aichat: init (#7207)

aichat is an all in one CLI tool for AI interactions.
On first run it prompts you to create a config so I made a home manager module to do this declaratively.

modules/modules.nix

@@ -61,6 +61,7 @@ let
       ./programs/aerc.nix
       ./programs/aerospace.nix
       ./programs/afew.nix
+      ./programs/aichat.nix
       ./programs/alacritty.nix
       ./programs/alot.nix
       ./programs/antidote.nix

modules/programs/aichat.nix

@@ -0,0 +1,72 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  inherit (lib) mkIf;
+
+  cfg = config.programs.aichat;
+
+  settingsFormat = pkgs.formats.yaml { };
+
+  inherit (pkgs.stdenv.hostPlatform) isLinux isDarwin;
+in
+{
+  meta.maintainers = [
+    lib.maintainers.jaredmontoya
+  ];
+
+  options.programs.aichat = {
+    enable = lib.mkEnableOption "aichat, an All-in-one LLM CLI tool";
+
+    package = lib.mkPackageOption pkgs "aichat" { nullable = true; };
+
+    settings = lib.mkOption {
+      inherit (settingsFormat) type;
+      default = { };
+      defaultText = lib.literalExpression "{ }";
+      example = lib.literalExpression ''
+        {
+          model = "Ollama:mistral-small:latest";
+          clients = [
+            {
+              type = "openai-compatible";
+              name = "Ollama";
+              api_base = "http://localhost:11434/v1";
+              models = [
+                {
+                  name = "llama3.2:latest";
+                }
+              ];
+            }
+          ];
+        }
+      '';
+      description = ''
+        Configuration written to
+        {file}`$XDG_CONFIG_HOME/aichat/config.yaml`
+        on Linux or on Darwin if [](#opt-xdg.enable) is set, otherwise
+        {file}`~/Library/Application Support/aichat/config.yaml`.
+        See
+        <https://github.com/sigoden/aichat/blob/main/config.example.yaml>
+        for supported values.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = mkIf (cfg.package != null) [ cfg.package ];
+
+    home.file."Library/Application Support/aichat/config.yaml" =
+      mkIf (cfg.settings != { } && (isDarwin && !config.xdg.enable))
+        {
+          source = settingsFormat.generate "aichat-config" cfg.settings;
+        };
+
+    xdg.configFile."aichat/config.yaml" = mkIf (cfg.settings != { } && (isLinux || config.xdg.enable)) {
+      source = settingsFormat.generate "aichat-config" cfg.settings;
+    };
+  };
+}