// --- Libraries ---
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <IRremote.h>
#include <RTClib.h>

// --- LCD Setup ---
LiquidCrystal_I2C lcd(0x27, 20, 4);

// --- RTC Setup ---
RTC_DS1307 rtc;

// --- IR Receiver Pin ---
#define IR_RECEIVE_PIN 11

// --- Photodiode Pins ---
const int pdTop = A0;
const int pdBottom = A1;
const int pdLeft = A2;
const int pdRight = A3;

// --- Motor Pins ---
const int enPin = 7;   // Enable for vertical
const int dirPin = 6;  // Direction for vertical
const int stepPin = 5; // Step for vertical
const int enPin2 = 4;  // Enable for horizontal
const int dirPin2 = 3; // Direction for horizontal
const int stepPin2 = 2;// Step for horizontal

// --- Mode Flags ---
bool manualMode = false;
bool useRTC = false;

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

  // LCD Init
  lcd.begin(20, 4);
  lcd.backlight();

  // IR Init
  IrReceiver.begin(IR_RECEIVE_PIN);

  // RTC Init
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  // Motor Pins
  pinMode(enPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  pinMode(stepPin, OUTPUT);
  pinMode(enPin2, OUTPUT);
  pinMode(dirPin2, OUTPUT);
  pinMode(stepPin2, OUTPUT);

  digitalWrite(enPin, LOW);
  digitalWrite(enPin2, LOW);

  lcd.setCursor(0, 0);
  lcd.print("Mode: AUTO");
}

void loop() {
  // Handle IR Input
  if (IrReceiver.decode()) {
    unsigned long code = IrReceiver.decodedIRData.command;
    IrReceiver.resume();

    switch (code) {
      case 0xA8: // OK button toggles mode
        manualMode = !manualMode;
        lcd.setCursor(0, 0);
        lcd.print("Mode: ");
        lcd.print(manualMode ? "MANUAL" : "AUTO   ");
        break;

      case 0x18: // 2 - Up
        if (manualMode) moveMotor(stepPin, dirPin, 5, true);
        break;
      case 0x4A: // 8 - Down
        if (manualMode) moveMotor(stepPin, dirPin, 5, false);
        break;
      case 0x10: // 4 - Left
        if (manualMode) moveMotor(stepPin2, dirPin2, 5, true);
        break;
      case 0x5A: // 6 - Right
        if (manualMode) moveMotor(stepPin2, dirPin2, 5, false);
        break;
    }
  }

  if (!manualMode) {
    // Read photodiodes (0–1023 scale)
    int topVal = analogRead(pdTop);
    int bottomVal = analogRead(pdBottom);
    int leftVal = analogRead(pdLeft);
    int rightVal = analogRead(pdRight);

    const int lightThreshold = 150;
    bool isLowLight = (topVal < lightThreshold && bottomVal < lightThreshold &&
                       leftVal < lightThreshold && rightVal < lightThreshold);

    Serial.print("Photodiodes: T="); Serial.print(topVal);
    Serial.print(" B="); Serial.print(bottomVal);
    Serial.print(" L="); Serial.print(leftVal);
    Serial.print(" R="); Serial.println(rightVal);

    if (isLowLight) {
      useRTC = true;
      DateTime now = rtc.now();
      lcd.setCursor(0, 1);
      lcd.print("RTC ");
      lcd.print(now.hour());
      lcd.print(":");
      lcd.print(now.minute());

      if (now.hour() >= 6 && now.hour() < 12) {
        moveMotor(stepPin2, dirPin2, 1, true); // East
      } else if (now.hour() >= 12 && now.hour() < 18) {
        moveMotor(stepPin2, dirPin2, 1, false); // West
      }
    } else {
      useRTC = false;
      lcd.setCursor(0, 1);
      lcd.print("PhotoTrack       ");

      if (topVal - bottomVal > 100) {
        moveMotor(stepPin, dirPin, 1, true); // Up
      } else if (bottomVal - topVal > 100) {
        moveMotor(stepPin, dirPin, 1, false); // Down
      }

      if (leftVal - rightVal > 100) {
        moveMotor(stepPin2, dirPin2, 1, true); // Left
      } else if (rightVal - leftVal > 100) {
        moveMotor(stepPin2, dirPin2, 1, false); // Right
      }
    }
  }

  delay(500);
}

void moveMotor(int stepPin, int dirPin, int steps, bool dir) {
  digitalWrite(dirPin, dir);
  for (int i = 0; i < steps; i++) {
    digitalWrite(stepPin, HIGH);
    delayMicroseconds(500);
    digitalWrite(stepPin, LOW);
    delayMicroseconds(500);
  }
}