#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define CKP_PIN 8
#define CMP_PIN 9
#define POT_PIN A0
#define BUTTON_LEFT 2
#define BUTTON_RIGHT 3

const char* pulseMenus[] = {"Mitsubishi", "Toyota", "Daihatsu"};
int menuIndex = 0;
int rpm = 0;
unsigned long previousMillis = 0;

const byte mitsubishiCKP[] = {1, 0, 1, 0, 1, 0, 1, 0};
const byte mitsubishiCMP[] = {1, 0, 0, 0, 1, 0, 0, 0};
const byte toyotaCKP[] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
const byte toyotaCMP[] = {1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
const byte daihatsuCKP[] = {1, 0, 1, 0, 1, 0, 1, 0};
const byte daihatsuCMP[] = {1, 0, 0, 0, 1, 0, 0, 0};

const byte* currentCKP;
const byte* currentCMP;
int currentCKPLength;
int currentCMPLength;

void setup() {
  pinMode(CKP_PIN, OUTPUT);
  pinMode(CMP_PIN, OUTPUT);
  pinMode(BUTTON_LEFT, INPUT_PULLUP);
  pinMode(BUTTON_RIGHT, INPUT_PULLUP);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    for(;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  attachInterrupt(digitalPinToInterrupt(BUTTON_LEFT), scrollLeft, FALLING);
  attachInterrupt(digitalPinToInterrupt(BUTTON_RIGHT), scrollRight, FALLING);

  selectMenu(menuIndex);
}

void loop() {
  int potValue = analogRead(POT_PIN);
  rpm = map(potValue, 0, 1023, 0, 12000);
  unsigned long currentMillis = millis();
  
  displayInfo();

  if (rpm == 0) {
    digitalWrite(CKP_PIN, LOW);
    digitalWrite(CMP_PIN, LOW);
    return;
  }

  int period = 60000 / rpm; // period in ms for one cycle at the given RPM
  int stepTime = period / currentCKPLength;

  if (currentMillis - previousMillis >= stepTime) {
    previousMillis = currentMillis;

    static int step = 0;
    digitalWrite(CKP_PIN, currentCKP[step]);
    digitalWrite(CMP_PIN, currentCMP[step % currentCMPLength]);

    step = (step + 1) % currentCKPLength;
  }
}

void displayInfo() {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("RPM: ");
  display.print(rpm);
  display.setCursor(0, 20);
  display.print("Menu: ");
  display.print(pulseMenus[menuIndex]);
  display.display();
}

void selectMenu(int index) {
  switch (index) {
    case 0:
      currentCKP = mitsubishiCKP;
      currentCMP = mitsubishiCMP;
      currentCKPLength = sizeof(mitsubishiCKP);
      currentCMPLength = sizeof(mitsubishiCMP);
      break;
    case 1:
      currentCKP = toyotaCKP;
      currentCMP = toyotaCMP;
      currentCKPLength = sizeof(toyotaCKP);
      currentCMPLength = sizeof(toyotaCMP);
      break;
    case 2:
      currentCKP = daihatsuCKP;
      currentCMP = daihatsuCMP;
      currentCKPLength = sizeof(daihatsuCKP);
      currentCMPLength = sizeof(daihatsuCMP);
      break;
  }
}

void scrollLeft() {
  menuIndex = (menuIndex - 1 + 3) % 3;
  selectMenu(menuIndex);
}

void scrollRight() {
  menuIndex = (menuIndex + 1) % 3;
  selectMenu(menuIndex);
}