#include <Arduino.h>
#include <U8g2lib.h> // u8g2 library is used to draw graphics on the OLED display
#include <Wire.h> // library required for IIC communication

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // initialization for the 128x64px OLED display
//U8G2_SSD1306_128X32_UNIVISION_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // initialization for the 128x32px OLED display, [full framebuffer, size = 512 bytes]
int str_width; // calculated width of the string
char buffer[20]; // helper buffer for displaying strings on the display


void setup(void) {
  u8g2.begin(); // start the u8g2 library
  pinMode(A0, INPUT); // set the analog input pin A0 as input
  Serial.begin(9600); // open the serial port at 9600 bps:

}

void loop(void) {

  int val = analogRead(0);
  int oil =  map(val, 0, 1023, -45, 225);
  Serial.print(oil);
  Serial.print("   ");

  double sinus = sin(radians(oil));
  double cosin = cos(radians(oil));

  double sinuspfeil1 = sin(radians(oil+90));
  double sinuspfeil2 = sin(radians(oil-90));
  double cosinpfeil1 = cos(radians(oil+90));
  double cosinpfeil2 = cos(radians(oil-90));
  Serial.print(sinus);
  Serial.print("   ");
  Serial.println(cosin);



  u8g2.setDrawColor(1); // set the drawing color to white


  u8g2.clearBuffer();
  u8g2.setFontMode(1);
  u8g2.setBitmapMode(1);
  u8g2.setFont(u8g2_font_ncenB08_tr);
  sprintf(buffer, "%d", oil); // convert compass degree integer to string, add the ' symbol that (somehow) looks like degree symbol (degree symbol is not present in the font)
  str_width = u8g2.getStrWidth(buffer); // calculate the string width
  u8g2.drawStr(64 - str_width / 2, 60, buffer); // draw centered string
 // u8g2.drawStr(56, 60, oil);
  u8g2.drawEllipse(62, 31, 31, 31);
  //u8g2.drawLine(62, 31, 62, 5);
  u8g2.drawLine(62, 31, 62+(-cosin*27), 31-(sinus*27));
  u8g2.drawLine(62, 31, 62+(-cosinpfeil1*2), 31-(sinuspfeil1*2));
  u8g2.drawLine(62, 31, 62+(-cosinpfeil2*2), 31-(sinuspfeil2*2));

  u8g2.drawLine(62+(-cosinpfeil1*2), 31-(sinuspfeil1*2), 62+(-cosin*27), 31-(sinus*27));
  u8g2.drawLine(62+(-cosinpfeil2*2), 31-(sinuspfeil2*2), 62+(-cosin*27), 31-(sinus*27));

  u8g2.sendBuffer();


}