// Include necessary libraries for SD card and HX711
#include "FS.h"
#include "SD.h"
#include "SPI.h"
#include "Adafruit_HX711.h"

// Define SD card pins
#define SD_MOSI     23
#define SD_MISO     19
#define SD_SCLK     18
#define SD_CS       5

// Define other hardware pins
#define LED_PIN     2
#define SWITCH_PIN  32

// Define HX711 pins
#define HX711_DATA_PIN 26
#define HX711_CLOCK_PIN 27

Adafruit_HX711 hx711(HX711_DATA_PIN, HX711_CLOCK_PIN);  // HX711 object

int filenumber = 0;          // To track file names for each session
File myFile;                 // File object to manage SD card files
bool isWriting = false;      // Flag to check if data is being written

void setup() {
  // Serial communication initialization
  Serial.begin(115200);

  // Set LED and switch pins
  pinMode(LED_PIN, OUTPUT);
  pinMode(SWITCH_PIN, INPUT);

  // Wait for serial connection
  while (!Serial) {
    delay(10);
  }

  Serial.println("Setup start");

  // Initialize SPI for SD card
  SPI.begin(SD_SCLK, SD_MISO, SD_MOSI, SD_CS);

  // Mount SD card
  if (!SD.begin(SD_CS)) {
    Serial.println("SD Card MOUNT FAIL");
  } else {
    Serial.println("SD Card MOUNT SUCCESS");
    digitalWrite(LED_PIN, HIGH);  // Turn on LED when SD card is mounted
    Serial.println("");
    delay(100);
    uint32_t cardSize = SD.cardSize() / (1024 * 1024);
    Serial.println("SDCard Size: " + String(cardSize) + "MB");
    
  }

  // Initialize HX711 for strain gauge
  hx711.begin();

  // Tare the scale (zero out the readings)
  Serial.println("Tareing...");
  for (uint8_t t = 0; t < 3; t++) {
    hx711.tareA(hx711.readChannelRaw(CHAN_A_GAIN_128));
    hx711.tareB(hx711.readChannelRaw(CHAN_B_GAIN_32));
    hx711.tareB(hx711.readChannelRaw(CHAN_B_GAIN_32));
    hx711.tareB(hx711.readChannelRaw(CHAN_B_GAIN_32));
  }

  Serial.println("Setup complete");
  pinMode(SWITCH_PIN, INPUT);
}

void loop() {
  // Check the state of the switch
  int switchState = digitalRead(SWITCH_PIN);

  // Start writing data to SD card if switch is pressed
  if (switchState == HIGH) {
    if (!isWriting) {
      // Generate a new file name for each session
      String fileName = "data" + String(filenumber) + ".csv";
      //char fileName[15];
      //sprintf(fileName, "data%d.csv", filenumber);

      Serial.println("Attempting to create a new file...");
      delay(100);
      myFile = SD.open(fileName, FILE_WRITE);
      
      if (myFile) {
        Serial.println("Started writing to " + fileName);
        isWriting = true;
      } else {
        Serial.println("Error opening " + fileName);
      }
    }

    // Poll strain gauge data and write to the SD card
    if (isWriting) {
      // Read strain data from HX711 (Channel A with Gain 128)
      int32_t strainValueA = hx711.readChannelBlocking(CHAN_A_GAIN_128);
      int32_t strainValueB = hx711.readChannelBlocking(CHAN_B_GAIN_32);

      // Log strain data to the SD card
      myFile.print("Strain A (Gain 128): ");
      myFile.print(strainValueA);
      myFile.print(", Strain B (Gain 32): ");
      myFile.println(strainValueB);

      // Print data to serial monitor for debugging
      Serial.print("Strain A (Gain 128): ");
      Serial.print(strainValueA);
      Serial.print(", Strain B (Gain 32): ");
      Serial.println(strainValueB);

      delay(50);  // Delay to control logging rate
    }

  } else {
    // Stop writing if the switch is released
    if (isWriting) {
      myFile.close();  // Close the file
      Serial.println("File saved and closed.");
      filenumber++;    // Increment file number for next session
      isWriting = false;  // Reset writing flag
    }
  }

  delay(100);  // Short delay for stability in the loop
}