From a2423dacd3aac611fd273424866d3cc0b6d3f1d4 Mon Sep 17 00:00:00 2001
From: Isaac Gravestock <isaac.gravestock@roche.com>
Date: Tue, 3 Dec 2024 13:45:39 +0100
Subject: [PATCH] hash cached models

---
 R/utilities.R                   | 31 ++++++++++++++++++++++++++++++-
 tests/testthat/test-utilities.R | 24 ++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/R/utilities.R b/R/utilities.R
index b4b3f2e1e..fcbd428fe 100644
--- a/R/utilities.R
+++ b/R/utilities.R
@@ -532,6 +532,33 @@ ensure_rstan <- function() {
     }
 }
 
+#' Get session hash
+#' 
+#' Gets a unique string based on the current R version and relevant packages.
+#' @keywords internal
+get_session_hash <- function() {
+    pkg_versions <- vapply(
+        sessionInfo(c("rbmi", "rstan", "Rcpp", "RcppEigen", "BH"))[["otherPkgs"]],
+        function(x) x[["Version"]],
+        character(1L)
+    )
+    version_string <- paste0(R.version.string, paste0(names(pkg_versions), pkg_versions, collapse = ":"))
+    temp_file <- tempfile()
+    writeLines(version_string, temp_file)
+    hash <- tools::md5sum(temp_file)
+    unlist(temp_file)
+    return(hash)
+}
+
+tidy_up_models <- function(cache_dir, keep_hash = NULL) {
+    files <- list.files(cache_dir, pattern = "(MMRM_).*(\\.stan|\\.rds)", full.names = TRUE)
+    if (!is.null(keep_hash)) {
+        keep_pattern <- paste0("(MMRM_", keep_hash, "(\\.stan|\\.rds)")
+        files <- grep(keep_pattern, files, invert = TRUE, value = TRUE)
+    }
+    unlink(files)
+}
+
 #' Get Compiled Stan Object
 #'
 #' Gets a compiled Stan object that can be used with `rstan::sampling()`
@@ -549,11 +576,13 @@ get_stan_model <- function() {
     }
     cache_dir <- getOption("rbmi.cache_dir")
     dir.create(cache_dir, showWarnings = FALSE, recursive = TRUE)
-    file_loc_cache <- file.path(cache_dir, "MMRM.stan")
+    session_hash <- get_session_hash()
+    file_loc_cache <- file.path(cache_dir, paste0("MMRM_", session_hash, ".stan"))
     if (!file.exists(file_loc_cache)) {
         message("Compiling Stan model please wait...")
     }
     file.copy(file_loc, file_loc_cache, overwrite = TRUE)
+    tidy_up_models(cache_dir, keep_hash = session_hash)
     rstan::stan_model(
         file = file_loc_cache,
         auto_write = TRUE,
diff --git a/tests/testthat/test-utilities.R b/tests/testthat/test-utilities.R
index 740617698..7534a4113 100644
--- a/tests/testthat/test-utilities.R
+++ b/tests/testthat/test-utilities.R
@@ -241,3 +241,27 @@ test_that("Stack", {
     expect_equal(mstack$pop(3), list(7))
     expect_error(mstack$pop(1), "items to return")
 })
+
+
+test_that("tidy_up_models", {
+    td <- tempdir()
+    files <- c(
+        file.path(td, "MMRM_123.rds"),
+        file.path(td, "MMRM_123.stan"),
+        file.path(td, "MMRM_456.stan"),
+        file.path(td, "MMRM_456.rds"),
+        file.path(td, "MMRM_456.log")
+    )
+    expect_equal(file.create(files), rep(TRUE, 5))
+    tidy_up_models(td, keep_hash = "123")
+    expect_equal(
+        file.exists(files), 
+        c(TRUE, TRUE, FALSE, FALSE, TRUE)
+    )
+    tidy_up_models(td)
+    expect_equal(
+        file.exists(files), 
+        c(FALSE, FALSE, FALSE, FALSE, TRUE)
+    )
+    file.remove(files[5])
+})
\ No newline at end of file