From a9f6c0aec2a2bf7ccfbed4ef8c8e72a228d34588 Mon Sep 17 00:00:00 2001
From: Stefan Ellmauthaler <stefan.ellmauthaler@tu-dresden.de>
Date: Mon, 2 Oct 2023 11:12:51 +0200
Subject: [PATCH] Define Overlays to use ExportPackage of flake utils plus

Signed-off-by: Stefan Ellmauthaler <stefan.ellmauthaler@tu-dresden.de>
---
 flake.nix                                | 34 +++++++++++++++++++-----
 lib/files.nix                            |  7 +++++
 modules/emacs.nix                        | 16 +++++++++++
 {modules => packages}/emacs/default.el   |  0
 {modules => packages}/emacs/default.nix  | 29 +++++++-------------
 {modules => packages}/emacs/packages.nix |  0
 6 files changed, 61 insertions(+), 25 deletions(-)
 create mode 100644 modules/emacs.nix
 rename {modules => packages}/emacs/default.el (100%)
 rename {modules => packages}/emacs/default.nix (80%)
 rename {modules => packages}/emacs/packages.nix (100%)

diff --git a/flake.nix b/flake.nix
index fb5409d..1e7be33 100644
--- a/flake.nix
+++ b/flake.nix
@@ -68,7 +68,9 @@
       discoverMachines
       withModules
       discoverTemplates
+      discoverOverlay
       ;
+    inherit (flake-utils-plus.lib) genPkgOverlay;
   in
     flake-utils-plus.lib.mkFlake rec {
       inherit self inputs;
@@ -91,12 +93,14 @@
           ];
       };
 
-      channels.nixpkgs.overlaysBuilder = channels: [
-        (final: prev: {unstable = channels.nixpkgs-unstable;})
-        (flake-utils-plus.lib.genPkgOverlay inputs.comma "comma")
-        #inputs.nix.overlay
-        inputs.emacs-overlay.overlay
-      ];
+      channels.nixpkgs.overlaysBuilder = channels:
+        [
+          (final: prev: {unstable = channels.nixpkgs-unstable;})
+          (flake-utils-plus.lib.genPkgOverlay inputs.comma "comma")
+          #inputs.nix.overlay
+          inputs.emacs-overlay.overlay
+        ]
+        ++ (nixpkgs.lib.attrValues overlays);
 
       hostDefaults = {
         system = "x86_64-linux";
@@ -140,6 +144,24 @@
           stateVersion = extended-lib.mkDefault "21.05";
         });
 
+      overlays = rec {
+        elss = discoverOverlay ./packages;
+        default = elss;
+        emacs-overlay = inputs.emacs-overlay.overlay;
+        flake-utils-plus = genPkgOverlay inputs.flake-utils-plus "fup-repl";
+      };
+
+      packages =
+        (flake-utils-plus.lib.exportPackages {
+            inherit
+              (overlays)
+              default
+              flake-utils-plus
+              ;
+          }
+          channels)
+        // {inherit (channels.nixpkgs) emacs;};
+
       outputsBuilder = channels: {
         devShells = let
           pkgs = channels.nixpkgs;
diff --git a/lib/files.nix b/lib/files.nix
index b96823d..91f3936 100644
--- a/lib/files.nix
+++ b/lib/files.nix
@@ -23,6 +23,13 @@ with prev; rec {
       name,
     }:
       import path);
+
+  discoverOverlay = dir: final: prev: (withModules dir ({
+    path,
+    name,
+  }:
+    nameValuePair name (final.callPackage path {})));
+
   discoverMachines = dir: args:
     withModules dir ({
       path,
diff --git a/modules/emacs.nix b/modules/emacs.nix
new file mode 100644
index 0000000..e0e6ca1
--- /dev/null
+++ b/modules/emacs.nix
@@ -0,0 +1,16 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; {
+  options.elss.programs.emacs.enable = mkEnableOption "Setup emacs package and install it";
+  config = mkIf config.elss.programs.emacs.enable {
+    services.emacs = {
+      enable = true;
+      defaultEditor = true;
+      package = pkgs.emacsPackage;
+    };
+  };
+}
diff --git a/modules/emacs/default.el b/packages/emacs/default.el
similarity index 100%
rename from modules/emacs/default.el
rename to packages/emacs/default.el
diff --git a/modules/emacs/default.nix b/packages/emacs/default.nix
similarity index 80%
rename from modules/emacs/default.nix
rename to packages/emacs/default.nix
index b7c11d7..175e74e 100644
--- a/modules/emacs/default.nix
+++ b/packages/emacs/default.nix
@@ -96,23 +96,14 @@ with lib; let
         #zenburn-theme
       ]
       ++ (with lpkgs; [org-roam-ui ligatures lean4-mode])));
-in {
-  options.elss.programs.emacs.enable =
-    mkEnableOption "Setup emacs package and install it";
-  config = mkIf config.elss.programs.emacs.enable {
-    services.emacs = {
-      enable = true;
-      defaultEditor = true;
-      package = emacsPackage;
-    };
-  };
-  #nixpkgs.overlays = [ (self: super: { emacsOrig = super.emacs; }) (import (builtins.fetchTarball {
-  #    url = https://github.com/nix-community/emacs-overlay/archive/master.tar.gz;
-  #})) ];
+in
+  emacsPackage
+#nixpkgs.overlays = [ (self: super: { emacsOrig = super.emacs; }) (import (builtins.fetchTarball {
+#    url = https://github.com/nix-community/emacs-overlay/archive/master.tar.gz;
+#})) ];
+#nixpkgs.overlays = [
+#  (import (builtins.fetchTarball {
+#    url = https://github.com/nix-community/emacs-overlay/archive/master.tar.gz;
+#  }))
+#];
 
-  #nixpkgs.overlays = [
-  #  (import (builtins.fetchTarball {
-  #    url = https://github.com/nix-community/emacs-overlay/archive/master.tar.gz;
-  #  }))
-  #];
-}
diff --git a/modules/emacs/packages.nix b/packages/emacs/packages.nix
similarity index 100%
rename from modules/emacs/packages.nix
rename to packages/emacs/packages.nix