1 files changed, 59 insertions, 0 deletions
diff --git a/plugins/neighbors/neighbors.py b/plugins/neighbors/neighbors.py
new file mode 100644
index 0000000..b3c6e99
--- /dev/null
+++ b/plugins/neighbors/neighbors.py
@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+"""
+Neighbor Articles Plugin for Pelican
+====================================
+
+This plugin adds ``next_article`` (newer) and ``prev_article`` (older)
+variables to the article's context
+"""
+from pelican import signals
+
+
+def iter3(seq):
+    it = iter(seq)
+    nxt = None
+    cur = next(it)
+    for prv in it:
+        yield nxt, cur, prv
+        nxt, cur = cur, prv
+    yield nxt, cur, None
+
+
+def get_translation(article, prefered_language):
+    if not article:
+        return None
+    for translation in article.translations:
+        if translation.lang == prefered_language:
+            return translation
+    return article
+
+
+def set_neighbors(articles, next_name, prev_name):
+    for nxt, cur, prv in iter3(articles):
+        exec("cur.{} = nxt".format(next_name))
+        exec("cur.{} = prv".format(prev_name))
+
+        for translation in cur.translations:
+            exec("translation.{} = get_translation(nxt, translation.lang)".format(next_name))
+            exec("translation.{} = get_translation(prv, translation.lang)".format(prev_name))
+
+
+def neighbors(generator):
+    set_neighbors(generator.articles, 'next_article', 'prev_article')
+
+    for category, articles in generator.categories:
+        articles.sort(key=(lambda x: x.date), reverse=(True))
+        set_neighbors(
+            articles, 'next_article_in_category', 'prev_article_in_category')
+
+    if hasattr(generator, 'subcategories'):
+        for subcategory, articles in generator.subcategories:
+            articles.sort(key=(lambda x: x.date), reverse=(True))
+            index = subcategory.name.count('/')
+            next_name = 'next_article_in_subcategory{}'.format(index)
+            prev_name = 'prev_article_in_subcategory{}'.format(index)
+            set_neighbors(articles, next_name, prev_name)
+
+
+def register():
+    signals.article_generator_finalized.connect(neighbors)