catch missing dependencies

DESCRIPTION

@@ -23,10 +23,13 @@ Imports:
     cmdstanr,
     data.table,
     ggplot2,
+    posterior,
     purrr
-Remotes:
-    stan-dev/cmdstanr,
-    Rdatatable/data.table
 Suggests: 
+    epinowcast,
     testthat (>= 3.0.0)
+Remotes:
+    stan-dev/cmdstanr,
+    Rdatatable/data.table,
+    epinowcast/epinowcast
 Config/testthat/edition: 3

NAMESPACE

@@ -51,3 +51,4 @@ import(brms)
 import(cmdstanr)
 import(data.table)
 import(ggplot2)
+importFrom(posterior,as_draws_df)

R/fitting-and-postprocessing.R

@@ -133,6 +133,7 @@ add_natural_scale_mean_sd <- function(dt) {
 
 #' Extract posterior samples for a lognormal brms model
 #' @export
+#' @importFrom posterior as_draws_df
 extract_lognormal_draws <- function(
   data, id_vars, from_dt = FALSE
 ) {

R/models.R

@@ -427,6 +427,12 @@ epinowcast_delay <- function(formula = ~ 1, data, by = c(),
                              sampler = epinowcast::enw_sample,
                              with_epinowcast_output = TRUE,
                              ...) {
+  # check if the epinowcast package is installed and error if not
+  if (!requireNamespace("epinowcast", quietly = TRUE)) {
+    stop(
+      "epinowcast is not installed. Please install it to use this function"
+    )
+  }
   data_as_counts <- data |>
     data.table::as.data.table() |>
     DT(, .(new_confirm = .N), by = c("ptime_daily", "stime_daily", by)) |>