rules

const (
	AreaSchema Area = iota
	AreaParameters
	AreaRequestBody
	AreaResponses
	AreaPaths
	AreaHeaders
	AreaSecurity
	AreaTags
	AreaComponents
	// AreaInfo's rules judge the versioning policy, not the wire contract:
	// info is annotation-only, so nothing in it can break a client, but
	// info.version is the declared shape of the change and can contradict it.
	AreaInfo
	// AreaServers has no rules yet: server changes are treated as deployment
	// metadata. It exists so the area taxonomy covers every top-level
	// document section a future rule could target.
	AreaServers
	AreaNone
)

const (
	DirectionRequest Direction = iota
	DirectionResponse
	DirectionNone
)

const (
	// EffectNone: the change has no accepted-set semantics (metadata,
	// lifecycle annotations, defaults).
	EffectNone Effect = iota
	// EffectWidens: the accepted set provably grows.
	EffectWidens
	// EffectNarrows: the accepted set provably shrinks.
	EffectNarrows
	// EffectIncomparable: the change both rejects payloads that were valid
	// and accepts payloads that were not, so neither set contains the other.
	EffectIncomparable
	// EffectUnknown: the check cannot tell which way the change goes.
	EffectUnknown
	// EffectViolation: the change breaks oasdiff's lifecycle governance
	// (removal before sunset, invalid or missing sunset, stability decrease)
	// rather than the wire contract.
	EffectViolation
)

const (
	// GuardReadOnly: the changed property is readOnly, so it does not
	// appear in requests; request-side effects are nullified.
	GuardReadOnly Guard = "read-only"
	// GuardWriteOnly: the changed property is writeOnly, so it does not
	// appear in responses; response-side effects are nullified.
	GuardWriteOnly Guard = "write-only"
	// GuardSanctioned: the removed element was deprecated and its sunset
	// period was honored, so the removal follows the deprecation contract.
	GuardSanctioned Guard = "sanctioned"
	// GuardNonSuccess: the affected response status is a non-success
	// status. The responses map does not promise that the server returns
	// only the statuses it lists, so neither documenting one more nor
	// dropping one changes what a conforming client can receive; the
	// effect is nullified.
	GuardNonSuccess Guard = "non-success"
	// GuardHasDefault: the changed element declares a default value.
	GuardHasDefault Guard = "has-default"
	// GuardNegotiated: the rule judges the availability of something the
	// client selects or relies on, such as a response status, media type,
	// or header, or the payload that inhabits one. Removing an option the
	// client chooses rejects that choice the way narrowing a request does,
	// and adding one harms nobody, so the level is derived as if the
	// element were on the request side: narrowing is breaking, widening is
	// not, the reverse of plain response polarity.
	GuardNegotiated Guard = "negotiated"
)

const (
	KindExistence Kind = iota
	KindRequiredness
	KindMutability
	KindType
	KindConstraints
	KindValues
	KindStructure
	KindLifecycle
	KindNone
)

const (
	ERR     Level = 3
	WARN    Level = 2
	INFO    Level = 1
	NONE    Level = 0
	INVALID Level = -1
)