#include <SD.h>

#define CS_PIN 10

File root;
int ledPin = 8;

String filename = "arduino.txt";

File myFile;
int myInt = -52;
float myFloat = -12.7;
String myString = "HELLO";
char myCharArray[] = "ArduinoGetStarted.com";
byte myByteArray[] = {'1', '2', '3', '4', '5'};

int knob;

void setup() {
  Serial.begin(9600);

  Serial.print("Initializing SD card... ");

  if (!SD.begin(CS_PIN)) {
    Serial.println("Card initialization failed!");
    while (true);
  }

  Serial.println("initialization done.");

  Serial.println("Files in the card:");
  root = SD.open("/");
  printDirectory(root, 0);
  Serial.println("");

  // Example of reading file from the card:
  File textFile = SD.open("wokwi.txt");
  if (textFile) {
    Serial.print("wokwi.txt: ");
    while (textFile.available()) {
      Serial.write(textFile.read());
    }
    textFile.close();
  } else {
    Serial.println("error opening wokwi.txt!");
  }

  // set the pin for the LED
  pinMode(ledPin, OUTPUT);

  // create new file by opening file for writing
  myFile = SD.open(filename, FILE_WRITE);

  if (myFile) {
    Serial.println("file opened");
    Serial.println("test");
    Serial.println(myInt);    // write int variable to SD card in line
    Serial.println(myFloat);  // write float variable to SD card in line
    Serial.println(myString); // write String variable to SD card in line
    Serial.println(myCharArray); // write char array to SD card in line
    Serial.write(myByteArray, 5);
    Serial.write("\n"); // new line

    myFile.println("test");
    myFile.println(myInt);    // write int variable to SD card in line
    myFile.println(myFloat);  // write float variable to SD card in line
    myFile.println(myString); // write String variable to SD card in line
    myFile.println(myCharArray); // write char array to SD card in line
    myFile.write(myByteArray, 5);
    myFile.write("\n"); // new line

    for (int i = 0; i < 5; i++) {
      myFile.write(myByteArray[i]); // new line

      if (i < 4)
        myFile.write(","); // comma
    }
    myFile.write("\n"); // new line
  
      // Write a set of data to the file and flash the LED
      // Run the LED and knob for 10 cycles
    for (int k = 1; k < 10; k++) {
      knob = analogRead(A0);
      myFile.println(knob);

      Serial.print("knob value = ");
      Serial.println(knob);

      digitalWrite(ledPin, HIGH);
      delay(knob);
      digitalWrite(ledPin, LOW);
      delay(knob);
    }

    myFile.close();
    Serial.println("data written");
  } else {
    Serial.print(F("SD Card: error on opening file arduino.txt"));
  }
  //}

    // Now read the data on the new file
  //if (PrintFlag) {
    myFile = SD.open(filename);

    if (myFile){
    Serial.print(filename);
    Serial.println(": opened");

      while (myFile.available()) {
        Serial.write(myFile.read());
      }
      myFile.close();
    } else {
      Serial.println("error opening file for reading!");
      } 
    Serial.println("file reading complete");
  //}

}

void loop() {
  int knob = analogRead(A0);

  Serial.println(knob);
  digitalWrite(ledPin, HIGH);
  delay(knob);
  digitalWrite(ledPin, LOW);
  delay(knob);
}

void printDirectory(File dir, int numTabs) {
  while (true) {

    File entry =  dir.openNextFile();
    if (! entry) {
      // no more files
      break;
    }
    for (uint8_t i = 0; i < numTabs; i++) {
      Serial.print('\t');
    }
    Serial.print(entry.name());
    if (entry.isDirectory()) {
      Serial.println("/");
      printDirectory(entry, numTabs + 1);
    } else {
      // files have sizes, directories do not
      Serial.print("\t\t");
      Serial.println(entry.size(), DEC);
    }
    entry.close();
  }
}