#!/usr/bin/env python3
# Fetch a file from the guest via the QEMU guest agent protocol
# (/tmp/qemu-guest-agent.sock, the virtio-serial QGA chardev - the same
# socket vgpu_vm.py exec uses). Usage: qga_fetch.py <guest_path> <host_path> [chunk]
import base64
import json
import socket
import sys

GUEST = sys.argv[1]
HOST = sys.argv[2]
CHUNK = int(sys.argv[3]) if len(sys.argv) > 3 else 1 << 20
SOCK = "/tmp/qemu-guest-agent.sock"


def recv_line(s):
    buf = b""
    while b"\n" not in buf:
        chunk = s.recv(65536)
        if not chunk:
            break
        buf += chunk
    return buf.split(b"\n", 1)[0]


def cmd(s, obj):
    s.sendall((json.dumps(obj) + "\r\n").encode())
    line = recv_line(s)
    return json.loads(line)


s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
s.settimeout(30.0)
s.connect(SOCK)
r = cmd(s, {"execute": "guest-file-open",
            "arguments": {"path": GUEST, "mode": "r"}})
h = r["return"]
print(f"handle={h}")
total = 0
with open(HOST, "wb") as out:
    while True:
        r = cmd(s, {"execute": "guest-file-read",
                    "arguments": {"handle": h, "count": CHUNK}})
        d = r["return"]
        buf = base64.b64decode(d.get("buf-b64", ""))
        if buf:
            out.write(buf)
            total += len(buf)
            print(f"\r{total}", end="", flush=True)
        if d.get("eof"):
            break
cmd(s, {"execute": "guest-file-close", "arguments": {"handle": h}})
print(f"\nFETCHED {total} bytes -> {HOST}")