add offset pagination and permalinking to posts

apps/threads.lua

@@ -57,6 +57,7 @@ app:post("thread_create", "/create", function(self)
 end)
 
 app:get("thread", "/:slug", function(self)
+  local posts_per_page = 10
   local thread = Threads:find({
     slug = self.params.slug
   })
@@ -67,7 +68,8 @@ app:get("thread", "/:slug", function(self)
   local post_count = Posts:count(db.clause({
     thread_id = thread.id
   }))
-  local pages = math.floor(post_count / 20)
+  self.pages = math.ceil(post_count / posts_per_page)
+  self.page = tonumber(self.params.page) or 1
   local posts = db.query([[
     SELECT
       posts.id, post_history.content, users.username, avatars.file_path AS avatar_path
@@ -80,15 +82,14 @@ app:get("thread", "/:slug", function(self)
     LEFT JOIN
       avatars ON users.avatar_id = avatars.id
     WHERE
-      posts.thread_id = ? and posts.id > ?
+      posts.thread_id = ?
     ORDER BY
       posts.created_at ASC
-    LIMIT 20
-  ]], thread.id, tonumber(self.params.cursor or 0))
+    LIMIT 20 OFFSET ?
+  ]], thread.id, (self.page - 1) * posts_per_page)
   self.topic = Topics:find(thread.topic_id)
   self.user = util.get_logged_in_user_or_transient(self)
   self.posts = posts
-  self.next_cursor = #posts > 0 and posts[#posts].id or nil
   return {render = "threads.thread"}
 end)