From 9799d3de2d270a9c40fcf81d600bfd71088e144d Mon Sep 17 00:00:00 2001
From: Michael Hoang <enzime@users.noreply.github.com>
Date: Thu, 30 Jan 2020 20:44:54 +1100
Subject: [PATCH] feh: add buttons option

Use `null` to disable keybindings or button mappings.
---
 modules/programs/feh.nix | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/modules/programs/feh.nix b/modules/programs/feh.nix
index 4342181fa..1b14e71f5 100644
--- a/modules/programs/feh.nix
+++ b/modules/programs/feh.nix
@@ -7,7 +7,7 @@ let
   cfg = config.programs.feh;
 
   disableBinding = func: key: func;
-  enableBinding = func: key: "${func} ${key}";
+  enableBinding = func: key: "${func} ${toString key}";
 
 in
 
@@ -15,12 +15,25 @@ in
   options.programs.feh = {
     enable = mkEnableOption "feh - a fast and light image viewer";
 
+    buttons = mkOption {
+      default = {};
+      type = with types; attrsOf (nullOr (either str int));
+      example = { zoom_in = 4; zoom_out = "C-4"; };
+      description = ''
+        Override feh's default mouse button mapping. If you want to disable an
+	action, set its value to null.
+        See <link xlink:href="https://man.finalrewind.org/1/feh/#x425554544f4e53"/> for
+        default bindings and available commands.
+      '';
+    };
+
     keybindings = mkOption {
       default = {};
-      type = types.attrsOf types.str;
+      type = types.attrsOf (types.nullOr types.str);
       example = { zoom_in = "plus"; zoom_out = "minus"; };
       description = ''
-        Set keybindings.
+        Override feh's default keybindings. If you want to disable a keybinding
+	set its value to null.
         See <link xlink:href="https://man.finalrewind.org/1/feh/#x4b455953"/> for
         default bindings and available commands.
       '';
@@ -28,14 +41,23 @@ in
   };
 
   config = mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = ((filterAttrs (n: v: v == "") cfg.keybindings) == {});
+	message = "To disable a keybinding, use `null` instead of an empty string.";
+      }
+    ];
+
     home.packages = [ pkgs.feh ];
 
-    xdg.configFile."feh/keys".text = ''
-      # Disable default keybindings
-      ${concatStringsSep "\n" (mapAttrsToList disableBinding cfg.keybindings)}
+    xdg.configFile."feh/buttons".text = ''
+      ${concatStringsSep "\n" (mapAttrsToList disableBinding (filterAttrs (n: v: v == null) cfg.buttons))}
+      ${concatStringsSep "\n" (mapAttrsToList enableBinding (filterAttrs (n: v: v != null) cfg.buttons))}
+    '';
 
-      # Enable new keybindings
-      ${concatStringsSep "\n" (mapAttrsToList enableBinding cfg.keybindings)}
+    xdg.configFile."feh/keys".text = ''
+      ${concatStringsSep "\n" (mapAttrsToList disableBinding (filterAttrs (n: v: v == null) cfg.keybindings))}
+      ${concatStringsSep "\n" (mapAttrsToList enableBinding (filterAttrs (n: v: v != null) cfg.keybindings))}
     '';
   };
 }