// ESP32 Air Quality Demo for Wokwi
// DHT22 + SSD1306 OLED + NeoPixel + Buzzer + ThingSpeak HTTP upload
// PM2.5 simulated via Serial: PM=<value> (e.g., PM=160)
//
// Wiring (Wokwi labels):
//   DHT22 : DATA->GPIO19 (esp:19), VCC->3V3, GND->GND
//   OLED  : SDA->GPIO21, SCL->GPIO22, VCC->3V3, GND->GND
//   NeoPx : DIN->GPIO4, VDD->5V, VSS->GND
//   Buzzer: +->GPIO15, - ->GND
//
// This build focuses on the mini chart + EMA smoothing only.
// Removed: MQTT, Telegram (kept quiet-hours, adaptive upload, profile advice).
//
// Libraries: Adafruit GFX, Adafruit SSD1306, Adafruit NeoPixel, DHT sensor library
// Timezone: Asia/Ho_Chi_Minh (UTC+7) via NTP.

#include <WiFi.h>
#include <HTTPClient.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_NeoPixel.h>
#include "DHT.h"
#include <Wire.h>
#include <Preferences.h>
#include <time.h>

// ---------------- Pins ----------------
#define PIN_DHT     19
#define PIN_SDA     21
#define PIN_SCL     22
#define PIN_NEOPX   4
#define PIN_BUZZER  15
#define DHTTYPE DHT22

// ---------------- Defaults ----------------
#define DEFAULT_PROFILE     1     // 0=Adult, 1=Child, 2=Elderly
#define DEFAULT_QH_START    22    // 22:00
#define DEFAULT_QH_END       6    // 06:00
#define DEFAULT_QH_ENABLE    1
#define DEFAULT_BUZZ_EN      1
#define DEFAULT_UPLOAD_S     30   // 30s base
#define DEFAULT_UPLOADMAX_S  300  // 5min cap

// ---------------- WiFi & ThingSpeak ----------------
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASS = "";
const char* TS_WRITE_KEY = "PUT_YOUR_TS_WRITE_KEY_HERE";

// ---------------- Objects ----------------
Adafruit_SSD1306 display(128, 64, &Wire, -1);
Adafruit_NeoPixel pixels(1, PIN_NEOPX, NEO_GRB + NEO_KHZ800);
DHT dht(PIN_DHT, DHTTYPE);
Preferences prefs;

// ---------------- State ----------------
float pm25 = 12.0; // simulated PM2.5 (µg/m³)
int   patientProfile;
int   quietStart, quietEnd;
bool  quietEnabled;
bool  buzzerEnabled;
unsigned long baseUploadMs, maxUploadMs;

float tempOverride = NAN;
float humOverride  = NAN;

int    failStreak = 0;
float  aqiEma = NAN;
const float EMA_ALPHA = 0.3f;

unsigned long lastUpload = 0;
int    lastUploadedAQI = -999;
float  lastUploadedPM  = -999;

// Mini chart buffer (≈100 seconds history)
const int CHART_W = 128;
const int CHART_H = 20;
const int CHART_N = 100;
int chartBuf[CHART_N];
int chartIdx = 0;
bool chartFilled = false;

// ---------------- Helpers ----------------
int computeAQI_PM25(float c) {
  if (isnan(c)) return -1;
  struct Brk { float Cl; float Ch; int Il; int Ih; };
  Brk bk[] = {
    {0.0, 12.0, 0, 50}, {12.1, 35.4, 51, 100}, {35.5, 55.4, 101,150},
    {55.5,150.4,151,200}, {150.5,250.4,201,300}, {250.5,350.4,301,400},
    {350.5,500.4,401,500}
  };
  for (auto &b : bk) {
    if (c >= b.Cl && c <= b.Ch) {
      return (int)round((b.Ih - b.Il) * (c - b.Cl) / (b.Ch - b.Cl) + b.Il);
    }
  }
  return 500;
}

String aqiCategory(int aqi) {
  if (aqi <= 50)   return "Tot";
  if (aqi <= 100)  return "Trung binh";
  if (aqi <= 150)  return "Nhay cam";
  if (aqi <= 200)  return "Xau";
  if (aqi <= 300)  return "Rat xau";
  return "Nguy hiem";
}

String profileLabel(int p) {
  if (p == 1) return "Tre em";
  if (p == 2) return "Nguoi gia";
  return "Nguoi lon";
}

// Advice by AQI band + profile + humidity tweak
String adviceForProfile(int aqi, float T, float H, int p) {
  String msg;
  if (p == 1) { // Child
    if (aqi <= 100)      msg = "Tre em: choi nhe trong nha.";
    else if (aqi <= 150) msg = "Giam hoat dong ngoai troi; tranh chay nhay; deo N95 khi can.";
    else if (aqi <= 200) msg = "O trong nha; bat may loc; N95 neu ra ngoai; theo doi ho/kho tho.";
    else if (aqi <= 300) msg = "O trong nha; dong cua; N95 bat buoc neu buoc ra ngoai; theo doi sat.";
    else                 msg = "Tranh ra ngoai; dung thuoc cap cuu neu kho tho; lien he y te neu nang.";
  } else if (p == 2) { // Elderly
    if (aqi <= 100)      msg = "Nguoi gia: hoat dong nhe trong nha.";
    else if (aqi <= 150) msg = "Giam van dong ngoai troi; deo N95 khi can; uong du nuoc.";
    else if (aqi <= 200) msg = "O trong nha; N95 neu ra ngoai; tranh mang vat nang, leo cau thang.";
    else if (aqi <= 300) msg = "O trong nha; dong cua; N95 bat buoc; theo doi nhip tho, dau nguc.";
    else                 msg = "Tranh di chuyen; goi nguoi ho tro; lien he y te neu kho tho.";
  } else { // Adult
    if (aqi <= 100)      msg = "Co the hoat dong binh thuong.";
    else if (aqi <= 150) msg = "Nhom nhay cam: han che ra ngoai.";
    else if (aqi <= 200) msg = "Deo N95; bat may loc; han che van dong manh.";
    else if (aqi <= 300) msg = "O trong nha; dong cua; N95 neu buoc ra ngoai.";
    else                 msg = "Tranh ra ngoai; N95 bat buoc; lien he y te neu kho tho.";
  }
  if (!isnan(H)) {
    if (H < 40) msg += " Do am <40% de kich ung.";
    else if (H > 70) msg += " Do am >70% de kho tho.";
  }
  return msg;
}

// tiny warning icon (triangle + "!") for OLED (monochrome)
void drawWarningIcon(int x, int y) {
  display.drawTriangle(x, y+20, x+10, y, x+20, y+20, SSD1306_WHITE);
  display.fillRect(x+9, y+6, 2, 8, SSD1306_WHITE);
  display.fillRect(x+9, y+16, 2, 2, SSD1306_WHITE);
}

void setPixel(uint8_t r, uint8_t g, uint8_t b, uint8_t brightness=40) {
  pixels.setBrightness(brightness);
  pixels.setPixelColor(0, pixels.Color(r,g,b));
  pixels.show();
}

// Quiet hours helpers
bool isQuietNow() {
  if (!quietEnabled) return false;
  struct tm ti;
  if (getLocalTime(&ti, 100)) {
    int h = ti.tm_hour;
    bool q = (quietStart <= quietEnd) ? (h >= quietStart && h < quietEnd)
                                      : (h >= quietStart || h < quietEnd);
    return q;
  }
  return false;
}

// Buzzer
void beep(int freq, int ms){
  if (!buzzerEnabled) return;
  if (isQuietNow()) return;
  tone(PIN_BUZZER, freq, ms);
  delay(ms + 10);
  noTone(PIN_BUZZER);
}

// ---------- NVS ----------
void saveSettings() {
  prefs.begin("aqmon", false);
  prefs.putInt("profile", patientProfile);
  prefs.putInt("qStart", quietStart);
  prefs.putInt("qEnd",   quietEnd);
  prefs.putBool("qEn",   quietEnabled);
  prefs.putBool("bzEn",  buzzerEnabled);
  prefs.putULong("upBase", baseUploadMs);
  prefs.putULong("upMax",  maxUploadMs);
  prefs.end();
}
void loadSettings() {
  prefs.begin("aqmon", true);
  patientProfile = prefs.getInt("profile", DEFAULT_PROFILE);
  quietStart     = prefs.getInt("qStart", DEFAULT_QH_START);
  quietEnd       = prefs.getInt("qEnd",   DEFAULT_QH_END);
  quietEnabled   = prefs.getBool("qEn",   DEFAULT_QH_ENABLE);
  buzzerEnabled  = prefs.getBool("bzEn",  DEFAULT_BUZZ_EN);
  baseUploadMs   = prefs.getULong("upBase", DEFAULT_UPLOAD_S * 1000UL);
  maxUploadMs    = prefs.getULong("upMax",  DEFAULT_UPLOADMAX_S * 1000UL);
  prefs.end();
}

// ---------- Serial ----------
void printHelp() {
  Serial.println("Commands:");
  Serial.println("  PM=<value>                 set PM2.5 in ug/m3 (0..1000)");
  Serial.println("  TEMP=<val|CLR>             override temperature (-40..85 C) or CLR");
  Serial.println("  HUM=<val|CLR>              override humidity (0..100 %) or CLR");
  Serial.println("  MODE=ADULT|CHILD|ELDERLY   switch patient profile (saved)");
  Serial.println("  QH=HH-HH | QH=OFF          quiet hours start-end (24h) or disable (saved)");
  Serial.println("  BUZZ=ON|OFF                enable/disable buzzer (saved)");
  Serial.println("  UPLOAD=<sec>               base upload interval seconds (saved)");
  Serial.println("  UPLOADMAX=<sec>            max upload/backoff cap seconds (saved)");
  Serial.println("  PUSH                       force immediate ThingSpeak upload");
  Serial.println("  TIME?                      show local time");
  Serial.println("  STATUS                     print current state");
  Serial.println("  HELP                       show this help");
}

void handleSerial() {
  static String buf;
  while (Serial.available()) {
    char c = Serial.read();
    if (c=='\n' || c=='\r') {
      buf.trim();
      if (buf.length() == 0) { buf=""; continue; }

      String up = buf; up.toUpperCase();

      if (up.startsWith("PM=")) {
        float v = up.substring(3).toFloat();
        if (v>=0 && v<=1000) { pm25 = v; Serial.printf("[OK] PM2.5=%.1f\n", pm25); }
        else Serial.println("[ERR] PM must be 0..1000");

      } else if (up.startsWith("TEMP=")) {
        String arg = up.substring(5); arg.trim();
        if (arg == "CLR") { tempOverride = NAN; Serial.println("[OK] TEMP override cleared"); }
        else { float v = arg.toFloat(); if (v>=-40 && v<=85) { tempOverride=v; Serial.printf("[OK] TEMP=%.1f\n", v);} else Serial.println("[ERR] TEMP -40..85"); }

      } else if (up.startsWith("HUM=")) {
        String arg = up.substring(4); arg.trim();
        if (arg == "CLR") { humOverride = NAN; Serial.println("[OK] HUM override cleared"); }
        else { float v = arg.toFloat(); if (v>=0 && v<=100) { humOverride=v; Serial.printf("[OK] HUM=%.1f\n", v);} else Serial.println("[ERR] HUM 0..100"); }

      } else if (up.startsWith("MODE=")) {
        String m = up.substring(5); m.trim(); m.toUpperCase();
        if (m=="ADULT"||m=="NGUOILON") patientProfile=0;
        else if (m=="CHILD"||m=="TREEM"||m=="TRE") patientProfile=1;
        else if (m=="ELDERLY"||m=="OLD"||m=="NGUOIGIA") patientProfile=2;
        else { Serial.println("[ERR] MODE must be ADULT/CHILD/ELDERLY"); buf=""; continue; }
        saveSettings(); Serial.printf("[OK] Profile=%s\n", profileLabel(patientProfile).c_str());

      } else if (up.startsWith("QH=")) {
        String arg = up.substring(3); arg.trim(); arg.toUpperCase();
        if (arg=="OFF") { quietEnabled=false; saveSettings(); Serial.println("[OK] Quiet hours OFF"); }
        else {
          int dash = arg.indexOf('-');
          if (dash>0) {
            int s = arg.substring(0,dash).toInt();
            int e = arg.substring(dash+1).toInt();
            if (s>=0&&s<=23&&e>=0&&e<=23) { quietStart=s; quietEnd=e; quietEnabled=true; saveSettings(); Serial.printf("[OK] QH %02d-%02d\n", s,e); }
            else Serial.println("[ERR] QH HH-HH 0..23");
          } else Serial.println("[ERR] QH HH-HH or OFF");
        }

      } else if (up.startsWith("BUZZ=")) {
        String arg = up.substring(5); arg.trim(); arg.toUpperCase();
        if (arg=="ON") { buzzerEnabled=true; saveSettings(); Serial.println("[OK] Buzzer ON"); }
        else if (arg=="OFF") { buzzerEnabled=false; saveSettings(); Serial.println("[OK] Buzzer OFF"); }
        else Serial.println("[ERR] BUZZ=ON|OFF");

      } else if (up.startsWith("UPLOADMAX=")) {
        unsigned long s = up.substring(10).toInt(); if (s>=15&&s<=3600){maxUploadMs=s*1000UL; saveSettings(); Serial.printf("[OK] UploadMax=%lus\n", s);} else Serial.println("[ERR] 15..3600");

      } else if (up.startsWith("UPLOAD=")) {
        unsigned long s = up.substring(7).toInt(); if (s>=15&&s<=3600){baseUploadMs=s*1000UL; saveSettings(); Serial.printf("[OK] UploadBase=%lus\n", s);} else Serial.println("[ERR] 15..3600");

      } else if (up=="PUSH") { lastUpload=0; Serial.println("[OK] Will upload soon"); }
      else if (up=="TIME?") { struct tm ti; if (getLocalTime(&ti, 1000)){ char b[32]; strftime(b,sizeof(b),"%Y-%m-%d %H:%M:%S",&ti); Serial.printf("Local: %s\n", b);} else Serial.println("Time not synced."); }
      else if (up=="STATUS") {
        Serial.printf("Profile:%s | QH:%s %02d-%02d | Buzzer:%s\n", profileLabel(patientProfile).c_str(), quietEnabled?"ON":"OFF", quietStart, quietEnd, buzzerEnabled?"ON":"OFF");
        Serial.printf("Upload base=%lus, max=%lus, failStreak=%d\n", baseUploadMs/1000UL, maxUploadMs/1000UL, failStreak);
        Serial.printf("PM2.5:%.1f AQI(EMA):%.0f\n", pm25, aqiEma);
      } else if (up=="HELP") printHelp();
      else Serial.println("[ERR] Unknown. Type HELP");

      buf = "";
    } else {
      buf += c;
    }
  }
}

// ---------- Connectivity & uploads ----------
void ensureWiFi() {
  if (WiFi.status() == WL_CONNECTED) return;
  Serial.printf("Connecting WiFi: %s\n", WIFI_SSID);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  unsigned long t0 = millis();
  while (WiFi.status() != WL_CONNECTED && millis()-t0 < 15000) { delay(500); Serial.print("."); }
  if (WiFi.status()==WL_CONNECTED) Serial.printf("\nWiFi OK, IP: %s\n", WiFi.localIP().toString().c_str());
  else Serial.println("\nWiFi failed.");
}

bool uploadThingSpeak(float pm25, int aqi, float t, float h) {
  ensureWiFi();
  if (WiFi.status() != WL_CONNECTED) return false;
  HTTPClient http;
  String url = String("https://api.thingspeak.com/update?api_key=") + TS_WRITE_KEY +
               "&field1=" + String(pm25,1) +
               "&field2=" + String(aqi) +
               "&field3=" + String(t,1) +
               "&field4=" + String(h,1);
  http.begin(url);
  http.setTimeout(10000);
  http.setUserAgent("ESP32-AQMon");
  int code = http.GET();
  bool ok = false;
  if (code > 0) {
    String payload = http.getString();
    Serial.printf("[ThingSpeak] HTTP %d, response: %s\n", code, payload.c_str());
    ok = (code == 200 && payload.toInt() > 0);
  } else {
    Serial.printf("[ThingSpeak] HTTP error: %d\n", code);
  }
  http.end();
  return ok;
}

// ---------- Mini Chart ----------
void chartPush(int aqi) {
  chartBuf[chartIdx] = constrain(aqi, 0, 500);
  chartIdx = (chartIdx + 1) % CHART_N;
  if (chartIdx == 0) chartFilled = true;
}

int mapAQIToChartY(int aqi) {
  // scale AQI 0..500 to chart height (1..CHART_H-2) with top origin
  int v = map(aqi, 0, 500, CHART_H-2, 1);
  if (v < 1) v=1; if (v>CHART_H-2) v=CHART_H-2;
  return v;
}

void drawChart(int x, int y) {
  // frame
  display.drawRect(x, y, CHART_W, CHART_H, SSD1306_WHITE);
  int count = chartFilled ? CHART_N : chartIdx;
  if (count < 2) return;

  // guide lines at ~AQI 150 and 300
  int y150 = y + mapAQIToChartY(150);
  int y300 = y + mapAQIToChartY(300);
  display.drawFastHLine(x+1, y150, CHART_W-2, SSD1306_WHITE);
  display.drawFastHLine(x+1, y300, CHART_W-2, SSD1306_WHITE);

  // draw line right-to-left to fit window width
  int w = CHART_W - 2;
  int step = max(1, count > w ? (count / w) : 1);
  int xi = CHART_W - 2;
  int idx = (chartIdx - 1 + CHART_N) % CHART_N;
  int prevY = mapAQIToChartY(chartBuf[idx]);
  for (int i = 1; i < count; i += step) {
    idx = (chartIdx - 1 - i + CHART_N) % CHART_N;
    int yy = mapAQIToChartY(chartBuf[idx]);
    // points inside chart box: offset by +1/+1
    display.drawLine(x+1+xi, y+prevY, x+1+xi-1, y+yy, SSD1306_WHITE);
    prevY = yy;
    xi -= 1;
    if (xi <= 0) break;
  }
}

// ---------- Setup & Loop ----------
void setup() {
  Serial.begin(115200);
  Serial.println("ESP32 – Air Quality + Mini Chart + ThingSpeak");
  Serial.println("Type HELP for commands.");

  // Load persisted settings
  loadSettings();
  Serial.printf("Loaded: Profile=%s, QH:%s %02d-%02d, Buzzer:%s, UpBase=%lus, UpMax=%lus\n",
    profileLabel(patientProfile).c_str(), quietEnabled? "ON":"OFF", quietStart, quietEnd,
    buzzerEnabled? "ON":"OFF", baseUploadMs/1000UL, maxUploadMs/1000UL);

  // Timezone UTC+7
  configTime(7*3600, 0, "pool.ntp.org", "time.nist.gov");

  Wire.begin(PIN_SDA, PIN_SCL);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("[WARN] SSD1306 not found.");
  } else {
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
  }

  dht.begin();
  pixels.begin();
  setPixel(0,0,0,0);

  pinMode(PIN_BUZZER, OUTPUT);
  digitalWrite(PIN_BUZZER, LOW);

  ensureWiFi();

  // randomize first upload slightly
  lastUpload = millis() + random(0, 5000);
}

void loop() {
  handleSerial();

  // Read sensors (or overrides)
  float temp = dht.readTemperature();
  float humid = dht.readHumidity();
  if (!isnan(tempOverride))  temp  = tempOverride;
  if (!isnan(humOverride)) humid = humOverride;
  if (isnan(temp))  temp  = 0;
  if (isnan(humid)) humid = 0;

  // AQI + smoothing (EMA)
  int aqi = computeAQI_PM25(pm25);
  if (isnan(aqiEma)) aqiEma = aqi;
  else               aqiEma = EMA_ALPHA*aqi + (1-EMA_ALPHA)*aqiEma;
  int aqiDisp = (int)round(aqiEma);

  // push AQI to chart buffer every ~1s
  static unsigned long lastChartPush = 0;
  if (millis() - lastChartPush > 1000) {
    chartPush(aqiDisp);
    lastChartPush = millis();
  }

  // OLED UI
  if (display.width() > 0) {
    // dim during quiet hours
    display.dim(isQuietNow());

    display.clearDisplay();
    display.setCursor(0,0);
    display.setTextSize(1);
    display.print("AQ Monitor | P: "); display.println(profileLabel(patientProfile));

    display.print("PM2.5: "); display.print(pm25,1); display.println(" ug/m3");
    display.print("AQI  : "); display.print(aqiDisp); display.print(" ("); display.print(aqiCategory(aqiDisp)); display.println(")");
    display.print("T: "); display.print(temp,1); display.print("C  H: "); display.print(humid,0); display.println("%");

    if (aqiDisp >= 151) {
      display.setTextSize(2);
      display.println("CANH BAO");
      display.setTextSize(1);
      drawWarningIcon(104, 0);
    } else {
      display.println("Trang thai on dinh.");
    }

    // Advice (2 lines)
    String adv = adviceForProfile(aqiDisp, temp, humid, patientProfile);
    for (int i = 0; i < adv.length() && i < 42; i += 21) {
      int end = i + 21; if (end > adv.length()) end = adv.length();
      display.println(adv.substring(i, end));
    }

    // Mini chart at bottom (x=0,y=44 height=20)
    drawChart(0, 44);

    display.display();
  }

  // LED color by AQI EMA
  if (aqiDisp <= 50)        setPixel(0, 180, 0);
  else if (aqiDisp <= 100)  setPixel(200, 120, 0);
  else if (aqiDisp <= 150)  setPixel(255, 80, 0);
  else if (aqiDisp <= 300)  setPixel(200, 0, 0);
  else                      setPixel(200, 0, 200);

  // Beep pattern by severity every 10s
  static unsigned long lastBeep = 0;
  if (aqiDisp >= 151 && millis() - lastBeep > 10000) {
    int n = (aqiDisp > 300) ? 4 : (aqiDisp > 200) ? 3 : 2;
    for (int i=0; i<n; ++i) { beep(2000, 150); delay(120); }
    lastBeep = millis();
  }

  // Adaptive ThingSpeak upload
  unsigned long now = millis();
  unsigned long interval = baseUploadMs;
  if (failStreak > 0) {
    unsigned long back = baseUploadMs << (failStreak > 4 ? 4 : failStreak);
    if (back > maxUploadMs) back = maxUploadMs;
    interval = back;
  }
  if (abs(aqiDisp - lastUploadedAQI) < 5 && fabs(pm25 - lastUploadedPM) < 3.0) {
    if (interval < 120000UL) interval = 120000UL;
  }
  if (now - lastUpload >= interval) {
    bool ok = uploadThingSpeak(pm25, aqiDisp, temp, humid);
    if (ok) {
      failStreak = 0; lastUploadedAQI = aqiDisp; lastUploadedPM = pm25; lastUpload = now + random(0,3000);
    } else {
      failStreak++; lastUpload = now + 5000UL;
    }
  }

  delay(200);
}