nodes_dispatch

var Dispatch = action.New("dispatch", func(ctx context.Context, req DispatchReq) (any, error) {
	resolver := contracts.ActionResolverFromContext(ctx)
	if resolver == nil {
		return nil, xerr.Internal("dispatch: no action resolver in context")
	}

	members := req.Members
	if members == "" && req.Pool != "" {
		pools := contracts.PoolsFromContext(ctx)
		if pools == nil {
			return nil, xerr.Internal("dispatch: pool table not available in context")
		}
		listed, ok := pools[req.Pool]
		if !ok {
			return nil, xerr.NotFound("dispatch: pool not declared: " + req.Pool)
		}
		members = strings.Join(listed, ",")
	}

	names := splitMembers(members)
	if len(names) == 0 {
		return nil, xerr.BadRequest("dispatch: members is empty")
	}

	if req.Chosen != "" {
		if target, ok := resolver.Action(req.Chosen); ok {
			if output, err := action.InvokeAny(ctx, target, req.Payload); err == nil {
				return output, nil
			}
		}
	}

	if req.Fallback != "" {
		if target, ok := resolver.Action(req.Fallback); ok {
			if output, err := action.InvokeAny(ctx, target, req.Payload); err == nil {
				return output, nil
			}
		}
	}

	var lastErr error
	for _, name := range names {
		target, ok := resolver.Action(name)
		if !ok {
			lastErr = xerr.NotFound("dispatch: member not registered: " + name)
			continue
		}
		output, err := action.InvokeAny(ctx, target, req.Payload)
		if err == nil {
			return output, nil
		}
		lastErr = err
	}
	if lastErr == nil {
		lastErr = xerr.NotFound("dispatch: no member succeeded")
	}
	return nil, lastErr
}).Description("Selects one action from a pool or list and invokes it").
	Tag("dispatch", "pool", "routing").
	Build()