diff --git a/wifi_deauth.py b/wifi_deauth.py
index 41320de..1a64ef8 100644
--- a/wifi_deauth.py
+++ b/wifi_deauth.py
@@ -1,10 +1,11 @@
 #!/usr/bin/env python3
-"""airodump-ng CSV parsing + wireless-interface discovery for the wifi deauth tool."""
+"""CSV parsing, interface discovery, and monitor-mode + card-state handling."""
 import os
 import re
 import subprocess
 import sys
 import tempfile
+import time
 
 
 def run(cmd, timeout=30):
@@ -58,6 +59,59 @@ def _phy_has_monitor(phy):
     return False
 
 
+class CardState:
+    def __init__(self, iface):
+        self.orig_iface = iface["iface"]
+        self.orig_addr = iface["addr"]
+        self.nm_was_active = (
+            run(["systemctl", "is-active", "NetworkManager"]).stdout.strip() == "active"
+        )
+        self.mon_iface = None
+        self.used_airmon = False
+
+
+def enable_monitor(state):
+    run(["airmon-ng", "check", "kill"])
+    before = {i["iface"] for i in list_wifi_interfaces()}
+    res = run(["airmon-ng", "start", state.orig_iface])
+    state.used_airmon = True
+    time.sleep(1)
+    after = list_wifi_interfaces()
+    new = {i["iface"] for i in after} - before
+    if new:
+        state.mon_iface = new.pop()
+    else:
+        m = re.search(r"enabled (?:for \[[^\]]+\]\S+ )?on (?:\[[^\]]+\])?(\S+?)\)", res.stdout)
+        if m:
+            state.mon_iface = m.group(1)
+        else:
+            for i in after:
+                if i["iface"] == state.orig_iface and i["type"] == "monitor":
+                    state.mon_iface = state.orig_iface
+    if not state.mon_iface:
+        raise RuntimeError("Could not determine monitor interface:\n" + res.stdout + res.stderr)
+    return state.mon_iface
+
+
+def reset_card(state):
+    if not state:
+        return
+    if state.mon_iface and state.used_airmon:
+        run(["airmon-ng", "stop", state.mon_iface])
+    names = {i["iface"]: i for i in list_wifi_interfaces()}
+    if state.orig_iface not in names and state.mon_iface in names:
+        run(["iw", state.mon_iface, "set", "type", "managed"])
+        run(["ip", "link", "set", state.mon_iface, "name", state.orig_iface])
+    names = {i["iface"]: i for i in list_wifi_interfaces()}
+    it = names.get(state.orig_iface)
+    if it and state.orig_addr not in ("?", None) and it["addr"].lower() != state.orig_addr.lower():
+        run(["ip", "link", "set", state.orig_iface, "down"])
+        run(["ip", "link", "set", state.orig_iface, "address", state.orig_addr])
+        run(["ip", "link", "set", state.orig_iface, "up"])
+    if state.nm_was_active:
+        run(["systemctl", "start", "NetworkManager"])
+
+
 def parse_airodump_csv(path):
     try:
         with open(path, encoding="utf-8", errors="replace") as f: