#include <Arduino.h>
#include <U8g2lib.h>
#include <Wire.h>
#include <RotaryEncoder.h>

U8G2_SH1106_128X64_NONAME_F_HW_I2C U8G2(U8G2_R0, 5, 4, U8X8_PIN_NONE);

int values[120];                                            // array for sine values
int buffer[120];                                            // buffer array used to shift sine values


void initArrays(void){
// fill arrays
for (int i = 0; i < 120; i++){
    float angle = i * 3;                                    // 3 * 120 = 360
    values[i] = (32 + (sin(angle * (M_PI / 180)) * 30));    // values shifted upwards by 32 for easier visualization
    buffer[i] = values[i];                                  // initialize buffer with the same values
  }
}

RotaryEncoder encoder(D9,D8);
#define pinSW D7
int menu = 1; 
int pos = 0;
int16_t value;
int16_t sens1 = 0;
int16_t sens2 = 0;
int16_t sens3 = 0;
int min_s1 = 530;
int max_s1 = 240;
int min_s2 = 530;
int max_s2 = 240;
int min_s3 = 530;
int max_s3 = 240;

void setup() { 
  Wire.begin();
  U8G2.begin();
  initArrays();
  pinMode (pinSW,INPUT);
  pinMode (D8,INPUT);
  pinMode (D9,INPUT);
  encoder.setPosition(1);
  Serial.begin(9600);
  updateMenu();  
} 

void loop() { 
  updateEncoder();
  executeSerial();
}

void updateEncoder(){
  encoder.tick();
  menu = encoder.getPosition();

  if(pos != menu){
  pos = menu;
  updateMenu();
}

  if(!digitalRead(pinSW)){
  executeAction();
  delay(200);
  updateMenu();
  }
  
}

int getValue(int sens){
  byte a,b;
  Wire.requestFrom(sens, 2);

  a = Wire.read();
  b = Wire.read();

  value = a;
  value = value << 8 | b;
  
  return value;
}

 void graph(){

    U8G2.drawVLine(0, 0, 64);                               // draw Y-axis
    U8G2.drawHLine(0, 63, 128);                             // draw X-axis
    
    if(!digitalRead(pinSW)){
      menu = 0;
      updateMenu();
    }

    executeSerial();

  sens1 = map(getValue(2),240,550,60,0);
    
    for (int j = 0 ; j < 120; j++){
      values[j] = buffer[j];                                // transfer values from buffer to output array
      U8G2.drawPixel(j+4, values[j]);                       // draw the sine wave with values from the array shifted 4 pixels to the right
    }
      U8G2.sendBuffer();
      U8G2.clearBuffer();
    for (int x = 0 ; x < 120; x++){                         // loop array via buffer
      if(x-1 < 0){
        buffer[x] = sens1;
      } else {
      buffer[x] = values[x-1];
      }
    }
  }

  void displaySensors() {
    
    if(!digitalRead(pinSW)){
      menu = 0;
      updateMenu();
    }

    executeSerial();

    U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setCursor(0, 20);
      U8G2.print("Sensor 1: ");
      U8G2.setCursor(64, 20);
      U8G2.print(getValue(2));
      U8G2.setCursor(0, 40);
      U8G2.print("Sensor 2: ");
      U8G2.setCursor(64, 40);
      U8G2.print(getValue(3));
      U8G2.setCursor(0, 60);
      U8G2.print("Sensor 3: ");
      U8G2.setCursor(64, 60);
      U8G2.print(getValue(4));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
  }

  void executeSerial(){
      char c = Serial.read();

      if(c == 'g') {
        menu = 1;
        updateMenu();
        executeAction();
      }

      if(c == 'c') {
        menu = 2;
        executeAction();
      }

      if(c == 'v') {
        menu = 3;
        executeAction();
      }

      if(c == 'm') {
        menu = 0;
      updateMenu();
      }
  }

  void calibrate() {

    if(!digitalRead(pinSW)){
      menu = 0;
      updateMenu();
    }

    executeSerial();
    
    do {
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 1");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MIN" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(2));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    min_s1 = getValue(2);
    delay(500);

    executeSerial();

    do{
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 1");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MAX" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(2));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    max_s1 = getValue(2);
    delay(500);

    executeSerial();

    do {
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 2");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MIN" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(3));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    min_s2 = getValue(3);
    delay(500);

    executeSerial();

    do{
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 2");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MAX" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(3));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    max_s2 = getValue(3);
    delay(500);

    executeSerial();

    do {
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 3");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MIN" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(4));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    min_s3 = getValue(4);
    delay(500);

    executeSerial();

    do{
      U8G2.setFont(u8g2_font_t0_11_tr);
      U8G2.setFontPosCenter();
      U8G2.setCursor(10, 10);
      U8G2.print("CALIBRATE SENSOR 3");
      U8G2.setFont(u8g2_font_t0_22_mf);
      U8G2.setFontPosBaseline();
      U8G2.drawButtonUTF8(15, 50, U8G2_BTN_INV, 0,  2,  2, "MAX" );
      U8G2.setCursor(65, 50);
      U8G2.print(getValue(4));
      U8G2.sendBuffer();
      U8G2.clearBuffer();
      executeSerial();
    } while(digitalRead(pinSW));
    max_s3 = getValue(4);

    executeSerial();
  }

 void updateMenu() {
  switch (menu) {

    case 0:
      delay(200);
      menu = 1;
      encoder.setPosition(1);
      break;

    case 1:
      U8G2.clearDisplay();
      U8G2.setFont(u8g2_font_ncenB14_tr);
      U8G2.setCursor(0, 25);
      U8G2.print(">Graph");
      U8G2.setCursor(0, 55);
      U8G2.print("  Calibrate");
      U8G2.sendBuffer();
      break;

    case 2:
      U8G2.clearDisplay();
      U8G2.setFont(u8g2_font_ncenB14_tr);
      U8G2.setCursor(0, 25);
      U8G2.print("  Graph");
      U8G2.setCursor(0, 55);
      U8G2.print(">Calibrate");
      U8G2.sendBuffer();
      break;

    case 3:
      U8G2.clearDisplay();
      U8G2.setFont(u8g2_font_ncenB14_tr);
      U8G2.setCursor(0, 25);
      U8G2.print(">Display Sensors");
      U8G2.setCursor(0, 55);
      U8G2.print("  Easteregg");
      U8G2.sendBuffer();
      break;

    case 4:
      U8G2.clearDisplay();
      U8G2.setFont(u8g2_font_ncenB14_tr);
      U8G2.setCursor(0, 25);
      U8G2.print("  Display Sensors");
      U8G2.setCursor(0, 55);
      U8G2.print(">Easteregg");
      U8G2.sendBuffer();
      break;

    case 5:
      menu = 4;
      encoder.setPosition(4);
      break;
  }
}

void executeAction() {
  switch (menu) {

    case 1:
      U8G2.clearDisplay();
      delay(500);
      while(digitalRead(pinSW)) {
      graph();
    }
      break;

    case 2:
    U8G2.clearDisplay();
    delay(500);
    while(digitalRead(pinSW)){
      calibrate();
    }
      break;

    case 3:
    U8G2.clearDisplay();
    delay(500);
    while(digitalRead(pinSW)){
      displaySensors();
    }
      break;

    case 4:
    U8G2.clearDisplay();
    delay(500);
    while(digitalRead(pinSW)){
      U8G2.setFont(u8g2_font_t0_11b_tr);
      U8G2.setCursor(0, 10);
      U8G2.print("Hollow Knight");
      U8G2.setCursor(0, 36);
      U8G2.print("Silksong");
      U8G2.setCursor(0, 62);
      U8G2.print("THIS YEAR!!!");
      U8G2.sendBuffer();
    }
      break;
  }
}