Error dialogues for invalid/unread vCard files

… instead of just being silent.

contact.scm

@@ -1,3 +1,5 @@
+#!/usr/bin/env -S csi -s
+
 ;; Copyright © 2024 Jaidyn Ann <jadedctrl@posteo.at>
 ;;
 ;; This program is free software: you can redistribute it and/or
@@ -62,12 +64,13 @@
 (define (init-qt cli-args)
   (set! *qt-app* (qt:init))
   (set! *qt-win* (create-window))
+  (qt:char-encoding 'utf8)
   (init-window *qt-win*)
   ;; Kick off the QT thread, then open the cli free-arg vCard file, if provided.
   ;; That is, like `$ contact freeArgFile.vcf`.
   (let [(qt-thread (thread-start! qt-loop))
         (last-arg (last-free-arg cli-args))]
-    (when (and (string? last-arg) (file-exists? last-arg))
+    (when (string? last-arg)
       (open-vcard-file *qt-win* last-arg))
     qt-thread))
 
@@ -210,13 +213,28 @@
 
 ;; Parse a vCard file and populate the window’s forms with its contents.
 (define (open-vcard-file window file)
-  (when (and (file-exists? file)
-             (file-readable? file))
-    (set! *vcard-pathname* file)
-    (thread-start! (lambda () (populate-with-vcard
-                               window
-                               (with-input-from-file file
-                                 vcard:read-vcard))))))
+  (set! *vcard-pathname* file)
+  (thread-start!
+   (lambda ()
+     (condition-case
+      (populate-with-vcard
+       window
+       (with-input-from-file file
+         vcard:read-vcard))
+      [(vcard)
+       (set! *vcard-pathname* #f)
+       (qt:message
+        (string-join (list "This file doesn’t seem to be a valid vCard file."
+                           "Please make sure you selected the right file, and take a look at it manually."))
+        title: "Parsing error" type: 'critical)]
+      [exn (file)
+           (set! *vcard-pathname* #f)
+           (qt:message
+            (string-join (list "Failed to open the file."
+                               ((condition-property-accessor 'exn 'message) exn)))
+            title: "File error" type: 'critical)]))))
+
+
 
 
 ;; Simply map vCard property-names to their corresponding name in the window’s