byte st =0; //variable que controla la pantalla en la que se encuentra
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <U8g2_for_Adafruit_GFX.h>
#include <SoftwareSerial.h>
U8G2_FOR_ADAFRUIT_GFX u8g2_for_adafruit_gfx;

#define DISTANCE_THRESHOLD 100  // Distance threshold in centimeters to switch display medium
#define OLED_RESET -1
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define MODE_CHANGE_INTERVAL 200  // Change mode every 10 seconds
#define EMIC_START_CHAR 0xFE      // Start character for Emic 2

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

void setup() {
  pinMode(13, OUTPUT);
  pinMode(2, INPUT_PULLUP); // SELECT
  pinMode(4, INPUT_PULLUP); // UP
  pinMode(7, INPUT_PULLUP); // DOWN
  Serial.begin(9600);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  u8g2_for_adafruit_gfx.begin(display);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true) {
      digitalWrite(13, 1); delay(400);
      digitalWrite(13, 0); delay(400);
    }
  }

  display.clearDisplay();
  u8g2_for_adafruit_gfx.setFont(u8g2_font_luBS08_te);
  u8g2_for_adafruit_gfx.setCursor(26,36);
  u8g2_for_adafruit_gfx.print(F("iBienvenido!"));
  display.display();
  delay(1000);
  oledPrincipal0();
}

/*Como los botones (up,down,select) funcionan dentro del menu y no tienen otra funcion exclusiva
Se puede tomar solo la lectura de sus pines en lugar de crearles una variable donde almacenar
su informacion. */

void loop() {
  //OPT 1
  if (!digitalRead(7) && st==0){oledPrincipal1();delay(100);}
  if (!digitalRead(7) && st==1){oledPrincipal2();delay(100);}
  if (!digitalRead(4) && st==1){oledPrincipal0();delay(100);}
  if (!digitalRead(4) && st==2){oledPrincipal1();delay(100);}
  if (!digitalRead(2) && st==0){oledopt1_0();delay(100);}
  if (!digitalRead(2) && st==1){oledopt2_0();delay(100);}
  if (!digitalRead(2) && st==2){oledopt3_0();delay(100);}

  //OPT 2
  if (!digitalRead(7) && st==4){oledopt2_1();delay(100);}
  if (!digitalRead(7) && st==6){oledopt2_2();delay(100);}
  if (!digitalRead(4) && st==6){oledopt2_0();delay(100);}
  if (!digitalRead(4) && st==8){oledopt2_1();delay(100);}
  if (!digitalRead(2) && st==4){oledopt2_00();delay(100);}
  if (!digitalRead(2) && st==6){oledopt2_10();delay(100);}
  if (!digitalRead(2) && st==5){oledopt2_0();delay(100);}
  if (!digitalRead(2) && st==7){oledopt2_1();delay(100);}
  if (!digitalRead(2) && st==8){oledPrincipal1();delay(100);}
}

void oledPrincipal0(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(5,10);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("> Abrir guante"));
  u8g2_for_adafruit_gfx.setCursor(20,25);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("  Medir distancia"));
  u8g2_for_adafruit_gfx.setCursor(20,40);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("    Configuracion"));
  display.display();
  st = 0;
}
void oledPrincipal1(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(20,10);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("      Abrir guante"));
  u8g2_for_adafruit_gfx.setCursor(5,25);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("> Medir distancia"));
  u8g2_for_adafruit_gfx.setCursor(20,40);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("    Configuracion"));
  display.display();
  st = 1;
}
void oledPrincipal2(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(20,10);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("      Abrir guante"));
  u8g2_for_adafruit_gfx.setCursor(20,25);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("  Medir distancia"));
  u8g2_for_adafruit_gfx.setCursor(5,40);                // start writing at this position
  u8g2_for_adafruit_gfx.print(F("> Configuracion"));
  display.display();
  st = 2;
}

void oledopt1_0(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(12,40);
  u8g2_for_adafruit_gfx.print(F("Abriendo guante"));
  display.display();
  st = 3;
}

void oledopt2_0(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(0,15);
  u8g2_for_adafruit_gfx.print(F("> Medicion promedio"));
  u8g2_for_adafruit_gfx.setCursor(0,35);
  u8g2_for_adafruit_gfx.print(F("Medicion constante"));
  u8g2_for_adafruit_gfx.setCursor(0,55);
  u8g2_for_adafruit_gfx.print(F("Volver"));
  display.display();
  st = 4;
}
void oledopt2_00(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(5,20);
  u8g2_for_adafruit_gfx.print(F("Tomando medicion"));
  u8g2_for_adafruit_gfx.setCursor(5,40);
  u8g2_for_adafruit_gfx.print(F(" # # # # #"));
  display.display();
  st = 5;
}
void oledopt2_1(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(0,15);
  u8g2_for_adafruit_gfx.print(F("Medicion promedio"));
  u8g2_for_adafruit_gfx.setCursor(0,35);
  u8g2_for_adafruit_gfx.print(F("> Medicion constante"));
  u8g2_for_adafruit_gfx.setCursor(0,55);
  u8g2_for_adafruit_gfx.print(F("Volver"));
  display.display();
  st = 6;
}
void oledopt2_10(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(12,20);
  u8g2_for_adafruit_gfx.print(F("Medicion obtenida"));
  u8g2_for_adafruit_gfx.setCursor(12,40);
  u8g2_for_adafruit_gfx.print(F("cm plg"));
  display.display();
  st = 7;
}
void oledopt2_2(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(0,15);
  u8g2_for_adafruit_gfx.print(F("Medicion promedio"));
  u8g2_for_adafruit_gfx.setCursor(0,35);
  u8g2_for_adafruit_gfx.print(F("Medicion constante"));
  u8g2_for_adafruit_gfx.setCursor(0,55);
  u8g2_for_adafruit_gfx.print(F("> Volver"));
  display.display();
  st = 8;
}

void oledopt3_0(){
  display.clearDisplay();
  u8g2_for_adafruit_gfx.setCursor(12,15);
  u8g2_for_adafruit_gfx.print(F("> Idioma"));
  u8g2_for_adafruit_gfx.setCursor(0,35);
  u8g2_for_adafruit_gfx.print(F("Unidad de medida"));
  display.display();
  st = 9;
}