#include <WiFi.h>
#include <WebServer.h>
#include <DNSServer.h>
#include <WiFiManager.h>
#include <Preferences.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

Preferences preferences;
LiquidCrystal_I2C lcd(0x27, 20, 4);

int userThreshold = 2500;
int maxAlarm = 0;
int rebootCount = 0;
const int potPin = 34;
char thresholdValue[6] = "2500";
unsigned long startTime = 0;

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("=== WIFI MANAGER ===");

  preferences.begin("iot_storage", false);
  userThreshold = preferences.getInt("user_threshold", 2500);
  maxAlarm = preferences.getInt("max_alarm", 0); 
  
  rebootCount = preferences.getInt("reboot_num", 0);
  rebootCount++;
  preferences.putInt("reboot_num", rebootCount);

  sprintf(thresholdValue, "%d", userThreshold);

  lcd.setCursor(0, 1);
  lcd.print("Max Alarm: ");
  lcd.print(maxAlarm);

  lcd.setCursor(0, 2);
  lcd.print("Connecting WiFi...");

  WiFi.disconnect(true, true);

  WiFiManager wm;
  wm.setConnectTimeout(3);
  wm.setConfigPortalTimeout(1);

  WiFiManagerParameter custom_threshold("threshold", "Temp Limit", thresholdValue, 5);
  wm.addParameter(&custom_threshold);

  if (!wm.autoConnect("ESP32-Auto-Config", NULL)) {
    WiFi.begin("Wokwi-GUEST", "");
    unsigned long startAttempt = millis();
    while (WiFi.status() != WL_CONNECTED && millis() - startAttempt < 5000) {
      delay(100);
    }
  }

  if (WiFi.status() != WL_CONNECTED) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WiFi FAILED");
    delay(3000);
    ESP.restart();
  }

  if (custom_threshold.getValue() != NULL && strlen(custom_threshold.getValue()) > 0) {
    userThreshold = atoi(custom_threshold.getValue());
    preferences.putInt("user_threshold", userThreshold);
  }
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("WiFi Connected");
  
  lcd.setCursor(0, 2);
  lcd.print("Max Alarm: ");
  lcd.print(maxAlarm);

  startTime = millis();
}

void loop() {
  int potValue = analogRead(potPin);
  unsigned long elapsed = (millis() - startTime) / 1000;
  unsigned long timeLeft = (elapsed < 15) ? (15 - elapsed) : 0;

  lcd.setCursor(0, 0);
  if (potValue > userThreshold) {
    lcd.print("!!! ALARM !!!       ");
  } else {
    lcd.print("WiFi Connected      ");
  }

  lcd.setCursor(0, 1);
  char rebootBuf[21];
  sprintf(rebootBuf, "Rbt: %d | Rem: %ds   ", rebootCount, timeLeft);
  lcd.print(rebootBuf);

  lcd.setCursor(0, 3);
  char potBuf[21];
  sprintf(potBuf, "Pot: %d      ", potValue);
  lcd.print(potBuf);

  if (potValue > 2500 && potValue > maxAlarm) {
    maxAlarm = potValue;
    preferences.putInt("max_alarm", maxAlarm);
    
    lcd.setCursor(0, 2);
    lcd.print("Max Alarm: ");
    lcd.print(maxAlarm);
    lcd.print("    ");
  }

  if (millis() - startTime >= 5000) {
    lcd.clear();
    lcd.setCursor(0, 1);
    lcd.print("  REBOOTING...  ");
    delay(1000);
    ESP.restart();
  }

  delay(500);
}