add subscribing and unsubscribing to threads

apps/threads.lua

@@ -9,6 +9,7 @@ local models = require("models")
 local Topics = models.Topics
 local Threads = models.Threads
 local Posts = models.Posts
+local Subscriptions = models.Subscriptions
 
 local POSTS_PER_PAGE = 10
 
@@ -97,7 +98,18 @@ app:get("thread", "/:slug", function(self)
   self.other_topics = db.query("SELECT topics.id, topics.name FROM topics")
   self.me = util.get_logged_in_user_or_transient(self)
   self.posts = posts
-
+  
+  if self.me:is_logged_in() then
+    self.is_subscribed = false
+    local subscription = Subscriptions:find({user_id = self.me.id, thread_id = thread.id})
+    if subscription then
+      self.is_subscribed = true
+      if posts[#posts].created_at > subscription.last_seen then
+        subscription:update({last_seen = os.time()})
+      end
+    end
+  end
+  
   self.page_title = thread.title
 
   return {render = "threads.thread"}
@@ -133,6 +145,10 @@ app:post("thread", "/:slug", function(self)
     return {redirect_to = self:url_for("thread", {slug = thread.slug}, {page = last_page}) .. "#latest-post"}
   end
   
+  if self.params.subscribe == "on" then
+    Subscriptions:create({user_id = user.id, thread_id = thread.id, last_seen = os.time()})
+  end
+  
   return {redirect_to = self:url_for("thread", {slug = thread.slug}, {page = last_page}) .. "#latest-post"}
 end)
 
@@ -206,4 +222,32 @@ app:post("thread_move", "/:slug/move", function(self)
   return {redirect_to = self:url_for("thread", {slug = self.params.slug})}
 end)
 
+app:post("thread_subscribe", "/:slug/subscribe", function(self)
+  local user = util.get_logged_in_user(self)
+  if not user then
+    return {status = 403}
+  end
+  local thread = Threads:find({slug = self.params.slug})
+  if not thread then
+    return {status = 404}
+  end
+  local subscription = Subscriptions:find({user_id = user.id, thread_id = thread.id})
+  if self.params.subscribe == "subscribe" then
+    local now = os.time()
+    if subscription then
+      subscription:delete()
+    end
+    Subscriptions:create({user_id = user.id, thread_id = thread.id, last_seen = now})
+    return {redirect_to = self:url_for("thread", {slug = thread.slug}, {after = self.params.first_visible_post})}
+  elseif self.params.subscribe == "unsubscribe" then
+    if not subscription then
+      return {status = 404}
+    end
+    subscription:delete()
+    return {redirect_to = self:url_for("thread", {slug = thread.slug}, {after = self.params.first_visible_post})}
+  end
+  
+  return {status = 400}
+end)
+
 return app