lazygit: add module (#1930)

Co-authored-by: Nicolas Berbiche <nic.berbiche@gmail.com>
Co-authored-by: Sumner Evans <me@sumnerevans.com>

modules/programs/lazygit.nix

@@ -0,0 +1,56 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.programs.lazygit;
+
+  yamlFormat = pkgs.formats.yaml { };
+
+  inherit (pkgs.stdenv.hostPlatform) isDarwin;
+
+in {
+  meta.maintainers = [ maintainers.kalhauge ];
+
+  options.programs.lazygit = {
+    enable = mkEnableOption "lazygit, a simple terminal UI for git commands";
+
+    settings = mkOption {
+      type = yamlFormat.type;
+      default = { };
+      defaultText = literalExample "{ }";
+      example = literalExample ''
+        {
+          gui.theme = {
+            lightTheme = true;
+            activeBorderColor = [ "blue" "bold" ];
+            inactiveBorderColor = [ "black" ];
+            selectedLineBgColor = [ "default" ];
+          };
+        }
+      '';
+      description = ''
+        Configuration written to
+        <filename>~/.config/lazygit/config.yml</filename> on Linux
+        or <filename>~/Library/Application Support/lazygit/config.yml</filename> on Darwin. See
+        <link xlink:href="https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md"/>
+        for supported values.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ pkgs.lazygit ];
+
+    home.file."Library/Application Support/lazygit/config.yml" =
+      mkIf (cfg.settings != { } && isDarwin) {
+        source = yamlFormat.generate "lazygit-config" cfg.settings;
+      };
+
+    xdg.configFile."lazygit/config.yml" =
+      mkIf (cfg.settings != { } && !isDarwin) {
+        source = yamlFormat.generate "lazygit-config" cfg.settings;
+      };
+  };
+}