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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels #define OLED_RESET
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; ex3D for 128x64, 0x3C for 128x32

#define BUZZER 5
#define LED_1 15
#define PB_CANCEL 34
#define PB_OK 32
#define PB_UP 33
#define PB_DOWN 35

// Declare objects
Adafruit_SSD1306 display (SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Global variables
int days = 0;
int hours = 0;
int minutes = 0;
int seconds = 0;

unsigned long timeNow = 0;
unsigned long timeLast = 0;

bool alarm_enabled = true;
int n_alarms = 2;
int alarm_hours[] = {0, 1};
int alarm_minutes[] = {1, 10};
bool alarm_triggered[] = {false, false};

int n_notes = 8;
int C = 262;
int D = 294;
int E = 330;
int F = 349;
int G = 392;
int A = 440;
int B = 494;
int C_H = 523;
int notes[] = {C, D, E, F, G, A, B, C_H};

int current_mode = 0;
int max_modes = 4;
String modes[] = {"1 - Set Time", "2 - Set Alarm 1", "3 - Set Alarm 2", "4 - Disable Alarms" };


void setup() {
  // Put your setup code here to run once
  pinMode(BUZZER, OUTPUT);
  pinMode(LED_1, OUTPUT);
  pinMode(PB_CANCEL, INPUT);
  pinMode(PB_OK, INPUT);
  pinMode(PB_UP, INPUT);
  pinMode(PB_DOWN, INPUT);

  Serial.begin(9600);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }

  // Turn on OLED display
  display.display();
  delay(2000);

  // Clear the buffer
  display.clearDisplay();

  print_line("Welcome to Medibox", 10, 20, 2);
  delay(2000);
  display.clearDisplay();
}

void loop() {
  delay(10); // this speeds up the simulation
  update_time_with_check_alarm();
  if (digitalRead(PB_OK) == LOW) {
    delay(200); // This delay is added to debounce the push button
    go_to_menu();
  }
}

void print_line(String text, int column, int row, int text_size) {

  display.setTextSize(text_size);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(column, row); // (column,row) - cursor is at the origin
  display.println(text);

  display.display();
}

void print_time_now(void) {
  display.clearDisplay();
  print_line(String(days), 0, 0, 2);
  print_line(":", 20, 0, 2);
  print_line(String(hours), 30, 0, 2);
  print_line(":", 50, 0, 2);
  print_line(String(minutes), 60, 0, 2);
  print_line(":", 80, 0, 2);
  print_line(String(seconds), 90, 0, 2);
}

void update_time() {
  // update time function will be accessed by multiple functions
  // Therefore it is best to
  timeNow = millis() / 1000; // seconds passed from bootup
  seconds = timeNow - timeLast;

  if (seconds >= 60) {
    minutes += 1; // minutes = minutes + 1
    timeLast += 60;
  }

  if (minutes == 60) {
    hours += 1;
    minutes = 0;
  }

  if (hours == 24) {
    days += 1;
    hours = 0;
  }
}

void ring_alarm() {
  display.clearDisplay();
  print_line("MEDICINE TIME!", 0, 0, 2);

  digitalWrite(LED_1, HIGH);

  bool break_happened = false;

  // Ring the buzzer
  while (break_happened == false && digitalRead(PB_CANCEL) == HIGH) {
    for (int i = 0; i < n_notes; i++) {
      if (digitalRead(PB_CANCEL) == LOW) {
        delay(200); // This is to prevent the bouncing of the push button
        break_happened = true;
        break;
      }
      tone(BUZZER, notes[i]);
      delay(500);
      noTone(BUZZER);
      delay(2);
    }
  }

  digitalWrite(LED_1, LOW);
  display.clearDisplay();
}

void update_time_with_check_alarm(void) {
  update_time();
  print_time_now();

  if (alarm_enabled == true) {
    for (int i = 0; i < n_alarms; i++) {
      if (alarm_triggered[i] == false && alarm_hours[i] == hours && alarm_minutes[i] == minutes) {
        ring_alarm();
        alarm_triggered[i] = true;
      }
    }
  }
}

// The int used in the beginning specifies, which variable type that would be returned as a result of that function
int wait_for_button_press() {
  while (true) {
    if (digitalRead(PB_UP) == LOW) {
      delay(200);
      return PB_UP;
    }

    else if (digitalRead(PB_DOWN) == LOW) {
      delay(200);
      return PB_DOWN;
    }

    else if (digitalRead(PB_OK) == LOW) {
      delay(200);
      return PB_OK;
    }

    else if (digitalRead(PB_CANCEL) == LOW) {
      delay(200);
      return PB_CANCEL;
    }
    update_time();
  }
}

void go_to_menu() {
  while (digitalRead(PB_CANCEL) == HIGH) {
    display.clearDisplay();
    print_line(modes[current_mode], 0, 0, 2);

    int pressed = wait_for_button_press();
    if (pressed == PB_UP) {
      delay(200);
      current_mode += 1;
      current_mode = current_mode % max_modes;
    }

    else if (pressed == PB_DOWN) {
      delay(200);
      current_mode -= 1;
      if (current_mode < 0) {
        current_mode = max_modes - 1;
      }
    }

    else if (pressed == PB_OK) {
      delay(200);
      Serial.println(current_mode);
      //run_mode(current_mode);
    }

    else if (pressed == PB_CANCEL) {
      delay(200);
      break;
    }
  }
}

void set_time() {

  int temp_hour = hours;
  while (true) {
    display.clearDisplay();
    print_line("Enter hour: " + String(temp_hour), 0, 0, 2);

    int pressed = wait_for_button_press();
    if (pressed == PB_UP) {
      delay(200);
      temp_hour += 1;
      temp_hour = temp_hour % 24;
    }

    else if (pressed == PB_DOWN) {
      delay(200);
      temp_hour -= 1;
      if (temp_hour < 0) {
        temp_hour = 23;
      }
    }

    else if (pressed == PB_OK) {
      delay(200);
      hours = temp_hour;
      break;
    }

    else if (pressed == PB_CANCEL) {
      delay(200);
      break;
    }
  }

  int temp_minute = minutes;
  while (true) {
    display.clearDisplay();
    print_line("Enter minute: " + String(temp_minute), 0, 0, 2);

    int pressed = wait_for_button_press();
    if (pressed == PB_UP) {
      delay(200);
      temp_minute += 1;
      temp_minute = temp_minute % 60;
    }

    else if (pressed == PB_DOWN) {
      delay(200);
      temp_minute -= 1;
      if (temp_minute < 0) {
        temp_minute = 59;
      }
    }

    else if (pressed == PB_OK) {
      delay(200);
      minutes = temp_minute;
      break;
    }

    else if (pressed == PB_CANCEL) {
      delay(200);
      break;
    }
  }

  display.clearDisplay();
  print_line("Time is set", 0, 0, 2);
  delay(1000);

}

void set_alarm(int alarm) {

  int temp_hour = alarm_hours[alarm];
  while (true) {
    display.clearDisplay();
    print_line("Enter hour: " + String(temp_hour), 0, 0, 2);

    int pressed = wait_for_button_press();
    if (pressed == PB_UP) {
      delay(200);
      temp_hour += 1;
      temp_hour = temp_hour % 24;
    }

    else if (pressed == PB_DOWN) {
      delay(200);
      temp_hour -= 1;
      if (temp_hour < 0) {
        temp_hour = 23;
      }
    }

    else if (pressed == PB_OK) {
      delay(200);
      alarm_hours[alarm] = temp_hour;
      break;
    }

    else if (pressed == PB_CANCEL) {
      delay(200);
      break;
    }
  }

  int temp_minute = alarm_minutes[alarm];
  while (true) {
    display.clearDisplay();
    print_line("Enter minute: " + String(temp_minute), 0, 0, 2);

    int pressed = wait_for_button_press();
    if (pressed == PB_UP) {
      delay(200);
      temp_minute += 1;
      temp_minute = temp_minute % 60;
    }

    else if (pressed == PB_DOWN) {
      delay(200);
      temp_minute -= 1;
      if (temp_minute < 0) {
        temp_minute = 59;
      }
    }

    else if (pressed == PB_OK) {
      delay(200);
      alarm_minutes[alarm] = temp_minute;
      break;
    }

    else if (pressed == PB_CANCEL) {
      delay(200);
      break;
    }
  }

  display.clearDisplay();
  print_line("Alarm is set", 0, 0, 2);
  delay(1000);
}

void run_mode(int mode) {
  if (mode == 0) {
    set_time();
  }

  if (mode == 1 || mode == 2) {
    set_alarm(mode - 1);
  }

  else if (mode == 3){
    alarm_enabled = false;
  }
}