import subprocess
import sys
import ipaddress
import threading
from concurrent.futures import ThreadPoolExecutor, as_completed

# Windows: prevent subprocess from opening visible console windows
_NO_WINDOW = subprocess.CREATE_NO_WINDOW if sys.platform == "win32" else 0

# Concurrent ping workers per platform
_MAX_WORKERS_WIN = 50
_MAX_WORKERS_OTHER = 64


def _ping_one(ip, is_win):
    """Ping a single IP. Returns True if host responds."""
    try:
        if is_win:
            # Capture stdout to check for TTL= — more reliable than returncode
            # on Windows (returncode can be 0 even for "Destination unreachable")
            r = subprocess.run(
                ["ping", "-n", "1", "-w", "500", str(ip)],
                stdout=subprocess.PIPE,
                stderr=subprocess.DEVNULL,
                timeout=3,
                creationflags=_NO_WINDOW
            )
            return r.returncode == 0 and b"TTL=" in r.stdout
        elif sys.platform == "darwin":
            r = subprocess.run(
                ["ping", "-c", "1", "-W", "300", str(ip)],
                stdout=subprocess.DEVNULL,
                stderr=subprocess.DEVNULL,
                timeout=2
            )
        else:
            r = subprocess.run(
                ["ping", "-c", "1", "-W", "1", str(ip)],
                stdout=subprocess.DEVNULL,
                stderr=subprocess.DEVNULL,
                timeout=2
            )
        return r.returncode == 0
    except Exception:
        return False


def _ping_sweep(network, progress_cb=None):
    """Ping tất cả host trong network đồng thời.
    Trả về list IP đã phản hồi. Gọi progress_cb(done, total) sau mỗi ping.
    """
    net = ipaddress.ip_network(network, strict=False)

    if net.num_addresses > 256:
        return []

    is_win = sys.platform == "win32"
    hosts = list(net.hosts())
    total = len(hosts)
    workers = min(_MAX_WORKERS_WIN if is_win else _MAX_WORKERS_OTHER, len(hosts))

    done_count = [0]
    lock = threading.Lock()
    alive = []

    def _ping_and_track(ip):
        ok = _ping_one(ip, is_win)
        with lock:
            done_count[0] += 1
            current = done_count[0]
        if progress_cb:
            progress_cb(current, total)
        return (str(ip), ok)

    with ThreadPoolExecutor(max_workers=workers) as executor:
        futures = [executor.submit(_ping_and_track, ip) for ip in hosts]
        for f in as_completed(futures):
            ip_str, ok = f.result()
            if ok:
                alive.append(ip_str)

    return alive


def scan_network(network, progress_cb=None, stage_cb=None):
    """Scan network: chỉ dùng ping để xác định thiết bị online."""
    if stage_cb:
        stage_cb("ping")
    alive_ips = _ping_sweep(network, progress_cb)

    results = [{"ip": ip_str, "mac": "N/A"} for ip_str in alive_ips]
    return sorted(results, key=lambda d: ipaddress.ip_address(d["ip"]))