package gateway

import "reflect"

// This file holds the optional "the adapter needs the owner to re-authorize it"
// capability surfaced by GET /api/v1/admin/channels (v0.39). It lives next to —
// not inside — the channel summary itself because the summary list is one of
// admin.go's larger handlers and the unwrap helper is reusable.

// rescanAware is the optional capability a channel adapter exposes when its
// session needs owner re-authorization that a reconnect cannot provide.
// *weixin_ilink.Adapter implements it (RescanRequired): iLink answering
// errcode=-14 means the bot token is dead and the owner must scan a fresh QR. The
// core adapter.PlatformAdapter contract is deliberately NOT extended, so adapters
// that do not need the capability stay untouched.
//
// A value is only ever reported when the adapter really produced it — a platform
// without the capability keeps the fields omitted rather than shipping a guess.
type rescanAware interface {
	// RescanRequired reports whether a new scan-code login is required, and why
	// (reason is "" when it is not).
	RescanRequired() (required bool, reason string)
}

// asRescanAware reports whether a registered channel value exposes the rescan
// capability. The registration wraps an adapter in cmd/cyrene's namedAdapter — an
// unexported struct embedding adapter.PlatformAdapter — which promotes only the
// interface's methods, so the concrete adapter's extra capability is reachable
// only by unwrapping the embedded field. A direct adapter value (tests,
// single-account registrations) is accepted as-is.
func asRescanAware(v any) (rescanAware, bool) {
	if ra, ok := v.(rescanAware); ok {
		return ra, true
	}
	inner, ok := unwrapNamedAdapter(v)
	if !ok {
		return nil, false
	}
	ra, ok := inner.(rescanAware)
	return ra, ok
}

// unwrapNamedAdapter returns the adapter a registration wrapper embeds in its
// exported PlatformAdapter field. asKookAdmin and asWeixinLoginAdmin perform the
// same unwrap for their own capability subsets and could share this helper.
func unwrapNamedAdapter(v any) (any, bool) {
	rv := reflect.ValueOf(v)
	if !rv.IsValid() {
		return nil, false
	}
	if rv.Kind() == reflect.Ptr {
		rv = rv.Elem()
	}
	if rv.Kind() != reflect.Struct {
		return nil, false
	}
	f := rv.FieldByName("PlatformAdapter")
	if !f.IsValid() || !f.CanInterface() {
		return nil, false
	}
	return f.Interface(), true
}