From 714f5c838dd4d69bb80925dc1aec1b4810a08c42 Mon Sep 17 00:00:00 2001
From: Martin Kremers <info@martinkremers.de>
Date: Sun, 14 Dec 2014 15:07:25 +0100
Subject: [PATCH] Enable multilevel table of contents

---
 src/cryogen_core/toc.clj | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/cryogen_core/toc.clj b/src/cryogen_core/toc.clj
index b30f60b..e44c212 100644
--- a/src/cryogen_core/toc.clj
+++ b/src/cryogen_core/toc.clj
@@ -2,10 +2,13 @@
  (:require [crouton.html :as html]
            [hiccup.core :as hiccup]))
 
+(def _h [:h1 :h2 :h3 :h4 :h5 :h6])
+(defn- compare_index [i1 i2] (- (.indexOf _h i2) (.indexOf _h i1)))
+
 (defn get-headings [content]
   (reduce
     (fn [headings {:keys [tag attrs content] :as elm}]
-      (if (some #{tag} [:h1 :h2 :h3])
+      (if (some #{tag} _h)
         (conj headings elm)
         (if-let [more-headings (get-headings content)]
           (into headings more-headings)
@@ -13,9 +16,16 @@
     [] content))
 
 (defn make-links [headings]
-  (into [:ol.contents]
-        (for [{[{{name :name} :attrs} title] :content} headings]
-          [:li [:a {:href (str "#" name)} title]])))
+  (loop [items headings acc nil _last nil]
+    (if-let [{tag :tag [{{name :name} :attrs} title] :content} (first items)]
+      (if (nil? name) (recur (rest items) acc nil)
+          (let [entry [:li [:a {:href (str "#" name)} title]]
+                jump (compare_index _last tag)]
+            (cond (> jump 0) (recur (rest items) (str acc "<ol>" (hiccup/html entry)) tag)
+                  (= jump 0) (recur (rest items) (str acc (hiccup/html entry)) tag)
+                  (< jump 0) (recur (rest items) (str acc (apply str (repeat (* -1 jump) "</ol>"))
+                                                      (hiccup/html entry)) tag))))
+      (str acc "</ol>"))))
 
 (defn generate-toc [html]
   (-> html
@@ -25,4 +35,4 @@
       :content
       (get-headings)
       (make-links)
-      (hiccup/html)))
+      (clojure.string/replace-first #"ol" "ol class=\"contents\"")))