// File Shared Master & Slave
#pragma once
#include <Arduino.h>

// ============================================================
// RS485 PROTOCOL DEFINITIONS (Master & Slave Shared Contract)
// ============================================================

constexpr uint8_t START_BYTE = 0xAA;
constexpr size_t PACKET_SIZE = 9; // 9 Byte: Start, Src, Dest, Cmd, Floor, Mode, Dir/Fault, CRC_Lo, CRC_Hi

// Indeks Byte Paket
constexpr uint8_t PKT_IDX_START     = 0;
constexpr uint8_t PKT_IDX_SRC       = 1; // Alamat pengirim (Master / Slave ID)
constexpr uint8_t PKT_IDX_DEST      = 2; // Alamat penerima tujuan
constexpr uint8_t PKT_IDX_CMD       = 3; // Kode perintah / status
constexpr uint8_t PKT_IDX_FLOOR     = 4; // Lantai target / saat ini
constexpr uint8_t PKT_IDX_MODE      = 5; // Mode sistem (Auto / Inspection dll)
constexpr uint8_t PKT_IDX_DIR_FAULT = 6; // Arah gerak & status *critical error*
constexpr uint8_t PKT_IDX_CRC_LO    = 7; // CRC Low Byte
constexpr uint8_t PKT_IDX_CRC_HI    = 8; // CRC High Byte

// Daftar Command / Perintah Protokol
constexpr uint8_t CMD_POLL_STATUS   = 0x10;
constexpr uint8_t CMD_CAR_CALL      = 0x20;
constexpr uint8_t CMD_DOOR_OPEN     = 0x30;
constexpr uint8_t CMD_DOOR_CLOSE    = 0x31;
constexpr uint8_t CMD_JOG_DOOR_OPEN = 0x40;
constexpr uint8_t CMD_JOG_DOOR_CLOSE= 0x41;
constexpr uint8_t CMD_EMERGENCY     = 0x50;
constexpr uint8_t CMD_LIGHT_TOGGLE  = 0x60;
constexpr uint8_t ACK               = 0x70;


// Slave Side
#include "RS485Manager.h"

extern SystemState systemState;
extern BuzzerManager buzzerMgr;
extern ButtonManager buttonMgr;

RS485Manager::RS485Manager() : lastByteTime(0), rxIdx(0) {
    for (size_t i = 0; i < PACKET_SIZE; ++i) {
        rxBuf[i] = 0;
    }
}

void RS485Manager::init() {
    Serial2.begin(9600, SERIAL_8N1, RS485_RX_PIN, RS485_TX_PIN);
    #ifdef RS485_DE_RE_PIN
    pinMode(RS485_DE_RE_PIN, OUTPUT);
    digitalWrite(RS485_DE_RE_PIN, LOW);
    #endif
}

void RS485Manager::sendResponse() {
    uint8_t pkt[PACKET_SIZE];
    pkt[PKT_IDX_START] = START_BYTE;
    pkt[PKT_IDX_SRC] = SLAVE_ADDRESS;
    pkt[PKT_IDX_DEST] = 0x01; // Alamat Master
    
    // Susun status data tombol/perintah ke byte CMD dan Floor
    if (buttonMgr.emergencyPressed) {
        pkt[PKT_IDX_CMD] = CMD_EMERGENCY;
        pkt[PKT_IDX_FLOOR] = 0x01;
    } else if (buttonMgr.isDoorJogOpenHeld) {
        pkt[PKT_IDX_CMD] = CMD_JOG_DOOR_OPEN;
        pkt[PKT_IDX_FLOOR] = 0x00;
    } else if (buttonMgr.isDoorJogCloseHeld) {
        pkt[PKT_IDX_CMD] = CMD_JOG_DOOR_CLOSE;
        pkt[PKT_IDX_FLOOR] = 0x00;
    } else if (buttonMgr.pendingLightToggle) {
        pkt[PKT_IDX_CMD] = CMD_LIGHT_TOGGLE;
        pkt[PKT_IDX_FLOOR] = 0x00;
    } else if (buttonMgr.pendingCall > 0) {
        pkt[PKT_IDX_CMD] = CMD_CAR_CALL;
        pkt[PKT_IDX_FLOOR] = buttonMgr.pendingCall;
    } else if (buttonMgr.pendingDoorCmd > 0) {
        pkt[PKT_IDX_CMD] = buttonMgr.pendingDoorCmd;
        pkt[PKT_IDX_FLOOR] = 0x00;
    } else {
        pkt[PKT_IDX_CMD] = CMD_POLL_STATUS;
        pkt[PKT_IDX_FLOOR] = systemState.getFloor();
    }

    pkt[PKT_IDX_MODE] = static_cast<uint8_t>(systemState.getMode());
    pkt[PKT_IDX_DIR_FAULT] = (static_cast<uint8_t>(systemState.getDir()) & 0x0F) | (systemState.isFault() ? 0x80 : 0x00);

    const uint16_t crc = CRCManager::calculate(pkt, PACKET_SIZE - 2);
    pkt[PKT_IDX_CRC_LO] = crc & 0xFF;
    pkt[PKT_IDX_CRC_HI] = (crc >> 8) & 0xFF;

    #ifdef RS485_DE_RE_PIN
    digitalWrite(RS485_DE_RE_PIN, HIGH);
    delayMicroseconds(50);
    #endif

    Serial2.write(pkt, PACKET_SIZE);
    Serial2.flush();

    #ifdef RS485_DE_RE_PIN
    delayMicroseconds(50);
    digitalWrite(RS485_DE_RE_PIN, LOW);
    #endif
}

void RS485Manager::handleIncoming() {
    while (Serial2.available()) {
        uint8_t b = Serial2.read();
        unsigned long now = millis();

        if (now - lastByteTime > 50) {
            rxIdx = 0;
        }
        lastByteTime = now;

        if (rxIdx == 0 && b != START_BYTE) {
            continue; // Abaikan sampai ketemu Start Byte
        }

        if (rxIdx < PACKET_SIZE) {
            rxBuf[rxIdx++] = b;
        }

        if (rxIdx == PACKET_SIZE) {
            uint16_t crcRec = rxBuf[PKT_IDX_CRC_LO] | (rxBuf[PKT_IDX_CRC_HI] << 8);
            
            if (crcRec == CRCManager::calculate(rxBuf, PACKET_SIZE - 2) && rxBuf[PKT_IDX_DEST] == SLAVE_ADDRESS) {
                const bool wasFault = systemState.isFault();
                const Mode wasMode = systemState.getMode();

                systemState.setOnline(true);
                systemState.setLastRxTime(millis());

                const Mode newMode = static_cast<Mode>(rxBuf[PKT_IDX_MODE]);
                const uint8_t dirFaultByte = rxBuf[PKT_IDX_DIR_FAULT];
                const Direction newDir = static_cast<Direction>(dirFaultByte & 0x0F);
                const bool newFault = ((dirFaultByte & 0x80) != 0);
                const uint8_t newFloor = rxBuf[PKT_IDX_FLOOR];

                systemState.setMode(newMode);
                systemState.setFault(newFault);

                if (newFault && !wasFault) {
                    buzzerMgr.startEmergency();
                } else if (!newFault && wasFault) {
                    buzzerMgr.stopEmergency();
                }

                if (buttonMgr.lastCalledFloor != 0 && newFloor == buttonMgr.lastCalledFloor) {
                    buzzerMgr.trigger(2, ARRIVAL_BEEP_ON_MS, ARRIVAL_BEEP_OFF_MS);
                }

                if (newFloor >= 1 && newFloor <= TOTAL_FLOORS && newFloor < 4 && buttonMgr.isLedFloorActive(newFloor)) {
                    digitalWrite(newFloor == 1 ? LED_F1 : newFloor == 2 ? LED_F2 : LED_F3, LOW);
                    buttonMgr.setLedFloorActive(newFloor, false);
                    buttonMgr.setLedCallTimestamp(newFloor, 0);
                }

                if (newFault) {
                    buttonMgr.turnOffAllCallLEDs();
                }

                if (newFault != wasFault || newMode != wasMode) {
                    systemState.setDisplayRefreshNeeded(true);
                }

                systemState.setFloor(newFloor);
                systemState.setDir(newDir);

                // Kirim respons balik ke Master setelah menerima polling/perintah
                sendResponse();
            }
            rxIdx = 0;
        }
    }
}


// Master Side