refactor(docs): move to flake modules

No need for a separate default.nix

flake-modules/docs.nix

@@ -1,24 +1,62 @@
-{ lib, ... }:
+{ lib, inputs, ... }:
 {
   perSystem =
     { pkgs, ... }:
     {
       packages =
         let
-          docs-pkg = import ../docs { inherit pkgs lib; };
-          inherit (docs-pkg)
-            docs
-            home-markdown
-            nixos-markdown
-            nvim-markdown
-            ;
+          filterVisible =
+            toplevelOption: option:
+            option // { visible = option.visible && builtins.elemAt option.loc 0 == toplevelOption; };
+          home-eval = lib.evalModules {
+            modules = [ ../home/options.nix ];
+            specialArgs = {
+              inherit pkgs;
+            };
+          };
+          nvim-eval = lib.evalModules { modules = [ ../nvim/options.nix ]; };
+          nixos-eval = lib.evalModules { modules = [ ../system/options.nix ]; };
+          home-markdown =
+            (pkgs.nixosOptionsDoc {
+              inherit (home-eval) options;
+              transformOptions = filterVisible "jhome";
+            }).optionsCommonMark;
+          nvim-markdown =
+            (pkgs.nixosOptionsDoc {
+              inherit (nvim-eval) options;
+              transformOptions = filterVisible "jhome";
+            }).optionsCommonMark;
+          nixos-markdown =
+            (pkgs.nixosOptionsDoc {
+              inherit (nixos-eval) options;
+              transformOptions = filterVisible "jconfig";
+            }).optionsCommonMark;
         in
         {
-          # Documentation
-          inherit docs;
           docs-home-markdown = home-markdown;
           docs-nixos-markdown = nixos-markdown;
           docs-nvim-markdown = nvim-markdown;
+          # Documentation
+          docs = pkgs.stdenvNoCC.mkDerivation {
+            name = "nixos-configuration-book";
+            src = inputs.self + "/docs";
+
+            patchPhase = ''
+              cleanup_md() {
+                sed \
+                  -e 's@\[/nix/store/[^\\]*-source/\(.*\)\\.nix\](.*)@[\1\\.nix](https://github.com/jalil-salame/configuration.nix/blob/main/\1.nix)@' \
+                  -e 's/^## /### /' \
+                  "$@"
+              }
+              # copy generated options removing the declared by statement
+              cleanup_md ${home-markdown} >> ./src/home-options.md
+              cleanup_md ${nvim-markdown} >> ./src/nvim-options.md
+              cleanup_md ${nixos-markdown} >> ./src/nixos-options.md
+            '';
+
+            nativeBuildInputs = [ pkgs.mdbook-toc ];
+            buildPhase = "${pkgs.mdbook}/bin/mdbook build --dest-dir $out";
+          };
         };
     };
 }