[base] added ogs6_py_install function and prompt in OGS6_vtu class

R/ogs6_vtu.R

@@ -14,6 +14,18 @@ OGS6_vtu <- R6::R6Class(
         #' @param vtu_path string: Path to .vtu file
         initialize = function(vtu_path) {
 
+            if(!reticulate::py_module_available("vtk")){
+                install <- askYesNo(paste("Python module `vtk` was not found.",
+                                          "Install `vtk`?"))
+
+                if(is.na(install) || !install){
+                    stop(paste("Python module `vtk` is required for `OGS6_vtu`",
+                               "initialization."), call. = FALSE)
+                }
+
+                ogs6_py_install()
+            }
+
             vtk_xml_ugr <- vtk$vtkXMLUnstructuredGridReader()
             vtk_xml_ugr$SetFileName(vtu_path)
             vtk_xml_ugr$Update()
@@ -326,6 +338,20 @@ validate_coordinates <- function(coordinates){
 }
 
 
+#===== ogs6_py_install =====
+
+
+#' Install Python dependencies
+#'
+#' Wrapper for `reticulate::py_install`. Installs the `vtk` library.
+#'
+#' @inheritParams reticulate::py_install
+#' @export
+ogs6_py_install <- function(method = "auto", conda = "auto") {
+    reticulate::py_install("vtk", method = method, conda = conda)
+}
+
+
 #===== ogs6_generate_structured_mesh =====