mpv: add extraInput option

modules/programs/mpv.nix

@@ -176,6 +176,20 @@ in {
           }
         '';
       };
+
+      extraInput = mkOption {
+        description = ''
+          Additional lines that are appended to {file}`$XDG_CONFIG_HOME/mpv/input.conf`.
+           See {manpage}`mpv(1)` for the full list of options.
+        '';
+        type = with types; lines;
+        default = "";
+        example = ''
+          esc         quit                        #! Quit
+          #           script-binding uosc/video   #! Video tracks
+          # additional comments
+        '';
+      };
     };
   };
 
@@ -199,8 +213,11 @@ in {
         ${optionalString (cfg.profiles != { }) (renderProfiles cfg.profiles)}
       '';
     })
-    (mkIf (cfg.bindings != { }) {
-      xdg.configFile."mpv/input.conf".text = renderBindings cfg.bindings;
+    (mkIf (cfg.bindings != { } || cfg.extraInput != "") {
+      xdg.configFile."mpv/input.conf".text = mkMerge [
+        (mkIf (cfg.bindings != { }) (renderBindings cfg.bindings))
+        (mkIf (cfg.extraInput != "") cfg.extraInput)
+      ];
     })
     {
       xdg.configFile = mapAttrs' (name: value:

tests/modules/programs/mpv/mpv-example-settings-expected-bindings

@@ -1,3 +1,4 @@
 Alt+0 set window-scale 0.5
 WHEEL_DOWN seek -10
 WHEEL_UP seek 10
+#           script-binding uosc/video                   #! Video tracks

tests/modules/programs/mpv/mpv-example-settings.nix

@@ -12,6 +12,10 @@
       "Alt+0" = "set window-scale 0.5";
     };
 
+    extraInput = ''
+      #           script-binding uosc/video                   #! Video tracks
+    '';
+
     config = {
       force-window = true;
       ytdl-format = "bestvideo+bestaudio";