#include <Wire.h>
#include <RTClib.h>
#include "HX711.h"

#define STEP_PIN 14
#define DIR_PIN 12
#define LED_PIN 25
#define BUZZER_PIN 26
#define HX711_DT 32
#define HX711_SCK 33

RTC_DS1307 rtc;
HX711 scale;

const int STEPS_PER_POSITION = 50;
const long WEIGHT_CHANGE_THRESHOLD = 50;

const char* names[4] = {
  "Morning", "Afternoon", "Evening", "Night"
};

int doseHour[4];
int doseMinute[4];
bool doseTriggered[4] = {false, false, false, false};

int currentPosition = 0;
int inputCompartment = 0;
String timeInput = "";

bool dosePending = false;
bool repeatAlarmDone = false;
bool alarmActive = false;
bool repeatAlarmActive = false;
bool weightBaselineSet = false;

long baselineWeight = 0;

unsigned long doseStart = 0;
unsigned long alarmStart = 0;
unsigned long lastWeightPrint = 0;

void moveMotor(int steps, bool direction) {
  digitalWrite(DIR_PIN, direction);

  for (int i = 0; i < steps; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(1000);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(1000);
  }
}

void startBuzzer(bool repeat) {
  tone(BUZZER_PIN, 2000);
  alarmStart = millis();
  alarmActive = true;
  repeatAlarmActive = repeat;
}

void stopBuzzer() {
  noTone(BUZZER_PIN);
  alarmActive = false;
  repeatAlarmActive = false;
}

void startDose(int i) {
  Serial.print("Dose due: ");
  Serial.println(names[i]);

  int movements = (i - currentPosition + 4) % 4;
  moveMotor(movements * STEPS_PER_POSITION, HIGH);
  currentPosition = i;

  digitalWrite(LED_PIN, HIGH);

  if (scale.is_ready()) {
    baselineWeight = scale.read();
    weightBaselineSet = true;

    Serial.print("Baseline weight reading: ");
    Serial.println(baselineWeight);
  } else {
    weightBaselineSet = false;
    Serial.println("HX711 not ready. Weight detection unavailable.");
  }

  dosePending = true;
  repeatAlarmDone = false;
  doseStart = millis();

  startBuzzer(false);
  Serial.println("Initial buzzer reminder: 1 minute.");
}

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);

  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  digitalWrite(LED_PIN, LOW);
  noTone(BUZZER_PIN);

  if (!rtc.begin()) {
    Serial.println("RTC not detected!");
    while (true) {
      delay(100);
    }
  }

  scale.begin(HX711_DT, HX711_SCK);

  Serial.println("SMART MEDICINE BOX");
  Serial.println("Enter dose times in 24-hour HH:MM format.");
  Serial.println("Compartment 1 - Morning: enter time.");
}

void loop() {
  while (Serial.available()) {
    char c = Serial.read();

    if (c == '\n' || c == '\r') {
      if (timeInput.length() > 0) {
        int colon = timeInput.indexOf(':');

        if (colon > 0 && inputCompartment < 4) {
          int h = timeInput.substring(0, colon).toInt();
          int m = timeInput.substring(colon + 1).toInt();

          if (h >= 0 && h <= 23 && m >= 0 && m <= 59) {
            doseHour[inputCompartment] = h;
            doseMinute[inputCompartment] = m;

            Serial.print(names[inputCompartment]);
            Serial.print(" time saved: ");
            Serial.println(timeInput);

            inputCompartment++;
            timeInput = "";

            if (inputCompartment < 4) {
              Serial.print("Enter ");
              Serial.print(names[inputCompartment]);
              Serial.println(" time:");
            } else {
              Serial.println("All four times saved. Schedule active.");
            }
          } else {
            Serial.println("Invalid time. Use HH:MM.");
            timeInput = "";
          }
        } else {
          Serial.println("Invalid input.");
          timeInput = "";
        }
      }
    } else if ((c >= '0' && c <= '9') || c == ':') {
      timeInput += c;
    }
  }

  // End the initial buzzer after 1 minute.
  if (alarmActive && !repeatAlarmActive &&
      millis() - alarmStart >= 60000UL) {
    stopBuzzer();
    Serial.println("Initial buzzer stopped. LED remains on.");
  }

  // End the repeat buzzer after 2 minutes.
  if (alarmActive && repeatAlarmActive &&
      millis() - alarmStart >= 120000UL) {
    stopBuzzer();
    Serial.println("Repeat buzzer stopped. Still monitoring.");
  }

  // Check for medicine collection by detecting a weight decrease.
  if (dosePending && weightBaselineSet && scale.is_ready()) {
    long currentWeight = scale.read();
    long decrease = baselineWeight - currentWeight;

    if (millis() - lastWeightPrint >= 1000) {
      Serial.print("Baseline: ");
      Serial.print(baselineWeight);
      Serial.print(" | Current: ");
      Serial.print(currentWeight);
      Serial.print(" | Decrease: ");
      Serial.println(decrease);
      lastWeightPrint = millis();
    }

    if (decrease >= WEIGHT_CHANGE_THRESHOLD) {
      dosePending = false;
      weightBaselineSet = false;

      digitalWrite(LED_PIN, LOW);
      stopBuzzer();

      Serial.println("Weight decrease detected.");
      Serial.println("Dose marked as collected. LED OFF.");
    }
  }

  // Repeat reminder after 30 minutes if the dose is still pending.
  if (dosePending && !repeatAlarmDone &&
      millis() - doseStart >= 1800000UL) {
    repeatAlarmDone = true;
    startBuzzer(true);

    Serial.println("Dose still pending after 30 minutes.");
    Serial.println("Repeat buzzer will sound for 2 minutes.");
  }

  // Check the four scheduled dose times.
  if (inputCompartment == 4 && !dosePending) {
    DateTime now = rtc.now();

    for (int i = 0; i < 4; i++) {
      if (now.hour() == doseHour[i] &&
          now.minute() == doseMinute[i] &&
          !doseTriggered[i]) {
        doseTriggered[i] = true;
        startDose(i);
        break;
      }
    }
  }

  delay(100);
}