View difference between Paste ID: F5X2QC0W and 7Gtn3S6W

 -- Set up modem
 rednet.open("back") -- Replace "right" with the side your modem is attached to
 
 -- Function to send a message to a chat
 local function sendMessage(serverID, command, chatID, username, text)
     rednet.send(serverID, command .. " " .. chatID .. " " .. username .. " " .. text)
     local id, reply = rednet.receive()
     if reply == "true" then
         print("Message sent successfully!")
     else
         print("Failed to send message.")
     end
 end
 
 -- Function to retrieve messages from a chat
 local function retrieveMessages(serverID, chatID, username)
     rednet.send(serverID, "retrieve " .. chatID .. " " .. username)
     local _, reply = rednet.receive(nil, 2)
 	return reply
 end
 
 
 local function updateChat()
 	while true do
 		local _, reply = rednet.receive()
 		if reply == "update" then
 			start = true
 		end
 	end
 end
 
 local function chatControls(serverID, chatID, username)
     local event, key = os.pullEvent("key")
     if key == keys.up then
         scrollPosition = math.max(1, scrollPosition - 1)
     elseif key == keys.down then
         scrollPosition = math.min(#dmessages - maxLines + 1, scrollPosition + 1)
     elseif key == keys.backspace then
         exitloop = true
     end
 	if scrollPosition >= #dmessages - maxLines + 1 then
         bottom = true
 		if key == keys.enter then
 			local text = read()
     		sendMessage(serverID, "send", chatID, username, text)
 		end
     else
  		bottom = false
 	end
 end
 
 local function displayNewChat(serverID, chatID, username)
     while true do
         if start then
 			dmessages = retrieveMessages(serverID, chatID, username)
 	        if dmessages == nil then
 	    		start = false
 				print("Error")
 				os.sleep(2)
                 return nil
 			elseif dmessages == "false" then
 	    		start = false
 				print("Access Denied")
 				os.sleep(2)
                 return nil
 	        else
 	    		dmessages[1] = "Users in Chat: " .. dmessages[1] .. "\n"
 	    		table.insert(dmessages, "----------------------")
 	    		table.insert(dmessages, " ")
 				if bottom then
                     scrollPosition = math.min(#dmessages - maxLines + 1, scrollPosition + 1)
                 end
 				startIndex = math.max(1, scrollPosition)
         		endIndex = math.min(#dmessages, scrollPosition + maxLines - 1)
 				term.clear()
             	term.setCursorPos(1, 1)
 				for i = startIndex, endIndex do
             		print(dmessages[i])
         		end
     	   	    start = false
     		end
     	end
 		os.sleep(0.001)
     end
 end
 
 local function displayMessages(serverID, chatID, username)
 	start = false
 	exitloop = false
 	scrollPosition = 1
 	dmessages = retrieveMessages(serverID, chatID, username)
     dmessages[1] = "Users in Chat: " .. dmessages[1] .. "\n"
     table.insert(dmessages, "----------------------")
     table.insert(dmessages, " ")
     maxLines = 15
     local startIndex = math.max(1, scrollPosition)
     local endIndex = math.min(#dmessages, scrollPosition + maxLines - 1)
     while true do
         term.clear()
         term.setCursorPos(1, 1)
         -- Display the database content after the instruction
         for i = startIndex, endIndex do
             print(dmessages[i])
         end
 
 		parallel.waitForAny(
 		function() chatControls(serverID, chatID, username) end,
 		function() displayNewChat(serverID, chatID, username) end
 		)
 		startIndex = math.max(1, scrollPosition)
         endIndex = math.min(#dmessages, scrollPosition + maxLines - 1)
 		if exitloop then
 			break
 		end
     end
 end
 
 
 -- Function to create a chat
 local function createChat(serverID, chatID, username)
     rednet.send(serverID, "create " .. chatID .. " " .. username)
     local _, reply = rednet.receive(nil, 3)
 	print(reply)
 	os.sleep(1)
     if reply == "true" then
         print("Chat " .. chatID .. " created successfully!")
     else
         print("Failed to create chat " .. chatID .. ".")
     end
 end
 
 -- Function to delete a chat
 local function deleteChat(serverID, chatID, username)
     rednet.send(serverID, "delete " .. chatID .. " " .. username)
     local _, reply = rednet.receive(nil, 3)
     if reply == nil then
 		print("Failed to delete chat " .. chatID .. ".")
     elseif reply == "denied" then
 		print("Failed to delete chat " .. chatID .. ". Not Owner of Chat")
 	else
         print("Chat " .. chatID .. " deleted successfully!")
     end
 end
 
 local function printChats(serverID, username)
     rednet.send(serverID, "chats " .. " " .. username)
     local _, reply = rednet.receive(nil, 3)
 	if type(reply) == "String" then
     	if reply == "no" then
 			print("Failed to connect to Server")
 	    elseif reply == "none" then
 			print("No Chats Found")
 		end
 	else
         for _, chatname in pairs(reply) do
 			print(chatname)
 		end
     end
 end
 
 
 function text(sender, serverID)
 	while true do
 	    print("Select an action: ")
 		print("1. Display Chats")
 		print("2. Enter a Chat")
 	    print("3. Create a chat")
 	    print("4. Delete a chat")
 	    print("5. Add User to Chat")
 		print("6. Remove User from Chat")
 	    print("7. Exit")
 
 	    local choice = tonumber(read())
 
 		if choice == 1 then
 			print("Chats Available: ")
 			printChats(serverID, sender)
 			print("Type Anything to Continue")
 			read()
 			term.clear()
     		term.setCursorPos(1, 1)
 		elseif choice == 2 then
 	        print("Enter chat ID to retrieve messages from:")
 	        local chatID = read()
 			reply = retrieveMessages(serverID, chatID, sender)
 			if reply == nil then
 				print("Chat does not Exist")
 				os.sleep(3)
 			elseif reply == "false" then
 				print("Access to Chat Denied")
 				os.sleep(3)
 				term.clear()
             	term.setCursorPos(1, 1)
 			else
 				term.clear()
             	term.setCursorPos(1, 1)
 				print("Text Controls are: \n")
 				print("Up and Down to Scroll \n")
 				print("Enter at Bottom of Chat to type \n")
 				print("Backspace to Leave Chat \n")
 				print("Type Anything to Continue")
 				read()
 				term.clear()
             	term.setCursorPos(1, 1)
 				parallel.waitForAny(
     	    		function() displayMessages(serverID, chatID, sender) end,
         			function() updateChat() end
     			)
 			end
     	elseif choice == 3 then
         	print("Enter chat ID to create:")
         	local chatID = read()
 	        createChat(serverID, chatID, sender)
     	elseif choice == 4 then
         	print("Enter chat ID to delete:")
 	        local chatID = read()
     	    deleteChat(serverID, chatID, sender)
 	    elseif choice == 5 then
     	    print("Enter chat ID:")
         	local chatID = read()
 	        print("Enter User to Add:")
     	    local auser = read()
         	sendMessage(serverID, "add", chatID, sender, auser)
 		elseif choice == 6 then
 			print("Enter chat ID:")
         	local chatID = read()
 	        print("Enter User to Remove:")
     	    local ruser = read()
         	sendMessage(serverID, "remove", chatID, sender, ruser)
 
 	    elseif choice == 7 then
     	    break
     	else
         	print("Invalid choice. Please try again.")
     	end
 	end
 end