#include <WiFi.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFiManager.h>
#include <time.h>


// --- OLED CONFIG FOR C3 SUPERMINI ---
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define SDA_PIN 8
#define SCL_PIN 9
#define OLED_ADDR 0x3C
#define BOOT_BUTTON 9 // On SuperMini BOOT button is GPIO 9, but we use it as SCL, so we use external button logic or skip. We will use GPIO 3 for reset
#define RESET_PIN 3


Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);


// IST Time
const long gmtOffset_sec = 19800;
const int daylightOffset_sec = 0;
const char* ntpServer = "pool.ntp.org";


void setup() {
  Serial.begin(115200);
  Wire.begin(SDA_PIN, SCL_PIN);
  pinMode(RESET_PIN, INPUT_PULLUP);


  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println("SSD1306 not found");
    while(1);
  }


  display.clearDisplay();
  display.setTextColor(WHITE);


  // WiFiManager Setup
  WiFiManager wm;
  // wm.resetSettings(); // Uncomment if you want to erase saved wifi


  // If BOOT button (GPIO 3) is pressed on power on, reset wifi
  if(digitalRead(RESET_PIN) == LOW){
    display.setTextSize(1);
    display.setCursor(0, 20);
    display.println("Reset WiFi Settings");
    display.display();
    wm.resetSettings();
    delay(2000);
  }


  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("C3 SuperMini Clock");
  display.setCursor(0, 20);
  display.println("Connecting WiFi...");
  display.setCursor(0, 40);
  display.println("If new, connect to:");
  display.setCursor(0, 50);
  display.println("AP: ESP32_Clock");
  display.display();


  // Creates AP ESP32_Clock if no wifi saved
  bool res = wm.autoConnect("ESP32_Clock");


  if(!res) {
    display.clearDisplay();
    display.setCursor(0, 20);
    display.println("Failed to connect");
    display.display();
    delay(2000);
    ESP.restart();
  }


  display.clearDisplay();
  display.setCursor(0, 20);
  display.println("WiFi Connected!");
  display.setCursor(0, 35);
  display.println(WiFi.localIP().toString());
  display.display();
  delay(1000);


  // NTP Start
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
}


void loop() {
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(0, 20);
    display.println("Waiting for NTP...");
    display.display();
    delay(1000);
    return;
  }


  char time_HM[6];
  char time_SEC[3];
  char dateStr[16];
  char dayStr[10];


  strftime(time_HM, sizeof(time_HM), "%H:%M", &timeinfo);
  strftime(time_SEC, sizeof(time_SEC), "%S", &timeinfo);
  strftime(dateStr, sizeof(dateStr), "%d %b %Y", &timeinfo);
  strftime(dayStr, sizeof(dayStr), "%A", &timeinfo);


  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.print(dayStr);


  int16_t x1, y1;
  uint16_t w, h;
  display.getTextBounds(dateStr, 0, 0, &x1, &y1, &w, &h);
  display.setCursor(128 - w, 0);
  display.print(dateStr);
  display.drawLine(0, 10, 128, 10, WHITE);


  // BIG CLOCK
  display.setTextSize(3);
  display.setCursor(2, 18);
  display.print(time_HM);


  display.setTextSize(2);
  display.setCursor(98, 25);
  display.print(time_SEC);


  if(timeinfo.tm_sec % 2 == 0){
    display.fillCircle(88, 28, 2, WHITE);
  }


  // Show IP at bottom
  display.setTextSize(1);
  display.setCursor(0, 56);
  display.print(WiFi.localIP());


  display.display();
  delay(500);
}