/**
 * VncTile — Live-Desktop der QEMU-VM (noVNC in einer WebView, RFB durch RVS).
 *
 * Nur aktiv, wenn das Desktop-Panel offen ist (focused): dann WebView mounten,
 * bei 'ready' den RVS-VNC-Tunnel oeffnen. Zwei Bedien-Leisten machen die VM auf
 * dem Handy voll bedienbar:
 *  - ctlBar (oben rechts): Fn-Leiste ein/aus, Software-Tastatur, Fit ↔ 1:1.
 *  - keyBar (oben, Fn):     echte Steuertasten, die keine Software-Tastatur
 *    liefert — Esc, Tab, Pfeile, Pos1/Ende/Bild, Einfg/Entf, Enter, F1–F12 und
 *    Sticky-Modifier Strg/Alt/Shift (fuer Strg+C, Strg+Alt+Entf, …).
 */

import React, { useCallback, useEffect, useRef, useState } from 'react';
import { Keyboard, NativeSyntheticEvent, ScrollView, StyleSheet, Text, TextInput, TextInputChangeEventData, TextInputKeyPressEventData, TouchableOpacity, View } from 'react-native';
import { WebView, WebViewMessageEvent } from 'react-native-webview';
import desktop from '../../services/desktop';
import { NOVNC_HTML } from '../assets/novncHtml';

interface Props {
  projectId: string;
  focused: boolean;
  port?: number; // VNC-Port der zu verbindenden VM (Default 5901 = Display :1)
}

// X11-Keysyms fuer Sondertasten, die kein druckbares Zeichen liefern.
const KEYSYM = { Backspace: 0xff08, Enter: 0xff0d, Tab: 0xff09 };
const MOD = { ctrl: 0xffe3, alt: 0xffe9, shift: 0xffe1 };
const cpToKeysym = (cp: number) => (cp < 0x100 ? cp : 0x01000000 + cp);

// Sondertasten fuer die Fn-Leiste (Label → Keysym).
const NAV_KEYS: { label: string; ks: number }[] = [
  { label: 'Esc', ks: 0xff1b }, { label: 'Tab', ks: 0xff09 },
  { label: '←', ks: 0xff51 }, { label: '↑', ks: 0xff52 }, { label: '↓', ks: 0xff54 }, { label: '→', ks: 0xff53 },
  { label: 'Pos1', ks: 0xff50 }, { label: 'Ende', ks: 0xff57 },
  { label: 'Bild↑', ks: 0xff55 }, { label: 'Bild↓', ks: 0xff56 },
  { label: 'Einfg', ks: 0xff63 }, { label: 'Entf', ks: 0xffff }, { label: '⏎', ks: 0xff0d },
];
const F_KEYS: { label: string; ks: number }[] = Array.from({ length: 12 }, (_, i) => ({ label: 'F' + (i + 1), ks: 0xffbe + i }));

const VncTile: React.FC<Props> = ({ projectId, focused, port = 5901 }) => {
  const webRef = useRef<WebView>(null);
  const kbdRef = useRef<TextInput>(null);
  const bufRef = useRef('');                        // Spiegel des TextInput-Textes
  const [status, setStatus] = useState<'idle' | 'connecting' | 'connected' | 'disconnected'>('idle');
  const [kbdOn, setKbdOn] = useState(false);
  const [keyBar, setKeyBar] = useState(false);      // Fn-Leiste sichtbar?
  const [mods, setMods] = useState({ ctrl: false, alt: false, shift: false });
  const modRef = useRef({ ctrl: false, alt: false, shift: false }); // Spiegel fuer Closures
  const unsubDataRef = useRef<null | (() => void)>(null);

  const teardown = useCallback(() => {
    if (unsubDataRef.current) { unsubDataRef.current(); unsubDataRef.current = null; }
    desktop.closeVnc();
  }, []);

  useEffect(() => {
    if (!focused) { teardown(); setStatus('idle'); }
    return () => teardown();
  }, [focused, teardown]);

  // Button-Zustand an die ECHTE Tastatur-Sichtbarkeit koppeln: Androids
  // Zurueck-Taste blendet die Tastatur aus, ohne den TextInput zu blurren —
  // ueber keyboardDidHide setzen wir das ⌨-Symbol trotzdem zurueck.
  useEffect(() => {
    if (!focused) return;
    const show = Keyboard.addListener('keyboardDidShow', () => setKbdOn(true));
    const hide = Keyboard.addListener('keyboardDidHide', () => setKbdOn(false));
    return () => { show.remove(); hide.remove(); };
  }, [focused]);

  const ctl = useCallback((fn: string) => {
    webRef.current?.injectJavaScript(`window.ariaVncCtl && window.ariaVncCtl.${fn}(); true;`);
  }, []);

  const sendKeysym = useCallback((ks: number) => {
    webRef.current?.injectJavaScript(`window.ariaVncKey && window.ariaVncKey.keysym(${ks}); true;`);
  }, []);
  const sendCombo = useCallback((modKeysyms: number[], ks: number) => {
    webRef.current?.injectJavaScript(`window.ariaVncKey && window.ariaVncKey.combo(${JSON.stringify(modKeysyms)}, ${ks}); true;`);
  }, []);

  // Aktive Sticky-Modifier als Keysym-Liste; nach dem Anwenden one-shot zuruecksetzen.
  const activeMods = useCallback(() => {
    const m = modRef.current; const a: number[] = [];
    if (m.ctrl) a.push(MOD.ctrl); if (m.alt) a.push(MOD.alt); if (m.shift) a.push(MOD.shift);
    return a;
  }, []);
  const clearMods = useCallback(() => {
    if (modRef.current.ctrl || modRef.current.alt || modRef.current.shift) {
      modRef.current = { ctrl: false, alt: false, shift: false };
      setMods(modRef.current);
    }
  }, []);
  const toggleMod = useCallback((k: 'ctrl' | 'alt' | 'shift') => {
    modRef.current = { ...modRef.current, [k]: !modRef.current[k] };
    setMods(modRef.current);
  }, []);

  // Eine Taste (fertiges Keysym) senden — mit ggf. aktiven Modifiern.
  const pressKey = useCallback((ks: number) => {
    const m = activeMods();
    if (m.length) { sendCombo(m, ks); clearMods(); } else sendKeysym(ks);
  }, [activeMods, sendCombo, clearMods, sendKeysym]);

  // Ein druckbares Zeichen senden — mit ggf. aktiven Modifiern (Strg+C etc.).
  const pressChar = useCallback((cp: number) => {
    const m = activeMods();
    if (m.length) { sendCombo(m, cpToKeysym(cp)); clearMods(); }
    else webRef.current?.injectJavaScript(`window.ariaVncKey && window.ariaVncKey.char(${cp}); true;`);
  }, [activeMods, sendCombo, clearMods]);

  // Tastatur ein-/ausblenden. Oeffnen: blur→focus erzwingt das Aufklappen auch
  // dann, wenn der TextInput noch fokussiert ist (Tastatur per Zurueck-Taste
  // versteckt). Schliessen: Keyboard.dismiss(); den Button-Zustand setzt der
  // keyboardDidShow/Hide-Listener — nicht hier —, damit er nie „haengen" bleibt.
  const toggleKbd = useCallback(() => {
    if (kbdOn) { Keyboard.dismiss(); }
    else { kbdRef.current?.blur(); setTimeout(() => kbdRef.current?.focus(), 30); }
  }, [kbdOn]);

  // Druckbare Zeichen: Prefix-Diff des (wachsenden) Feldes → nur neu Getipptes an
  // die VM. Loeschungen kommen ueber onKeyPress(Backspace), daher hier nur Inserts.
  const onKbdChange = useCallback((e: NativeSyntheticEvent<TextInputChangeEventData>) => {
    const text = e.nativeEvent.text || '';
    const prev = bufRef.current;
    let i = 0;
    const min = Math.min(prev.length, text.length);
    while (i < min && prev.charCodeAt(i) === text.charCodeAt(i)) i++;
    for (const ch of text.slice(i)) { const cp = ch.codePointAt(0); if (cp) pressChar(cp); }
    bufRef.current = text;
    if (text.length > 200) { bufRef.current = ''; kbdRef.current?.setNativeProps({ text: '' }); }
  }, [pressChar]);

  // Sondertasten der Software-Tastatur: Backspace feuert auf Android zuverlaessig
  // als keyPress; die Return-Taste (Haken) kommt als onSubmitEditing (s.u.).
  const onKbdKeyPress = useCallback((e: NativeSyntheticEvent<TextInputKeyPressEventData>) => {
    const k = e.nativeEvent.key;
    if (k === 'Backspace') pressKey(KEYSYM.Backspace);
    else if (k === 'Enter') pressKey(KEYSYM.Enter);
  }, [pressKey]);

  const onMessage = useCallback((e: WebViewMessageEvent) => {
    let m: any;
    try { m = JSON.parse(e.nativeEvent.data); } catch { return; }
    if (m.event === 'ready') {
      setStatus('connecting');
      unsubDataRef.current = desktop.onVncData((b64) => {
        const js = `window.ariaVnc && window.ariaVnc.onData(${JSON.stringify(b64)}); true;`;
        webRef.current?.injectJavaScript(js);
      });
      desktop.openVnc(projectId, port);
    } else if (m.event === 'vnc_send') {
      desktop.sendInput(m.b64);
    } else if (m.event === 'vnc_close') {
      desktop.closeVnc();
    } else if (m.event === 'vnc_state') {
      if (m.state === 'connected') setStatus('connected');
      else if (m.state === 'disconnected') setStatus('disconnected');
    }
  }, [projectId, port]);

  if (!focused) {
    return (
      <View style={styles.placeholder}>
        <Text style={styles.icon}>🖥️</Text>
        <Text style={styles.text}>Desktop</Text>
        <Text style={styles.sub}>Panel öffnen zum Verbinden</Text>
      </View>
    );
  }

  const connected = status === 'connected';
  return (
    <View style={styles.container}>
      <WebView
        ref={webRef}
        style={styles.web}
        originWhitelist={['*']}
        source={{ html: NOVNC_HTML, baseUrl: 'https://aria-vnc.local/' }}
        onMessage={onMessage}
        javaScriptEnabled
        domStorageEnabled
        mixedContentMode="always"
        androidLayerType="hardware"
        keyboardDisplayRequiresUserAction={false}
      />

      {/* Verstecktes Eingabefeld: fokussiert → Android-Tastatur tippt in die VM.
          keyboardType=visible-password schaltet Autokorrektur/Vorschlaege ab und
          liefert saubere Einzelzeichen. Offscreen, aber fokussierbar. */}
      <TextInput
        ref={kbdRef}
        style={styles.hiddenInput}
        onChange={onKbdChange}
        onKeyPress={onKbdKeyPress}
        onSubmitEditing={() => pressKey(KEYSYM.Enter)}
        keyboardType="visible-password"
        returnKeyType="send"
        autoCapitalize="none"
        autoCorrect={false}
        spellCheck={false}
        blurOnSubmit={false}
        caretHidden
        contextMenuHidden
        multiline={false}
      />

      {/* Steuerungs-Leiste — nur wenn verbunden */}
      {connected && (
        <View style={styles.ctlBar}>
          <TouchableOpacity style={[styles.ctlBtn, keyBar && styles.ctlBtnOn]} onPress={() => setKeyBar(v => !v)} activeOpacity={0.7}>
            <Text style={styles.ctlText}>Fn</Text>
          </TouchableOpacity>
          <TouchableOpacity style={[styles.ctlBtn, kbdOn && styles.ctlBtnOn]} onPress={toggleKbd} activeOpacity={0.7}>
            <Text style={styles.ctlText}>⌨</Text>
          </TouchableOpacity>
          <TouchableOpacity style={styles.ctlBtn} onPress={() => ctl('toggleFit')} activeOpacity={0.7}>
            <Text style={styles.ctlText}>⤢</Text>
          </TouchableOpacity>
        </View>
      )}

      {/* Fn-Leiste — echte Steuertasten (oben, ueber der Software-Tastatur). */}
      {connected && keyBar && (
        <View style={styles.keyBar} pointerEvents="box-none">
          <ScrollView horizontal showsHorizontalScrollIndicator={false} keyboardShouldPersistTaps="always" contentContainerStyle={styles.keyRow}>
            <TouchableOpacity style={[styles.key, mods.ctrl && styles.keyOn]} onPress={() => toggleMod('ctrl')} activeOpacity={0.7}><Text style={styles.keyText}>Strg</Text></TouchableOpacity>
            <TouchableOpacity style={[styles.key, mods.alt && styles.keyOn]} onPress={() => toggleMod('alt')} activeOpacity={0.7}><Text style={styles.keyText}>Alt</Text></TouchableOpacity>
            <TouchableOpacity style={[styles.key, mods.shift && styles.keyOn]} onPress={() => toggleMod('shift')} activeOpacity={0.7}><Text style={styles.keyText}>Shift</Text></TouchableOpacity>
            {NAV_KEYS.map(k => (
              <TouchableOpacity key={k.label} style={styles.key} onPress={() => pressKey(k.ks)} activeOpacity={0.7}><Text style={styles.keyText}>{k.label}</Text></TouchableOpacity>
            ))}
          </ScrollView>
          <ScrollView horizontal showsHorizontalScrollIndicator={false} keyboardShouldPersistTaps="always" contentContainerStyle={styles.keyRow}>
            {F_KEYS.map(k => (
              <TouchableOpacity key={k.label} style={styles.key} onPress={() => pressKey(k.ks)} activeOpacity={0.7}><Text style={styles.keyText}>{k.label}</Text></TouchableOpacity>
            ))}
            <TouchableOpacity style={styles.key} onPress={() => ctl('cad')} activeOpacity={0.7}><Text style={styles.keyTextSm}>Strg+Alt+Entf</Text></TouchableOpacity>
          </ScrollView>
        </View>
      )}

      {!connected && (
        <View style={styles.overlay} pointerEvents="none">
          <Text style={styles.overlayText}>
            {status === 'connecting' ? 'Verbinde …' : status === 'disconnected' ? 'Getrennt' : ''}
          </Text>
        </View>
      )}
    </View>
  );
};

const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: '#000000' },
  web: { flex: 1, backgroundColor: '#000000' },
  placeholder: { flex: 1, backgroundColor: '#000000', alignItems: 'center', justifyContent: 'center' },
  icon: { fontSize: 64, marginBottom: 16 },
  text: { color: '#FFFFFF', fontSize: 18, fontWeight: '700' },
  sub: { color: '#9090B0', fontSize: 14, marginTop: 8 },
  ctlBar: {
    position: 'absolute',
    top: 34,
    right: 8,
    flexDirection: 'row',
    gap: 6,
  },
  ctlBtn: {
    backgroundColor: 'rgba(18,18,42,0.9)',
    borderColor: '#2A2A3E',
    borderWidth: 1,
    borderRadius: 10,
    paddingHorizontal: 10,
    paddingVertical: 7,
    minWidth: 38,
    alignItems: 'center',
    justifyContent: 'center',
  },
  ctlBtnOn: { backgroundColor: 'rgba(0,150,255,0.85)', borderColor: '#0096FF' },
  ctlText: { color: '#E0E0F0', fontSize: 16, fontWeight: '700' },
  ctlTextSmall: { color: '#E0E0F0', fontSize: 11, fontWeight: '700' },
  // Fokussierbar (nicht display:none), aber aus dem Sichtfeld geschoben.
  hiddenInput: { position: 'absolute', width: 1, height: 1, top: -100, left: -100, opacity: 0, padding: 0 },
  keyBar: { position: 'absolute', top: 74, left: 0, right: 0, gap: 5 },
  keyRow: { paddingHorizontal: 6, gap: 5, alignItems: 'center' },
  key: {
    backgroundColor: 'rgba(18,18,42,0.92)', borderColor: '#2A2A3E', borderWidth: 1,
    borderRadius: 8, paddingHorizontal: 9, paddingVertical: 7, minWidth: 34,
    alignItems: 'center', justifyContent: 'center',
  },
  keyOn: { backgroundColor: 'rgba(0,150,255,0.85)', borderColor: '#0096FF' },
  keyText: { color: '#E0E0F0', fontSize: 13, fontWeight: '700' },
  keyTextSm: { color: '#E0E0F0', fontSize: 10, fontWeight: '700' },
  overlay: { position: 'absolute', top: 12, left: 0, right: 0, alignItems: 'center' },
  overlayText: { color: '#9090B0', fontSize: 12, backgroundColor: 'rgba(0,0,0,0.6)', paddingHorizontal: 10, paddingVertical: 4, borderRadius: 10, overflow: 'hidden' },
});

export default VncTile;
