#include <WiFi.h>
#include <HTTPClient.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Preferences.h>

// OLED Display
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

// LCD Display (I2C)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Keypad setup
const byte ROWS = 4, COLS = 3;
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};
byte rowPins[ROWS] = {4, 5, 18, 19};
byte colPins[COLS] = {23, 25, 2};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
String keypadBuffer = "";

// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ThingsBoard server & token
const char* tbServer = "http://thingsboard.cloud";
const char* tbToken = "wofqkaayfjmgcg8hh7wm";

// Data values
float batt = 100;
String latitude = "3.0738";
String longitude = "101.4996";

// Timing
unsigned long previousMillis_upload = 0;
unsigned long previousMillis_display = 0;
const long upload_interval = 20000;  // 20s
const long display_interval = 1000;  // 1s

// Button, LED, Buzzer
#define BUTTON_PIN 14
#define LED_PIN 26
#define BUZZER_PIN 27
bool buttonPressed = false;

// Preferences for saving keypad entry
Preferences preferences;

void setup() {
  Serial.begin(9600);
  preferences.begin("keypad", false); // flash storage

  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("❌ OLED failed");
    while (1);
  }

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0); lcd.print("System Booting...");
  lcd.setCursor(0, 1); lcd.print("GPS Tracker Ready");

  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(1);
  display.setCursor(10, 25); display.println("ThingsBoard Uploader");
  display.display();
  delay(3000);

  WiFi.begin(ssid, password);
  lcd.clear();
  lcd.setCursor(0, 0); lcd.print("Connecting WiFi");

  int i = 0;
  while (WiFi.status() != WL_CONNECTED && i < 20) {
    delay(500);
    Serial.print(".");
    i++;
  }
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\n✅ WiFi Connected!");
    lcd.setCursor(0, 1); lcd.print("WiFi Connected!");
  } else {
    lcd.setCursor(0, 1); lcd.print("WiFi Failed!");
  }
  delay(2000);

  lcd.clear();
  lcd.setCursor(0, 0); lcd.print("Enter Value:");

  String lastEntry = preferences.getString("entry", "none");
  Serial.println("🔎 Last saved entry: " + lastEntry);
}

void loop() {
  unsigned long currentMillis = millis();

  // Refresh OLED
  if (currentMillis - previousMillis_display >= display_interval) {
    previousMillis_display = currentMillis;
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(0, 0); display.print("Lat: "); display.println(latitude);
    display.setCursor(0, 10); display.print("Lng: "); display.println(longitude);
    display.setCursor(0, 20); display.print("Batt: "); display.print(batt); display.println(" %");
    display.display();
  }

  // Send periodic telemetry
  if (currentMillis - previousMillis_upload >= upload_interval) {
    previousMillis_upload = currentMillis;
    sendTelemetry(latitude, longitude, batt);
    batt -= 0.5; if (batt < 0) batt = 100;
  }

  // Button triggers LED, buzzer, and sends mark location
  if (digitalRead(BUTTON_PIN) == LOW && !buttonPressed) {
    buttonPressed = true;
    Serial.println("🔘 Button pressed!");
    digitalWrite(LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    sendMarkLocation(latitude, longitude);
  }
  if (digitalRead(BUTTON_PIN) == HIGH) {
    buttonPressed = false;
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }

  // Keypad input
  char key = keypad.getKey();
  if (key) {
    Serial.print("Key: "); Serial.println(key);
    if (key >= '0' && key <= '9') {
      keypadBuffer += key;
      lcd.clear();
      lcd.setCursor(0, 0); lcd.print("Enter Value:");
      lcd.setCursor(0, 1); lcd.print(keypadBuffer);
    } else if (key == '#') {
      if (keypadBuffer.length() > 0) {
        lcd.clear();
        lcd.setCursor(0, 0); lcd.print("Sending & Saving...");
        sendKeypadValue(keypadBuffer);
        preferences.putString("entry", keypadBuffer);
        lcd.setCursor(0, 1); lcd.print("Data Sent!");
        delay(2000);
        keypadBuffer = "";
        lcd.clear();
        lcd.setCursor(0, 0); lcd.print("Enter Value:");
      }
    } else if (key == '*') {
      keypadBuffer = "";
      lcd.clear();
      lcd.setCursor(0, 0); lcd.print("Entry Cleared");
      delay(1000);
      lcd.clear();
      lcd.setCursor(0, 0); lcd.print("Enter Value:");
    }
  }
}

void sendTelemetry(String lat, String lng, float battery) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("🚫 WiFi not connected!");
    return;
  }

  String url = String(tbServer) + "/api/v1/" + tbToken + "/telemetry";
  String payload = "{\"latitude\":" + lat + ",\"longitude\":" + lng + ",\"battery\":" + String(battery) + "}";

  HTTPClient http;
  http.begin(url);
  http.addHeader("Content-Type", "application/json");
  int httpCode = http.POST(payload);
  if (httpCode > 0) {
    Serial.print("✅ Telemetry sent! HTTP "); Serial.println(httpCode);
  } else {
    Serial.print("❌ Failed telemetry. HTTP "); Serial.println(httpCode);
  }
  http.end();
}

void sendKeypadValue(String value) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("🚫 WiFi not connected!");
    return;
  }

  String url = String(tbServer) + "/api/v1/" + tbToken + "/telemetry";
  String payload = "{\"keypad_value\":\"" + value + "\"}";

  HTTPClient http;
  http.begin(url);
  http.addHeader("Content-Type", "application/json");
  int httpCode = http.POST(payload);
  if (httpCode > 0) {
    Serial.print("✅ Keypad value sent! HTTP "); Serial.println(httpCode);
  } else {
    Serial.print("❌ Failed keypad send. HTTP "); Serial.println(httpCode);
  }
  http.end();
}

void sendMarkLocation(String lat, String lng) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("🚫 WiFi not connected!");
    return;
  }

  String url = String(tbServer) + "/api/v1/" + tbToken + "/telemetry";
  // Updated to overwrite main latitude & longitude
  String payload = "{\"latitude\":" + lat + ",\"longitude\":" + lng + "}";

  HTTPClient http;
  http.begin(url);
  http.addHeader("Content-Type", "application/json");
  int httpCode = http.POST(payload);
  if (httpCode > 0) {
    Serial.print("✅ Mark location sent! HTTP "); Serial.println(httpCode);
  } else {
    Serial.print("❌ Failed to send mark. HTTP "); Serial.println(httpCode);
  }
  http.end();
}