package catalogue

import (
	"regexp"
	"slices"
)

// What a module may call an event, and what a consumer may ask for.
//
// A module names an event **locally**: `order.placed`, not a subject and not a routing key
// (design 29 §1). A consumer names the emitter and the event: `billing.order.placed`. The mesh
// derives the subject from those, so reorganising the subject space leaves every manifest correct.
//
// **Nothing checked this until every manifest in the catalogue was wrong the same way**
// (novox/hq 04-ISSUES/127). All thirty-seven kept the old bus's routing key —
// `module.<module>.<verb>` — which the derivation read as "a module called `module`", so every
// cross-module subscription in the mesh pointed at a namespace nobody publishes to. Nothing failed:
// the services started and none of them reacted. The documentation on these fields taught the old
// form too, which is why the drift was uniform rather than scattered.

// eventName is one name in a local event: lower-case, and no wildcard.
var eventName = regexp.MustCompile(`^[a-z0-9][a-z0-9-]*$`)

// The wildcards a consumer may use, spelled the mesh's way and derived to whatever the transport
// spells them as.
//
// **A manifest holds no transport token**, which is the whole point of naming locally: the bus the
// mesh runs on today spells these `*` and `#`, and the one being built spells them `*` and `>`. A
// manifest that said either would be a manifest that stopped being true when the wire changed.
const (
	// OneName stands for exactly one name.
	OneName = "*"
	// TheRest stands for one or more names, and may only come last.
	TheRest = "**"
)

// The events a provider says about its consumers (novox/hq ADR 0224): a consumer it has failed
// without one success for minutes, and that consumer succeeding again or being withdrawn. The
// controller follows them from every module and `status` names a consumer failing until it recovers.
//
// **And what becomes of a consumer the mesh stopped asking for** (novox/hq ADR 0230): retired — its
// access disabled and its data kept — after the same answer in five passes, waiting for a person when
// more would go than the bound allows, re-enabled when asked for again, and deleted only by a person's
// `cleanup delete`. One event, its `change` saying which.
const (
	ProvisionerFailing    = "provisioner.failing"
	ProvisionerRecovered  = "provisioner.recovered"
	ProvisionerRetirement = "provisioner.retirement"
)

// ProvisionerEvents are all three, in the order they are said.
var ProvisionerEvents = []string{ProvisionerFailing, ProvisionerRecovered, ProvisionerRetirement}

// EmitsAll is every event a module may publish: what it declares and, for a module that receives
// contributions — a provider, running a provisioner over them — the provider's standing events.
//
// **Derived, not declared**, because they are the mesh's rule about every provider rather than
// anything one module chose to say: a provider whose manifest forgot them would fail its consumers
// as silently as on 2026-10-05, with its announcement refused by the bus (novox/hq issue 179). Every
// grant of a module's publishing reads this, never the declared list alone.
func (m Manifest) EmitsAll() []string {
	out := append([]string(nil), m.Emits...)
	if len(m.Receives) == 0 {
		return out
	}
	for _, e := range ProvisionerEvents {
		if !slices.Contains(out, e) {
			out = append(out, e)
		}
	}
	return out
}