// Bettet externe RDP-Clients als Kindfenster in das MrTerm-Fenster ein (Anzeige im Tab).
//   Windows: mstsc.exe wird gestartet, sein Sitzungsfenster (TscShellContainerClass) rahmenlos über den Tab gelegt.
//   Linux:   FreeRDP mit /parent-window:<XID>, Position/Größe/Sichtbarkeit über libX11 (MrTerm läuft dafür unter X11/XWayland).
// Alle Koordinaten sind physische Pixel relativ zum Client-Bereich des MrTerm-Fensters.
const { spawn } = require('child_process');

let koffi = null;
try { koffi = require('koffi'); } catch { /* ohne koffi nur externe Fenster */ }
const i18n = require('../i18n');

// ------------------------------------------------------------------ Windows
// Chromium zeichnet per DirectComposition über alle nativen Kindfenster – ein per SetParent eingehängtes
// mstsc bliebe unsichtbar (schwarz). Stattdessen wird das Sitzungsfenster rahmenlos und als "owned window"
// von MrTerm exakt über den Tab gelegt: Es liegt immer über MrTerm, minimiert sich mit und hat keinen Taskleisten-Eintrag.
// Mit "dynamic resolution" passt mstsc die Auflösung der Sitzung an, sobald sich die Fenstergröße ändert.
function winApi() {
  if (winApi.api) return winApi.api;
  const u = koffi.load('user32.dll');
  const EnumProc = koffi.proto('bool __stdcall MrTermEnumProc(intptr hwnd, intptr lParam)');
  const WinEventProc = koffi.proto('void __stdcall MrTermWinEventProc(intptr hook, uint32 event, intptr hwnd, long idObject, long idChild, uint32 thread, uint32 time)');
  const POINT = koffi.struct('MrTermPOINT', { x: 'int', y: 'int' });
  const RECT = koffi.struct('MrTermRECT', { left: 'int', top: 'int', right: 'int', bottom: 'int' });
  winApi.api = {
    EnumWindows: u.func('bool __stdcall EnumWindows(MrTermEnumProc *cb, intptr lParam)'),
    EnumChildWindows: u.func('bool __stdcall EnumChildWindows(intptr hwnd, MrTermEnumProc *cb, intptr lParam)'),
    SetWinEventHook: u.func('intptr __stdcall SetWinEventHook(uint32 min, uint32 max, intptr mod, MrTermWinEventProc *cb, uint32 pid, uint32 tid, uint32 flags)'),
    UnhookWinEvent: u.func('bool __stdcall UnhookWinEvent(intptr hook)'),
    GetDlgItem: u.func('intptr __stdcall GetDlgItem(intptr hwnd, int id)'),
    PostMessageW: u.func('bool __stdcall PostMessageW(intptr hwnd, uint32 msg, uintptr w, intptr l)'),
    GetAncestor: u.func('intptr __stdcall GetAncestor(intptr hwnd, uint32 flags)'),
    GetWindowRect: u.func('bool __stdcall GetWindowRect(intptr hwnd, _Out_ MrTermRECT *rect)'),
    SetLayeredWindowAttributes: u.func('bool __stdcall SetLayeredWindowAttributes(intptr hwnd, uint32 key, uint8 alpha, uint32 flags)'),
    WinEventProc,
    GetWindowThreadProcessId: u.func('uint32 __stdcall GetWindowThreadProcessId(intptr hwnd, _Out_ uint32 *pid)'),
    GetClassNameW: u.func('int __stdcall GetClassNameW(intptr hwnd, void *buf, int max)'),
    IsWindowVisible: u.func('bool __stdcall IsWindowVisible(intptr hwnd)'),
    IsWindow: u.func('bool __stdcall IsWindow(intptr hwnd)'),
    GetWindowLongPtrW: u.func('intptr __stdcall GetWindowLongPtrW(intptr hwnd, int idx)'),
    SetWindowLongPtrW: u.func('intptr __stdcall SetWindowLongPtrW(intptr hwnd, int idx, intptr value)'),
    SetWindowPos: u.func('bool __stdcall SetWindowPos(intptr hwnd, intptr after, int x, int y, int cx, int cy, uint32 flags)'),
    ShowWindow: u.func('bool __stdcall ShowWindow(intptr hwnd, int cmd)'),
    SetForegroundWindow: u.func('bool __stdcall SetForegroundWindow(intptr hwnd)'),
    ClientToScreen: u.func('bool __stdcall ClientToScreen(intptr hwnd, _Inout_ MrTermPOINT *pt)'),
    POINT,
  };
  return winApi.api;
}

const buf = Buffer.alloc(512);
const className = (hwnd) => buf.toString('utf16le', 0, winApi().GetClassNameW(hwnd, buf, 256) * 2);
function childClasses(hwnd) {
  const out = new Set();
  winApi().EnumChildWindows(hwnd, (c) => { out.add(className(c)); return true; }, 0);
  return out;
}

const GWL_STYLE = -16, GWL_EXSTYLE = -20, GWLP_HWNDPARENT = -8;
const WS_CHILD = 0x40000000, WS_POPUP = 0x80000000, WS_CAPTION = 0x00c00000, WS_THICKFRAME = 0x00040000;
const WS_SYSMENU = 0x00080000, WS_MINIMIZEBOX = 0x00020000, WS_MAXIMIZEBOX = 0x00010000;
const WS_EX_APPWINDOW = 0x00040000, WS_EX_TOOLWINDOW = 0x00000080, WS_EX_LAYERED = 0x00080000;
const FRAME = WS_CAPTION | WS_THICKFRAME | WS_SYSMENU | WS_MINIMIZEBOX | WS_MAXIMIZEBOX;
const SWP_NOSIZE = 0x1, SWP_NOZORDER = 0x4, SWP_NOACTIVATE = 0x10, SWP_FRAMECHANGED = 0x20, SWP_SHOWWINDOW = 0x40;
const SW_HIDE = 0, SW_SHOWNOACTIVATE = 4, SW_SHOW = 5;
const EVENT_OBJECT_CREATE = 0x8000, EVENT_OBJECT_SHOW = 0x8002, WINEVENT_OUTOFCONTEXT = 0, GA_ROOT = 2, LWA_ALPHA = 2;
const BM_CLICK = 0xf5, ID_CERT_YES = 14004, ID_CERT_VIEW = 13443; // Zertifikatswarnung von mstsc: "Ja", "Zertifikat anzeigen"

class WinEmbed {
  constructor(parentHandle) { this.parent = Number(parentHandle.readBigUInt64LE(0)); this.visible = true; }

  // args: mstsc-Kommandozeile. Mit /v:… statt .rdp-Datei zeigt mstsc keine Sicherheitswarnung "Unbekannter Herausgeber".
  start({ args }) {
    this.proc = spawn('mstsc.exe', args, { stdio: 'ignore' });
    this.hookWindows();
    this.proc.on('exit', () => this.unhook());
    return this.proc;
  }

  // Fängt die Fenster von mstsc ab, sobald sie entstehen (läuft über die Nachrichtenschleife des Electron-Hauptthreads):
  //   Sitzungsfenster  -> noch unsichtbar rahmenlos über den Tab legen, damit nie ein normales mstsc-Fenster aufblitzt
  //   "Verbindung wird hergestellt" (Dialog mit Fortschrittsbalken) -> unsichtbar lassen, der Tab zeigt den Status selbst
  //   andere Dialoge (Zertifikat, Fehler) -> brauchen eine Entscheidung, daher mittig über dem Tab einblenden
  hookWindows() {
    const api = winApi();
    this.cb = koffi.register((_hook, event, hwnd, idObject, idChild) => {
      try {
        if (idObject !== 0 || idChild !== 0 || Number(api.GetAncestor(hwnd, GA_ROOT)) !== Number(hwnd)) return;
        const cls = className(hwnd);
        if (cls === 'TscShellContainerClass') {
          if (event === EVENT_OBJECT_CREATE || !this.hwnd) this.adopt(hwnd);
          if (event === EVENT_OBJECT_SHOW) this.onSessionShown();
        } else if (cls === '#32770') {
          const isCert = () => api.GetDlgItem(hwnd, ID_CERT_YES) && api.GetDlgItem(hwnd, ID_CERT_VIEW);
          if (event === EVENT_OBJECT_CREATE) this.setAlpha(hwnd, 0);
          else if (childClasses(hwnd).has('msctls_progress32')) api.ShowWindow(hwnd, SW_HIDE);
          else if (this.acceptCert && isCert()) api.PostMessageW(api.GetDlgItem(hwnd, ID_CERT_YES), BM_CLICK, 0, 0);
          else { if (isCert()) this.certPrompted = true; this.presentDialog(hwnd); }
        }
      } catch { /* Fenster kann bereits wieder zu sein */ }
    }, koffi.pointer(api.WinEventProc));
    this.hook = api.SetWinEventHook(EVENT_OBJECT_CREATE, EVENT_OBJECT_SHOW, 0, this.cb, this.proc.pid, 0, WINEVENT_OUTOFCONTEXT);
  }

  unhook() {
    if (this.hook) { winApi().UnhookWinEvent(this.hook); this.hook = null; }
    if (this.cb) { koffi.unregister(this.cb); this.cb = null; }
  }

  setAlpha(hwnd, alpha) {
    const api = winApi();
    api.SetWindowLongPtrW(hwnd, GWL_EXSTYLE, ((Number(api.GetWindowLongPtrW(hwnd, GWL_EXSTYLE)) >>> 0) | WS_EX_LAYERED) >>> 0);
    api.SetLayeredWindowAttributes(hwnd, 0, alpha, LWA_ALPHA);
  }

  presentDialog(hwnd) {
    const api = winApi();
    api.SetWindowLongPtrW(hwnd, GWLP_HWNDPARENT, this.parent);
    const r = {};
    api.GetWindowRect(hwnd, r);
    const b = this.bounds || { x: 0, y: 0, width: 0, height: 0 };
    const pt = { x: b.x + Math.round((b.width - (r.right - r.left)) / 2), y: b.y + Math.round((b.height - (r.bottom - r.top)) / 2) };
    api.ClientToScreen(this.parent, pt);
    api.SetWindowPos(hwnd, 0, pt.x, pt.y, 0, 0, SWP_NOSIZE | SWP_NOZORDER);
    this.setAlpha(hwnd, 255);
    api.SetForegroundWindow(hwnd);
  }

  // Sitzungsfenster rahmenlos und ohne Taskleisten-Eintrag als "owned window" von MrTerm
  adopt(hwnd) {
    const api = winApi();
    this.hwnd = hwnd;
    const style = (((Number(api.GetWindowLongPtrW(hwnd, GWL_STYLE)) >>> 0) & ~(FRAME | WS_CHILD)) | WS_POPUP) >>> 0;
    api.SetWindowLongPtrW(hwnd, GWL_STYLE, style);
    const ex = ((((Number(api.GetWindowLongPtrW(hwnd, GWL_EXSTYLE)) >>> 0) & ~WS_EX_APPWINDOW) | WS_EX_TOOLWINDOW) >>> 0);
    api.SetWindowLongPtrW(hwnd, GWL_EXSTYLE, ex);
    api.SetWindowLongPtrW(hwnd, GWLP_HWNDPARENT, this.parent);
    // Bis zur Anmeldung außerhalb des Bildschirms parken: mstsc zentriert seine Dialoge über diesem Fenster,
    // so bleibt auch "Verbindung wird hergestellt" unsichtbar, bevor der Hook ihn ausblenden kann.
    if (!this.connected) api.SetWindowPos(hwnd, 0, -32000, -32000, this.bounds?.width || 800, this.bounds?.height || 600, SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED);
  }

  // mstsc blendet das Sitzungsfenster erst nach erfolgreicher Anmeldung ein und setzt dabei Rahmen und Größe neu
  onSessionShown() {
    this.connected = true;
    this.adopt(this.hwnd);
    if (!this.visible) winApi().ShowWindow(this.hwnd, SW_HIDE);
    this.setBounds();
    this.detectFixedSize();
    this.setBounds();
    this.onConnected?.();
  }

  // Ohne dynamische Auflösung (Server zu alt, xrdp < 0.10 …) begrenzt mstsc das Fenster auf die Sitzungsgröße –
  // erkennbar daran, dass es sich nicht vergrößern lässt. Dann hilft nur Neuverbinden mit der neuen Größe.
  detectFixedSize() {
    const api = winApi();
    const r = {};
    api.GetWindowRect(this.hwnd, r);
    api.SetWindowPos(this.hwnd, 0, r.left, r.top, r.right - r.left + 32, r.bottom - r.top + 32, SWP_NOZORDER | SWP_NOACTIVATE);
    const g = {};
    api.GetWindowRect(this.hwnd, g);
    this.fixedSize = g.right - g.left < r.right - r.left + 32 ? { width: r.right - r.left, height: r.bottom - r.top } : null;
  }

  // Zertifikat wurde für diese Sitzung bestätigt (Rückfrage gezeigt und danach verbunden) – gilt für Neuverbindungen beim Größenändern
  get certAccepted() { return this.acceptCert || (this.certPrompted && this.connected); }

  checkFixedSize() {
    clearTimeout(this.resizeTimer);
    const b = this.bounds;
    if (!this.fixedSize || !this.visible || (Math.abs(b.width - this.fixedSize.width) < 8 && Math.abs(b.height - this.fixedSize.height) < 8)) return;
    this.resizeTimer = setTimeout(() => this.onResizeNeeded?.(this.bounds), 800);
  }

  // Wartet, bis die Sitzung steht (Sitzungsfenster sichtbar)
  attach(bounds, isCancelled) {
    this.bounds = bounds;
    return new Promise((resolve) => {
      const t0 = Date.now();
      const done = (ok) => { clearInterval(iv); this.onConnected = null; resolve(ok); };
      this.onConnected = () => done(true);
      const iv = setInterval(() => {
        if (this.connected) done(true);
        else if (isCancelled() || this.proc.exitCode !== null || Date.now() - t0 > 120000) done(false);
      }, 250);
    });
  }

  // b: physische Pixel relativ zum Client-Bereich von MrTerm -> Bildschirmkoordinaten
  setBounds(b) {
    if (b) this.bounds = b;
    if (!this.hwnd || !this.bounds) return;
    const api = winApi();
    const pt = { x: this.bounds.x, y: this.bounds.y };
    api.ClientToScreen(this.parent, pt);
    api.SetWindowPos(this.hwnd, 0, pt.x, pt.y, Math.max(50, this.bounds.width), Math.max(50, this.bounds.height),
      SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED | (this.visible && this.connected ? SWP_SHOWWINDOW : 0));
    if (this.connected) this.checkFixedSize();
  }
  reposition() { this.setBounds(); }
  show() { this.visible = true; if (this.hwnd && this.connected) { winApi().ShowWindow(this.hwnd, SW_SHOWNOACTIVATE); this.setBounds(); } }
  hide() { this.visible = false; clearTimeout(this.resizeTimer); if (this.hwnd) winApi().ShowWindow(this.hwnd, SW_HIDE); }
  focus() { if (this.hwnd && this.visible) winApi().SetForegroundWindow(this.hwnd); }
  // Aus MrTerm lösen und als normales Fenster weiterlaufen lassen
  detach() {
    if (!this.hwnd) return;
    this.unhook();
    const api = winApi();
    api.SetWindowLongPtrW(this.hwnd, GWLP_HWNDPARENT, 0);
    const style = ((((Number(api.GetWindowLongPtrW(this.hwnd, GWL_STYLE)) >>> 0) & ~WS_POPUP) | FRAME) >>> 0);
    api.SetWindowLongPtrW(this.hwnd, GWL_STYLE, style);
    const ex = ((((Number(api.GetWindowLongPtrW(this.hwnd, GWL_EXSTYLE)) >>> 0) & ~WS_EX_TOOLWINDOW) | WS_EX_APPWINDOW) >>> 0);
    api.SetWindowLongPtrW(this.hwnd, GWL_EXSTYLE, ex);
    api.ShowWindow(this.hwnd, SW_SHOW);
    api.SetWindowPos(this.hwnd, 0, 80, 80, this.bounds?.width || 1280, this.bounds?.height || 800, SWP_NOZORDER | SWP_FRAMECHANGED | SWP_SHOWWINDOW);
    this.hwnd = null;
  }
  kill() { clearTimeout(this.resizeTimer); this.unhook(); try { this.proc?.kill(); } catch {} }
}

// ------------------------------------------------------------------ Linux (X11)
function x11() {
  if (x11.api) return x11.api;
  const l = koffi.load('libX11.so.6');
  x11.api = {
    XOpenDisplay: l.func('void *XOpenDisplay(const char *name)'),
    XQueryTree: l.func('int XQueryTree(void *d, unsigned long w, _Out_ unsigned long *root, _Out_ unsigned long *parent, _Out_ void **children, _Out_ unsigned int *n)'),
    XFree: l.func('int XFree(void *p)'),
    XMoveResizeWindow: l.func('int XMoveResizeWindow(void *d, unsigned long w, int x, int y, unsigned int wd, unsigned int ht)'),
    XMapWindow: l.func('int XMapWindow(void *d, unsigned long w)'),
    XUnmapWindow: l.func('int XUnmapWindow(void *d, unsigned long w)'),
    XRaiseWindow: l.func('int XRaiseWindow(void *d, unsigned long w)'),
    XSetInputFocus: l.func('int XSetInputFocus(void *d, unsigned long w, int revert, unsigned long time)'),
    XReparentWindow: l.func('int XReparentWindow(void *d, unsigned long w, unsigned long parent, int x, int y)'),
    XFlush: l.func('int XFlush(void *d)'),
    XSync: l.func('int XSync(void *d, int discard)'),
  };
  x11.api.display = x11.api.XOpenDisplay(null);
  if (!x11.api.display) throw new Error(i18n.t('No connection to the X server (MrTerm is not running under X11/XWayland).'));
  return x11.api;
}

function x11Children(win) {
  const X = x11();
  const root = [0], parent = [0], children = [null], n = [0];
  if (!X.XQueryTree(X.display, win, root, parent, children, n) || !children[0]) return [];
  const list = koffi.decode(children[0], 'unsigned long', n[0]).map(Number);
  X.XFree(children[0]);
  return list;
}

class LinuxEmbed {
  constructor(parentHandle) {
    this.parent = Number(parentHandle.readBigUInt64LE(0));
    x11(); // früh scheitern, falls kein X11
  }

  start({ client, args, password }) {
    this.before = new Set(x11Children(this.parent));
    this.proc = spawn(client, [...args, `/parent-window:${this.parent}`], { stdio: [password ? 'pipe' : 'ignore', 'ignore', 'pipe'] });
    if (password) { this.proc.stdin.write(password + '\n'); this.proc.stdin.end(); }
    this.err = '';
    this.proc.stderr.on('data', (d) => { this.err = (this.err + d).slice(-4000); });
    return this.proc;
  }

  async attach(bounds, isCancelled) {
    const t0 = Date.now();
    while (Date.now() - t0 < 120000) {
      if (isCancelled() || this.proc.exitCode !== null) return false;
      const fresh = x11Children(this.parent).filter((w) => !this.before.has(w));
      if (fresh.length) {
        this.xwin = fresh[fresh.length - 1];
        this.setBounds(bounds);
        return true;
      }
      await new Promise((r) => setTimeout(r, 250));
    }
    return false;
  }

  setBounds(b) {
    if (!this.xwin) return;
    this.bounds = b;
    const X = x11();
    X.XMoveResizeWindow(X.display, this.xwin, b.x, b.y, Math.max(50, b.width), Math.max(50, b.height));
    X.XRaiseWindow(X.display, this.xwin);
    X.XFlush(X.display);
  }
  show() { if (!this.xwin) return; const X = x11(); X.XMapWindow(X.display, this.xwin); if (this.bounds) this.setBounds(this.bounds); X.XFlush(X.display); }
  hide() { if (!this.xwin) return; const X = x11(); X.XUnmapWindow(X.display, this.xwin); X.XFlush(X.display); }
  focus() { if (!this.xwin) return; const X = x11(); X.XSetInputFocus(X.display, this.xwin, 2, 0); X.XFlush(X.display); }
  reposition() {}
  detach() { /* FreeRDP-Fenster lassen sich nicht sauber herauslösen – Sitzung stattdessen extern neu starten */ }
  kill() { try { this.proc?.kill(); } catch {} }
}

function embedSupported() {
  if (!koffi) return { ok: false, reason: i18n.t('koffi not available') };
  if (process.platform === 'win32') return { ok: true };
  if (process.platform === 'linux') {
    try { x11(); return { ok: true }; } catch (e) { return { ok: false, reason: e.message }; }
  }
  return { ok: false, reason: i18n.t('Platform not supported') };
}

function createEmbed(parentHandle) {
  return process.platform === 'win32' ? new WinEmbed(parentHandle) : new LinuxEmbed(parentHandle);
}

module.exports = { createEmbed, embedSupported };