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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET 4
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

RTC_DS3231 rtc;

const int STATUS_LED_PIN = 10;
const int RELAY_PIN = 11;
const int BELL_DURATION = 4000; // ms

struct breakTime {
  char breakDesc;
  int startHour;
  int startMinute;
  int startSecond;
  int endHour;
  int endMinute;
  int endSecond;
  char breakDays;
  // bool onSunday = false;
  // bool onMonday = false;
  // bool onTuesday = false;
  // bool onWednesday = false;
  // bool onThursday = false;
  // bool onFriday = false;
  // bool onSaturday = false;
  // bool onWeekdays = false;
  // bool onWeekends = false;
};


struct breakTime breakTimes[3] = {
    {"First Break", 10, 0, 0, 10, 30, 0, "0111110"},
    {"Lunch Break", 12, 0, 0, 13, 0, 0, "0111110"},
    {"Second Break", 16, 15, 0, 16, 40, 0, "0111110"}//,
    // {"", 0, 0, 0, 0, 0, 0, "0000000"},
    // {"", 0, 0, 0, 0, 0, 0, "0000000"},
    // {"", 0, 0, 0, 0, 0, 0, "0000000"}
  };

breakTime currentBreak;
breakTime nextBreak;
bool currentBreakBool = false;

void setup() {
  // put your setup code here, to run once
  Serial.begin(115200);
  Serial.println("Serial Initialized");
  Wire.begin();
  
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(14, 26);
  display.println("Break Alarm");
  
  
  pinMode(STATUS_LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);

  digitalWrite(STATUS_LED_PIN, LOW);
  digitalWrite(RELAY_PIN, LOW);

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

  if (rtc.lostPower()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
  
  breakTime nB = {"", 0, 0, 0, 0, 0, 0, "0000000"};
  nextBreak = nB;
  currentBreak = nB;

  delay(2000);
  //display.clearDisplay();
}

void loop() {
  // put your main code here, to run repeatedly
  display.clearDisplay();
  DateTime now = rtc.now();
  showCurrentTime(now);

  delay(1000);
  if (nextBreak.startHour == 0) {
    nextBreak = getNextBreak(now);
  }
  showNextBreakTime(nextBreak);

  // Serial.print(nextBreak.startHour);
  // Serial.print("  ");
  // Serial.print(nextBreak.startMinute);
  // Serial.print("  ");
  // Serial.println(nextBreak.startSecond);

  long currentSeconds = (long)now.hour() * 3600 + (long)now.minute() * 60 + (long)now.second();
  long nextBreakStartSeconds = (long)nextBreak.startHour * 3600 + (long)nextBreak.startMinute * 60 + (long)nextBreak.startSecond;
  long nextBreakEndSeconds = (long)nextBreak.endHour * 3600 + (long)nextBreak.endMinute * 60 + (long)nextBreak.endSecond;

  if (currentSeconds == nextBreakStartSeconds) {
    // next break is starting
    bell((String)nextBreak.breakDesc + " Start");
    digitalWrite(STATUS_LED_PIN, HIGH);
  } else if (currentSeconds == nextBreakEndSeconds) {
    // current break is ending
    bell((String)nextBreak.breakDesc + " End");
    digitalWrite(STATUS_LED_PIN, LOW);
    nextBreak = getNextBreak(now);
  } else if (currentSeconds > nextBreakStartSeconds && currentSeconds < nextBreakEndSeconds) {
    // current break in progress
    digitalWrite(STATUS_LED_PIN, HIGH);
  }

  display.display();
}

breakTime getNextBreak(DateTime now) {
  long currentSeconds = ((long)now.hour() * 3600 + (long)now.minute() * 60 + (long)now.second());
  int size = sizeof(breakTimes) / sizeof(breakTimes[0]);
  breakTime nB = {"", 99, 99, 99, 99, 99, 99, "0000000"};

  for (int i = 0; i < size; i++) {
    long breakStartSeconds = (long)breakTimes[i].startHour * 3600 + (long)breakTimes[i].startMinute * 60 + (long)breakTimes[i].startSecond;
    long breakEndSeconds = (long)breakTimes[i].endHour * 3600 + (long)breakTimes[i].endMinute * 60 + (long)breakTimes[i].endSecond;
    long timeToBreak = breakStartSeconds - currentSeconds;
    long timeToEndBreak = breakEndSeconds - currentSeconds;
    // Serial.print("Time to break:  ");
    // Serial.println(timeToBreak);
    if (timeToBreak > 0) {
      // the break is coming up
      // Serial.print(nB.endHour);
      // Serial.print("  ");
      // Serial.print(nB.endMinute);
      // Serial.print("  ");
      // Serial.println(nB.endSecond);
      long nextBreakStartSeconds = (long)nB.endHour * 3600 + (long)nB.endMinute * 60 + (long)nB.endSecond;
      long timeToNextBreak = nextBreakStartSeconds - currentSeconds;
      //Serial.print("Time to current next break:  ");
      //Serial.println(timeToNextBreak);
      if (timeToBreak < timeToNextBreak) {
        // the current break is earlier than the stored next break
        nB = breakTimes[i];
      }
    } else if (timeToBreak < 0 && timeToEndBreak > 0) {
      // currently in a break
      nextBreak = breakTimes[i];
      break;
    }
  }
  Serial.print("nB startHour: ");
  Serial.println(nB.startHour);
  return nB;
}

void bell(String bellName) {
  //display.clearDisplay();
  display.setCursor(0, 0);
  display.setTextSize(3);
  display.setTextColor(WHITE);
  display.println(bellName);
  //display.display();
  
  digitalWrite(RELAY_PIN, HIGH);
  delay(BELL_DURATION);
  digitalWrite(RELAY_PIN, LOW);
}

void showCurrentTime(DateTime now)
{
  char day_format[] = "DDD";
  char date_format[] = "MMM DD, YYYY";
  char time_format[] = "hh:mm:ss ap";

  String _day = now.toString(day_format);
  String _date = now.toString(date_format);
  String _time = now.toString(time_format);

  //display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 0);
  display.print(_day);
  display.print("      ");
  display.println(_date);
  display.print("     ");
  display.println(_time);
  //display.display();
}

void showNextBreakTime(breakTime bt)
{
  // Serial.print(bt.startHour);
  // Serial.print("  ");
  // Serial.print(bt.startMinute);
  // Serial.print("  ");
  // Serial.println(bt.startSecond);
  
  
  if (bt.startHour == 99) {
    display.setCursor(40, 30);
    display.println("No breaks");
    display.print("     ");
    display.println("remain today");
    Serial.println("No more breaks.");
    //display.display();
    return;
  }

  // String h;
  // String m;
  // String s;
  String ampm = "am";
  // h = String(bt.startHour);
  // m = bt.startMinute;
  // s = bt.startSecond;

  Serial.println(bt.startHour);
  // Serial.println(h);

  if (bt.startHour > 12) { ampm = "pm"; }
  // if (bt.startHour > 12) { h = bt.startHour - 12; }
  // if (bt.startHour < 10) { h = "0" + h; }
  // if (bt.startMinute < 10) { m = "0" + m; }
  // if (bt.startSecond < 10) { s = "0" + s; }

  // Serial.print(h);
  // Serial.print(" : ");
  // Serial.print(m);
  // Serial.print(" : ");
  // Serial.println(s);

  char *timeStr;
  sprintf(timeStr, "%d:%d:%d", bt.startHour, bt.startMinute, bt.startSecond);

  //String _time = (String)hour + ":" + (String)bt.startMinute + ":" + (String)bt.startSecond + " " + ampm;
  //String _time = h + ":" + m + ":" + s + " " + ampm;

  Serial.println(timeStr);
  //display.clearDisplay();
  //display.setTextSize(1);
  //display.setTextColor(WHITE);
  display.setCursor(32, 20);
  display.println("Next Break:");
  //display.print("     ");
  display.print(timeStr);
  //display.display();
}