#include <SPI.h>
#include <Wire.h>
#include <U8g2lib.h>
#include <TimerOne.h>

#include "globals.h"
#include "Out.h"

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0x3C
#define CLK 2
#define DT 3


U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);

byte play = 1;
byte BPM = 100;

unsigned long minute = 60000000L;
byte ppqn = 96;
unsigned long period = (minute / BPM) / ppqn;

volatile boolean beatToggle = false;

Out out1(4);
Out out2(5);
Out out3(6);
Out out4(7);
Out out5(8);
Out out6(9);
Out out7(10);
Out out8(11);

byte btnPin = 13;
byte btnState = 0;

volatile long rPotPos = 0;
unsigned long rPotLastUpdate = 0;
const unsigned long rPotThrottle = 50;

unsigned long screenLastUpdate = 0;
const unsigned long screenThrottle = 200;
byte forceScreenUpdate = 1;


void setup() {
  Serial.begin(9600);

  pinMode(btnPin, INPUT_PULLUP);
  
  // rotary encoder set up
  pinMode(CLK, INPUT_PULLUP);
  pinMode(DT, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(CLK), updateEncoder, FALLING);

  // screen setup
  u8g2.begin();

  // display.clearDisplay();
  // display.setTextSize(2);
  // display.setTextColor(WHITE);
  // display.setCursor(0, 0);
  //
  // String bpmString = "BPM: ";
  // String bpmCalculatedString = bpmString + BPM;
  // display.println(bpmCalculatedString);
  //
  // display.display();

  // init timer
  Timer1.initialize(1000000);
  Timer1.attachInterrupt(clock);
  Timer1.setPeriod(period);

  // init outputs
  out1.setLen(period);
  out2.setLen(period);
  out3.setLen(period);
  out4.setLen(period);
  out5.setLen(period);
  out6.setLen(period);
  out7.setLen(period);
  out8.setLen(period);

  // manual setup
  out1.setDiv(8, 0);
  out1.setWidth(50);

  out2.setDiv(4, 0);
  out2.setWidth(50);

  out3.setDiv(2, 0);
  out3.setWidth(50);

  out4.setDiv(1);
  out4.setWidth(50);

  out5.setDiv(2);
  out5.setWidth(50);

  out6.setDiv(4);
  out6.setWidth(50);

  out7.setDiv(8);
  out7.setWidth(50);

  out8.setDiv(16);
  out8.setWidth(50);
}

void clock(void) {
  if (play == 1) {
    beatToggle = true;
  }
}

void loop() {
  if (beatToggle) {
    out1.turnOn();
    out2.turnOn();
    out3.turnOn();
    out4.turnOn();
    out5.turnOn();
    out6.turnOn();
    out7.turnOn();
    out8.turnOn();

    beatToggle = false;
  }

    out1.turnOff();
    out2.turnOff();
    out3.turnOff();
    out4.turnOff();
    out5.turnOff();
    out6.turnOff();
    out7.turnOff();
    out8.turnOff();

    checkBtn();
    checkRPot();
    updateScreen();
}

void updateScreen() {
  unsigned long currentTime = millis();
  if (currentTime - screenLastUpdate >= screenThrottle && forceScreenUpdate == 1) {
    screenLastUpdate = currentTime;
    forceScreenUpdate = 0;
    // The firstPage()/nextPage() loop manages where the drawing commands go
    u8g2.firstPage();
    do {
      // --- Drawing Commands for the CURRENT Page ---
      // All drawing commands must live INSIDE this do/while loop.
      u8g2.setFont(u8g2_font_helvR08_tf);
      u8g2.setCursor(0, 10);
      u8g2.print(F("BPM: "));
      u8g2.print(BPM); // Example of dynamic data

    } while (u8g2.nextPage());
  }
}

void checkBtn() {
  byte currentBtnState = digitalRead(btnPin);
  if (currentBtnState != btnState) {
    if (currentBtnState == 1) {
      play = (play == 1) ? 0 : 1;
    };
  }
  btnState = currentBtnState;
};

void checkRPot() {
    if (millis() - rPotLastUpdate >= rPotThrottle) {

    noInterrupts(); 
    long currentPos = rPotPos;
    interrupts();

    // Print position only if it has changed
    static long previousPos = -999; 
    if (currentPos != previousPos) {
      Serial.print("Encoder Position: ");
      Serial.println(currentPos);
      
      if (currentPos > previousPos) {
        handleBPMChange(1);
      } else {
        handleBPMChange(0);
      }

      forceScreenUpdate = 1;
      
      previousPos = currentPos;
    }
    
    rPotLastUpdate = millis(); // Reset the timer for throttling the output
  }
}

void handleBPMChange(byte increase) {
  if (increase == 1) {
    BPM++;
  } else {
    BPM--;
  }

  period = (minute / BPM) / ppqn;
  Timer1.setPeriod(period);
}

void updateEncoder() {
  // The ISR should be as short and fast as possible
  // Check the state of the DT pin to determine direction
  if (digitalRead(3) == LOW) {
    rPotPos++; // Clockwise
  } else {
    rPotPos--; // Counter-clockwise
  }
}