From 0093ab0404148dcea031c117aa4f082a27540149 Mon Sep 17 00:00:00 2001
From: Aliwoto <woto@kaizoku.cyou>
Date: Wed, 1 Nov 2023 23:44:40 +0330
Subject: [PATCH] Add support for cross-chat replies.

Signed-off-by: Aliwoto <woto@kaizoku.cyou>
---
 pyrogram/types/messages_and_media/message.py | 32 +++++++++++---
 pyrogram/utils.py                            | 45 +++++++++++++++++---
 2 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/pyrogram/types/messages_and_media/message.py b/pyrogram/types/messages_and_media/message.py
index 7e7bf2c3da6..64f73929549 100644
--- a/pyrogram/types/messages_and_media/message.py
+++ b/pyrogram/types/messages_and_media/message.py
@@ -852,17 +852,37 @@ async def _parse(
                 if isinstance(message.reply_to, raw.types.MessageReplyStoryHeader):
                     parsed_message.reply_to_message_id = message.reply_to.story_id
 
+                setattr(parsed_message, "is_cross_chat", False)
                 if replies:
                     try:
-                        key = (parsed_message.chat.id, parsed_message.reply_to_message_id)
+                        is_cross_chat = \
+                            message.reply_to and \
+                            hasattr(message.reply_to, "reply_to_peer_id") and \
+                            message.reply_to.reply_to_peer_id and \
+                            hasattr(message.reply_to.reply_to_peer_id, "channel_id") and \
+                            message.reply_to.reply_to_peer_id.channel_id
+                        if is_cross_chat:
+                            key = (f"-100{message.reply_to.reply_to_peer_id.channel_id}",
+                                message.reply_to.reply_to_msg_id)
+                            setattr(parsed_message, "is_cross_chat", True)
+                        else:
+                            key = (parsed_message.chat.id, parsed_message.reply_to_message_id)
+                        
                         reply_to_message = client.message_cache[key]
 
                         if not reply_to_message:
-                            reply_to_message = await client.get_messages(
-                                parsed_message.chat.id,
-                                reply_to_message_ids=message.id,
-                                replies=replies - 1
-                            )
+                            if is_cross_chat:
+                                reply_to_message = await client.get_messages(
+                                    chat_id=key[0],
+                                    message_ids=key[1],
+                                    replies=replies - 1
+                                )
+                            else:
+                                reply_to_message = await client.get_messages(
+                                    chat_id=key[0],
+                                    reply_to_message_ids=key[1],
+                                    replies=replies - 1
+                                )
 
                         parsed_message.reply_to_message = reply_to_message
                     except MessageIdsEmpty:
diff --git a/pyrogram/utils.py b/pyrogram/utils.py
index 9806dd5b57e..52e0464458c 100644
--- a/pyrogram/utils.py
+++ b/pyrogram/utils.py
@@ -112,7 +112,7 @@ async def parse_messages(
 
     if replies:
         messages_with_replies = {
-            i.id: i.reply_to.reply_to_msg_id
+            i.id: i.reply_to
             for i in messages.messages
             if not isinstance(i, raw.types.MessageEmpty) and i.reply_to
         }
@@ -127,15 +127,46 @@ async def parse_messages(
             else:
                 chat_id = 0
 
-            reply_messages = await client.get_messages(
-                chat_id,
-                reply_to_message_ids=messages_with_replies.keys(),
-                replies=replies - 1
-            )
+            # whether all messages are inside of our current chat
+            is_all_within_chat = True
+            for current_message_id in messages_with_replies:
+                if messages_with_replies[current_message_id].reply_to_peer_id:
+                    is_all_within_chat = False
+                    break
+
+            reply_messages: List[pyrogram.types.Message] = []
+            if is_all_within_chat:
+                # fast path: fetch all messages within the same chat
+                reply_messages = await client.get_messages(
+                    chat_id,
+                    reply_to_message_ids=messages_with_replies.keys(),
+                    replies=replies - 1
+                )
+            else:
+                # slow path: fetch all messages individually
+                for current_message_id in messages_with_replies:
+                    target_reply_to = messages_with_replies[current_message_id]
+                    to_be_added_msg = None
+                    the_chat_id = chat_id
+                    if target_reply_to.reply_to_peer_id:
+                        the_chat_id = f"-100{target_reply_to.reply_to_peer_id.channel_id}"
+                    to_be_added_msg = await client.get_messages(
+                        chat_id=the_chat_id,
+                        message_ids=target_reply_to.reply_to_msg_id,
+                        replies=replies - 1
+                    )
+                    if isinstance(to_be_added_msg, list):
+                        for current_to_be_added in to_be_added_msg:
+                            reply_messages.append(current_to_be_added)
+                    elif to_be_added_msg:
+                        reply_messages.append(to_be_added_msg)
 
             for message in parsed_messages:
-                reply_id = messages_with_replies.get(message.id, None)
+                reply_to = messages_with_replies.get(message.id, None)
+                if not reply_to:
+                    continue
 
+                reply_id = reply_to.reply_to_msg_id
                 for reply in reply_messages:
                     if reply.id == reply_id:
                         message.reply_to_message = reply