From bebc304ef84af54757cbde350e78d63237491ac0 Mon Sep 17 00:00:00 2001
From: Steffen Wolf <Steffen.Wolf@xfab.com>
Date: Mon, 6 May 2024 14:14:04 +0200
Subject: [PATCH] Introduce clean_media function in class openxml_document and
 use it in remove_slide function

---
 R/openxml_document.R | 24 +++++++++++++++++++++++-
 R/ppt_classes.R      |  1 +
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/R/openxml_document.R b/R/openxml_document.R
index 2121965f..7954ba89 100644
--- a/R/openxml_document.R
+++ b/R/openxml_document.R
@@ -54,8 +54,30 @@ openxml_document <- R6Class(
     },
     relationship = function(){
       private$rels_doc
-    }
+    },
+    clean_media = function() {
+      # get package directory
+      package_dir <- dirname(dirname(dirname(private$rels_filename)))
+      # find .xml.rels files
+      rel_files <- list.files(package_dir, pattern = "\\.xml.rels$", recursive = TRUE, full.names = TRUE)
+
+      # collect media files that are referenced in .xml.rels files
+      media_file_rels <- lapply(rel_files, function(xml){
+        zz <- xml2::read_xml(xml)
+        rels <- xml2::xml_children(zz)
+        targets <- xml2::xml_attr(rels, "Target")
+        grep("^\\.\\./media/", targets, value = TRUE)
+      })
+      media_file_rels <- file.path(dirname(dirname(private$rels_filename)), sub("\\.\\./", "", unique(unlist(media_file_rels))))
 
+      # get files in media folder
+      media_folder <- grep("/media$", list.dirs(package_dir), value = TRUE)
+      media_files <- list.files(media_folder, recursive = TRUE, full.names = TRUE)
+
+      # delete unused files
+      files_to_delete <- media_files[!(media_files %in% media_file_rels)]
+      unlink(files_to_delete, force = TRUE)
+    }
   ),
   private = list(
 
diff --git a/R/ppt_classes.R b/R/ppt_classes.R
index 3753ac79..b1084745 100644
--- a/R/ppt_classes.R
+++ b/R/ppt_classes.R
@@ -79,6 +79,7 @@ presentation <- R6Class(
       private$slide_rid <- private$slide_rid[-dropid]
 
       private$update_xml()
+      self$clean_media()
 
       self
     }