add reference df so that DM can be joined on the fly

R/calculate_study_day.R

@@ -1,9 +1,31 @@
 #' `calculate_study_day` Performs the Study Day Calculation
 #'
-calculate_study_day <- function(ds_in, refdt, tgdt) {
+calculate_study_day <- function(ds_in,
+                                ds_ref,
+                                refdt,
+                                tgdt,
+                                merge_key = "USUBJID") {
+
   assertthat::assert_that(is.data.frame(ds_in))
-  assertthat::assert_that(hasName(ds_in, refdt))
+  assertthat::assert_that(is.data.frame(ds_ref))
+  assertthat::assert_that(hasName(ds_ref, refdt))
   assertthat::assert_that(hasName(ds_in, tgdt))
+  assertthat::assert_that(hasName(ds_ref, merge_key))
+  assertthat::assert_that(hasName(ds_in, merge_key))
+
+  if (!identical(ds_in, ds_ref)) {
+    ds_ref <- unique(ds_ref[c(merge_key, refdt)])
+
+    check_refdt_uniqueness <- ds_ref %>%
+      dplyr::group_by(dplyr::pick({{merge_key}})) %>%
+      dplyr::filter(n() > 1)
+    if (nrow(check_refdt_uniqueness) > 0) {
+      stop("Reference date is not unique for each patient!")
+    }
+
+    ds_in <- ds_in %>%
+      dplyr::left_join(ds_ref, by = structure(names = merge_key, .Data = merge_key))
+  }
 
   # question: should I assume that refdt/tgdt was converted to Date already?
   # If assume that refdt and tgdt are already dates