#!/usr/bin/env bash
# GOTT Remote Agent - Linux Bash Client
# Verbindet sich per WebSocket zum GOTT-Server und fuehrt Befehle aus.
#
# Verwendung:
#   curl -s https://gott.example.com/remote.sh | bash
#   oder:
#   chmod +x remote.sh && ./remote.sh
#   oder mit eigener URL:
#   WS_URL="wss://example.com/api/remote" ./remote.sh

WS_URL="${WS_URL:-{{WS_URL}}}"

# Python finden
PYTHON=""
for cmd in python3 python py; do
    if command -v "$cmd" &>/dev/null; then
        PYTHON="$cmd"
        break
    fi
done

if [ -z "$PYTHON" ]; then
    echo ""
    echo "  [FEHLER] Python nicht gefunden!"
    echo "  Bitte installiere Python 3: sudo apt install python3"
    echo ""
    exit 1
fi

# Python-Script inline ausfuehren
exec "$PYTHON" - "$WS_URL" << 'PYTHON_SCRIPT'
import sys
import os
import json
import subprocess
import signal
import socket
import ssl
import hashlib
import base64
import struct
import time
from urllib.parse import urlparse

WS_URL = sys.argv[1] if len(sys.argv) > 1 else "ws://localhost/api/remote"

CYAN = "\033[96m"
GREEN = "\033[92m"
YELLOW = "\033[93m"
RED = "\033[91m"
GRAY = "\033[90m"
WHITE = "\033[97m"
RESET = "\033[0m"

def cprint(msg, color=""):
    print(f"{color}{msg}{RESET}", flush=True)

class WebSocketClient:
    """Minimaler WebSocket-Client (RFC 6455) ohne externe Abhaengigkeiten."""

    def __init__(self, url):
        self.url = url
        self.sock = None
        self.closed = False

    def connect(self):
        parsed = urlparse(self.url)
        use_ssl = parsed.scheme in ("wss", "https")
        host = parsed.hostname
        port = parsed.port or (443 if use_ssl else 80)
        path = parsed.path or "/"
        if parsed.query:
            path += "?" + parsed.query

        self.sock = socket.create_connection((host, port), timeout=10)
        if use_ssl:
            ctx = ssl.create_default_context()
            self.sock = ctx.wrap_socket(self.sock, server_hostname=host)

        # WebSocket-Handshake
        key = base64.b64encode(os.urandom(16)).decode()
        handshake = (
            f"GET {path} HTTP/1.1\r\n"
            f"Host: {host}\r\n"
            f"Upgrade: websocket\r\n"
            f"Connection: Upgrade\r\n"
            f"Sec-WebSocket-Key: {key}\r\n"
            f"Sec-WebSocket-Version: 13\r\n"
            f"\r\n"
        )
        self.sock.sendall(handshake.encode())

        # Response lesen
        response = b""
        while b"\r\n\r\n" not in response:
            chunk = self.sock.recv(4096)
            if not chunk:
                raise ConnectionError("Handshake fehlgeschlagen")
            response += chunk

        status_line = response.split(b"\r\n")[0].decode()
        if "101" not in status_line:
            raise ConnectionError(f"WebSocket-Handshake fehlgeschlagen: {status_line}")

        self.sock.settimeout(None)

    def send(self, data):
        if self.closed:
            return
        payload = data.encode("utf-8")
        frame = bytearray()
        frame.append(0x81)  # FIN + Text

        length = len(payload)
        if length < 126:
            frame.append(0x80 | length)  # Mask-Bit gesetzt
        elif length < 65536:
            frame.append(0x80 | 126)
            frame.extend(struct.pack(">H", length))
        else:
            frame.append(0x80 | 127)
            frame.extend(struct.pack(">Q", length))

        # Masking Key (Client muss maskieren)
        mask = os.urandom(4)
        frame.extend(mask)
        masked = bytearray(b ^ mask[i % 4] for i, b in enumerate(payload))
        frame.extend(masked)

        self.sock.sendall(frame)

    def recv(self):
        if self.closed:
            return None

        def read_exact(n):
            data = b""
            while len(data) < n:
                chunk = self.sock.recv(n - len(data))
                if not chunk:
                    raise ConnectionError("Verbindung geschlossen")
                data += chunk
            return data

        header = read_exact(2)
        opcode = header[0] & 0x0F
        is_masked = header[1] & 0x80
        length = header[1] & 0x7F

        if opcode == 0x8:  # Close
            self.closed = True
            return None
        if opcode == 0x9:  # Ping
            self.send_pong()
            return self.recv()

        if length == 126:
            length = struct.unpack(">H", read_exact(2))[0]
        elif length == 127:
            length = struct.unpack(">Q", read_exact(8))[0]

        if is_masked:
            mask = read_exact(4)
            data = read_exact(length)
            data = bytearray(b ^ mask[i % 4] for i, b in enumerate(data))
        else:
            data = read_exact(length)

        return data.decode("utf-8")

    def send_pong(self):
        if self.closed:
            return
        frame = bytearray([0x8A, 0x80])  # FIN + Pong, Mask-Bit, Length 0
        frame.extend(os.urandom(4))  # Mask key
        self.sock.sendall(frame)

    def close(self):
        if self.closed:
            return
        self.closed = True
        try:
            # Close-Frame senden
            frame = bytearray([0x88, 0x82])  # FIN + Close, Mask-Bit, Length 2
            mask = os.urandom(4)
            frame.extend(mask)
            # Status 1000 (Normal Closure) maskiert
            code = struct.pack(">H", 1000)
            frame.extend(bytearray(b ^ mask[i % 4] for i, b in enumerate(code)))
            self.sock.sendall(frame)
        except Exception:
            pass
        try:
            self.sock.close()
        except Exception:
            pass


def main():
    print()
    cprint("  ============================", CYAN)
    cprint("   GOTT Remote Agent", CYAN)
    cprint("  ============================", CYAN)
    print()
    cprint(f"  Verbinde zu: {WS_URL}", GRAY)
    print()

    ws = WebSocketClient(WS_URL)
    running = True

    def on_signal(sig, frame):
        nonlocal running
        running = False

    signal.signal(signal.SIGINT, on_signal)
    signal.signal(signal.SIGTERM, on_signal)

    try:
        ws.connect()
    except Exception as e:
        cprint(f"  [FEHLER] Verbindung fehlgeschlagen: {e}", RED)
        cprint(f"  URL: {WS_URL}", GRAY)
        return

    cprint("  [OK] Verbunden!", GREEN)

    # Hello-Message senden
    hostname = os.uname().nodename if hasattr(os, "uname") else socket.gethostname()
    username = os.environ.get("USER", os.environ.get("LOGNAME", "unknown"))
    import platform
    os_version = f"{platform.system()} {platform.release()}"

    hello = json.dumps({
        "type": "hello",
        "hostname": hostname,
        "username": username,
        "os": os_version
    })
    ws.send(hello)

    cprint(f"  Host: {username}@{hostname} ({os_version})", GRAY)
    print()
    cprint("  Warte auf Befehle... (Strg+C zum Beenden)", YELLOW)
    print()

    while running and not ws.closed:
        try:
            raw = ws.recv()
        except (ConnectionError, OSError):
            cprint("  Verbindung verloren.", RED)
            break

        if raw is None:
            cprint("  Server hat Verbindung geschlossen.", YELLOW)
            break

        try:
            msg = json.loads(raw)
        except json.JSONDecodeError:
            continue

        msg_type = msg.get("type", "")

        if msg_type == "execute":
            command = msg.get("command", "")
            timestamp = time.strftime("%H:%M:%S")
            print(f"  {CYAN}[{timestamp}] Ausfuehren: {WHITE}{command}{RESET}", flush=True)

            exit_code = 0
            stdout = ""
            stderr = ""

            try:
                result = subprocess.run(
                    ["bash", "-c", command],
                    capture_output=True,
                    text=True,
                    timeout=300
                )
                stdout = result.stdout
                stderr = result.stderr
                exit_code = result.returncode
            except subprocess.TimeoutExpired:
                stderr = "Timeout nach 300 Sekunden"
                exit_code = 124
            except Exception as e:
                stderr = str(e)
                exit_code = 1

            response = json.dumps({
                "type": "result",
                "exitCode": exit_code,
                "output": stdout or "",
                "error": stderr or ""
            })
            ws.send(response)

            # Kurzausgabe lokal
            if stdout:
                preview = stdout[:200] + "..." if len(stdout) > 200 else stdout.rstrip()
                cprint(f"  -> {preview}", GRAY)
            if stderr:
                cprint(f"  [stderr] {stderr.rstrip()}", RED)
            color = GREEN if exit_code == 0 else RED
            cprint(f"  [Exit: {exit_code}]", color)
            print()

        elif msg_type == "ping":
            ws.send('{"type":"pong"}')

        elif msg_type == "pong":
            pass

        else:
            cprint(f"  Unbekannte Nachricht: {msg_type}", YELLOW)

    ws.close()
    print()
    cprint("  Verbindung beendet.", YELLOW)


main()
PYTHON_SCRIPT