add invite system

app/models.py

@@ -1,5 +1,6 @@
 from .db import Model, db
 from .constants import PermissionLevel
+from flask import current_app
 import time
 
 class Users(Model):
@@ -48,7 +49,8 @@ class Users(Model):
                 COUNT(DISTINCT posts.id) AS post_count,
                 COUNT(DISTINCT threads.id) AS thread_count,
                 MAX(threads.title) FILTER (WHERE threads.created_at = latest.created_at) AS latest_thread_title,
-                MAX(threads.slug) FILTER (WHERE threads.created_at = latest.created_at) AS latest_thread_slug
+                MAX(threads.slug) FILTER (WHERE threads.created_at = latest.created_at) AS latest_thread_slug,
+                inviter.username AS inviter_username
             FROM users
             LEFT JOIN posts ON posts.user_id = users.id
             LEFT JOIN threads ON threads.user_id = users.id
@@ -57,6 +59,7 @@ class Users(Model):
                 FROM threads
                 GROUP BY user_id
                 ) latest ON latest.user_id = users.id
+            LEFT JOIN users AS inviter ON inviter.id = users.invited_by
             WHERE users.id = ?"""
         return db.fetch_one(q, self.id)
 
@@ -83,6 +86,18 @@ class Users(Model):
 
         return True
 
+    def can_invite(self):
+        if not current_app.config['DISABLE_SIGNUP']:
+            return True
+
+        if current_app.config['MODS_CAN_INVITE'] and self.is_mod():
+            return True
+
+        if current_app.config['USERS_CAN_INVITE'] and not self.is_guest():
+            return True
+
+        return False
+
 
 class Topics(Model):
     table = "topics"
@@ -285,3 +300,7 @@ class Reactions(Model):
 
 class PasswordResetLinks(Model):
     table = "password_reset_links"
+
+
+class InviteKeys(Model):
+    table = 'invite_keys'