From d6537416aa7533e3138dae0e712f0ca4190116f8 Mon Sep 17 00:00:00 2001
From: K900 <me@0upti.me>
Date: Tue, 3 Oct 2023 12:48:48 +0300
Subject: [PATCH 1/2] sddm: backport a bunch of Wayland fixes

---
 .../display-managers/sddm/default.nix         | 21 ++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/pkgs/applications/display-managers/sddm/default.nix b/pkgs/applications/display-managers/sddm/default.nix
index 04826274bb69..94550f69d941 100644
--- a/pkgs/applications/display-managers/sddm/default.nix
+++ b/pkgs/applications/display-managers/sddm/default.nix
@@ -1,4 +1,4 @@
-{ mkDerivation, lib, fetchFromGitHub
+{ mkDerivation, lib, fetchFromGitHub, fetchpatch
 , cmake, extra-cmake-modules, pkg-config, qttools
 , libxcb, libXau, pam, qtbase, qtdeclarative, qtquickcontrols2, systemd, xkeyboardconfig
 }:
@@ -16,6 +16,25 @@ mkDerivation rec {
   patches = [
     ./sddm-ignore-config-mtime.patch
     ./sddm-default-session.patch
+
+    # FIXME: all of the following are Wayland related backports, drop in next release
+    # Don't use Qt virtual keyboard on Wayland
+    (fetchpatch {
+      url = "https://github.com/sddm/sddm/commit/07631f2ef00a52d883d0fd47ff7d1e1a6bc6358f.patch";
+      hash = "sha256-HTSw3YeT4z9ldr4sLmsnrPQ+LA8/a6XxrF+KUFqXUlM=";
+    })
+
+    # Fix running sddm-greeter manually in Wayland sessions
+    (fetchpatch {
+      url = "https://github.com/sddm/sddm/commit/e27b70957505dc7b986ab2fa68219af546c63344.patch";
+      hash = "sha256-6hzrFeS2epL9vzLOA29ZA/dD3Jd4rPMBHhNp+FBq1bA=";
+    })
+
+    # Prefer GreeterEnvironment over PAM environment
+    (fetchpatch {
+      url = "https://github.com/sddm/sddm/commit/9e7791d5fb375933d20f590daba9947195515b26.patch";
+      hash = "sha256-JNsVTJNZV6T+SPqPkaFf3wg8NDqXGx8NZ4qQfZWOli4=";
+    })
   ];
 
   postPatch = ''

From 76917ca3ae8fa50e49f774176e8d9b112aa00680 Mon Sep 17 00:00:00 2001
From: K900 <me@0upti.me>
Date: Sat, 8 Jul 2023 12:00:23 +0300
Subject: [PATCH 2/2] nixos/sddm: add option to enable Wayland support via
 Weston

---
 .../services/x11/display-managers/sddm.nix    | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/nixos/modules/services/x11/display-managers/sddm.nix b/nixos/modules/services/x11/display-managers/sddm.nix
index 47e60236eaeb..25470e2d3c2f 100644
--- a/nixos/modules/services/x11/display-managers/sddm.nix
+++ b/nixos/modules/services/x11/display-managers/sddm.nix
@@ -33,6 +33,8 @@ let
 
       # Implementation is done via pkgs/applications/display-managers/sddm/sddm-default-session.patch
       DefaultSession = optionalString (dmcfg.defaultSession != null) "${dmcfg.defaultSession}.desktop";
+
+      DisplayServer = if cfg.wayland.enable then "wayland" else "x11";
     };
 
     Theme = {
@@ -62,6 +64,7 @@ let
     Wayland = {
       EnableHiDPI = cfg.enableHidpi;
       SessionDir = "${dmcfg.sessionData.desktops}/share/wayland-sessions";
+      CompositorCommand = lib.optionalString cfg.wayland.enable cfg.wayland.compositorCommand;
     };
   } // lib.optionalAttrs dmcfg.autoLogin.enable {
     Autologin = {
@@ -184,6 +187,32 @@ in
           '';
         };
       };
+
+      # Experimental Wayland support
+      wayland = {
+        enable = mkEnableOption "experimental Wayland support";
+
+        compositorCommand = mkOption {
+          type = types.str;
+          internal = true;
+
+          # This is basically the upstream default, but with Weston referenced by full path
+          # and the configuration generated from NixOS options.
+          default = let westonIni = (pkgs.formats.ini {}).generate "weston.ini" {
+              libinput = {
+                enable-tap = xcfg.libinput.mouse.tapping;
+                left-handed = xcfg.libinput.mouse.leftHanded;
+              };
+              keyboard = {
+                keymap_model = xcfg.xkbModel;
+                keymap_layout = xcfg.layout;
+                keymap_variant = xcfg.xkbVariant;
+                keymap_options = xcfg.xkbOptions;
+              };
+            }; in "${pkgs.weston}/bin/weston --shell=fullscreen-shell.so -c ${westonIni}";
+          description = lib.mdDoc "Command used to start the selected compositor";
+        };
+      };
     };
   };