add infobox support

app/routes/mod.py

@@ -1,6 +1,8 @@
-from flask import Blueprint, abort, redirect, url_for, request, render_template
+from flask import Blueprint, abort, redirect, url_for, request, render_template, flash
+from ..constants import InfoboxKind
 from ..auth import is_logged_in, get_active_user, csrf_verified
 from ..models import Topics, Threads
+from slugify import slugify
 bp = Blueprint('mod', __name__, url_prefix='/mod/')
 
 @bp.before_request
@@ -39,9 +41,21 @@ def edit_topic_post(topic_id):
     topic = Topics.find({'id': topic_id})
     if not topic:
         abort(404)
+
+    target_name = request.form.get('name').strip()
+
+    name_exists = Topics.count([
+        ('lower(name)', '=', target_name.lower()),
+        ('id', '!=', topic.id)
+    ]) > 0
+    if name_exists:
+        flash(f'A topic named "{target_name}" already exists.', InfoboxKind.ERROR)
+        return redirect(url_for('.edit_topic', topic_id=topic_id))
+
     topic.update({
-        'name': request.form.get('name').strip(),
+        'name': target_name,
         'description': request.form.get('description').strip(),
+        'slug': slugify(target_name[:50]),
     })
     return redirect(url_for('topics.topic_by_id', topic_id=topic.id))