// ==================================================================================
// Copyright (c) 2000-2019 Ericsson Telecom AB AB
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v2.0
// which accompanies this distribution, and is available at
// https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html
// ==================================================================================
// Contributors:
//  Krisztian Gulyas - initial implementation and initial documentation
//
//  File:               SimpleTCP.ttcn
//  Rev:                 
//  Prodnr:              
// ==================================================================================

// ==============================================================================
//
// Helper module for simple TCP/IP communication using the IPL4asp library
//
// ==============================================================================
module SimpleTCP
{
    // import basic definitions of TCP/IP communication
    import from IPL4asp_Types all;
	import from IPL4asp_PortType all;

    // basic TCP connection data type
    type record ConnectionData {
        charstring  host,           // host name [string]
        integer     portNumber      // port number [integer]
    }

    // ------------------------------------------------------------------------------
    // Helper function for simple TCP message send and receive
    //
    // 0) Register message lenght callback (function)
    // 1) Initalize TCP connection
    // 2) Sending out TCP message with given PDU
    // 3) if necessary: catching reply message, get PDU
    //
    // parameters:
    //      - testPort          // IPL4asp_PT type TCP/IP testport [IPL4asp_PT]
    //      - msgLenCallback    // message length function callback
    //      - local             // local host/port  [ConnectionData]
    //      - remote            // remote host/port [ConnectionData]
    //      - pduOut            // these octets will be sent out as the part of TCP message [octets]
    //      - pduIn             // these octets are received from incomming TCP message [octets]
    //      - expectResponse    // expected response message from host/port [true/false]
    // return:
    //      - TCP communication was success [true/false]
    //
    // ------------------------------------------------------------------------------

    function sendReceiveMsg (
        IPL4asp_PT              testPort,       // IPL4asp_PT type TCP/IP testport [IPL4asp_PT]
        f_IPL4_getMsgLen        msgLenCallback,
        ConnectionData          local,
        ConnectionData          remote,
        in octetstring          pduOut,
        inout octetstring       pduIn,
        boolean                 expectResponse
        ) return boolean                        // TCP commution result
    {
        var boolean res := false;               // send/receive result, default = false

        var Result connectionResult, closingResult;

        // register message lenght callback
        f_IPL4_setGetMsgLen(testPort, -1, msgLenCallback, {});

        // connect to the socket and check result
        connectionResult := f_IPL4_connect(
            testPort,
            remote.host, remote.portNumber,
            local.host, local.portNumber,
            -1,
            { tcp := {}},
            {
                { reuseAddress := {enable := true} }
            });

        if (ispresent(connectionResult.errorCode)) {
            log("  [!!] TCP port connection error: ", connectionResult);
        }
        else {
            // successfully connected to the given host/port
            log("  [::] TCP port [", remote.host, "/", remote.portNumber, "] connected.");

            // send and receive TCP message
            var ASP_SendTo      tcp_msg_send;
            var ASP_RecvFrom    tcp_msg_received;

            // Timer with 0.1 s duration
            timer T := 0.1;

            // set up TCP message
            tcp_msg_send := { connectionResult.connId, remote.host, remote.portNumber, { tcp := {} }, pduOut }

            // send out TCP message to the given port
            testPort.send(tcp_msg_send);
            log("  [=>] TCP message sent...");

            // process received message if needed
            if (expectResponse) {

                // start timer with 0.1 s
                T.start;

                alt
                {
                    [] testPort.receive(ASP_RecvFrom : ?) -> value tcp_msg_received
                    {
                        log("  [<=] TCP message received ");
                        pduIn := tcp_msg_received.msg;
                        res := true;
                    }
                    [] T.timeout {
                        log("  [!!] Timeout (no response) ");
                    }
                }
            }
            else {
                log("  [::] Expecting no response");
                res := true;
            }

            // close the connection and check result
            closingResult := f_IPL4_close(testPort, connectionResult.connId, { unspecified := {} });

            if (ispresent(closingResult.errorCode)) {
                log("  [!!] TCP port closing error: ", connectionResult.errorCode);
            }
            else {
                log("  [::] TCP port [", remote.host, "/", remote.portNumber, "] closed");
            }

            // 0.1 second delay (proper closing of TCP operations)
            T.start; T.timeout;

        }

        return res;
    }

}