From 19ad70455fef1bc4328b23dbe905d604aa0671c1 Mon Sep 17 00:00:00 2001
From: Dan <14043624+delivrance@users.noreply.github.com>
Date: Mon, 10 Dec 2018 15:15:21 +0100
Subject: [PATCH] Update welcome_bot.py example Delete the previous message in
 case of consecutive member joins and send a new one containing the names of
 all the previous new members

---
 examples/welcome_bot.py | 38 ++++++++++++++++++++++++++++----------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/examples/welcome_bot.py b/examples/welcome_bot.py
index 5dbb44fb..2598a802 100644
--- a/examples/welcome_bot.py
+++ b/examples/welcome_bot.py
@@ -6,22 +6,40 @@ to make it only work for specific messages in a specific chat.
 
 from pyrogram import Client, Emoji, Filters
 
-MENTION = "[{}](tg://user?id={})"
-MESSAGE = "{} Welcome to [Pyrogram](https://docs.pyrogram.ml/)'s group chat {}!"
+USER = "**{}**"
+MESSAGE = "{} Welcome to [Pyrogram](https://docs.pyrogram.ml/)'s group chat {{}}!".format(Emoji.SPARKLES)
 
-app = Client("my_account")
+app = Client("dan_prod")
+
+enabled_groups = Filters.chat("PyrogramLounge")
+last_welcomes = {}
 
 
-@app.on_message(Filters.chat("PyrogramChat") & Filters.new_chat_members)
+@app.on_message(enabled_groups & Filters.new_chat_members)
 def welcome(client, message):
-    # Build the new members list (with mentions) by using their first_name
-    new_members = [MENTION.format(i.first_name, i.id) for i in message.new_chat_members]
+    chat_id = message.chat.id
 
-    # Build the welcome message by using an emoji and the list we built above
-    text = MESSAGE.format(Emoji.SPARKLES, ", ".join(new_members))
+    # Get the previous welcome message and members, if any
+    previous_welcome, previous_members = last_welcomes.pop(chat_id, (None, []))
 
-    # Send the welcome message
-    message.reply(text, disable_web_page_preview=True)
+    # Delete the previous message, if exists
+    if previous_welcome:
+        previous_welcome.delete()
+
+    # Build the new members list by using their first_name. Also append the previous members, if any
+    new_members = [USER.format(i.first_name) for i in message.new_chat_members] + previous_members
+
+    # Build the welcome message by using an emoji and the list we created above
+    text = MESSAGE.format(", ".join(new_members))
+
+    # Actually send the welcome and save the new message and the new members list
+    last_welcomes[message.chat.id] = message.reply(text, disable_web_page_preview=True), new_members
+
+
+@app.on_message(enabled_groups)
+def reset(client, message):
+    # Don't make the bot delete the previous welcome in case someone talks in the middle
+    last_welcomes.pop(message.chat.id, None)
 
 
 app.run()  # Automatically start() and idle()