From ed5c44a26040d41d8df88edc93f16801c21aea72 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Tue, 5 Jun 2018 21:27:49 +0200
Subject: [PATCH] Support deleting more than 100 messages at once

---
 telethon/telegram_client.py | 19 +++++++++----------
 telethon/utils.py           | 12 ++++++++++++
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/telethon/telegram_client.py b/telethon/telegram_client.py
index 6345ebb2..fb4f07ef 100644
--- a/telethon/telegram_client.py
+++ b/telethon/telegram_client.py
@@ -1092,25 +1092,24 @@ class TelegramClient(TelegramBareClient):
                 This has no effect on channels or megagroups.
 
         Returns:
-            The :tl:`AffectedMessages`.
+            A list of :tl:`AffectedMessages`, each item being the result
+            for the delete calls of the messages in chunks of 100 each.
         """
         if not utils.is_list_like(message_ids):
             message_ids = (message_ids,)
 
-        message_ids = [
+        message_ids = (
             m.id if isinstance(m, (Message, MessageService, MessageEmpty))
             else int(m) for m in message_ids
-        ]
-
-        if entity is None:
-            return self(messages.DeleteMessagesRequest(message_ids, revoke=revoke))
-
-        entity = self.get_input_entity(entity)
+        )
 
+        entity = self.get_input_entity(entity) if entity else None
         if isinstance(entity, InputPeerChannel):
-            return self(channels.DeleteMessagesRequest(entity, message_ids))
+            return self([channels.DeleteMessagesRequest(entity, list(c))
+                         for c in utils.chunks(message_ids)])
         else:
-            return self(messages.DeleteMessagesRequest(message_ids, revoke=revoke))
+            return self([messages.DeleteMessagesRequest(list(c), revoke)
+                         for c in utils.chunks(message_ids)])
 
     def iter_messages(self, entity, limit=None, offset_date=None,
                       offset_id=0, max_id=0, min_id=0, add_offset=0,
diff --git a/telethon/utils.py b/telethon/utils.py
index 806f7848..312b47ac 100644
--- a/telethon/utils.py
+++ b/telethon/utils.py
@@ -2,6 +2,7 @@
 Utilities for working with the Telegram API itself (such as handy methods
 to convert between an entity like an User, Chat, etc. into its Input version)
 """
+import itertools
 import math
 import mimetypes
 import os
@@ -56,6 +57,17 @@ class Default:
     """
 
 
+def chunks(iterable, size=100):
+    """
+    Turns the given iterable into chunks of the specified size,
+    which is 100 by default since that's what Telegram uses the most.
+    """
+    it = iter(iterable)
+    size -= 1
+    for head in it:
+        yield itertools.chain([head], itertools.islice(it, size))
+
+
 def get_display_name(entity):
     """
     Gets the display name for the given entity, if it's an :tl:`User`,