/**
 * PPT Remote Server
 * Controls PowerPoint (Windows) or LibreOffice Impress (Linux) via WebSocket.
 *
 * Commands (client → server):
 *   { "cmd": "next" }
 *   { "cmd": "prev" }
 *   { "cmd": "start" }   — start slideshow
 *   { "cmd": "end" }     — end slideshow
 *   { "cmd": "status" }  — request current slide info
 *
 * Events (server → client):
 *   { "event": "slide", "current": 3, "total": 10 }
 *   { "event": "image", "data": "<base64 jpeg>" }
 *   { "event": "error", "message": "..." }
 */

const PORT = 8765;
const IS_LINUX = process.platform === "linux";

// ─── Helpers ──────────────────────────────────────────────────────────────────

async function run(cmd: string, args: string[]): Promise<string> {
  const proc = Bun.spawn([cmd, ...args], { stdout: "pipe", stderr: "pipe" });
  const [out, err] = await Promise.all([
    new Response(proc.stdout).text(),
    new Response(proc.stderr).text(),
  ]);
  await proc.exited;
  if (err.trim()) console.error(`[stderr]`, err.trim());
  return out.trim();
}

function parseSlide(raw: string): { current: number; total: number } {
  const [c, t] = raw.split("/").map(Number);
  return { current: c || 0, total: t || 0 };
}

// ─── Driver interface ─────────────────────────────────────────────────────────

interface Driver {
  next(): Promise<{ current: number; total: number }>;
  prev(): Promise<{ current: number; total: number }>;
  start(): Promise<{ current: number; total: number }>;
  end(): Promise<{ current: number; total: number }>;
  status(): Promise<{ current: number; total: number }>;
  slideImage(index: number): Promise<string>; // base64 jpeg/png
}

// ─── Windows Driver (PowerShell + COM) ───────────────────────────────────────

function ps(script: string) {
  return run("powershell", ["-NoProfile", "-NonInteractive", "-Command", script]);
}

const WindowsDriver: Driver = {
  async next() {
    const raw = await ps(`
      $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
      $app.ActivePresentation.SlideShowWindow.View.Next()
      Start-Sleep -Milliseconds 300
      $v = $app.ActivePresentation.SlideShowWindow.View
      "$($v.CurrentShowPosition)/$($app.ActivePresentation.Slides.Count)"
    `);
    return parseSlide(raw);
  },

  async prev() {
    const raw = await ps(`
      $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
      $app.ActivePresentation.SlideShowWindow.View.Previous()
      Start-Sleep -Milliseconds 300
      $v = $app.ActivePresentation.SlideShowWindow.View
      "$($v.CurrentShowPosition)/$($app.ActivePresentation.Slides.Count)"
    `);
    return parseSlide(raw);
  },

  async start() {
    const raw = await ps(`
      $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
      $app.ActivePresentation.SlideShowSettings.Run() | Out-Null
      Start-Sleep -Milliseconds 800
      $v = $app.ActivePresentation.SlideShowWindow.View
      "$($v.CurrentShowPosition)/$($app.ActivePresentation.Slides.Count)"
    `);
    return parseSlide(raw);
  },

  async end() {
    const raw = await ps(`
      $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
      $app.ActivePresentation.SlideShowWindow.View.Exit()
      "0/$($app.ActivePresentation.Slides.Count)"
    `);
    return parseSlide(raw);
  },

  async status() {
    const raw = await ps(`
      try {
        $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
        $total = $app.ActivePresentation.Slides.Count
        try {
          $v = $app.ActivePresentation.SlideShowWindow.View
          "$($v.CurrentShowPosition)/$total"
        } catch { "0/$total" }
      } catch { "0/0" }
    `);
    return parseSlide(raw);
  },

  async slideImage(index: number) {
    return ps(`
      try {
        $app = [Runtime.InteropServices.Marshal]::GetActiveObject('PowerPoint.Application')
        $slide = $app.ActivePresentation.Slides(${index})
        $tmp = [System.IO.Path]::GetTempFileName() -replace '\\.tmp$','.jpg'
        $slide.Export($tmp, 'JPG', 800, 600)
        $bytes = [System.IO.File]::ReadAllBytes($tmp)
        [System.Convert]::ToBase64String($bytes)
        Remove-Item $tmp -ErrorAction SilentlyContinue
      } catch { Write-Error $_.Exception.Message; "" }
    `);
  },
};

// ─── Linux Driver (Python UNO + xdotool) ─────────────────────────────────────
//
// Prerequisites:
//   - LibreOffice Impress started with UNO socket listener:
//       libreoffice --impress --accept="socket,host=localhost,port=2002;urp;StarOffice.ServiceManager"
//   - python3 with uno module (ships with LibreOffice)
//   - xdotool  (sudo apt install xdotool)
//
// The Python helper talks to LibreOffice over UNO to read slide state.
// Navigation uses xdotool to send keys to the Impress window (most reliable
// method that works with both windowed and fullscreen slideshow modes).

function pyUno(script: string): Promise<string> {
  // Inline python passed via -c; single-quotes escaped for shell
  return run("python3", ["-c", script]);
}

/** Returns the window ID of the LibreOffice Impress window */
async function libreofficeWinId(): Promise<string> {
  return run("xdotool", ["search", "--name", "LibreOffice Impress"]);
}

const LinuxDriver: Driver = {
  async next() {
    const wid = (await libreofficeWinId()).split("\n")[0].trim();
    await run("xdotool", ["key", "--window", wid, "Right"]);
    await Bun.sleep(300);
    return LinuxDriver.status();
  },

  async prev() {
    const wid = (await libreofficeWinId()).split("\n")[0].trim();
    await run("xdotool", ["key", "--window", wid, "Left"]);
    await Bun.sleep(300);
    return LinuxDriver.status();
  },

  async start() {
    // F5 starts the slideshow from the beginning; Shift+F5 from current slide
    const wid = (await libreofficeWinId()).split("\n")[0].trim();
    await run("xdotool", ["key", "--window", wid, "shift+F5"]);
    await Bun.sleep(1000);
    return LinuxDriver.status();
  },

  async end() {
    const wid = (await libreofficeWinId()).split("\n")[0].trim();
    await run("xdotool", ["key", "--window", wid, "Escape"]);
    await Bun.sleep(300);
    const { total } = await LinuxDriver.status();
    return { current: 0, total };
  },

  async status() {
    const raw = await pyUno(`
import sys
try:
    import uno
    from com.sun.star.beans import PropertyValue
    localCtx = uno.getComponentContext()
    resolver = localCtx.ServiceManager.createInstanceWithContext(
        "com.sun.star.bridge.UnoUrlResolver", localCtx)
    ctx = resolver.resolve(
        "uno:socket,host=localhost,port=2002;urp;StarOffice.ComponentContext")
    smgr = ctx.ServiceManager
    desktop = smgr.createInstanceWithContext("com.sun.star.frame.Desktop", ctx)
    comp = desktop.getCurrentComponent()
    draw = comp.DrawPages
    total = draw.Count
    try:
        controller = comp.getCurrentController()
        current = controller.getCurrentPage().PageIndex + 1
    except:
        current = 0
    print(f"{current}/{total}")
except Exception as e:
    print(f"0/0", file=sys.stderr)
    print("0/0")
`);
    return parseSlide(raw);
  },

  async slideImage(index: number) {
    // Export the slide via UNO as PNG, return base64
    const raw = await pyUno(`
import sys, os, base64, tempfile
try:
    import uno
    from com.sun.star.beans import PropertyValue
    localCtx = uno.getComponentContext()
    resolver = localCtx.ServiceManager.createInstanceWithContext(
        "com.sun.star.bridge.UnoUrlResolver", localCtx)
    ctx = resolver.resolve(
        "uno:socket,host=localhost,port=2002;urp;StarOffice.ComponentContext")
    smgr = ctx.ServiceManager
    desktop = smgr.createInstanceWithContext("com.sun.star.frame.Desktop", ctx)
    comp = desktop.getCurrentComponent()
    draw = comp.DrawPages
    slide = draw.getByIndex(${index - 1})
    tmp = tempfile.mktemp(suffix='.png')
    graphicExporter = smgr.createInstanceWithContext(
        "com.sun.star.drawing.GraphicExportFilter", ctx)
    graphicExporter.setSourceDocument(slide)
    props = []
    def mkprop(name, val):
        p = PropertyValue()
        p.Name = name
        p.Value = val
        return p
    props.append(mkprop("URL", uno.systemPathToFileUrl(tmp)))
    props.append(mkprop("MediaType", "image/png"))
    props.append(mkprop("Selection", slide))
    graphicExporter.filter(tuple(props))
    with open(tmp, 'rb') as f:
        print(base64.b64encode(f.read()).decode())
    os.unlink(tmp)
except Exception as e:
    print("", file=sys.stdout)
    print(str(e), file=sys.stderr)
`);
    return raw;
  },
};

// ─── Select driver based on platform ─────────────────────────────────────────

const driver: Driver = IS_LINUX ? LinuxDriver : WindowsDriver;
console.log(`Platform: ${process.platform} — using ${IS_LINUX ? "LibreOffice/Linux" : "PowerPoint/Windows"} driver`);

// ─── WebSocket server ─────────────────────────────────────────────────────────

const clients = new Set<import("bun").ServerWebSocket<unknown>>();

function broadcast(payload: object) {
  const msg = JSON.stringify(payload);
  for (const ws of clients) ws.send(msg);
}

async function handleCmd(cmd: string): Promise<void> {
  const navCmds = ["next", "prev", "start", "end", "status"] as const;
  type NavCmd = typeof navCmds[number];

  if (!(navCmds as readonly string[]).includes(cmd)) {
    broadcast({ event: "error", message: `Unknown command: ${cmd}` });
    return;
  }

  const { current, total } = await driver[cmd as NavCmd]();
  broadcast({ event: "slide", current, total });

  if (current > 0 && cmd !== "end") {
    const b64 = await driver.slideImage(current);
    if (b64) broadcast({ event: "image", data: b64 });
  }
}

const server = Bun.serve({
  port: PORT,

  fetch(req, server) {
    if (!req.headers.get("upgrade")) {
      return new Response(
        `PPT Remote Server — ${IS_LINUX ? "LibreOffice" : "PowerPoint"} mode\n` +
        `WebSocket: ws://<host>:${PORT}`,
        { headers: { "Content-Type": "text/plain" } }
      );
    }
    const ok = server.upgrade(req);
    return ok ? undefined : new Response("WebSocket upgrade failed", { status: 500 });
  },

  websocket: {
    open(ws) {
      clients.add(ws);
      console.log(`Client connected (${clients.size} total)`);
      driver.status().then(async ({ current, total }) => {
        ws.send(JSON.stringify({ event: "slide", current, total }));
        if (current > 0) {
          const b64 = await driver.slideImage(current);
          if (b64) ws.send(JSON.stringify({ event: "image", data: b64 }));
        }
      });
    },

    async message(ws, message) {
      let cmd: string;
      try {
        ({ cmd } = JSON.parse(message as string));
      } catch {
        ws.send(JSON.stringify({ event: "error", message: "Invalid JSON" }));
        return;
      }
      try {
        await handleCmd(cmd);
      } catch (err) {
        console.error("[cmd error]", err);
        ws.send(JSON.stringify({ event: "error", message: String(err) }));
      }
    },

    close(ws) {
      clients.delete(ws);
      console.log(`Client disconnected (${clients.size} total)`);
    },
  },
});

console.log(`PPT Remote Server listening on ws://0.0.0.0:${PORT}`);