/* rtu.c — simulates a substation RTU */

#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>
#include <signal.h>

#include "cs104_slave.h"
#include "hal_thread.h"
#include "hal_time.h"

static bool running    = true;
static float voltage   = 11.2;   /* kV */
static float current   = 450.0;  /* A  */
static bool  breaker1  = false;  /* OFF */
static bool  breaker2  = false;  /* OFF */

void sigint_handler(int s) { running = false; }

/* ── connection events ──────────────────────────────────────── */
static void connectionEventHandler(void* p, IMasterConnection con, CS104_PeerConnectionEvent event) {
    if (event == CS104_CON_EVENT_CONNECTION_OPENED)
        printf("[RTU] SCADA connected\n");
    else if (event == CS104_CON_EVENT_CONNECTION_CLOSED)
        printf("[RTU] SCADA disconnected\n");
    else if (event == CS104_CON_EVENT_ACTIVATED)
        printf("[RTU] Data transfer started\n");
}

/* ── accept all connections ─────────────────────────────────── */
static bool connectionRequestHandler(void* p, const char* ip) {
    printf("[RTU] Connection request from %s — accepted\n", ip);
    return true;
}

/* ── send all current values (General Interrogation) ────────── */
static bool interrogationHandler(void* p, IMasterConnection con, CS101_ASDU asdu, uint8_t qoi) {
    printf("[RTU] General Interrogation received\n");

    CS101_AppLayerParameters alParams = IMasterConnection_getApplicationLayerParameters(con);

    /* confirm GI received */
    IMasterConnection_sendACT_CON(con, asdu, false);

    /* send voltage IOA 100 */
    CS101_ASDU a1 = CS101_ASDU_create(alParams, false,
        CS101_COT_INTERROGATED_BY_STATION, 0, 1, false, false);
    InformationObject io1 = (InformationObject)
        MeasuredValueShort_create(NULL, 100, voltage, IEC60870_QUALITY_GOOD);
    CS101_ASDU_addInformationObject(a1, io1);
    InformationObject_destroy(io1);
    IMasterConnection_sendASDU(con, a1);
    CS101_ASDU_destroy(a1);

    /* send current IOA 101 */
    CS101_ASDU a2 = CS101_ASDU_create(alParams, false,
        CS101_COT_INTERROGATED_BY_STATION, 0, 1, false, false);
    InformationObject io2 = (InformationObject)
        MeasuredValueShort_create(NULL, 101, current, IEC60870_QUALITY_GOOD);
    CS101_ASDU_addInformationObject(a2, io2);
    InformationObject_destroy(io2);
    IMasterConnection_sendASDU(con, a2);
    CS101_ASDU_destroy(a2);

    /* send breaker1 IOA 200 */
    CS101_ASDU a3 = CS101_ASDU_create(alParams, false,
        CS101_COT_INTERROGATED_BY_STATION, 0, 1, false, false);
    InformationObject io3 = (InformationObject)
        SinglePointInformation_create(NULL, 200, breaker1, IEC60870_QUALITY_GOOD);
    CS101_ASDU_addInformationObject(a3, io3);
    InformationObject_destroy(io3);
    IMasterConnection_sendASDU(con, a3);
    CS101_ASDU_destroy(a3);

    /* send breaker2 IOA 201 */
    CS101_ASDU a4 = CS101_ASDU_create(alParams, false,
        CS101_COT_INTERROGATED_BY_STATION, 0, 1, false, false);
    InformationObject io4 = (InformationObject)
        SinglePointInformation_create(NULL, 201, breaker2, IEC60870_QUALITY_GOOD);
    CS101_ASDU_addInformationObject(a4, io4);
    InformationObject_destroy(io4);
    IMasterConnection_sendASDU(con, a4);
    CS101_ASDU_destroy(a4);

    /* GI complete */
    IMasterConnection_sendACT_TERM(con, asdu);
    printf("[RTU] GI complete — sent voltage=%.1f current=%.1f breaker1=%d breaker2=%d\n",
           voltage, current, breaker1, breaker2);

    return true;
}

/* ── handle commands from SCADA ─────────────────────────────── */
static bool asduHandler(void* p, IMasterConnection con, CS101_ASDU asdu) {

    /* single command C_SC_NA_1 */
    if (CS101_ASDU_getTypeID(asdu) == C_SC_NA_1) {
        if (CS101_ASDU_getCOT(asdu) == CS101_COT_ACTIVATION) {

            InformationObject io = CS101_ASDU_getElement(asdu, 0);
            if (io) {
                int  ioa   = InformationObject_getObjectAddress(io);
                bool state = SingleCommand_getState((SingleCommand)io);
                InformationObject_destroy(io);

                printf("[RTU] Command received — IOA=%d state=%s\n",
                       ioa, state ? "ON" : "OFF");

                if (ioa == 200) {
                    breaker1 = state;
                    printf("[RTU] Breaker 1 → %s\n", breaker1 ? "ON" : "OFF");
                    CS101_ASDU_setCOT(asdu, CS101_COT_ACTIVATION_CON);
                }
                else if (ioa == 201) {
                    breaker2 = state;
                    printf("[RTU] Breaker 2 → %s\n", breaker2 ? "ON" : "OFF");
                    CS101_ASDU_setCOT(asdu, CS101_COT_ACTIVATION_CON);
                }
                else {
                    CS101_ASDU_setCOT(asdu, CS101_COT_UNKNOWN_IOA);
                }

                IMasterConnection_sendASDU(con, asdu);
            }
        }
        return true;
    }

    return false;
}

/* ── main ───────────────────────────────────────────────────── */
int main() {
    signal(SIGINT, sigint_handler);

    CS104_Slave slave = CS104_Slave_create(10, 10);
    CS104_Slave_setLocalAddress(slave, "0.0.0.0");
    CS104_Slave_setLocalPort(slave, 2404);

    CS101_AppLayerParameters alParams = CS104_Slave_getAppLayerParameters(slave);

    CS104_Slave_setConnectionEventHandler(slave,   connectionEventHandler,   NULL);
    CS104_Slave_setConnectionRequestHandler(slave, connectionRequestHandler, NULL);
    CS104_Slave_setInterrogationHandler(slave,     interrogationHandler,     NULL);
    CS104_Slave_setASDUHandler(slave,              asduHandler,              NULL);

    CS104_Slave_start(slave);

    if (!CS104_Slave_isRunning(slave)) {
        printf("[RTU] Failed to start!\n");
        CS104_Slave_destroy(slave);
        return 1;
    }

    printf("[RTU] Running on port 2404\n");
    printf("[RTU] IOA 100=voltage  101=current  200=breaker1  201=breaker2\n\n");

    uint64_t lastSent = 0;

    while (running) {
        uint64_t now = Hal_getMonotonicTimeInMs();

        /* every 3s — send spontaneous measurements */
        if (now >= lastSent + 3000) {
            lastSent = now;

            /* simulate small fluctuations */
            voltage += ((rand() % 10) - 5) * 0.1;
            current += ((rand() % 20) - 10) * 1.0;

            /* voltage — IOA 100 */
            CS101_ASDU a1 = CS101_ASDU_create(alParams, false,
                CS101_COT_PERIODIC, 0, 1, false, false);
            InformationObject io1 = (InformationObject)
                MeasuredValueShort_create(NULL, 100, voltage, IEC60870_QUALITY_GOOD);
            CS101_ASDU_addInformationObject(a1, io1);
            InformationObject_destroy(io1);
            CS104_Slave_enqueueASDU(slave, a1);
            CS101_ASDU_destroy(a1);

            /* current — IOA 101 */
            CS101_ASDU a2 = CS101_ASDU_create(alParams, false,
                CS101_COT_PERIODIC, 0, 1, false, false);
            InformationObject io2 = (InformationObject)
                MeasuredValueShort_create(NULL, 101, current, IEC60870_QUALITY_GOOD);
            CS101_ASDU_addInformationObject(a2, io2);
            InformationObject_destroy(io2);
            CS104_Slave_enqueueASDU(slave, a2);
            CS101_ASDU_destroy(a2);

            printf("[RTU →] voltage=%.2fkV  current=%.1fA  breaker1=%s  breaker2=%s\n",
                   voltage, current,
                   breaker1 ? "ON" : "OFF",
                   breaker2 ? "ON" : "OFF");
        }

        Thread_sleep(10);
    }

    printf("[RTU] Shutting down\n");
    CS104_Slave_stop(slave);
    CS104_Slave_destroy(slave);
    return 0;
}