refactor(home): extract shared wezterm module

Add a `metacfg.tools.wezterm` home-manager module so wezterm.lua
configuration can be reused across hosts instead of being duplicated
inline. Migrate halo and amd to the new module and enable it on rialo
(font size 14, term = xterm-256color).

homes/aarch64-darwin/harald@rialo/default.nix

@@ -32,6 +32,10 @@
         enable = true;
         userEmail = "harald@subzero.xyz";
       };
+      wezterm = {
+        enable = true;
+        term = "xterm-256color";
+      };
     };
   };
 

homes/x86_64-linux/harald@amd/default.nix

@@ -20,6 +20,10 @@
     };
     tools = {
       git.enable = true;
+      wezterm = {
+        enable = true;
+        backgroundImage = ./terminal-background.png;
+      };
     };
     gui.kbd.ellipsis = true;
   };
@@ -71,18 +75,4 @@
 
   xdg.enable = true;
   xdg.mime.enable = true;
-
-  xdg.configFile."wezterm/wezterm.lua".text = ''
-    local wezterm = require("wezterm")
-    local config = wezterm.config_builder()
-    local act = wezterm.action
-
-    config.enable_kitty_keyboard = true
-    config.enable_scroll_bar = true
-    config.window_background_image = '${./terminal-background.png}'
-
-    config.term = 'wezterm'
-
-    return config
-  '';
 }

homes/x86_64-linux/harald@halo/default.nix

@@ -20,6 +20,10 @@
     };
     tools = {
       git.enable = true;
+      wezterm = {
+        enable = true;
+        backgroundImage = ./terminal-background.png;
+      };
     };
     gui.kbd.ellipsis = true;
   };
@@ -71,18 +75,4 @@
 
   xdg.enable = true;
   xdg.mime.enable = true;
-
-  xdg.configFile."wezterm/wezterm.lua".text = ''
-    local wezterm = require("wezterm")
-    local config = wezterm.config_builder()
-    local act = wezterm.action
-
-    config.enable_kitty_keyboard = true
-    config.enable_scroll_bar = true
-    config.window_background_image = '${./terminal-background.png}'
-
-    config.term = 'wezterm'
-
-    return config
-  '';
 }

modules/home/tools/wezterm/default.nix

@@ -0,0 +1,46 @@
+{
+  lib,
+  config,
+  ...
+}:
+
+let
+  inherit (lib)
+    types
+    mkEnableOption
+    mkIf
+    optionalString
+    boolToString
+    ;
+  inherit (lib.metacfg) mkOpt mkBoolOpt;
+
+  cfg = config.metacfg.tools.wezterm;
+in
+{
+  options.metacfg.tools.wezterm = {
+    enable = mkEnableOption "wezterm config";
+    fontSize = mkOpt types.int 14 "Font size for wezterm.";
+    enableKittyKeyboard = mkBoolOpt true "Enable the kitty keyboard protocol.";
+    enableScrollBar = mkBoolOpt true "Enable the scroll bar.";
+    backgroundImage = mkOpt (types.nullOr types.path) null "Path to a window background image.";
+    term = mkOpt types.str "wezterm" "Value to set for `config.term`.";
+    extraConfig = mkOpt types.lines "" "Extra Lua appended before `return config`.";
+  };
+
+  config = mkIf cfg.enable {
+    xdg.configFile."wezterm/wezterm.lua".text = ''
+      local wezterm = require("wezterm")
+      local config = wezterm.config_builder()
+
+      config.enable_kitty_keyboard = ${boolToString cfg.enableKittyKeyboard}
+      config.enable_scroll_bar = ${boolToString cfg.enableScrollBar}
+      ${optionalString (
+        cfg.backgroundImage != null
+      ) "config.window_background_image = '${cfg.backgroundImage}'"}
+      config.font_size = ${toString cfg.fontSize}
+      config.term = '${cfg.term}'
+      ${cfg.extraConfig}
+      return config
+    '';
+  };
+}