#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <RTClib.h>
#include <SPI.h>
#include <SD.h>

#define SCREEN_WIDTH 128 // Largura do display em pixels
#define SCREEN_HEIGHT 64 // Altura do display em pixels
#define OLED_RESET -1    // Pino de reset do OLED (-1 se não for usado)
#define LED_PIN 2        // Pino do LED integrado no ESP32

boolean state = false;      // Variável global para o estado do LED
unsigned long previousMillis = 0; // Armazena o tempo da última mudança de estado
const long interval = 1000; // Intervalo de 1 segundo para piscar o LED

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
RTC_DS1307 rtc;

File myFile;
const int CS = 5;

/*
SD Card pinout:

DO/MISO - pin 23
DI/MOSI - pin 19
SCK/CLK - pin 18
CS - pin 5

*/
void setup() {
  Serial.begin(115200);
  Serial.println("Iniciando...");

  // Configura o LED como saída
  pinMode(LED_PIN, OUTPUT);

  // Inicialização do display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Endereço I2C 0x3C para display 128x64
    Serial.println(F("Erro ao iniciar o display SSD1306"));
    for (;;); // Loop infinito em caso de erro
  }
  Serial.println("Display ok!");

  if (!rtc.begin()) {
    Serial.println("Erro ao inicializar o RTC.");
    display.println("Erro RTC");
    display.display();
    while (1);
  }

  Serial.begin(9600);    // Set serial baud rate to 9600
  delay(500);
  while (!Serial) { ; }  // wait for serial port to connect. Needed for native USB port only
  Serial.println("Initializing SD card...");
  if (!SD.begin(CS)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
  
  WriteFile("/test.txt", "Ok!");
  ReadFile("/test.txt");

}

void loop() {
  DateTime now = rtc.now();  

  // Pisca o LED lentamente
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis; // Atualiza o tempo da última mudança
    state = !state;                 // Alterna o estado do LED
    digitalWrite(LED_PIN, state ? HIGH : LOW);
  }
  
  // Limpa o display
  display.clearDisplay();

  // Configura o texto a ser exibido
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  char dateStr[11]; // "dd/mm/yyyy" = 10 chars + 1 para o terminador null
  sprintf(dateStr, "%02d/%02d/%04d", now.day(), now.month(), now.year());
  display.println(dateStr);
  display.setTextSize(2);
  display.setCursor(0, 20);
  char timeStr[9]; // "hh:mm:ss" = 8 chars + 1 para o terminador null
  sprintf(timeStr, "%02d:%02d:%02d", now.hour(), now.minute(), now.second());
  display.println(timeStr);
  display.display(); // Atualiza o display para mostrar o texto
  
}

////////////////////////////////
void WriteFile(const char * path, const char * message){
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  myFile = SD.open(path, FILE_WRITE);
  // if the file opened okay, write to it:
  if (myFile) {
    Serial.printf("Writing to %s ", path);
    myFile.println(message);
    myFile.close(); // close the file:
    Serial.println("completed.");
  } 
  // if the file didn't open, print an error:
  else {
    Serial.println("error opening file ");
    Serial.println(path);
  }
}


void ReadFile(const char * path){
  // open the file for reading:
  myFile = SD.open(path);
  if (myFile) {
     Serial.printf("Reading file from %s\n", path);
     // read from the file until there's nothing else in it:
    while (myFile.available()) {
      Serial.write(myFile.read());
    }
    myFile.close(); // close the file:
  } 
  else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }
}