oh-my-posh: add module

modules/programs/oh-my-posh.nix

@@ -0,0 +1,94 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+
+  cfg = config.programs.oh-my-posh;
+
+  jsonFormat = pkgs.formats.json { };
+
+  configArgument = if cfg.settings != { } then
+    "--config ${config.xdg.configHome}/oh-my-posh/config.json"
+  else if cfg.useTheme != null then
+    "--config ${cfg.package}/share/oh-my-posh/themes/${cfg.useTheme}.omp.json"
+  else
+    "";
+
+in {
+  meta.maintainers = [ maintainers.arjan-s ];
+
+  options.programs.oh-my-posh = {
+    enable = mkEnableOption "oh-my-posh, a prompt theme engine for any shell";
+
+    package = mkPackageOption pkgs "oh-my-posh" { };
+
+    settings = mkOption {
+      type = jsonFormat.type;
+      default = { };
+      example = literalExpression ''
+        builtins.fromJSON (builtins.unsafeDiscardStringContext (builtins.readFile "''${pkgs.oh-my-posh}/share/oh-my-posh/themes/space.omp.json"))'';
+      description = ''
+        Configuration written to
+        <filename>$XDG_CONFIG_HOME/oh-my-posh/config.json</filename>. See
+        <link xlink:href="https://ohmyposh.dev/docs/configuration/overview"/>
+        for details. The <literal>useTheme</literal> option is ignored when this
+        option is used.
+      '';
+    };
+
+    useTheme = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      description = ''
+        Use one of the official themes. This should be a name from this list:
+        <link xlink:href="https://ohmyposh.dev/docs/themes"/>. Because a theme
+        is essentially a configuration file, this option is not used when a
+        <literal>configFile</literal> is set.
+      '';
+    };
+
+    enableBashIntegration = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to enable Bash integration.
+      '';
+    };
+
+    enableZshIntegration = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to enable Zsh integration.
+      '';
+    };
+
+    enableFishIntegration = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to enable Fish integration.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ cfg.package ];
+
+    xdg.configFile."oh-my-posh/config.json" = mkIf (cfg.settings != { }) {
+      source = jsonFormat.generate "oh-my-posh-settings" cfg.settings;
+    };
+
+    programs.bash.initExtra = mkIf cfg.enableBashIntegration ''
+      eval "$(${cfg.package}/bin/oh-my-posh init bash ${configArgument})"
+    '';
+
+    programs.zsh.initExtra = mkIf cfg.enableZshIntegration ''
+      eval "$(${cfg.package}/bin/oh-my-posh init zsh ${configArgument})"
+    '';
+
+    programs.fish.shellInit = mkIf cfg.enableFishIntegration ''
+      ${cfg.package}/bin/oh-my-posh init fish ${configArgument} | source
+    '';
+  };
+}