font ChatFont = "Arial#12";

string STR_Received = "#100";
string STR_Sent = "#100";
string STR_Input = "#100";

string STR_ChatLine01 = "#100";
string STR_ChatLine02 = "#100";
string STR_ChatLine03 = "#100";
string STR_ChatLine04 = "#100";
string STR_ChatLine05 = "#100";

text TXT_ChatWindow // The "Chatwindow"
{
	strings = 5;
	string = STR_ChatLine01,STR_ChatLine02,STR_ChatLine03,STR_ChatLine04,STR_ChatLine05;
	pos_x = 10;
	pos_y = 10;
	font = ChatFont;
}

text TXT_ChatInput // The input line to type new messages
{
	string = STR_Input;
	pos_x = 10;
	pos_y = 100;
	font = ChatFont;
}

function chat_init() // Call this function in your MAIN FUNCTION
{
	TXT_ChatWindow.visible = on;
	TXT_ChatInput.visible = on;
}

	/*
	As you can only send strings to the server as client,
	we must send any chat message to the serve first
	*/
	function SendMsgToServer()
	{
		// Prepare string
		str_cpy(STR_Sent, player_name); // First, we'll add the player name
		str_cat(STR_Sent, ": "); // then a :
		str_cat(STR_Sent, STR_Input); // and finally the message
		
		// Send string
		send_string(STR_Sent); // Now we send the string to the server
		
		wait(1); // Wait 1 frame for the message to be sent -- VERY IMPORTANT
		
		// Empty the strings to avoid duplication
		str_cpy(STR_Sent, "");
		str_cpy(STR_Input, "");
	}

function InputText()
{
	if(inkey_active){ return; } // If already active, RETURN!
	
	inkey(STR_Input); // Input focus on STR_Input
	
	if(result == 13) // If input is ended by ENTER
	{
		SendMsgToServer(); // Send message
	}
}

on_enter = InputText; // Bind Input function to enter key

function ReceiveMessage() // Function when the client receives messages from the server
{
	wait(1); // wait one frame -- IMPORTANT
	
	/*
	 To avoid that a server that has been started as "-sv -cl"
	 gets the message twice, use ifndef server;
	*/
	ifndef server;
		if(str_len(STR_Received) > 0) // If we received a valid chat message
		{
			// Reorder Chat
			str_cpy(STR_ChatLine01, STR_ChatLine02); // 2 > 1
			str_cpy(STR_ChatLine02, STR_ChatLine03); // 3 > 2
			str_cpy(STR_ChatLine03, STR_ChatLine04); // 4 > 3
			str_cpy(STR_ChatLine04, STR_ChatLine05); // 5 > 4
			str_cpy(STR_ChatLine05, STR_Received); // New message > 5
			
			wait(1); // Wait one frame -- IMPORTANT, as always
			
			str_cpy(STR_Received,""); // Empty the received string
		}
	endif; // Close the ifndef
	
	ifdef server;
		wait(1); // To avoid an empty function. 
	endif;
}

on_client = ReceiveMessage; // Bind ReceiveMessage function on the Client-Receive-Data event

function ReceiveMessage_Server() // The same function as above, but for the server and slightly changed
{
	wait(1); // wait 1 frame -- IMPORTANT
	
	if(str_len(STR_Sent)>0) // If we got a valid chat message
	{
		// Copy
		str_cpy(STR_Received,STR_Sent);
		
		// Order
		str_cpy(STR_ChatLine01, STR_ChatLine02); // 2 > 1
		str_cpy(STR_ChatLine02, STR_ChatLine03); // 3 > 2
		str_cpy(STR_ChatLine03, STR_ChatLine04); // 4 > 3
		str_cpy(STR_ChatLine04, STR_ChatLine05); // 5 > 4
		str_cpy(STR_ChatLine05, STR_Received); // New message > 5
		
		// IMPORTANT -- DON'T empty the message yet
		// Send it to all clients first!
		send_string(STR_Received);
		
		wait(1); // Wait 1 frame for the message to be sent -- IMPORTANT
		
		// Empty
		str_cpy(STR_Received,"");
		str_cpy(STR_Sent,"");
	}
}

on_server = ReceiveMessage_Server; // Bind ReceiveMessage_Server to the Server-Receive-Event