//Libraries
#include <Wire.h>
#include <U8g2lib.h> 

//Select the option that matches the dimensions of the OLED
U8G2_SSD1306_128X64_NONAME_F_HW_I2C DISPA(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

//Pins for SDA and SCL
#define SDA 4  
#define SCL 5

//Pin numbers
int LED = D9;
int JoyX = A2;
int JoyY = A1;

//Create string variable to show direction message in display
String Direction = "Hello";

//---------------------------------------------------------------------------------

void setup() {
  //Turn on serial monitor
  Serial.begin(9600);
  //LED
  pinMode(LED, OUTPUT);

  //Joystick pinout
  pinMode(JoyX, INPUT);
  pinMode(JoyY, INPUT);
  
  //SDA and SCL pinout
  pinMode(SDA, OUTPUT);  
  pinMode(SCL, OUTPUT);
  // Set I2C bus speed on board and both displays
  Wire.setClock(100000);
  DISPA.setBusClock(100000);
  //Set I2C Adress (0x78/0x7A, or 0x3C/0x3D)
  DISPA.setI2CAddress(0x78);
  //Turn on OLED and get it ready to accept data
  DISPA.begin();
  //Select a font
  DISPA.setFont(u8g2_font_logisoso16_tf );
  //Make sure the display buffer is clear
  DISPA.clearBuffer();
}

//---------------------------------------------------------------------------------
//Function to enter joystick values and know the direction
int signal(int a, int b) { //(X,Y)
  if((a>=490 && a<=494)&&(b>=468 && b<=474)){ //STOP
    return 0; //#s for each direction, bc Arduino IDE's functions don't return strings
  }
  else if (a==511){ //UP
    return 1;
  }
  else if(a==0){ //DONW
    return 2;
  }
  else if(b==0){ //LEFT
    return 3;
  }
  else if(b==511){ //RIGHT
    return 4;
  }
}
//---------------------------------------------------------------------------------

void loop() {
//Clear display
  DISPA.clearBuffer();
//LED and read analog values from joystick
  digitalWrite(LED, HIGH);
  int ValorX = analogRead(JoyX)/8;
  int ValorY = analogRead(JoyY)/8;
//Show things in display
  DISPA.setCursor(25, 20); //(X,Y)
  DISPA.print("Joystick");
  DISPA.setCursor(5, 40); //(X,Y)
  DISPA.print("X: ");
  DISPA.setCursor(25, 40); //(X,Y)
  DISPA.print(ValorX);
  DISPA.setCursor(75, 40); //(X,Y)
  DISPA.print("Y: ");
  DISPA.setCursor(95, 40); //(X,Y)
  DISPA.print(ValorY);
//Enter analog values into the function to know direction
  int DirNumb = signal(ValorX, ValorY);
//Assign string values to each value from the function
  if(DirNumb == 0){
    Direction = "STOP";
  }
  else if(DirNumb == 1){
    Direction = "UP";
  }
  else if(DirNumb == 2){
    Direction = "DOWN";
  }
  else if(DirNumb == 3){
    Direction = "LEFT";
  }
  else if(DirNumb == 4){
    Direction = "RIGHT";
  }
  DISPA.setCursor(50, 60); //(X,Y)
  DISPA.print(Direction); //Print the direction in OLED
  DISPA.sendBuffer(); //Command to show things on display
}