Manage default applications with home-manager

home.nix

@@ -7,7 +7,81 @@
   ];
 
   xsession.enable = true;
-  xdg.userDirs.enable = true;
+
+  xdg = {
+    userDirs.enable = true;
+
+    mimeApps = {
+      enable = true;
+
+      defaultApplications =
+        let
+          applications = {
+            telegram = {
+              mimeApp = "org.telegram.desktop.desktop";
+              mimeTypes = [ "x-scheme-handler/tg" ];
+            };
+
+            librewolf = {
+              mimeApp = "librewolf.desktop";
+
+              mimeTypes = [
+                "x-scheme-handler/http"
+                "text/html"
+                "application/xhtml+xml"
+                "x-scheme-handler/https"
+                "application/pdf"
+              ];
+            };
+
+            gnomeTextEditor = {
+              mimeApp = "org.gnome.TextEditor.desktop";
+              mimeTypes = [ "text/plain" ];
+            };
+
+            thunderbird = {
+              mimeApp = "thunderbird.desktop";
+              mimeTypes = [ "x-scheme-handler/mailto" ];
+            };
+
+            loupe = {
+              mimeApp = "org.gnome.Loupe.desktop";
+              mimeTypes = [
+                "image/jpeg"
+                "image/png"
+                "image/gif"
+                "image/webp"
+                "image/tiff"
+                "image/x-tga"
+                "image/vnd-ms.dds"
+                "image/x-dds"
+                "image/bmp"
+                "image/vnd.microsoft.icon"
+                "image/vnd.radiance"
+                "image/x-exr"
+                "image/x-portable-bitmap"
+                "image/x-portable-graymap"
+                "image/x-portable-pixmap"
+                "image/x-portable-anymap"
+                "image/x-qoi"
+                "image/svg+xml"
+                "image/svg+xml-compressed"
+                "image/avif"
+                "image/heic"
+                "image/jxl"
+              ];
+            };
+          };
+
+          mimeTypesForApp = { mimeApp, mimeTypes }: map
+            (
+              mimeType: { "${mimeType}" = mimeApp; }
+            )
+            mimeTypes;
+        in
+        lib.zipAttrs (lib.flatten (map mimeTypesForApp (builtins.attrValues applications)));
+    };
+  };
 
   home = {
     username = "pim";