// ==========================================================
// HEALTHGUARD AI HEALTHCARE SYSTEM
// FINAL COMPLETE VERSION
// ESP32 + OLED + ECG + ThingSpeak + Telegram
// ==========================================================

#include <WiFi.h>
#include <HTTPClient.h>
#include <WiFiClientSecure.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <math.h>

// ================= WIFI =================

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

// ================= THINGSPEAK =================

String apiKey = "GXWQCVCZKNZQ9YDB";

// ================= TELEGRAM =================

String botToken = "8756116302:AAGrg2pjgnuDNO8pEMzT4nLIPTiJHyti9IA";
String chatID   = "7053488830";

// ================= OLED =================

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

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

// ================= PINS =================

#define BUZZER     13
#define LED_GREEN  25
#define LED_YELLOW 26
#define LED_RED    27

// ================= VARIABLES =================

float hr, spo2, sysBP, diaBP, bpm;

// ECG

float ecgX = 0;
int lastY = 32;
int xPos = 0;

// ================= DEMO =================

#define DEMO_DURATION 7000UL

int demoState = 0;

unsigned long demoStateStart = 0;

// ================= TIMING =================

unsigned long lastUpload = 0;
unsigned long lastAlert  = 0;

#define UPLOAD_INTERVAL 15000UL
#define ALERT_INTERVAL 5000UL

// ==========================================================
// ECG FUNCTION
// ==========================================================

float ecgFunc(float x) {

  return  0.12 * exp(-pow((x - 0.20) / 0.040, 2))
        - 0.25 * exp(-pow((x - 0.37) / 0.015, 2))
        + 1.20 * exp(-pow((x - 0.40) / 0.010, 2))
        - 0.35 * exp(-pow((x - 0.43) / 0.012, 2))
        + 0.35 * exp(-pow((x - 0.70) / 0.040, 2));
}

// ==========================================================
// DEMO STATES
// ==========================================================

void applyDemoState() {

  unsigned long now = millis();

  if (now - demoStateStart >= DEMO_DURATION) {

    demoState = (demoState + 1) % 3;

    demoStateStart = now;
  }

  // SAFE

  if (demoState == 0) {

    hr    = 82;
    spo2  = 98;
    sysBP = 118;
    diaBP = 78;
    bpm   = 80;
  }

  // ARRHYTHMIA

  else if (demoState == 1) {

    hr    = 123;
    spo2  = 95;
    sysBP = 140;
    diaBP = 92;
    bpm   = 110;
  }

  // STROKE

  else {

    hr    = 135;
    spo2  = 89;
    sysBP = 160;
    diaBP = 100;
    bpm   = 130;
  }
}

// ==========================================================
// THINGSPEAK
// ==========================================================

void uploadCloud() {

  if (WiFi.status() != WL_CONNECTED)
    return;

  HTTPClient http;

  String url =
    "http://api.thingspeak.com/update?api_key=" + apiKey +
    "&field1=" + String((int)hr) +
    "&field2=" + String((int)spo2) +
    "&field3=" + String((int)sysBP) +
    "&field4=" + String((int)diaBP) +
    "&field5=" + String((int)bpm);

  http.begin(url);

  int code = http.GET();

  Serial.print("ThingSpeak HTTP: ");
  Serial.println(code);

  http.end();
}

// ==========================================================
// TELEGRAM
// ==========================================================

void sendTelegram(String message) {

  if (WiFi.status() != WL_CONNECTED)
    return;

  WiFiClientSecure client;

  client.setInsecure();

  HTTPClient http;

  message.replace(" ", "%20");
  message.replace("\n", "%0A");

  String url =
    "https://api.telegram.org/bot" + botToken +
    "/sendMessage?chat_id=" + chatID +
    "&text=" + message;

  http.begin(client, url);

  int code = http.GET();

  Serial.print("Telegram HTTP: ");
  Serial.println(code);

  http.end();
}

// ==========================================================
// SETUP
// ==========================================================

void setup() {

  Serial.begin(115200);

  Wire.begin(21, 22);

  pinMode(BUZZER, OUTPUT);

  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_YELLOW, OUTPUT);
  pinMode(LED_RED, OUTPUT);

  // ================= OLED =================

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {

    Serial.println("OLED Failed");

    while (1);
  }

  display.clearDisplay();

  display.setTextColor(WHITE);

  display.setTextSize(1);

  display.setCursor(10, 20);
  display.println("HealthGuard AI");

  display.setCursor(10, 35);
  display.println("System Ready");

  display.display();

  // ================= WIFI =================

  WiFi.begin(ssid, password);

  Serial.print("Connecting WiFi");

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

    delay(500);

    Serial.print(".");
  }

  Serial.println("\nWiFi Connected");

  Serial.println(WiFi.localIP());

  sendTelegram("✅ HealthGuard System Started");

  delay(2000);

  display.clearDisplay();

  demoStateStart = millis();
}

// ==========================================================
// LOOP
// ==========================================================

void loop() {

  // ================= DEMO =================

  applyDemoState();

  String statusText = "";

  // RESET OUTPUTS

  digitalWrite(LED_GREEN, LOW);
  digitalWrite(LED_YELLOW, LOW);
  digitalWrite(LED_RED, LOW);

  noTone(BUZZER);

  // ================= SAFE =================

  if (demoState == 0) {

    statusText = "STATUS SAFE";

    digitalWrite(LED_GREEN, HIGH);
  }

  // ================= ARRHYTHMIA =================

  else if (demoState == 1) {

    statusText = "! ARRHYTHMIA !";

    digitalWrite(LED_YELLOW, HIGH);

    tone(BUZZER, 1000);
  }

  // ================= STROKE =================

  else {

    statusText = "** STROKE ALERT **";

    digitalWrite(LED_RED, HIGH);

    tone(BUZZER, 2000);
  }

  unsigned long now = millis();

  // ================= THINGSPEAK =================

  if (now - lastUpload >= UPLOAD_INTERVAL) {

    lastUpload = now;

    uploadCloud();
  }

  // ================= TELEGRAM =================

  if (now - lastAlert >= ALERT_INTERVAL) {

    lastAlert = now;

    // ARRHYTHMIA

    if (demoState == 1) {

      sendTelegram(
        "🚨 HEALTH ALERT 🚨\n\n"
        "⚠️ Arrhythmia Detected\n\n"

        "❤️ HR: " + String((int)hr) +
        "\n🫁 SpO2: " + String((int)spo2) +
        "\n🩸 BP: " + String((int)sysBP) + "/" + String((int)diaBP) +
        "\n📈 BPM: " + String((int)bpm) +

        "\n\n📍 Patient Location:"
        "\nhttps://maps.google.com/?q=11.0168,76.9558"

        "\n\n🏥 Nearby Hospitals:"
        "\n1. KMCH Hospital - 2.4 km"
        "\n2. Ganga Hospital - 3.1 km"
        "\n3. PSG Hospital - 4.8 km"

        "\n\n🚑 Immediate monitoring recommended"
      );
    }

    // STROKE

    else if (demoState == 2) {

      sendTelegram(
        "🚨 CRITICAL HEALTH ALERT 🚨\n\n"
        "🧠 Stroke Risk Detected\n\n"

        "❤️ HR: " + String((int)hr) +
        "\n🫁 SpO2: " + String((int)spo2) +
        "\n🩸 BP: " + String((int)sysBP) + "/" + String((int)diaBP) +
        "\n📈 BPM: " + String((int)bpm) +

        "\n\n📍 Patient Location:"
        "\nhttps://maps.google.com/?q=11.0168,76.9558"

        "\n\n🏥 Nearby Emergency Hospitals:"
        "\n1. KMCH Hospital - 2.4 km"
        "\n2. Ganga Hospital - 3.1 km"
        "\n3. PSG Hospital - 4.8 km"

        "\n\n🚑 Emergency medical attention required immediately"
      );
    }
  }

  // =====================================================
  // OLED UPDATE
  // =====================================================

  // CLEAR TOP + STATUS ONLY

  display.fillRect(0, 0, 128, 16, BLACK);

  display.fillRect(0, 54, 128, 10, BLACK);

  // ================= TOP INFO =================

  display.setTextSize(1);

  display.setCursor(0, 0);
  display.print("HR:");
  display.print((int)hr);

  display.setCursor(64, 0);
  display.print("SpO2:");
  display.print((int)spo2);

  display.setCursor(0, 8);
  display.print("BP:");
  display.print((int)sysBP);
  display.print("/");
  display.print((int)diaBP);

  display.setCursor(64, 8);
  display.print("BPM:");
  display.print((int)bpm);

  // ================= ECG =================

  float yVal = ecgFunc(fmod(ecgX, 1.0));

  int y = 42 - (int)(yVal * 25);

  display.drawLine(xPos, lastY, xPos + 1, y, WHITE);

  lastY = y;

  xPos++;

  if (xPos >= 128) {

    xPos = 0;

    // CLEAR ONLY ECG AREA

    display.fillRect(0, 16, 128, 34, BLACK);
  }

  ecgX += 0.01;

  // ================= STATUS =================

  display.fillRect(0, 54, 128, 10, BLACK);

  display.setCursor(0, 54);

  display.print(statusText);

  // SHOW OLED

  display.display();

  delay(100);
}