Add categories tidy command

hamstertools/__init__.py

@@ -106,7 +106,7 @@ def delete_categories(ids):
     results = get_categories(ids)
 
     for r in results:
-        sql = 'SELECT COUNT(id) FROM activities WHERE category_id = ?'
+        sql = 'select count(id) from activities where category_id = ?'
         count = c.execute(sql, (r[0],)).fetchone()[0]
         click.echo('@{0[0]}: {0[1]} ({1} activities)'.format(r, count))
 
@@ -169,6 +169,30 @@ def list_category_activities(ids):
         click.echo('@{0[0]}: {0[2]} » {0[1]}'.format(r))
 
 
+@categories.command('tidy')
+def tidy_categories():
+    """ Remove categories with no activities """
+
+    sql = 'SELECT categories.id, categories.name FROM categories LEFT JOIN activities ON categories.id = activities.category_id WHERE activities.id IS NULL'
+    categories = c.execute(sql).fetchall()
+
+    click.echo('Found {0} empty categories:'.format(len(categories)))
+
+    for cat in categories:
+        click.echo('@{0[0]}: {0[1]}'.format(cat))
+
+    click.confirm('Do you want to continue?', abort=True)
+
+    sql = 'DELETE FROM categories '
+
+    sql = sql + 'WHERE id IN ({seq})'.format(
+        seq=','.join(['?'] * len(categories))
+    )
+
+    c.execute(sql, [cat[0] for cat in categories])
+    conn.commit()
+
+
 @cli.group()
 def activities():
     pass