Improve scan2paperless script

pkgs/scan2paperless.nix

@@ -2,16 +2,28 @@ self:
 with self; ''
   export PATH=${lib.makeBinPath [pkgs.coreutils pkgs.sane-frontends pkgs.sane-backends pkgs.ghostscript pkgs.imagemagick]}
 
-  while true;
+  NAME=$([ "$1" == "" ] && date -Iseconds || echo "$1")
-  do
-    read -p "Press Enter to continue or Ctrl+C to stop" < /dev/tty
 
+  TMPDIR=$(mktemp -d)
+
+  echo "Using ''${NAME}.pdf as filename"
+  RESPONSE=""
+
+  while [ -z "$RESPONSE" ];
+  do
     DATETIME=$(date -Iseconds)
+    echo "Starting scan $DATETIME"
     scanimage \
       -d "''${SCANNER_DEFAULT_DEVICE}" \
       --format=jpeg \
       --resolution 300 \
       --progress \
-      -o "''${SCANNER_OUTPUT_DIR}/''${DATETIME}.jpg"
+      -o "''${TMPDIR}/''${DATETIME}.jpg"
+
+    read -p "Press ENTER to scan another page, or any other key to generate the final PDF: " RESPONSE < /dev/tty
   done
+
+  ${python39Packages.img2pdf}/bin/img2pdf --output "''${SCANNER_OUTPUT_DIR}/''${NAME}.pdf" ''${TMPDIR}/*
+
+  rm -rf TMPDIR
 ''