#include <SD.h>
#define CS_PIN 5
File Myfile;

void listDir(String Path)
{
  Serial.printf("Listing directory: %s\n", Path);

  File root;
  root = SD.open(Path);
  if (!root)
  {
    Serial.println("Failed to open directory");
    return;
  }
  if (!root.isDirectory())
  {
    Serial.println("Not a directory");
    return;
  }

  File file = root.openNextFile();
  while (file)
  {
    if (file.isDirectory())
    {
      Serial.print("  DIR : ");
      Serial.println(file.name());
    }
    else
    {
      Serial.print("  FILE: ");
      Serial.print(file.name());
      Serial.print("  SIZE: ");
      Serial.println(file.size());
    }
    file = root.openNextFile();
  }
}

String Encryption(String Value)
{
  Serial.println(Value);
  char Key = 'Q';
  int length = Value.length();
  for (int i = 0; i < length; i++)
  {
    Value[i] = (Value[i] ^ Key);
  }
  return Value;
}


String ReadFile(String filename)
{
  if (!SD.exists(filename))
  {
    return "";
  }
  Myfile.setTimeout(10000);
  Myfile = SD.open(filename, FILE_READ);
  if (Myfile.available())
  {
    String read_data = Myfile.readString();
    Myfile.close();
    return read_data;
  }
}

String format_file_name(String filename)
{
  filename.trim();
  if (!filename.startsWith("/"))
  {
    filename = "/" + filename;
  }
  if (!filename.endsWith(".txt"))
  {
    filename = filename + ".ino";
  }
  return filename;
}

void print_on_serial(String Orignal_Data, String Modified_Data, String filename,String flag) {
  if (Orignal_Data == "")
  {
    Serial.printf("%s Dosen`t exist", filename);
  }
  else
  {
    if (flag[0] == 'r')
    {
      Serial.print("\n-----------------------------------------------\n");
      Serial.print("\nData From File is:");
      Serial.print(Orignal_Data);
      Serial.print("\nResult Data is :");
      Serial.print(Modified_Data);
      Serial.print("\n-----------------------------------------------\n");
    }
    else if (flag[0] == 'w')
    {
      Serial.print("\n-----------------------------------------------\n");
      Serial.print("\nSerial Input is : ");
      Serial.print(Orignal_Data);
      Serial.print("\nData : ");
      Serial.print(Modified_Data);
      Serial.print("\nSaved in :");
      Serial.print(filename);
      Serial.print("\n-----------------------------------------------\n");
    }
  }
}

boolean WriteFile(String filename, String Input)
{

  Serial.printf("Writing file: %s\n", filename);

  File file = SD.open(filename, FILE_WRITE);
  if (!file)
  {
    Serial.println("Failed to open file for writing");
    return false;
  }
  if (file.print(Input))
  {
    Serial.println("File written");
    return true;
  }
  else
  {
    Serial.println("Write failed");
    return false;
  }
  file.close();
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.setTimeout(600);
  Serial.print("Initializing SD card... ");
  if (!SD.begin(CS_PIN)) {
    Serial.println("Card initialization failed!");
    while (true);
  }
  Serial.println("\ninitialization done.");
  listDir("/");
}

void loop() {

  while (Serial.available() > 0) {
    String S_input = Serial.readString();
    Serial.println(S_input);
    int edrt = S_input.indexOf("@");
    int didx = S_input.indexOf("@", edrt + 1 );
    String Mode = S_input.substring(0, edrt);
    Mode.toLowerCase();
    String F_name = S_input.substring(edrt + 1, didx);
    String In_Da = S_input.substring(didx + 1, S_input.length());
    In_Da.trim();
    Mode.trim();
    String F_F_name = format_file_name(F_name);
    if (Mode[0] == 'r' || Mode[3] == 'd') {
      String Read_Data = ReadFile(F_F_name);
      String Result = Encryption(Read_Data);
      print_on_serial(Read_Data,Result,F_name,Mode);
    }
    if (Mode[0] == 'w' || Mode[4] == 'e') {
      String Data_After_Encrypt = Encryption(In_Da);
      boolean wrtn = WriteFile(F_F_name,Data_After_Encrypt);
      if(!wrtn){
        Serial.println("We can`t Write Data in file!");
      }
      print_on_serial(In_Da,Data_After_Encrypt,F_F_name,Mode);
    }
  }



  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
}