/*
  ESP2_HMI_Gateway_AllInOne.ino
  Purificadora Contactor - Dual ESP32 system
  ESP#2 = HMI + Sensor T3 (AJ-SR04M crudo) + keypad 4x4 + LCD 20x4 I2C + UDP

  Features included (hasta el momento):
   - WiFi STA conectándose al AP PURIF_CTRL (sin internet)
   - Lee T3 por AJ-SR04M y envía a ESP1 por UDP: T3=..;OK=..;SEQ=..;
   - LCD20x4 I2C (SDA=21, SCL=22)
   - Keypad 4x4 con menú:
        HOME (A=Menu, D=Info, C=Diag)
        Menu principal: Duración, Umbrales, Calibración, MQTT Config
        Duración: AUTO/60/120/180/240 (envía CMD=DUR)
        Umbrales: LOW/HIGH/RAW (edición + confirm, envía CMD=THR)
        Calibración: T1/T2 (vía ESP1) y T3 local
        MQTT Config: EN, IP, PORT (guarda en NVS local y manda CMD=MQTT a ESP1)
   - INFO: muestra IP/RSSI local, estado ESP1, y rota: fail counters / uptime / MQTT short
   - DIAG industrial: muestra STA/RSSI/IP, MQTT EN/CONN/host:port, MQF/MQERR/MQAGE, NTP/NTPAGE/HEAP/RST
   - Acciones mantenimiento desde INFO/DIAG:
        INFO: # reset fails (CMD=RSTFAIL)
        DIAG: # reset mqtt fails (CMD=RSTMQ)
              * reintento STA (CMD=STARETRY)
              A forzar NTP (CMD=NTP)
              D reiniciar ESP1 (confirmación)
*/

#include <WiFi.h>
#include <WiFiUdp.h>
#include <Wire.h>
#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <Preferences.h>

// ---------------- WIFI / UDP ----------------
const char* FW_VER = "ESP2-HMI v1.6";

const char* WIFI_SSID = "PURIF_CTRL";
const char* WIFI_PASS = "12345678";
IPAddress ESP1_IP(192,168,4,1);

const uint16_t UDP_PORT_TX_TO_ESP1   = 4210;
const uint16_t UDP_PORT_RX_FROM_ESP1 = 4211;

WiFiUDP udp;

// ---------------- LCD ----------------
LiquidCrystal_I2C lcd(0x27, 20, 4);

// ---------------- Keypad 4x4 ----------------
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
// PINS keypad (ejemplo). Ajusta si tu cableado es diferente.
byte rowPins[ROWS] = {13, 14, 18, 19};
byte colPins[COLS] = {25, 26, 27, 33};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// ---------------- Sensor T3 (AJ-SR04M) ----------------
const int PIN_T3_TRIG = 15;
const int PIN_T3_ECHO = 34; // input-only ok
float T3_DIST_EMPTY_CM = 180.0f;
float T3_DIST_FULL_CM  = 25.0f;

// ---------------- NVS local ESP2 ----------------
Preferences prefs;
const char* PREF_NS2 = "purif2";

// MQTT config stored in ESP2 and sent to ESP1
bool mqtt_en = false;
String mqtt_ip = "192.168.4.2";
int mqtt_port = 1883;

// ---------------- State from ESP1 ----------------
float t1_pct = NAN, t2_pct = NAN, t3_pct_remote = NAN;
String modeStr = "OFF", whyStr = "OK";
String proc_state = "STBY", proc_cyc = "IDLE";
int rem_sec = -1, sessrem_sec = -1;

float thr_low = NAN, thr_high = NAN, thr_raw = NAN;

// Calibration info from ESP1
float t1_cm = NAN, t2_cm = NAN;
float t1_e = NAN, t1_f = NAN, t2_e = NAN, t2_f = NAN;

// Heartbeat/Uptime from ESP1
int esp1_hb = 0;
uint32_t esp1_up_s = 0;
int esp2ok_remote = -1;
uint32_t esp2age_remote_ms = 0;

// Fail counters from ESP1
uint32_t fc_comm = 0, fc_sens = 0, fc_raw = 0;

// STA/MQTT status from ESP1
int sta_on = 0;
String sta_ip = "0.0.0.0";

int mq_en_remote = 0;
int mq_conn = 0;
String mq_host = "";
int mq_port = 0;

// DIAG from ESP1
int rssi_sta = -127;
uint32_t mqf = 0;
int mqerr = 0;
uint32_t mqage = 0;
int ntp_ok = 0;
uint32_t ntpage = 0;
uint32_t heap_free = 0;
String rst = "";

// Watchdog ESP1
uint32_t lastEsp1RxMs = 0;
const uint32_t ESP1_OFFLINE_MS = 4000;

// ---------------- UI ----------------
enum ScreenMode {
  HOME=0,
  MENU_MAIN,

  MENU_DUR,
  CONFIRM_DUR,

  MENU_THR,
  EDIT_LOW,
  EDIT_HIGH,
  EDIT_RAW,
  CONFIRM_THR,

  MENU_CAL,
  CAL_VIEW,
  CAL_CONFIRM,

  MENU_MQTT,
  EDIT_MQTT_IP,
  EDIT_MQTT_PORT,
  CONFIRM_MQTT_SEND,

  MAINT,

  INFO,
  DIAG,
  CONFIRM_RST_ESP1
};

ScreenMode screen = HOME;

// --- Keypad diagnostics ---
char lastKey = 0;
uint32_t lastKeyMs = 0;
String lastKeyStr() {
  if (!lastKey) return String("-");
  return String(lastKey);
}


int selectedDurationMin = 60;
String editBuf;

int calTank = 1;
String calPendingAct = "";

// Home rotator
uint32_t homeRotateMs = 0;
int homeRotateIdx = 0;
const uint32_t HOME_ROTATE_PERIOD_MS = 3000;

// Quick message overlay (for short menu)
String quickMsg = "";
uint32_t quickMsgUntilMs = 0;


// DIAG rotator
int diagIdx = 0;
uint32_t diagMs = 0;

// ---------------- helpers ----------------
void lcdPrintLine(uint8_t row, const String &text) {
  lcd.setCursor(0, row);
  String t = text;
  while (t.length() < 20) t += ' ';
  lcd.print(t.substring(0, 20));
}
String fmtPct(float v) {
  if (isnan(v) || v < 0) return "--.-";
  char b[8]; snprintf(b, sizeof(b), "%4.1f", v);
  return String(b);
}
String fmtMMSS(int sec) {
  if (sec < 0) return "--:--";
  int m = sec / 60, s = sec % 60;
  char b[8]; snprintf(b, sizeof(b), "%02d:%02d", m, s);
  return String(b);
}
String fmtVal(float v) {
  if (isnan(v) || v < 0) return "--";
  char b[10]; snprintf(b, sizeof(b), "%4.1f", v);
  return String(b);
}
void editBufBackspace(){ if (editBuf.length()>0) editBuf.remove(editBuf.length()-1); }
bool editBufToFloat(float &out){ if (editBuf.length()==0) return false; out = editBuf.toFloat(); return true; }

bool esp1Online() { return (lastEsp1RxMs != 0) && (millis() - lastEsp1RxMs <= ESP1_OFFLINE_MS); }
uint32_t esp1AgeMs() { if (lastEsp1RxMs == 0) return 999999; return millis() - lastEsp1RxMs; }

String fmtAge(uint32_t s){
  if (s > 99999) return "--";
  if (s < 60) return String(s) + "s";
  uint32_t m = s/60;
  if (m < 60) return String(m) + "m";
  uint32_t h = m/60;
  return String(h) + "h";
}

// ---------------- T3 SR04M ----------------
float readDistanceCmOnceT3() {
  digitalWrite(PIN_T3_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(PIN_T3_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_T3_TRIG, LOW);
  uint32_t dur = pulseIn(PIN_T3_ECHO, HIGH, 30000);
  if (dur == 0) return NAN;
  return (float)dur / 58.2f;
}
float median5(float a[5]) {
  for (int i=0;i<5;i++)
    for (int j=i+1;j<5;j++)
      if (a[j] < a[i]) { float t=a[i]; a[i]=a[j]; a[j]=t; }
  return a[2];
}
bool readT3cm(float &cmOut) {
  float vals[5]; int ok=0;
  for (int i=0;i<5;i++){
    float cm = readDistanceCmOnceT3();
    if (!isnan(cm) && cm>2 && cm<400) vals[ok++] = cm;
    delay(30);
  }
  if (ok < 3) return false;
  while (ok < 5) { vals[ok] = vals[ok-1]; ok++; }
  cmOut = median5(vals);
  return true;
}
bool cmToPct(float cm, float distEmpty, float distFull, float &pctOut){
  float denom = (distEmpty - distFull);
  if (fabs(denom) < 1e-3) return false;
  float pct = (distEmpty - cm) / denom * 100.0f;
  if (pct < 0) pct = 0;
  if (pct > 100) pct = 100;
  pctOut = pct;
  return true;
}
bool readT3(float &cmOut, float &pctOut) {
  if (!readT3cm(cmOut)) return false;
  if (!cmToPct(cmOut, T3_DIST_EMPTY_CM, T3_DIST_FULL_CM, pctOut)) return false;
  return true;
}

// ---------------- NVS local ----------------
void loadLocalConfig() {
  prefs.begin(PREF_NS2, true);
  T3_DIST_EMPTY_CM = prefs.getFloat("t3e", T3_DIST_EMPTY_CM);
  T3_DIST_FULL_CM  = prefs.getFloat("t3f", T3_DIST_FULL_CM);

  mqtt_en = prefs.getBool("mq_en", mqtt_en);
  mqtt_ip = prefs.getString("mq_ip", mqtt_ip.c_str());
  mqtt_port = prefs.getInt("mq_port", mqtt_port);

  prefs.end();
}
void saveLocalConfig() {
  prefs.begin(PREF_NS2, false);
  prefs.putFloat("t3e", T3_DIST_EMPTY_CM);
  prefs.putFloat("t3f", T3_DIST_FULL_CM);

  prefs.putBool("mq_en", mqtt_en);
  prefs.putString("mq_ip", mqtt_ip);
  prefs.putInt("mq_port", mqtt_port);

  prefs.end();
}

// ---------------- UDP ----------------
void udpSendToEsp1(const String &payload) {
  udp.beginPacket(ESP1_IP, UDP_PORT_TX_TO_ESP1);
  udp.write((const uint8_t*)payload.c_str(), payload.length());
  udp.endPacket();
}

// Commands to ESP1
void sendDurCmd(int minutes) { udpSendToEsp1("CMD=DUR;MIN=" + String(minutes) + ";"); }


void sendMaintStartFixed(int minutes) { udpSendToEsp1("CMD=MAINT;EN=1;CH=1;MIN=" + String(minutes) + ";"); }
void sendMaintStop() { udpSendToEsp1("CMD=MAINTSTOP;"); }
void sendMaintOff() { udpSendToEsp1("CMD=MAINT;EN=0;"); }


void quickSetDuration(int minutes) {
  // For short menu: send without confirmation and show an overlay message on HOME.
  sendDurCmd(minutes);
  quickMsg = "DUR " + String(minutes) + "m enviada";
  quickMsgUntilMs = millis() + 1200;
  if (screen != HOME) {
    screen = HOME;
    renderScreen();
  } else {
    renderHome();
  }
}

void sendThrCmd(float low, float high, float rawMin) {
  String cmd = "CMD=THR;LOW=" + String((int)roundf(low)) +
               ";HIGH=" + String((int)roundf(high)) +
               ";RAW=" + String((int)roundf(rawMin)) + ";";
  udpSendToEsp1(cmd);
}
void sendCalCmdEsp1(int tank, const String &act) { udpSendToEsp1("CMD=CAL;T=" + String(tank) + ";ACT=" + act + ";"); }
void sendMqttCfgToEsp1() {
  String cmd = "CMD=MQTT;EN=" + String(mqtt_en ? 1 : 0) +
               ";HOST=" + mqtt_ip +
               ";PORT=" + String(mqtt_port) +
               ";USER=;PASS=;";
  udpSendToEsp1(cmd);
}

// Maintenance commands
void sendRstFail() { udpSendToEsp1("CMD=RSTFAIL;"); }
void sendRstMq()   { udpSendToEsp1("CMD=RSTMQ;"); }
void sendStaRetry(){ udpSendToEsp1("CMD=STARETRY;"); }
void sendForceNtp(){ udpSendToEsp1("CMD=NTP;"); }
void sendRestartEsp1(){ udpSendToEsp1("CMD=RST;"); }

// Parse ESP1 KV packet
void parseKeyValPacket(const String &pkt) {
  lastEsp1RxMs = millis();

  int i = 0;
  while (i < (int)pkt.length()) {
    int eq = pkt.indexOf('=', i);
    if (eq < 0) break;
    int sc = pkt.indexOf(';', eq);
    if (sc < 0) sc = pkt.length();

    String k = pkt.substring(i, eq); k.trim();
    String v = pkt.substring(eq+1, sc); v.trim();

    if (k == "HB") esp1_hb = v.toInt();
    else if (k == "UP") esp1_up_s = (uint32_t)v.toInt();
    else if (k == "ESP2OK") esp2ok_remote = v.toInt();
    else if (k == "ESP2AGE") esp2age_remote_ms = (uint32_t)v.toInt();

    else if (k == "FC_COMM") fc_comm = (uint32_t)v.toInt();
    else if (k == "FC_SENS") fc_sens = (uint32_t)v.toInt();
    else if (k == "FC_RAW")  fc_raw  = (uint32_t)v.toInt();

    else if (k == "T1") t1_pct = v.toFloat();
    else if (k == "T2") t2_pct = v.toFloat();
    else if (k == "T3") t3_pct_remote = v.toFloat();

    else if (k == "MODE") modeStr = v;
    else if (k == "WHY")  whyStr = v;
    else if (k == "STATE") proc_state = v;
    else if (k == "CYC") proc_cyc = v;
    else if (k == "REM") rem_sec = v.toInt();
    else if (k == "SESSREM") sessrem_sec = v.toInt();
    else if (k == "LOW")  thr_low = v.toFloat();
    else if (k == "HIGH") thr_high = v.toFloat();
    else if (k == "RAW")  thr_raw = v.toFloat();

    else if (k == "T1CM") t1_cm = v.toFloat();
    else if (k == "T2CM") t2_cm = v.toFloat();
    else if (k == "T1E") t1_e = v.toFloat();
    else if (k == "T1F") t1_f = v.toFloat();
    else if (k == "T2E") t2_e = v.toFloat();
    else if (k == "T2F") t2_f = v.toFloat();

    else if (k == "STA") sta_on = v.toInt();
    else if (k == "STAIP") sta_ip = v;

    else if (k == "MQEN") mq_en_remote = v.toInt();
    else if (k == "MQCONN") mq_conn = v.toInt();
    else if (k == "MQHOST") mq_host = v;
    else if (k == "MQPORT") mq_port = v.toInt();

    else if (k == "RSSI") rssi_sta = v.toInt();
    else if (k == "MQF") mqf = (uint32_t)v.toInt();
    else if (k == "MQERR") mqerr = v.toInt();
    else if (k == "MQAGE") mqage = (uint32_t)v.toInt();
    else if (k == "NTP") ntp_ok = v.toInt();
    else if (k == "NTPAGE") ntpage = (uint32_t)v.toInt();
    else if (k == "HEAP") heap_free = (uint32_t)v.toInt();
    else if (k == "RST") rst = v;

    i = sc + 1;
  }
}

void udpPollRx() {
  int p = udp.parsePacket();
  if (p <= 0) return;
  String pkt; pkt.reserve(1200);
  while (p--) pkt += (char)udp.read();
  parseKeyValPacket(pkt);
}

// ---------------- UI strings ----------------
String homeLine2() {
  // Rotates information on line 2 while keeping line 3 for quick menu.
  if (homeRotateIdx == 0) {
    String m = modeStr; if (m.length()>5) m = m.substring(0,5);
    String w = whyStr;  if (w.length()>9) w = w.substring(0,9);
    return "Modo:" + m + " Why:" + w;
  }

  if (homeRotateIdx == 1) {
    return "Cyc:" + fmtMMSS(rem_sec) + " Ses:" + fmtMMSS(sessrem_sec);
  }

  if (homeRotateIdx == 2) {
    int L = isnan(thr_low)  ? 30 : (int)roundf(thr_low);
    int H = isnan(thr_high) ? 85 : (int)roundf(thr_high);
    int R = isnan(thr_raw)  ? 20 : (int)roundf(thr_raw);
    return "L/H/R:" + String(L) + "/" + String(H) + "/" + String(R);
  }

  if (homeRotateIdx == 3) {
    String s = String("STA:") + (sta_on ? "ON " : "OFF");
    if (sta_on) s += " " + sta_ip;
    return s;
  }

  if (homeRotateIdx == 4) {
    String s = "MQTT:";
    s += (mq_en_remote ? "EN " : "OFF");
    s += (mq_conn ? " CONN" : " DISC");
    return s;
  }

  return "FC C/S/R:" + String(fc_comm) + "/" + String(fc_sens) + "/" + String(fc_raw);
}

// ---------------- UI render ----------------
void renderHome() {
  lcdPrintLine(0, "T1 " + fmtPct(t1_pct) + "%  T2 " + fmtPct(t2_pct) + "%");
  lcdPrintLine(1, "T3 " + fmtPct(t3_pct_remote) + "% (crudo)");

  if (!esp1Online()) {
    lcdPrintLine(2, "ESP1:OFFLINE       ");
    lcdPrintLine(3, "Age:" + String(esp1AgeMs()/1000) + "s            ");
    return;
  }

  // Line 2 rotates (modo/diag). Line 3 is the short quick menu.
  lcdPrintLine(2, homeLine2());

  if (quickMsgUntilMs && millis() < quickMsgUntilMs && quickMsg.length()) {
    lcdPrintLine(3, quickMsg);
  } else {
    lcdPrintLine(3, "1)60 2)120 3)180 B=M");
  }
}

void renderMenuMain() {
  lcdPrintLine(0, "MENU");
  lcdPrintLine(1, "1) Duracion (min)");
  lcdPrintLine(2, "2) Umbrales (%)");
  lcdPrintLine(3, "3) Cal  4)MQTT B=Salir");
}

void renderMenuDur() {
  lcdPrintLine(0, "TIEMPO PURIFICACION");
  lcdPrintLine(1, "0)AUTO 1)60m");
  lcdPrintLine(2, "2)120  3)180");
  lcdPrintLine(3, "4)240  #=OK B=Back");
}
void renderConfirmDur() {
  lcdPrintLine(0, "Enviar duracion?");
  lcdPrintLine(1, (selectedDurationMin==0) ? "Seleccion: AUTO" : ("Seleccion: " + String(selectedDurationMin) + " min"));
  lcdPrintLine(2, "#=Confirmar  *=No");
  lcdPrintLine(3, "B=Menu");
}

void renderMenuThr() {
  lcdPrintLine(0, "UMBRALES ACTUALES");
  lcdPrintLine(1, "1)LOW  :" + fmtVal(thr_low)  + "%");
  lcdPrintLine(2, "2)HIGH :" + fmtVal(thr_high) + "%");
  lcdPrintLine(3, "3)RAWmin:" + fmtVal(thr_raw) + "% #=Enviar");
}
void renderEdit(const String &title, float currentVal) {
  lcdPrintLine(0, title);
  lcdPrintLine(1, "Actual: " + fmtVal(currentVal) + "%");
  lcdPrintLine(2, "Nuevo : " + (editBuf.length()? editBuf : String("_")));
  lcdPrintLine(3, "#=OK *=Del B=Back");
}
void renderConfirmThr() {
  float low  = isnan(thr_low)  ? 30.0f : thr_low;
  float high = isnan(thr_high) ? 85.0f : thr_high;
  float raw  = isnan(thr_raw)  ? 20.0f : thr_raw;

  lcdPrintLine(0, "Enviar UMBRALES?");
  lcdPrintLine(1, "LOW " + fmtVal(low) + " HIGH " + fmtVal(high));
  lcdPrintLine(2, "RAW " + fmtVal(raw));
  lcdPrintLine(3, "#=Enviar *=No B=Menu");
}

void renderMenuCal() {
  lcdPrintLine(0, "CALIBRACION DIST");
  lcdPrintLine(1, "1) Tinaco 1 (ESP1)");
  lcdPrintLine(2, "2) Tinaco 2 (ESP1)");
  lcdPrintLine(3, "3) Tinaco 3 (ESP2)");
}
void renderCalView() {
  if (calTank == 3) {
    float cm= NAN, pct=NAN;
    readT3(cm, pct);
    lcdPrintLine(0, "T3 CM:" + fmtVal(cm));
    lcdPrintLine(1, "FULL:" + fmtVal(T3_DIST_FULL_CM) + " EMP:" + fmtVal(T3_DIST_EMPTY_CM));
    lcdPrintLine(2, "#=FULL *=EMP A=Ref");
    lcdPrintLine(3, "B=Back");
    return;
  }
  float cm = (calTank==1) ? t1_cm : t2_cm;
  float e  = (calTank==1) ? t1_e  : t2_e;
  float f  = (calTank==1) ? t1_f  : t2_f;

  lcdPrintLine(0, String("T") + String(calTank) + " CM:" + fmtVal(cm));
  lcdPrintLine(1, "FULL:" + fmtVal(f) + " EMP:" + fmtVal(e));
  lcdPrintLine(2, "#=FULL *=EMP A=Ref");
  lcdPrintLine(3, "B=Back");
}
void renderCalConfirm() {
  lcdPrintLine(0, "CONFIRMAR CAPTURA");
  lcdPrintLine(1, "T" + String(calTank) + " " + calPendingAct + " ?");
  lcdPrintLine(2, "#=SI    *=NO");
  lcdPrintLine(3, "B=Back");
}

// MQTT menu
void renderMenuMqtt() {
  lcdPrintLine(0, "MQTT CONFIG (ESP2)");
  lcdPrintLine(1, String("1)EN: ") + (mqtt_en ? "SI " : "NO "));
  lcdPrintLine(2, "2)IP:" + mqtt_ip);
  lcdPrintLine(3, "3)PORT:" + String(mqtt_port) + " #=SEND B=Back");
}
void renderEditMqttIp() {
  lcdPrintLine(0, "EDIT MQTT IP");
  lcdPrintLine(1, "Actual:" + mqtt_ip);
  lcdPrintLine(2, "Nuevo :" + (editBuf.length()? editBuf : String("_")));
  lcdPrintLine(3, "0-9 .  #=OK *=Del B=Back");
}
void renderEditMqttPort() {
  lcdPrintLine(0, "EDIT MQTT PORT");
  lcdPrintLine(1, "Actual:" + String(mqtt_port));
  lcdPrintLine(2, "Nuevo :" + (editBuf.length()? editBuf : String("_")));
  lcdPrintLine(3, "0-9  #=OK *=Del B=Back");
}
void renderConfirmMqttSend() {
  lcdPrintLine(0, "Enviar MQTT a ESP1?");
  lcdPrintLine(1, String("EN:") + (mqtt_en?"1":"0") + " IP:" + mqtt_ip);
  lcdPrintLine(2, "PORT:" + String(mqtt_port));
  lcdPrintLine(3, "#=SI  *=NO  B=Back");
}


void renderMaint() {
  lcdPrintLine(0, "MODO MANTENIMIENTO");
  lcdPrintLine(1, "Bomba fija: CH1");
  lcdPrintLine(2, "1)4min 2)7min");
  if (quickMsgUntilMs > millis()) lcdPrintLine(3, quickMsg);
  else lcdPrintLine(3, "D=OFF #STOP B=Salir");
}

void renderInfo() {
  IPAddress ip = WiFi.localIP();
  int rssi = WiFi.RSSI();
  lcdPrintLine(0, String("INFO ") + FW_VER);
  lcdPrintLine(1, "IP:" + ip.toString());
  lcdPrintLine(2, "RSSI:" + String(rssi) + " ESP1:" + (esp1Online() ? "ON " : "OFF"));

  static int infoIdx = 0;
  static uint32_t infoMs = 0;
  if (millis() - infoMs > 2500) { infoMs = millis(); infoIdx = (infoIdx + 1) % 3; }

  if (infoIdx == 0) {
    lcdPrintLine(3, "FC C/S/R:" + String(fc_comm) + "/" + String(fc_sens) + "/" + String(fc_raw));
  } else if (infoIdx == 1) {
    lcdPrintLine(3, "UP:" + String(esp1_up_s/60) + "m Age:" + String(esp1AgeMs()/1000) + "s");
  } else {
    String s = "MQ " + String(mq_en_remote ? "EN" : "OFF") + " " + String(mq_conn ? "OK" : "NO");
    if (mq_host.length()) {
      s += " " + mq_host;
      if (mq_port > 0) s += ":" + String(mq_port);
    }
    lcdPrintLine(3, s);
  }
}

void renderDiag() {
  if (millis() - diagMs > 2500) { diagMs = millis(); diagIdx = (diagIdx + 1) % 4; }

  lcdPrintLine(0, String("DIAG K:") + lastKeyStr() + " C>N B<");

  if (diagIdx == 0) {
    String l1 = String("STA:") + (sta_on ? "ON " : "OFF") + " RSSI:" + String(rssi_sta);
    lcdPrintLine(1, l1);
    lcdPrintLine(2, "IP:" + sta_ip);
    lcdPrintLine(3, "ESP1Age:" + String(esp1AgeMs()/1000) + "s");
  } else if (diagIdx == 1) {
    String l1 = String("MQTT:") + (mq_en_remote ? "EN " : "OFF") + (mq_conn ? " CONN" : " DISC");
    lcdPrintLine(1, l1);
    String l2 = "H:" + (mq_host.length()? mq_host : String("-"));
    if (mq_port > 0) l2 += ":" + String(mq_port);
    lcdPrintLine(2, l2);
    lcdPrintLine(3, "WHY:" + whyStr);
  } else if (diagIdx == 2) {
    lcdPrintLine(1, "MQF:" + String(mqf) + " ERR:" + String(mqerr));
    lcdPrintLine(2, "MQAGE:" + fmtAge(mqage));
    lcdPrintLine(3, "MODE:" + modeStr + " " + proc_state);
  } else {
    lcdPrintLine(1, String("NTP:") + (ntp_ok ? "OK" : "NO") + " AGE:" + fmtAge(ntpage));
    lcdPrintLine(2, "HEAP:" + String(heap_free));
    String rr = rst.length()? rst : String("-");
    if (rr.length() > 20) rr = rr.substring(0,20);
    lcdPrintLine(3, "RST:" + rr);
  }
}

void renderConfirmRstEsp1() {
  lcdPrintLine(0, "REINICIAR ESP1?");
  lcdPrintLine(1, "#=SI   *=NO");
  lcdPrintLine(2, "B=Cancel");
  lcdPrintLine(3, " ");
}

void renderScreen() {
  lcd.clear();
  switch(screen){
    case HOME: renderHome(); break;
    case MENU_MAIN: renderMenuMain(); break;

    case MENU_DUR: renderMenuDur(); break;
    case CONFIRM_DUR: renderConfirmDur(); break;

    case MENU_THR: renderMenuThr(); break;
    case EDIT_LOW: renderEdit("EDIT LOW (%)", thr_low); break;
    case EDIT_HIGH: renderEdit("EDIT HIGH (%)", thr_high); break;
    case EDIT_RAW: renderEdit("EDIT RAW_MIN (%)", thr_raw); break;
    case CONFIRM_THR: renderConfirmThr(); break;

    case MENU_CAL: renderMenuCal(); break;
    case CAL_VIEW: renderCalView(); break;
    case CAL_CONFIRM: renderCalConfirm(); break;

    case MENU_MQTT: renderMenuMqtt(); break;

    case MAINT: renderMaint(); break;
    case EDIT_MQTT_IP: renderEditMqttIp(); break;
    case EDIT_MQTT_PORT: renderEditMqttPort(); break;
    case CONFIRM_MQTT_SEND: renderConfirmMqttSend(); break;

    case INFO: renderInfo(); break;
    case DIAG: renderDiag(); break;
    case CONFIRM_RST_ESP1: renderConfirmRstEsp1(); break;
  }
}

// ---------------- Key handler ----------------
void handleKey(char k) {
  // store last key for diagnostics
  lastKey = k;
  lastKeyMs = millis();
  if (screen == HOME) {
    // Short menu (rápido): 1/2/3 envían duración sin confirmación
    if (k == '1') { quickSetDuration(60); return; }
    if (k == '2') { quickSetDuration(120); return; }
    if (k == '3') { quickSetDuration(180); return; }

    if (k == 'A') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == 'B') { screen = MAINT; renderScreen(); return; }
    if (k == 'D') { screen = INFO; renderScreen(); return; }
    if (k == 'C') { screen = DIAG; renderScreen(); return; }
    return;
  }


  if (screen == MAINT) {
    // Menú corto de mantenimiento: bomba fija CH1.
    // 1 = 4 min, 2 = 7 min. No hay confirmación.
    if (k == '1') { sendMaintStartFixed(4); quickMsg = "MAINT CH1 4m"; quickMsgUntilMs = millis() + 1200; renderMaint(); return; }
    if (k == '2') { sendMaintStartFixed(7); quickMsg = "MAINT CH1 7m"; quickMsgUntilMs = millis() + 1200; renderMaint(); return; }
    if (k == '#') { sendMaintStop(); quickMsg = "MAINT STOP"; quickMsgUntilMs = millis() + 1200; renderMaint(); return; }

    // Tecla para SALIR de mantenimiento (deshabilita maint en ESP1 y regresa a HOME)
    if (k == 'D') { sendMaintOff(); quickMsg = "MAINT OFF"; quickMsgUntilMs = millis() + 1200; screen = HOME; renderScreen(); return; }

    if (k == 'B') { screen = HOME; renderScreen(); return; }
    return;
  }

  if (screen == INFO) {
    if (k == 'B') { screen = HOME; renderScreen(); return; }
    if (k == 'C') { screen = DIAG; renderScreen(); return; }
    if (k == '#') { sendRstFail(); lcdPrintLine(3,"Reset FAIL enviado "); delay(600); renderInfo(); return; }
    return;
  }

  if (screen == DIAG) {
    if (k == 'B') { screen = INFO; renderScreen(); return; }
    if (k == 'C') { diagIdx = (diagIdx + 1) % 4; renderDiag(); return; }

    // Maintenance actions
    if (k == '#') { sendRstMq(); lcdPrintLine(3,"RSTMQ enviado      "); delay(500); renderDiag(); return; }
    if (k == '*') { sendStaRetry(); lcdPrintLine(3,"STA retry enviado  "); delay(500); renderDiag(); return; }
    if (k == 'A') { sendForceNtp(); lcdPrintLine(3,"NTP cmd enviado    "); delay(500); renderDiag(); return; }
    if (k == 'D') { screen = CONFIRM_RST_ESP1; renderScreen(); return; }

    return;
  }

  if (screen == CONFIRM_RST_ESP1) {
    if (k == 'B' || k == '*') { screen = DIAG; renderScreen(); return; }
    if (k == '#') { sendRestartEsp1(); lcdPrintLine(3,"RST enviado        "); delay(600); screen = DIAG; renderScreen(); return; }
    return;
  }

  if (screen == MENU_MAIN) {
    if (k == 'B') { screen = HOME; renderScreen(); return; }
    if (k == '1') { screen = MENU_DUR; renderScreen(); return; }
    if (k == '2') { screen = MENU_THR; renderScreen(); return; }
    if (k == '3') { screen = MENU_CAL; renderScreen(); return; }
    if (k == '4') { screen = MENU_MQTT; renderScreen(); return; }
    return;
  }

  // DUR
  if (screen == MENU_DUR) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '0') selectedDurationMin = 0;
    else if (k == '1') selectedDurationMin = 60;
    else if (k == '2') selectedDurationMin = 120;
    else if (k == '3') selectedDurationMin = 180;
    else if (k == '4') selectedDurationMin = 240;
    else if (k == '#') { screen = CONFIRM_DUR; renderScreen(); return; }
    return;
  }
  if (screen == CONFIRM_DUR) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '*') { screen = MENU_DUR; renderScreen(); return; }
    if (k == '#') { sendDurCmd(selectedDurationMin); delay(350); screen = HOME; renderScreen(); return; }
    return;
  }

  // THR
  if (screen == MENU_THR) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '1') { editBuf=""; screen = EDIT_LOW; renderScreen(); return; }
    if (k == '2') { editBuf=""; screen = EDIT_HIGH; renderScreen(); return; }
    if (k == '3') { editBuf=""; screen = EDIT_RAW; renderScreen(); return; }
    if (k == '#') { screen = CONFIRM_THR; renderScreen(); return; }
    return;
  }
  if (screen == EDIT_LOW || screen == EDIT_HIGH || screen == EDIT_RAW) {
    if (k == 'B') { screen = MENU_THR; renderScreen(); return; }
    if (k == '*') editBufBackspace();
    else if (k == '#') {
      float v; if (editBufToFloat(v)) {
        if (screen == EDIT_LOW) thr_low = v;
        else if (screen == EDIT_HIGH) thr_high = v;
        else thr_raw = v;
      }
      screen = MENU_THR; renderScreen(); return;
    } else if (k >= '0' && k <= '9') {
      if (editBuf.length() < 5) editBuf += k;
    }
    if (screen == EDIT_LOW) renderEdit("EDIT LOW (%)", thr_low);
    else if (screen == EDIT_HIGH) renderEdit("EDIT HIGH (%)", thr_high);
    else renderEdit("EDIT RAW_MIN (%)", thr_raw);
    return;
  }
  if (screen == CONFIRM_THR) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '*') { screen = MENU_THR; renderScreen(); return; }
    if (k == '#') {
      float low  = isnan(thr_low)  ? 30.0f : thr_low;
      float high = isnan(thr_high) ? 85.0f : thr_high;
      float raw  = isnan(thr_raw)  ? 20.0f : thr_raw;
      sendThrCmd(low, high, raw);
      delay(350);
      screen = HOME; renderScreen(); return;
    }
    return;
  }

  // CAL
  if (screen == MENU_CAL) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '1') { calTank = 1; screen = CAL_VIEW; renderScreen(); sendCalCmdEsp1(1,"VIEW"); return; }
    if (k == '2') { calTank = 2; screen = CAL_VIEW; renderScreen(); sendCalCmdEsp1(2,"VIEW"); return; }
    if (k == '3') { calTank = 3; screen = CAL_VIEW; renderScreen(); return; }
    return;
  }
  if (screen == CAL_VIEW) {
    if (k == 'B') { screen = MENU_CAL; renderScreen(); return; }
    if (k == 'A') { if (calTank==3) renderCalView(); else sendCalCmdEsp1(calTank,"VIEW"); return; }
    if (k == '#') { calPendingAct="FULL"; screen = CAL_CONFIRM; renderScreen(); return; }
    if (k == '*') { calPendingAct="EMPTY"; screen = CAL_CONFIRM; renderScreen(); return; }
    return;
  }
  if (screen == CAL_CONFIRM) {
    if (k == 'B') { screen = CAL_VIEW; renderScreen(); return; }
    if (k == '*') { screen = CAL_VIEW; renderScreen(); return; }
    if (k == '#') {
      if (calTank == 3) {
        float cm;
        if (readT3cm(cm)) {
          if (calPendingAct == "FULL") T3_DIST_FULL_CM = cm;
          else T3_DIST_EMPTY_CM = cm;
          saveLocalConfig();
        }
      } else {
        sendCalCmdEsp1(calTank, calPendingAct);
      }
      screen = CAL_VIEW; renderScreen(); return;
    }
    return;
  }

  // MQTT MENU
  if (screen == MENU_MQTT) {
    if (k == 'B') { screen = MENU_MAIN; renderScreen(); return; }
    if (k == '1') { mqtt_en = !mqtt_en; saveLocalConfig(); renderMenuMqtt(); return; }
    if (k == '2') { editBuf=""; screen = EDIT_MQTT_IP; renderScreen(); return; }
    if (k == '3') { editBuf=""; screen = EDIT_MQTT_PORT; renderScreen(); return; }
    if (k == '#') { screen = CONFIRM_MQTT_SEND; renderScreen(); return; }
    return;
  }

  if (screen == EDIT_MQTT_IP) {
    if (k == 'B') { screen = MENU_MQTT; renderScreen(); return; }
    if (k == '*') editBufBackspace();
    else if (k == '#') {
      if (editBuf.length() >= 7 && editBuf.indexOf('.') > 0) {
        mqtt_ip = editBuf;
        saveLocalConfig();
      }
      screen = MENU_MQTT; renderScreen(); return;
    } else if ((k >= '0' && k <= '9') || k == '.') {
      if (editBuf.length() < 15) editBuf += k;
    }
    renderEditMqttIp();
    return;
  }

  if (screen == EDIT_MQTT_PORT) {
    if (k == 'B') { screen = MENU_MQTT; renderScreen(); return; }
    if (k == '*') editBufBackspace();
    else if (k == '#') {
      int p = editBuf.toInt();
      if (p > 0 && p < 65536) {
        mqtt_port = p;
        saveLocalConfig();
      }
      screen = MENU_MQTT; renderScreen(); return;
    } else if (k >= '0' && k <= '9') {
      if (editBuf.length() < 5) editBuf += k;
    }
    renderEditMqttPort();
    return;
  }

  if (screen == CONFIRM_MQTT_SEND) {
    if (k == 'B') { screen = MENU_MQTT; renderScreen(); return; }
    if (k == '*') { screen = MENU_MQTT; renderScreen(); return; }
    if (k == '#') {
      sendMqttCfgToEsp1();
      lcdPrintLine(3, "Enviado a ESP1     ");
      delay(700);
      screen = MENU_MQTT;
      renderScreen();
      return;
    }
    return;
  }
}

// ---------------- setup/loop ----------------
void setup() {
  Serial.begin(115200);

  pinMode(PIN_T3_TRIG, OUTPUT);
  digitalWrite(PIN_T3_TRIG, LOW);
  pinMode(PIN_T3_ECHO, INPUT);

  loadLocalConfig();

  Wire.begin(21, 22);
  lcd.init();
  lcd.backlight();

  // Keypad tuning for real hardware (debounce/hold)
  keypad.setDebounceTime(30);
  keypad.setHoldTime(500);

  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);

  uint32_t t0 = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - t0 < 12000) delay(250);

  udp.begin(UDP_PORT_RX_FROM_ESP1);

  homeRotateMs = millis();
  homeRotateIdx = 0;

  diagMs = millis();
  diagIdx = 0;

  screen = HOME;
  renderScreen();
}

void loop() {
  // keys
  char k = keypad.getKey();
  if (k) handleKey(k);

  // rx from esp1
  udpPollRx();

  // home rotator
  if (screen == HOME && esp1Online()) {
    uint32_t now = millis();
    if (now - homeRotateMs >= HOME_ROTATE_PERIOD_MS) {
      homeRotateMs = now;
      homeRotateIdx = (homeRotateIdx + 1) % 5;
      lcdPrintLine(2, homeLine2());
    }
  }

  // periodic UI refresh
  static uint32_t lastUi = 0;
  if (millis() - lastUi > 900) {
    lastUi = millis();
    if (screen == HOME) renderHome();
    else if (screen == CAL_VIEW) renderCalView();
    else if (screen == INFO) renderInfo();
    else if (screen == MENU_MQTT) renderMenuMqtt();
    else if (screen == MAINT) renderMaint();
    else if (screen == DIAG) renderDiag();
  }

  // Send T3 to ESP1
  static uint32_t lastMeasMs = 0;
  static uint32_t seq = 0;
  if (millis() - lastMeasMs > 1500) {
    lastMeasMs = millis();
    float cm, pct;
    bool ok = readT3(cm, pct);

    String msg = "T3=" + String(ok ? pct : -1.0f, 1) +
                 ";OK=" + String(ok ? 1 : 0) +
                 ";SEQ=" + String(seq++) + ";";
    udpSendToEsp1(msg);
  }

  // WiFi reconnect
  static uint32_t lastWifiChk = 0;
  if (millis() - lastWifiChk > 3000) {
    lastWifiChk = millis();
    if (WiFi.status() != WL_CONNECTED) {
      WiFi.disconnect();
      WiFi.begin(WIFI_SSID, WIFI_PASS);
    }
  }
}