#include <WiFi.h>
#include <time.h>
#include <Wire.h>
#include <RTClib.h>
#include <Adafruit_NeoPixel.h>

// ======================================
// WLAN
// ======================================

const char* ssid     = "Wokwi-GUEST";
const char* password = "";

// ======================================
// Zeitzone Deutschland
// ======================================

const char* timeZone = "CET-1CEST,M3.5.0/2,M10.5.0/3";

const char* ntpServer = "pool.ntp.org";

// ======================================
// LED Ring
// ======================================

#define LED_PIN      2
#define LED_COUNT   16
#define BRIGHTNESS 240

Adafruit_NeoPixel ring(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);

// ======================================
// RTC
// ======================================

RTC_DS3231 rtc;

bool ntpOK = false;

// ======================================
// Farben
// ======================================

uint32_t colorHour;
uint32_t colorMinute;
uint32_t colorSecond;

// ======================================

void setup() {

  Serial.begin(115200);

  delay(500);

  // LED Ring

  ring.begin();

  ring.setBrightness(BRIGHTNESS);

  ring.clear();

  ring.show();

  colorHour   = ring.Color(0, 0, 255);     // Blau
  colorMinute = ring.Color(255, 0, 80);    // Pink
  colorSecond = ring.Color(0, 255, 0);     // Grün

  // I2C

  Wire.begin(21,22);

  // RTC

  if (!rtc.begin()) {

    Serial.println("DS3231 nicht gefunden!");

  } else {

    Serial.println("DS3231 gefunden.");
  }

  // WLAN

  connectWiFi();

  // NTP

  syncTimeFromNTP();

  // RTC synchronisieren

  if (ntpOK) {

    updateRTCFromSystemTime();

  } else {

    Serial.println("NTP fehlgeschlagen - RTC wird verwendet.");
  }
}

// ======================================

void loop() {

  int h,m,s;

  if (ntpOK) {

    struct tm timeinfo;

    if (getLocalTime(&timeinfo)) {

      h = timeinfo.tm_hour;

      m = timeinfo.tm_min;

      s = timeinfo.tm_sec;

    } else {

      readTimeFromRTC(h,m,s);
    }

  } else {

    readTimeFromRTC(h,m,s);
  }

  showBinaryTime(h,m,s);

  delay(250);
}

// ======================================

void connectWiFi() {

  Serial.print("Verbinde WLAN");

  WiFi.begin(ssid,password);

  unsigned long startAttempt = millis();

  while (WiFi.status() != WL_CONNECTED &&
         millis() - startAttempt < 15000) {

    Serial.print(".");

    delay(500);
  }

  if (WiFi.status() == WL_CONNECTED) {

    Serial.println();

    Serial.println("WLAN verbunden.");

    Serial.print("IP: ");

    Serial.println(WiFi.localIP());

  } else {

    Serial.println();

    Serial.println("WLAN-Verbindung fehlgeschlagen.");
  }
}

// ======================================

void syncTimeFromNTP() {

  if (WiFi.status() != WL_CONNECTED) {

    ntpOK = false;

    return;
  }

  Serial.println("Hole Zeit per NTP...");

  // Automatische Sommer-/Winterzeit

  configTzTime(timeZone, ntpServer);

  struct tm timeinfo;

  if (getLocalTime(&timeinfo,15000)) {

    ntpOK = true;

    Serial.println("NTP erfolgreich.");

    Serial.println(&timeinfo,"%d.%m.%Y %H:%M:%S");

  } else {

    ntpOK = false;

    Serial.println("NTP fehlgeschlagen.");
  }
}

// ======================================

void updateRTCFromSystemTime() {

  struct tm timeinfo;

  if (getLocalTime(&timeinfo)) {

    rtc.adjust(DateTime(

      timeinfo.tm_year + 1900,

      timeinfo.tm_mon + 1,

      timeinfo.tm_mday,

      timeinfo.tm_hour,

      timeinfo.tm_min,

      timeinfo.tm_sec

    ));

    Serial.println("RTC aktualisiert.");
  }
}

// ======================================

void readTimeFromRTC(int &h,int &m,int &s) {

  DateTime now = rtc.now();

  h = now.hour();

  m = now.minute();

  s = now.second();
}

// ======================================

void showBinaryTime(int hour, int minute, int second) {

  ring.clear();

  // 24h in 12h umwandeln

  int displayHour = hour % 12;

  if (displayHour == 0) {

    displayHour = 12;
  }

  // ==========================
  // Sekunden LED 0 - 5
  // ==========================

  for (int bit = 0; bit < 6; bit++) {

    if (second & (1 << bit)) {

      ring.setPixelColor(bit, colorSecond);
    }
  }

  // ==========================
  // Minuten LED 6 - 11
  // ==========================

  for (int bit = 0; bit < 6; bit++) {

    if (minute & (1 << bit)) {

      ring.setPixelColor(6 + bit, colorMinute);
    }
  }

  // ==========================
  // Stunden LED 12 - 15
  // ==========================

  for (int bit = 0; bit < 4; bit++) {

    if (displayHour & (1 << bit)) {

      ring.setPixelColor(12 + bit, colorHour);
    }
  }

  ring.show();
}