#include <Wire.h>
#include <RTClib.h>

#include <SoftwareSerial.h>
#include <ModbusMaster.h>
#include <SD.h>
#include <SPI.h>

#define SD_CS_PIN 10 // Chip Select for SD Card
//RS485 pins
#define DE_RE_PIN 4
#define RX_PIN 3     // SoftwareSerial RX pin
#define TX_PIN 2     // SoftwareSerial TX pin
#define SLAVE_ID 101

RTC_DS3231 rtc; // Create an RTC object
File dataFile;
SoftwareSerial modbusSerial(RX_PIN, TX_PIN); // Create a software serial instance
ModbusMaster node;

void setup()
{
    Serial.begin(9600); // For debugging
    Serial.println("Startup \n");

    // Initialize RTC
    if (!rtc.begin())
    {
        Serial.println("Couldn't find RTC\n");
    }

    if (rtc.lostPower())
    {
        Serial.println("RTC lost power, let's set the time!\n");
        // Comment out the following line once the time is set to avoid resetting on every start
        rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    }
    
    Serial.print("Time: ");
    Serial.print(rtc.now().timestamp());
    Serial.println("\n");

    // Initialize SD card
    Serial.println("SD card initializing...");
    pinMode(SD_CS_PIN, OUTPUT);
    
    if (!SD.begin(SPI_HALF_SPEED, SD_CS_PIN ))
    {
        Serial.println("SD card initialization failed!\n");
        return;
    }
    Serial.println("SD card initialized.\n");

    Serial.println("Initialize RS485 module / Modbus \n");
    

    pinMode(DE_RE_PIN, OUTPUT);
    digitalWrite(DE_RE_PIN, LOW); // Set to LOW for receiving mode initially

    modbusSerial.begin(9600 );
//
//    while (!modbusSerial) {
//    }
    node.begin(SLAVE_ID, modbusSerial); 
    node.preTransmission(preTransmission);
    node.postTransmission(postTransmission);
}

void preTransmission()
{
  digitalWrite(DE_RE_PIN, HIGH); // Enable RS485 transmit
}

void postTransmission()
{
  digitalWrite(DE_RE_PIN, LOW); // Disable RS485 transmit
}


void writeFile(char *str)
{
    if (!dataFile)
    {
        Serial.println("Error opening file");
        return;
    }
    DateTime now = rtc.now();
    // Log the current date and time
    dataFile.print(now.year(), DEC);
    dataFile.print('-');
    dataFile.print(now.month(), DEC);
    dataFile.print('-');
    dataFile.print(now.day(), DEC);
    dataFile.print(" ");
    dataFile.print(now.hour(), DEC);
    dataFile.print(':');
    dataFile.print(now.minute(), DEC);
    dataFile.print(':');
    dataFile.print(now.second(), DEC);
    dataFile.print(",");
    dataFile.print(str);

    dataFile.println();
}

String getFilename()
{
    DateTime now = rtc.now();
    String mb = "";
    mb += now.year();
    mb += now.month();
    mb += now.day();
    mb += ".csv";

    return mb;
}
static unsigned long lastRefreshTime = 0;
void loop()
{
     uint8_t result = result = node.readHoldingRegisters(2705 , 2);

    // Check if the read was successful
    if (result == node.ku8MBSuccess)
    {
      Serial.print("Read successful: ");

    } else {
      Serial.print("Read error: ");
      Serial.println(result, HEX);
    }




    if(millis() - lastRefreshTime >= 1000)
    {
      lastRefreshTime += 1000;

      Serial.print("Time: ");
      Serial.print(rtc.now().timestamp());
      //   Serial.print("\nHeep:");
      //  Serial.print(ESP.getFreeHeap());
      Serial.print("\n");
  
      // Open file for writing
      String filename = getFilename();
      Serial.print("Open Card ");
      Serial.print(filename.c_str());
      Serial.print("\n");
  
      dataFile = SD.open(filename.c_str(), FILE_WRITE);
  
  
      if (dataFile)
      {
          dataFile.close(); // Close the file
          Serial.print("Data written to SD card: ");
          Serial.print(filename.c_str());
          Serial.print("\n");
      }
  
      Serial.print("\n\n");
      
    }
}