	EmulationVersion string
	// Strategy is the strategy that coordinated leader election will use for picking the leader.
	// If multiple candidates for the same Lease return different strategies, the strategy provided
	// by the candidate with the latest BinaryVersion will be used. If there is still conflict,
	// this is a user error and coordinated leader election will not operate the Lease until resolved.
	// +listType=atomic
	// +required
	Strategy CoordinatedLeaseStrategy
}

type LeaseList struct {
	metav1.TypeMeta
	// +optional
	metav1.ListMeta

	// items is a list of schema objects.
	Items []Lease
}

type LeaseSpec struct {
	// holderIdentity contains the identity of the holder of a current lease.
	// If Coordinated Leader Election is used, the holder identity must be
	// equal to the elected LeaseCandidate.metadata.name field.
	// +optional
	HolderIdentity *string
	// leaseDurationSeconds is a duration that candidates for a lease need
	// to wait to force acquire it. This is measure against time of last
	// observed renewTime.
	// +optional
	LeaseDurationSeconds *int32
	// acquireTime is a time when the current lease was acquired.
	// +optional
	AcquireTime *metav1.MicroTime
	// renewTime is a time when the current holder of a lease has last
	// updated the lease.
	// +optional
	RenewTime *metav1.MicroTime
	// leaseTransitions is the number of transitions of a lease between
	// holders.
	// +optional
	LeaseTransitions *int32
	// Strategy indicates the strategy for picking the leader for coordinated leader election.
	// If the field is not specified, there is no active coordination for this lease.
	// (Alpha) Using this field requires the CoordinatedLeaderElection feature gate to be enabled.
	// +featureGate=CoordinatedLeaderElection
	// +optional
	Strategy *CoordinatedLeaseStrategy
	// PreferredHolder signals to a lease holder that the lease has a
	// more optimal holder and should be given up.
	// This field can only be set if Strategy is also set.
	// +featureGate=CoordinatedLeaderElection
	// +optional
	PreferredHolder *string
}