// Package relayinfo implements the Nosterm capability handshake.
//
// A standard NIP-11 relay information document describes supported NIPs. A
// "nostermd" additionally advertises a `features` array so that a Nosterm
// client can enable/disable UI capabilities and gracefully fall back when
// connected to a plain Nostr relay that omits it.
//
// The upstream nip11.RelayInformationDocument has no `features` field and its
// custom JSON marshaller drops unknown keys, so the relay serves NIP-11 itself
// and merges these fields into the JSON object.
package relayinfo

const (
	// SoftwareName is advertised as the NIP-11 `software` value.
	SoftwareName = "nostermd"
	// SoftwareVersion is advertised as the NIP-11 `version` value.
	SoftwareVersion = "0.1.0"
)

// baseFeatures advertised by every relay build. Presence/typing/moderation/etc.
// are declared here as they are implemented; the baseline relay supports managed
// NIP-29 channels only. Runtime-dependent features (e.g. federation) are added
// in Extras based on configuration.
var baseFeatures = []string{
	"channels", // NIP-29 managed group channels
}

// Extras returns the extra top-level keys merged into the NIP-11 document JSON.
// Keeping this in one place makes the handshake easy to extend. `federated`
// reflects whether this relay has any federation peer configured, so a client
// can surface that a channel here may be mirrored elsewhere.
func Extras(federated bool) map[string]any {
	features := append([]string{}, baseFeatures...)
	if federated {
		features = append(features, "federation") // chat-only relay↔relay mirroring
	}
	return map[string]any{
		"software": SoftwareName,
		"version":  SoftwareVersion,
		"features": features,
	}
}