From f3e32115ee099764e03efbedb6252b01fae2a6ae Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 6 Aug 2023 22:25:37 +0100
Subject: [PATCH] extremely hacky first pass at autogenerated module docs

---
 ci.nix                  |  3 +-
 doc/extract-options.nix | 55 ++++++++++++++++++++++++++++
 doc/parse-options.fnl   | 80 +++++++++++++++++++++++++++++++++++++++++
 doc/user.rst            |  8 ++---
 4 files changed, 139 insertions(+), 7 deletions(-)
 create mode 100644 doc/extract-options.nix
 create mode 100644 doc/parse-options.fnl

diff --git a/ci.nix b/ci.nix
index 657f481..dbc9fb7 100644
--- a/ci.nix
+++ b/ci.nix
@@ -26,9 +26,10 @@ let
       }).buildEnv;
       doc = pkgs.stdenv.mkDerivation {
         name = "liminix-doc";
-        nativeBuildInputs = with pkgs; [ gnumake sphinx ];
+        nativeBuildInputs = with pkgs; [ gnumake sphinx  fennel luaPackages.dkjson ];
         src = ./doc;
         buildPhase = ''
+          cat ${(import ./doc/extract-options.nix).doc} | fennel --correlate parse-options.fnl > modules.rst
           make html
         '';
         installPhase = ''
diff --git a/doc/extract-options.nix b/doc/extract-options.nix
new file mode 100644
index 0000000..5ac00bf
--- /dev/null
+++ b/doc/extract-options.nix
@@ -0,0 +1,55 @@
+let
+  overlay = import ../overlay.nix;
+  pkgs = import <nixpkgs> ( {
+    overlays = [overlay];
+    config = {
+      allowUnsupportedSystem = true; # mipsel
+      permittedInsecurePackages = [
+        "python-2.7.18.6"       # kernel backports needs python <3
+      ];
+    };
+  });
+  inherit (pkgs) lib;
+  inherit (lib) types;
+  modulenames =
+    builtins.attrNames
+      (lib.filterAttrsRecursive
+        (n: t:
+          (t=="directory") ||
+          ((t=="regular") && ((builtins.match ".*\\.nix$" n) != null)))
+        (builtins.readDir ../modules));
+  modulefiles = builtins.map (n: builtins.toPath "${../modules}/${n}") modulenames;
+  eval = (lib.evalModules {
+    modules = [
+      { _module.args = { inherit pkgs; lib = pkgs.lib; }; }
+    ] ++ modulefiles;
+  });
+  conf = eval.config;
+  optToDoc = name: opt : {
+    inherit name;
+    description = opt.description or null;
+    default = opt.default or null;
+    visible =
+      if (opt ? visible && opt.visible == "shallow")
+      then true
+      else opt.visible or true;
+    readOnly = opt.readOnly or false;
+    type = opt.type.description or "unspecified";
+  };
+  spliceServiceDefn = item :
+    if item.type == "parametrisable s6-rc service definition"
+    then
+      let sd = lib.attrByPath item.loc ["not found"] conf;
+      in item // {
+        parameters =
+          let x = lib.mapAttrsToList optToDoc sd.parameters; in x;
+      }
+    else
+      item;
+  o = builtins.map spliceServiceDefn
+    (pkgs.lib.optionAttrSetToDocList eval.options);
+in {
+  doc = pkgs.writeText "options.json"
+    (builtins.unsafeDiscardStringContext (builtins.toJSON o))
+  ;
+}
diff --git a/doc/parse-options.fnl b/doc/parse-options.fnl
new file mode 100644
index 0000000..d8f0913
--- /dev/null
+++ b/doc/parse-options.fnl
@@ -0,0 +1,80 @@
+(local json (require :dkjson))
+
+(local { : view } (require :fennel))
+
+(fn headline [name]
+  (let [(_ _ basename) (string.find name ".*/([^/].*)")
+        len (basename:len)]
+    (print basename)
+    (print (string.rep "=" len))))
+
+(fn strip-newlines [text]
+  (and text
+       (-> text
+           (string.gsub "\n([^\n])" " %1")
+           (string.gsub "\n\n+" "\n"))))
+
+(fn indent [n text]
+  (let [margin (string.rep " " n)]
+    (.. margin (string.gsub text "\n +" (.. "\n" margin )))))
+
+(fn extract-text [description]
+  (and description
+;       (do (print (view description)) true)
+       (-> (match description
+             { :type "literalExpression" : text } text
+             {} nil
+             nil nil
+             t description)
+           strip-newlines)))
+
+(fn print-option [o offset]
+  (let [i (or offset 0)]
+    (print (indent i (.. " * option ``" o.name "``")))
+    (print (indent (+ 4 i)
+                   (or (extract-text o.description) "(no description)")))
+    (print)
+    (print (indent (+ 4 i) (.. "**type** " o.type "\n")))
+    (print (indent (+ 4 i)
+                   (.. "**default** "
+                       (or (extract-text (?. o :default)) "(none)")
+                       "\n"
+                       )))
+    (print )))
+
+(fn print-service [o]
+  (print (.. " * service ``" o.name "``"))
+  (print (indent 4 (or (extract-text o.description) "(no description)")))
+  (print)
+  (print (indent 4 "**Service parameters**\n"))
+  (each [_ param (ipairs o.parameters)]
+    (print-option param 4)))
+
+(fn sort-options [module]
+  (table.sort module (fn [a b] (< a.name b.name)))
+  module)
+
+(let [raw (json.decode (io.read "*a"))
+      modules {}]
+  (each [_ option (ipairs raw)]
+    (let [[path] option.declarations
+          e (or (. modules path) [])]
+      (table.insert e option)
+      (tset modules path e)))
+  (each [name module (pairs modules)]
+    (print (headline name))
+    (let [options (sort-options module)]
+      (each [_ o (ipairs options)]
+        (if (= o.type "parametrisable s6-rc service definition")
+            (print-service o)
+            (print-option o))))))
+
+;; for each element el, add to table modules keyed on
+;; el.declarations
+
+;; for each value in modules
+;;   print title
+;;   elements = (sort elements on el.name)
+;;   for each el in elements
+;;     is option or service? print whichever
+;;
diff --git a/doc/user.rst b/doc/user.rst
index 667dd03..99722f3 100644
--- a/doc/user.rst
+++ b/doc/user.rst
@@ -316,11 +316,7 @@ Caveats
 
 * it cannot upgrade the kernel, only userland
 
-
-
-Configuration Options
+Configuration options
 *********************
 
-
-
-Module docs will go here. This part of the doc should be autogenerated.
+.. include:: modules.rst