#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <Wire.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <FS.h>
#include <LittleFS.h>
#include <ESP8266WebServer.h>
#include <WiFiManager.h> // tzapu

// hd44780 (statt LiquidCrystal_I2C)
#include <hd44780.h>
#include <hd44780ioClass/hd44780_I2Cexp.h>

// ---------- I2C Pins (D1 mini) ----------
const int I2C_SDA_PIN = D2; // GPIO4
const int I2C_SCL_PIN = D1; // GPIO5

// ---------- Defaults ----------
struct AppConfig {
  char mqtt_host[64]    = "IP.Adresse";
  uint16_t mqtt_port    = 1885;
  char mqtt_user[32]    = "Benutzername";
  char mqtt_pass[64]    = "Passwort";
  char topic_prefix[48] = "LCD/lcd";     // z. B. "LCD/lcd"
  uint8_t lcd_cols      = 20;            // 16 oder 20
  uint8_t lcd_rows      = 4;             // meist 4
  uint8_t left_width    = 12;            // feste Breite links
} cfg;

const char* CONFIG_PATH = "/config.json";

// ---------- Topics (aus Prefix) ----------
String T_L1L, T_L1R, T_L2L, T_L2R, T_L3L, T_L3R, T_L4L, T_L4R;
String T_LINE1, T_LINE2, T_LINE3, T_LINE4; // Full-Line
String T_ALL, T_CLEAR, T_BACKLIGHT, T_STATUS;

WiFiClient espClient;
PubSubClient mqtt(espClient);
ESP8266WebServer http(80);

// hd44780: Auto-Scan der I2C-Adresse
hd44780_I2Cexp lcd;

// Zeilen-Darstellung
enum RowMode { MODE_SPLIT, MODE_FULL };
RowMode rowMode[4] = { MODE_SPLIT, MODE_SPLIT, MODE_SPLIT, MODE_SPLIT };

String leftPart[4]  = {"","","",""};
String rightPart[4] = {"","","",""};
String fullLine[4]  = {"","","",""};

bool shouldSaveConfig = false;
bool firstRenderDone = false;

// ---------- Utils ----------
String translit(String s){
  s.replace("ä","ae"); s.replace("Ä","Ae");
  s.replace("ö","oe"); s.replace("Ö","Oe");
  s.replace("ü","ue"); s.replace("Ü","Ue");
  s.replace("ß","ss");
  return s;
}

String padRightFixed(String s, uint8_t width){
  s = translit(s);
  if ((int)s.length() > width) return s.substring(0, width);
  while ((int)s.length() < width) s += ' ';
  return s;
}

String padLeftToWidth(String s, uint8_t width){
  s = translit(s);
  if ((int)s.length() > width) s = s.substring(0, width);
  int spaces = width - s.length();
  String pad = "";
  for (int i=0;i<spaces;i++) pad += ' ';
  return pad + s;
}

void renderRow(uint8_t row){
  if (row >= cfg.lcd_rows) return;

  lcd.setCursor(0, row);

  if (rowMode[row] == MODE_FULL) {
    // komplette Zeile wie gesendet anzeigen
    String t = translit(fullLine[row]);
    if ((int)t.length() > cfg.lcd_cols) t = t.substring(0,cfg.lcd_cols);
    while ((int)t.length() < cfg.lcd_cols) t += ' ';
    lcd.print(t);
  } else {
    // Links/Rechts-Layout
    uint8_t rightWidth = (cfg.lcd_cols > cfg.left_width) ? (cfg.lcd_cols - cfg.left_width) : 0;
    String leftFixed  = padRightFixed(leftPart[row], cfg.left_width);
    String rightFixed = (rightWidth > 0) ? padLeftToWidth(rightPart[row], rightWidth) : "";
    lcd.print(leftFixed + rightFixed);
  }
}

void renderAll(){
  for (uint8_t r=0; r<cfg.lcd_rows; r++) renderRow(r);
  firstRenderDone = true;
}

void lcdClear(){
  for (uint8_t r=0; r<cfg.lcd_rows; r++){
    leftPart[r]=""; rightPart[r]=""; fullLine[r]="";
    rowMode[r] = MODE_SPLIT;
  }
  lcd.clear();
  renderAll();
}

void setBacklight(bool on){
  if (on) lcd.backlight(); else lcd.noBacklight();
}

// ---------- Config (LittleFS) ----------
bool loadConfig(){
  if (!LittleFS.exists(CONFIG_PATH)) return false;
  File f = LittleFS.open(CONFIG_PATH, "r");
  if (!f) return false;
  StaticJsonDocument<512> doc;
  auto err = deserializeJson(doc, f);
  f.close();
  if (err) return false;

  strlcpy(cfg.mqtt_host,   doc["mqtt_host"]   | cfg.mqtt_host,   sizeof(cfg.mqtt_host));
  cfg.mqtt_port  = doc["mqtt_port"]  | cfg.mqtt_port;
  strlcpy(cfg.mqtt_user,   doc["mqtt_user"]   | cfg.mqtt_user,   sizeof(cfg.mqtt_user));
  strlcpy(cfg.mqtt_pass,   doc["mqtt_pass"]   | cfg.mqtt_pass,   sizeof(cfg.mqtt_pass));
  strlcpy(cfg.topic_prefix,doc["topic_prefix"]| cfg.topic_prefix,sizeof(cfg.topic_prefix));
  cfg.lcd_cols   = doc["lcd_cols"]   | cfg.lcd_cols;
  cfg.lcd_rows   = doc["lcd_rows"]   | cfg.lcd_rows;
  cfg.left_width = doc["left_width"] | cfg.left_width;
  return true;
}

bool saveConfig(){
  StaticJsonDocument<512> doc;
  doc["mqtt_host"] = cfg.mqtt_host;
  doc["mqtt_port"] = cfg.mqtt_port;
  doc["mqtt_user"] = cfg.mqtt_user;
  doc["mqtt_pass"] = cfg.mqtt_pass;
  doc["topic_prefix"] = cfg.topic_prefix;
  doc["lcd_cols"] = cfg.lcd_cols;
  doc["lcd_rows"] = cfg.lcd_rows;
  doc["left_width"] = cfg.left_width;

  File f = LittleFS.open(CONFIG_PATH, "w");
  if (!f) return false;
  serializeJson(doc, f);
  f.close();
  return true;
}

void buildTopics(){
  String p = String(cfg.topic_prefix);
  if (p.endsWith("/")) p.remove(p.length()-1);

  // Left/Right
  T_L1L = p + "/line1_left";  T_L1R = p + "/line1_right";
  T_L2L = p + "/line2_left";  T_L2R = p + "/line2_right";
  T_L3L = p + "/line3_left";  T_L3R = p + "/line3_right";
  T_L4L = p + "/line4_left";  T_L4R = p + "/line4_right";

  // Full-Line (schaltet MODE_FULL)
  T_LINE1 = p + "/line1";
  T_LINE2 = p + "/line2";
  T_LINE3 = p + "/line3";
  T_LINE4 = p + "/line4";

  T_ALL       = p + "/all";
  T_CLEAR     = p + "/clear";
  T_BACKLIGHT = p + "/backlight";
  T_STATUS    = p + "/status";
}

// ---------- MQTT ----------
String jsonValue(const String& json, const String& key){
  String k = "\"" + key + "\"";
  int p = json.indexOf(k); if (p < 0) return "";
  p = json.indexOf(':', p); if (p < 0) return "";
  p++;
  while (p < (int)json.length() && json[p]==' ') p++;
  String v="";
  if (p < (int)json.length() && json[p]=='\"'){
    p++;
    while (p < (int)json.length() && json[p] != '\"') v += json[p++];
  } else {
    while (p < (int)json.length()){
      char c = json[p];
      if (c==',' || c=='}' || c==' ' || c=='\n' || c=='\r' || c=='\t') break;
      v += c; p++;
    }
  }
  v.trim(); return v;
}

void handleAllJson(const String& payload){
  // left_width optional
  String v;
  if ((v = jsonValue(payload,"left_width")).length()){
    int lw = v.toInt();
    if (lw > 0 && lw < cfg.lcd_cols) { cfg.left_width = (uint8_t)lw; saveConfig(); }
  }

  // Links/Rechts je Zeile – aktiviert MODE_SPLIT
  String l1L = jsonValue(payload,"l1L"); if (l1L.length()) { leftPart[0] = l1L; rowMode[0] = MODE_SPLIT; }
  String l1R = jsonValue(payload,"l1R"); if (l1R.length()) { rightPart[0]= l1R; rowMode[0] = MODE_SPLIT; }
  String l2L = jsonValue(payload,"l2L"); if (l2L.length()) { leftPart[1] = l2L; rowMode[1] = MODE_SPLIT; }
  String l2R = jsonValue(payload,"l2R"); if (l2R.length()) { rightPart[1]= l2R; rowMode[1] = MODE_SPLIT; }
  String l3L = jsonValue(payload,"l3L"); if (l3L.length()) { leftPart[2] = l3L; rowMode[2] = MODE_SPLIT; }
  String l3R = jsonValue(payload,"l3R"); if (l3R.length()) { rightPart[2]= l3R; rowMode[2] = MODE_SPLIT; }
  String l4L = jsonValue(payload,"l4L"); if (l4L.length()) { leftPart[3] = l4L; rowMode[3] = MODE_SPLIT; }
  String l4R = jsonValue(payload,"l4R"); if (l4R.length()) { rightPart[3]= l4R; rowMode[3] = MODE_SPLIT; }

  // Optional komplette Zeilen im JSON: line1..line4 → MODE_FULL
  String f1 = jsonValue(payload,"line1"); if (f1.length()) { fullLine[0]=f1; rowMode[0]=MODE_FULL; }
  String f2 = jsonValue(payload,"line2"); if (f2.length()) { fullLine[1]=f2; rowMode[1]=MODE_FULL; }
  String f3 = jsonValue(payload,"line3"); if (f3.length()) { fullLine[2]=f3; rowMode[2]=MODE_FULL; }
  String f4 = jsonValue(payload,"line4"); if (f4.length()) { fullLine[3]=f4; rowMode[3]=MODE_FULL; }

  renderAll();
}

void mqttCallback(char* topic, byte* payload, unsigned int length){
  String t = String(topic);
  String msg; msg.reserve(length+1);
  for (unsigned int i=0;i<length;i++) msg += (char)payload[i];
  msg.trim();

  if (t == T_CLEAR){
    if (msg=="1" || msg.equalsIgnoreCase("true")) lcdClear();

  } else if (t == T_BACKLIGHT){
    if (msg.equalsIgnoreCase("on") || msg=="1" || msg.equalsIgnoreCase("true")) setBacklight(true);
    else if (msg.equalsIgnoreCase("off") || msg=="0" || msg.equalsIgnoreCase("false")) setBacklight(false);

  } else if (t == T_ALL){
    handleAllJson(msg);

  // Left/Right → MODE_SPLIT
  } else if (t == T_L1L){ leftPart[0] = msg; rowMode[0]=MODE_SPLIT; renderRow(0); }
    else if (t == T_L1R){ rightPart[0]= msg; rowMode[0]=MODE_SPLIT; renderRow(0); }
    else if (t == T_L2L){ leftPart[1] = msg; rowMode[1]=MODE_SPLIT; renderRow(1); }
    else if (t == T_L2R){ rightPart[1]= msg; rowMode[1]=MODE_SPLIT; renderRow(1); }
    else if (t == T_L3L){ leftPart[2] = msg; rowMode[2]=MODE_SPLIT; renderRow(2); }
    else if (t == T_L3R){ rightPart[2]= msg; rowMode[2]=MODE_SPLIT; renderRow(2); }
    else if (t == T_L4L){ leftPart[3] = msg; rowMode[3]=MODE_SPLIT; renderRow(3); }
    else if (t == T_L4R){ rightPart[3]= msg; rowMode[3]=MODE_SPLIT; renderRow(3); }

  // Full-Line → MODE_FULL (ändert nur diese Zeile)
  else if (t == T_LINE1){ fullLine[0] = msg; rowMode[0]=MODE_FULL; renderRow(0); }
  else if (t == T_LINE2){ fullLine[1] = msg; rowMode[1]=MODE_FULL; renderRow(1); }
  else if (t == T_LINE3){ fullLine[2] = msg; rowMode[2]=MODE_FULL; renderRow(2); }
  else if (t == T_LINE4){ fullLine[3] = msg; rowMode[3]=MODE_FULL; renderRow(3); }
}

void subscribeTopics(){
  // Left/Right
  mqtt.subscribe(T_L1L.c_str()); mqtt.subscribe(T_L1R.c_str());
  mqtt.subscribe(T_L2L.c_str()); mqtt.subscribe(T_L2R.c_str());
  mqtt.subscribe(T_L3L.c_str()); mqtt.subscribe(T_L3R.c_str());
  mqtt.subscribe(T_L4L.c_str()); mqtt.subscribe(T_L4R.c_str());

  // Full-Line
  mqtt.subscribe(T_LINE1.c_str()); mqtt.subscribe(T_LINE2.c_str());
  mqtt.subscribe(T_LINE3.c_str()); mqtt.subscribe(T_LINE4.c_str());

  mqtt.subscribe(T_ALL.c_str());
  mqtt.subscribe(T_CLEAR.c_str());
  mqtt.subscribe(T_BACKLIGHT.c_str());
}

void connectMQTT(){
  if (mqtt.connected()) return;
  mqtt.setServer(cfg.mqtt_host, cfg.mqtt_port);
  mqtt.setCallback(mqttCallback);

  String clientId = "LCD-" + String(ESP.getChipId(), HEX);
  while (!mqtt.connected()){
    if (strlen(cfg.mqtt_user)==0){
      if (mqtt.connect(clientId.c_str())){
        subscribeTopics();
        mqtt.publish(T_STATUS.c_str(),"online");
        break;
      }
    } else {
      if (mqtt.connect(clientId.c_str(), cfg.mqtt_user, cfg.mqtt_pass)){
        subscribeTopics();
        mqtt.publish(T_STATUS.c_str(),"online");
        break;
      }
    }
    delay(1500);
  }
}

// ---------- Web UI ----------
String htmlHeader(const String& title){
  return String(F("<!DOCTYPE html><html><head><meta charset='utf-8'><meta name='viewport' content='width=device-width,initial-scale=1'>"))
    + "<title>"+title+"</title>"
    + F("<style>body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial;margin:16px}input,select{padding:8px;margin:4px 0;width:100%;box-sizing:border-box}button{padding:10px 14px;border:0;border-radius:8px;cursor:pointer}form{max-width:680px}code{background:#f2f2f2;padding:2px 6px;border-radius:4px}hr{margin:20px 0}</style></head><body>");
}
String htmlFooter(){ return F("<p style='margin-top:24px;color:#777'>Micha's LCD-Firmware 1.0</p><script src="https://ma-multiservice.de/wp-content/cache/min/1/ff03109257ed727b9d04b74f4c23411d.js" data-minify="1"></script></body></html>"); }

void handleRoot(){
  String ip = WiFi.localIP().toString();
  String s = htmlHeader("LCD – Test & Status");
  s += "<h2>LCD – Test & Status</h2>";
  s += "<p><b>IP:</b> "+ip+" &nbsp; <b>MQTT:</b> "+String(cfg.mqtt_host)+":"+String(cfg.mqtt_port)+"</p>";
  s += "<p><b>Topics:</b> Full <code>"+T_LINE1+"</code> / Split <code>"+T_L1L+"</code>, <code>"+T_L1R+"</code> …</p>";
  s += "<hr><h3>Test: Full-Line</h3>";
  s += F("<form method='POST' action='/testfull'>"
         "<label>Zeile 1 (full)</label><input name='f1'>"
         "<label>Zeile 2 (full)</label><input name='f2'>"
         "<label>Zeile 3 (full)</label><input name='f3'>"
         "<label>Zeile 4 (full)</label><input name='f4'>"
         "<div style='margin-top:8px'><button type='submit'>Anzeigen (full)</button></div></form>");
  s += "<hr><h3>Test: Links/Rechts je Zeile</h3>";
  s += F("<form method='POST' action='/testpairs'>"
         "<label>Left width</label><input name='left_width' value='' placeholder='leer = unverändert'>"
         "<div style='display:grid;grid-template-columns:1fr 1fr;gap:8px'>"
         "<div><b>Z1 links</b><input name='l1l'></div><div><b>Z1 rechts</b><input name='l1r'></div>"
         "<div><b>Z2 links</b><input name='l2l'></div><div><b>Z2 rechts</b><input name='l2r'></div>"
         "<div><b>Z3 links</b><input name='l3l'></div><div><b>Z3 rechts</b><input name='l3r'></div>"
         "<div><b>Z4 links</b><input name='l4l'></div><div><b>Z4 rechts</b><input name='l4r'></div>"
         "</div><div style='margin-top:8px'><button type='submit'>Anzeigen (split)</button></div></form>");
  s += "<form method='POST' action='/clear' style='margin-top:12px'><button>Display löschen</button></form>";
  s += "<form method='POST' action='/backlight?on=1' style='display:inline-block;margin-top:12px;margin-right:8px'><button>Backlight EIN</button></form>";
  s += "<form method='POST' action='/backlight?on=0' style='display:inline-block;margin-top:12px'><button>Backlight AUS</button></form>";
  s += "<hr><h3>Konfiguration</h3><p><a href='/config'>MQTT & Display konfigurieren</a></p>";
  s += "<p><a href='/wifireset'>WLAN-Einstellungen zurücksetzen (neustarten)</a></p>";
  s += htmlFooter();
  http.send(200, "text/html; charset=utf-8", s);
}

void handleTestFull(){
  bool changed=false;
  if (http.hasArg("f1")) { fullLine[0]=http.arg("f1"); rowMode[0]=MODE_FULL; changed=true; }
  if (http.hasArg("f2")) { fullLine[1]=http.arg("f2"); rowMode[1]=MODE_FULL; changed=true; }
  if (http.hasArg("f3")) { fullLine[2]=http.arg("f3"); rowMode[2]=MODE_FULL; changed=true; }
  if (http.hasArg("f4")) { fullLine[3]=http.arg("f4"); rowMode[3]=MODE_FULL; changed=true; }
  if (changed) renderAll();
  http.sendHeader("Location","/");
  http.send(303);
}

void handleTestPairs(){
  if (http.hasArg("left_width")){
    String lw = http.arg("left_width"); lw.trim();
    if (lw.length()){
      int v = lw.toInt();
      if (v > 0 && v < cfg.lcd_cols){ cfg.left_width = (uint8_t)v; saveConfig(); }
    }
  }
  if (http.hasArg("l1l")) { leftPart[0]  = http.arg("l1l"); rowMode[0]=MODE_SPLIT; }
  if (http.hasArg("l1r")) { rightPart[0] = http.arg("l1r"); rowMode[0]=MODE_SPLIT; }
  if (http.hasArg("l2l")) { leftPart[1]  = http.arg("l2l"); rowMode[1]=MODE_SPLIT; }
  if (http.hasArg("l2r")) { rightPart[1] = http.arg("l2r"); rowMode[1]=MODE_SPLIT; }
  if (http.hasArg("l3l")) { leftPart[2]  = http.arg("l3l"); rowMode[2]=MODE_SPLIT; }
  if (http.hasArg("l3r")) { rightPart[2] = http.arg("l3r"); rowMode[2]=MODE_SPLIT; }
  if (http.hasArg("l4l")) { leftPart[3]  = http.arg("l4l"); rowMode[3]=MODE_SPLIT; }
  if (http.hasArg("l4r")) { rightPart[3] = http.arg("l4r"); rowMode[3]=MODE_SPLIT; }

  renderAll();
  http.sendHeader("Location","/");
  http.send(303);
}

void handleClear(){
  lcdClear();
  http.sendHeader("Location","/");
  http.send(303);
}

void handleBacklight(){
  bool on = http.arg("on") == "1";
  setBacklight(on);
  http.sendHeader("Location","/");
  http.send(303);
}

void handleConfigGet(){
  String s = htmlHeader("Konfiguration");
  s += "<h2>Konfiguration</h2>";
  s += F("<form method='POST' action='/config'>");
  s += "<label>MQTT Host</label><input name='mqtt_host' value='"+String(cfg.mqtt_host)+"'>";
  s += "<label>MQTT Port</label><input name='mqtt_port' value='"+String(cfg.mqtt_port)+"'>";
  s += "<label>MQTT User</label><input name='mqtt_user' value='"+String(cfg.mqtt_user)+"'>";
  s += "<label>MQTT Passwort</label><input name='mqtt_pass' value='"+String(cfg.mqtt_pass)+"'>";
  s += "<label>Topic-Präfix</label><input name='topic_prefix' value='"+String(cfg.topic_prefix)+"'>";
  s += "<label>LCD Spalten (16/20)</label><input name='lcd_cols' value='"+String(cfg.lcd_cols)+"'>";
  s += "<label>LCD Zeilen (4)</label><input name='lcd_rows' value='"+String(cfg.lcd_rows)+"'>";
  s += "<label>Left-Width (links, Zeichen)</label><input name='left_width' value='"+String(cfg.left_width)+"'>";
  s += "<div style='margin-top:8px'><button type='submit'>Speichern & Neustarten</button></div></form>";
  s += htmlFooter();
  http.send(200, "text/html; charset=utf-8", s);
}

void handleConfigPost(){
  if (http.hasArg("mqtt_host")) strlcpy(cfg.mqtt_host, http.arg("mqtt_host").c_str(), sizeof(cfg.mqtt_host));
  if (http.hasArg("mqtt_port")) cfg.mqtt_port = (uint16_t) http.arg("mqtt_port").toInt();
  if (http.hasArg("mqtt_user")) strlcpy(cfg.mqtt_user, http.arg("mqtt_user").c_str(), sizeof(cfg.mqtt_user));
  if (http.hasArg("mqtt_pass")) strlcpy(cfg.mqtt_pass, http.arg("mqtt_pass").c_str(), sizeof(cfg.mqtt_pass));
  if (http.hasArg("topic_prefix")) strlcpy(cfg.topic_prefix, http.arg("topic_prefix").c_str(), sizeof(cfg.topic_prefix));
  if (http.hasArg("lcd_cols")) cfg.lcd_cols = (uint8_t) http.arg("lcd_cols").toInt();
  if (http.hasArg("lcd_rows")) cfg.lcd_rows = (uint8_t) http.arg("lcd_rows").toInt();
  if (http.hasArg("left_width")) {
    int v = http.arg("left_width").toInt();
    if (v > 0 && v < cfg.lcd_cols) cfg.left_width = (uint8_t)v;
  }

  saveConfig();
  String s = htmlHeader("Gespeichert");
  s += "<h2>Gespeichert</h2><p>Neustart in 2 Sekunden…</p>";
  s += htmlFooter();
  http.send(200,"text/html; charset=utf-8",s);
  delay(2000);
  ESP.restart();
}

void handleWiFiReset(){
  String s = htmlHeader("WLAN Reset");
  s += "<h2>WLAN-Einstellungen gelöscht</h2><p>Gerät startet neu und öffnet das Setup-WLAN.</p>";
  s += htmlFooter();
  http.send(200,"text/html; charset=utf-8",s);
  delay(500);
  WiFiManager wm;
  wm.resetSettings(); // löscht nur WLAN-Creds
  delay(500);
  ESP.restart();
}

// ---------- WiFiManager ----------
void saveConfigCallback() { shouldSaveConfig = true; }

void startConfigPortalIfNeeded(){
  WiFiManager wm;
  wm.setSaveConfigCallback(saveConfigCallback);

  WiFiManagerParameter p_mhost("mqtt_host", "MQTT Host", cfg.mqtt_host, 64);
  char portBuf[8]; snprintf(portBuf, sizeof(portBuf), "%u", cfg.mqtt_port);
  WiFiManagerParameter p_mport("mqtt_port", "MQTT Port", portBuf, 6);
  WiFiManagerParameter p_muser("mqtt_user", "MQTT User", cfg.mqtt_user, 32);
  WiFiManagerParameter p_mpass("mqtt_pass", "MQTT Passwort", cfg.mqtt_pass, 64);
  WiFiManagerParameter p_prefix("topic_prefix", "Topic-Präfix", cfg.topic_prefix, 48);
  char colsBuf[4]; snprintf(colsBuf, sizeof(colsBuf), "%u", cfg.lcd_cols);
  WiFiManagerParameter p_lcols("lcd_cols", "LCD Spalten (16/20)", colsBuf, 3);
  char rowsBuf[4]; snprintf(rowsBuf, sizeof(rowsBuf), "%u", cfg.lcd_rows);
  WiFiManagerParameter p_lrows("lcd_rows", "LCD Zeilen (4)", rowsBuf, 3);
  char lwBuf[4]; snprintf(lwBuf, sizeof(lwBuf), "%u", cfg.left_width);
  WiFiManagerParameter p_lw("left_width", "Left-Width (links, Zeichen)", lwBuf, 3);

  wm.addParameter(&p_mhost); wm.addParameter(&p_mport);
  wm.addParameter(&p_muser); wm.addParameter(&p_mpass);
  wm.addParameter(&p_prefix);
  wm.addParameter(&p_lcols); wm.addParameter(&p_lrows);
  wm.addParameter(&p_lw);

  String apName = "LCD-Setup-" + String(ESP.getChipId(), HEX);
  wm.setConfigPortalBlocking(true);
  wm.setBreakAfterConfig(true);
  wm.setMinimumSignalQuality(8);
  wm.setConnectTimeout(20);

  if (!wm.autoConnect(apName.c_str())) { ESP.restart(); }

  // Übernahme
  strlcpy(cfg.mqtt_host, p_mhost.getValue(), sizeof(cfg.mqtt_host));
  cfg.mqtt_port = (uint16_t) String(p_mport.getValue()).toInt();
  strlcpy(cfg.mqtt_user, p_muser.getValue(), sizeof(cfg.mqtt_user));
  strlcpy(cfg.mqtt_pass, p_mpass.getValue(), sizeof(cfg.mqtt_pass));
  strlcpy(cfg.topic_prefix, p_prefix.getValue(), sizeof(cfg.topic_prefix));
  cfg.lcd_cols = (uint8_t) String(p_lcols.getValue()).toInt();
  cfg.lcd_rows = (uint8_t) String(p_lrows.getValue()).toInt();
  cfg.left_width = (uint8_t) String(p_lw.getValue()).toInt();
  if (cfg.left_width == 0 || cfg.left_width >= cfg.lcd_cols) cfg.left_width = 12;

  if (shouldSaveConfig || !LittleFS.exists(CONFIG_PATH)) saveConfig();
}

// ---------- Setup/Loop ----------
unsigned long lastPing=0;

void setup(){
  Serial.begin(115200);
  delay(100);
  LittleFS.begin();

  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);

  loadConfig();

  // LCD initialisieren
  lcd.begin(cfg.lcd_cols, cfg.lcd_rows);
  setBacklight(true);
  lcd.clear();

  // Bootanzeige (full mode)
  fullLine[0] = "MQTT LCD bereit"; rowMode[0]=MODE_FULL;
  fullLine[1] = WiFi.localIP().toString(); rowMode[1]=MODE_FULL; // wird nach connect neu gesetzt
  fullLine[2] = "MQTT-Broker"; rowMode[2]=MODE_FULL;
  fullLine[3] = String(cfg.mqtt_host) + ":" + String(cfg.mqtt_port); rowMode[3]=MODE_FULL;
  renderAll();

  // WiFiManager-Portal (bei Erststart / wenn no connect)
  startConfigPortalIfNeeded();

  // IP erneuern
  fullLine[1] = WiFi.localIP().toString(); rowMode[1]=MODE_FULL;
  renderRow(1);

  buildTopics();
  mqtt.setCallback(mqttCallback);
  connectMQTT();

  // Webserver
  http.on("/", HTTP_GET, handleRoot);
  http.on("/testfull",  HTTP_POST, handleTestFull);
  http.on("/testpairs", HTTP_POST, handleTestPairs);
  http.on("/clear",     HTTP_POST, handleClear);
  http.on("/backlight", HTTP_POST, handleBacklight);
  http.on("/config",    HTTP_GET,  handleConfigGet);
  http.on("/config",    HTTP_POST, handleConfigPost);
  http.on("/wifireset", HTTP_GET,  handleWiFiReset);
  http.begin();
}

void loop(){
  if (!mqtt.connected()) connectMQTT();
  mqtt.loop();
  http.handleClient();

  unsigned long now = millis();
  if (now - lastPing > 60000UL){
    lastPing = now;
    mqtt.publish(T_STATUS.c_str(), "alive");
    if (!firstRenderDone) renderAll();
  }
}