Auto-detect terminal on first run

data/hu.kramo.Cartridges.gschema.xml.in

@@ -89,7 +89,7 @@
     <key name="desktop" type="b">
       <default>true</default>
     </key>
-    <key name='desktop-terminal' enum='@APP_ID@.terminals'>
+    <key name="desktop-terminal" enum="@APP_ID@.terminals">
       <default>"xdg-terminal-exec"</default>
     </key>
     <key name="desktop-terminal-custom-exec" type="s">
@@ -141,5 +141,8 @@
     <key name="steam-limiter-tokens-history" type="s">
       <default>"[]"</default>
     </key>
+    <key name="terminal-check-done" type="b">
+      <default>false</default>
+    </key>
   </schema>
 </schemalist>

src/main.py

@@ -20,6 +20,8 @@
 import json
 import lzma
 import os
+import shlex
+import subprocess
 import sys
 from typing import Any, Optional
 
@@ -73,6 +75,10 @@ class CartridgesApplication(Adw.Application):
 
         if os.name == "nt":
             migrate_files_v1_to_v2()
+        else:
+            if not shared.state_schema.get_boolean("terminal-check-done"):
+                self.check_desktop_terminals()
+                shared.state_schema.set_boolean("terminal-check-done", True)
 
         # Set fallback icon-name
         Gtk.Window.set_default_icon_name(shared.APP_ID)
@@ -143,6 +149,22 @@ class CartridgesApplication(Adw.Application):
 
         self.win.present()
 
+    def check_desktop_terminals(self) -> None:
+        """Look for an installed terminal for desktop entries"""
+        terminals = ("xdg-terminal-exec", "kgx", "gnome-terminal", "konsole", "xterm")
+
+        for index, command in enumerate(terminals):
+            command = f"type {command} &> /dev/null"
+            if os.getenv("FLATPAK_ID") == shared.APP_ID:
+                command = "flatpak-spawn --host /bin/sh -c " + shlex.quote(command)
+
+            try:
+                subprocess.run(command, shell=True, check=True)
+                shared.schema.set_enum("desktop-terminal", index + 1)
+                return
+            except subprocess.CalledProcessError:
+                pass
+
     def load_games_from_disk(self) -> None:
         if shared.games_dir.is_dir():
             for game_file in shared.games_dir.iterdir():