diff --git a/.gitignore b/.gitignore
index 0bf8259..794845b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+config.yaml
 # ---> Python
 # Byte-compiled / optimized / DLL files
 __pycache__/
diff --git a/antidrift.py b/antidrift.py
index 5da6aa3..6c59b96 100644
--- a/antidrift.py
+++ b/antidrift.py
@@ -1,194 +1,82 @@
 #!/usr/bin/env python3
 
-import os
-import re
-import subprocess
+import logging
 import shutil
 import sys
 import time
-from typing import List, Tuple, Set
-import psutil
-from config import Config
+import re
+import xwindow
+from config import Config, Block
+from typing import List
 
 
-def is_window_blocked(window_name: str, blocked: List[re.Pattern]) -> bool:
-    for b in blocked:
-        if b.findall(window_name):
-            return True
-    return False
+def check_for_xdotool():
+    r = shutil.which("xdotool")
+    if not r:
+        logging.critical("Please install xdotool")
+        sys.exit(1)
 
 
-def get_active_window_name_and_pid() -> Tuple[str, str]:
-    cmd = ["xdotool", "getactivewindow", "getwindowname", "getwindowpid"]
-    p = subprocess.run(cmd, capture_output=True)
-    if p.returncode != 0:
-        return ("", "")
-    window_name, window_pid, _ = p.stdout.decode().split("\n")
-    return (window_name, window_pid)
+def init_logging():
+    FORMAT = '%(levelname)-8s | %(message)s'
+    logging.basicConfig(format=FORMAT, level=logging.DEBUG)
 
 
-def kill_sequence(blocked: List[re.Pattern]) -> None:
-    def to_display(name: str) -> str:
-        return name if len(name) < 30 else name[:30] + "..."
+def window_is_blocked(config: Config) -> bool:
+    # These should be selectable in the future (not all at the same time)
+    blackblocks = config.blackblocks
+    whiteblocks = config.whiteblocks
 
-    for count in range(5, 0, -1):
-        window_name, window_pid = get_active_window_name_and_pid()
-        if not is_window_blocked(window_name, blocked):
-            notify(f"[okay] {to_display(window_name)}")
-            return
-        notify(f"[kill {count}s] {to_display(window_name)}")
-        time.sleep(1)
-
-    p = psutil.Process(int(window_pid))
-    p.terminate()
+    window = xwindow.XWindow()
+    if not window.keywords:
+        return False
+    for b in blackblocks:
+        for k in b.keywords:
+            if k in window.keywords:
+                xwindow.notify(f"{window.name[:30]} blocked by {b.name}.")
+                logging.warning(f"{window.name[:30]} blocked by {b.name}.")
+                return True
+    if config.blackblocks_only:
+        logging.debug(f"All non-blacklisted windows are allowed.")
+        return False
+    for w in whiteblocks:
+        for k in w.keywords:
+            if k in window.keywords:
+                logging.debug(f"{window.name[:30]} allowed by {w.name}.")
+                return False
+    xwindow.notify(f"{window.name[:30]} not on any whitelist.")
+    return True
 
 
-def notify(message: str) -> None:
-    """ Notify user via the Xorg notify-send command. """
-    env = {
-        **os.environ,
-        "DBUS_SESSION_BUS_ADDRESS": "unix:path=/run/user/1000/bus"
-    }
-    user = env.get("SUDO_USER", None)
-    if user is None:
-        cmd = ["notify-send", message]
+def enforce(config: Config):
+    if not window_is_blocked(config):
+        return
+    xwindow.notify(f"AntiDrift will minimize the window in {config.minimize_delay} seconds.")
+    time.sleep(config.minimize_delay)
+    window = xwindow.XWindow()
+    if window_is_blocked(config):
+        window = xwindow.XWindow()
+        xwindow.notify(f"Minimize {window.name[:30]}.")
+        window.minimize()
     else:
-        cmd = ["runuser", "-m", "-u", user, "notify-send", message]
-    subprocess.run(cmd, env=env)
+        xwindow.notify(f"We are gucci again.")
 
 
-def write_pid_file(config: Config) -> str:
-    p = psutil.Process()
-    pid_file = os.path.join(config.directory, f"{p.pid}.pid")
-    with open(pid_file, "w") as f:
-        f.write(str(p.pid))
-    return pid_file
-
-
-def terminate_existing_blocker(config: Config) -> None:
-    this_pid = psutil.Process().pid
-    pid_files = [f for f in config.directory if f.endswith(".pid")]
-    for pid_file in pid_files:
-        pid = int(pid_file.replace(".pid", ""))
-        if this_pid == pid:
-            continue
-        try:
-            p = psutil.Process(pid)
-            p.terminate()
-        except psutil.NoSuchProcess:
-            print(f"Could not terminate {p.pid=}.")
-        pid_file = os.path.join(config.directory, pid_file)
-        try:
-            os.remove(pid_file)
-        except PermissionError:
-            print(f"Could not remove {pid_file=}.")
-
-
-def load_blocked_patterns(config: Config) -> List[re.Pattern]:
-    blocked = []
-    for block in config.blocks:
-        for item in block.items:
-            s = "".join([block.prefix, item, block.postfix])
-            r = re.compile(s, re.IGNORECASE)
-            blocked.append(r)
-    return blocked
-
-
-def init(config: Config) -> None:
-    terminate_existing_blocker(config)
-    write_pid_file(config)
-
-
-def run_checks(config: Config) -> None:
-    # shutil.which("xdotool")
-    # That's what we do if anything goes wrong:
-    # xkill --all
-    pass
-
-
-def kill_window_if_blocked(blocked: List[re.Pattern]) -> None:
-    window_name, window_pid = get_active_window_name_and_pid()
-    if is_window_blocked(window_name, blocked):
-        kill_sequence(blocked)
-
-
-def is_process_active(process_name: str) -> bool:
-    for proc in psutil.process_iter(): 
-        if proc.name() == process_name:
-            return True
-    return False
-
-
-def enforce_aw_commit():
-    def aw_commit_active():
-        return is_process_active("aw-commit")
-
-    def to_display(name: str) -> str:
-        return name if len(name) < 30 else name[:30] + "..."
-
-    if aw_commit_active():
-        return
-
-    for _ in range(10, 0, -1):
-        notify(f"[warning] aw-commit not running")
-        time.sleep(1)
-        if aw_commit_active():
-            return
-
-    if aw_commit_active():
-        return
-    
-    window_name, window_pid = get_active_window_name_and_pid()
-    if window_name:
-        notify(f"[kill aw-commit not running] {to_display(window_name)}")
-        p = psutil.Process(int(window_pid))
-        p.terminate()
-    return enforce_aw_commit()
-
-
-def main_root(config: Config) -> None:
-    init(config)
-    blocked = load_blocked_patterns(config)
+def session(config: Config):
+    logging.info(f"Start session with {len(config.whiteblocks)} whiteblocks")
     while True:
-        time.sleep(config.sleep_time)
-        run_checks(config)
-        kill_window_if_blocked(blocked)
-        if config.enforce_aw_commit:
-            enforce_aw_commit()
+        enforce(config)
+        time.sleep(config.check_delay)
 
 
 def main() -> None:
-    """ Run main_root as root except while debugging. """
-    config_path = "~/.config/aw-focus/config.json"
-    config = Config.load_config(config_path)
-
-    if config.start_as_user:
-        terminate_existing_blocker(config)
-        main_root(config)
-
-    if os.geteuid() == 0:
-        newpid = os.fork()
-        if newpid == 0:
-            main_root(config)
-    else:
-        cmd = ["sudo", config.aw_focus_cmd] + sys.argv[1:]
-        subprocess.Popen(cmd)
+    init_logging()
+    logging.info("AntiDrift running")
+    check_for_xdotool()
+    config = Config.load("config.yaml")
+    session(config)
 
 
 if __name__ == "__main__":
     main()
 
-
-def load_window_names(config: Config) -> Set[str]:
-    window_names_file = os.path.join(config.directory, config.window_names)
-    if not os.path.isfile(window_names_file):
-        return set()
-    with open(window_names_file, "r") as f:
-        return {l.strip() for l in f.readlines()}
-
-
-def write_window_names(config: Config, window_names: Set[str]) -> None:
-    window_names_file = os.path.join(config.directory, config.window_names)
-    window_names = "\n".join(sorted(list(window_names)))
-    with open(window_names_file, "w") as f:
-        f.write(window_names)
\ No newline at end of file
diff --git a/config.py b/config.py
index 013590b..fe0f059 100644
--- a/config.py
+++ b/config.py
@@ -1,33 +1,36 @@
 import json
 import os
+import yaml
+from pathlib import Path
 from typing import List
 from pydantic import BaseModel
 
 
 class Block(BaseModel):
-    name: str = ''
-    prefix: str = ''
-    postfix: str = ''
-    items: List[str]
+    name: str
+    keywords: List[str]
+
+
+def load(filename: str) -> List[Block]:
+    result = [Block(path=filename, **block) for block in block_list]
+    return result
 
 
 class Config(BaseModel):
-    directory: str
-    blocks: List[Block]
-    start_as_user: bool = True
-    sleep_time: int = 1
-    aw_focus_cmd: str = "aw-focus"
-    window_names: str = "window_names.txt"
-    enforce_aw_commit: bool = True
+    blackblocks: List[Block]
+    whiteblocks: List[Block]
+    check_delay: int = 1
+    minimize_delay: int = 5
+    blackblocks_only: bool = True
 
     class Config:
         extra = 'forbid'
 
     @classmethod
-    def load_config(cls, config_file: str) -> Config:
+    def load(cls, config_file: str) -> Config:
         config_file = os.path.expanduser(config_file)
-        with open(config_file, 'r', encoding='utf8') as f:
-            config_dict = json.load(f)
+        with open(config_file, "r") as f:
+            config_dict = yaml.safe_load(f)
         config = cls(**config_dict)
-        config.directory = os.path.expanduser(config.directory)
         return config
+
diff --git a/obsolete.py b/obsolete.py
new file mode 100644
index 0000000..19234b5
--- /dev/null
+++ b/obsolete.py
@@ -0,0 +1,171 @@
+
+def is_window_blocked(window_name: str, blocked: List[re.Pattern]) -> bool:
+    for b in blocked:
+        if b.findall(window_name):
+            return True
+    return False
+
+
+def kill_sequence(blocked: List[re.Pattern]) -> None:
+    def to_display(name: str) -> str:
+        return name if len(name) < 30 else name[:30] + "..."
+
+    for count in range(5, 0, -1):
+        window_name, window_pid = get_active_window_name_and_pid()
+        if not is_window_blocked(window_name, blocked):
+            notify(f"[okay] {to_display(window_name)}")
+            return
+        notify(f"[kill {count}s] {to_display(window_name)}")
+        time.sleep(1)
+
+    p = psutil.Process(int(window_pid))
+    p.terminate()
+
+
+def notify(message: str) -> None:
+    """ Notify user via the Xorg notify-send command. """
+    env = {
+        **os.environ,
+        "DBUS_SESSION_BUS_ADDRESS": "unix:path=/run/user/1000/bus"
+    }
+    user = env.get("SUDO_USER", None)
+    if user is None:
+        cmd = ["notify-send", message]
+    else:
+        cmd = ["runuser", "-m", "-u", user, "notify-send", message]
+    subprocess.run(cmd, env=env)
+
+
+def write_pid_file(config: Config) -> str:
+    p = psutil.Process()
+    pid_file = os.path.join(config.directory, f"{p.pid}.pid")
+    with open(pid_file, "w") as f:
+        f.write(str(p.pid))
+    return pid_file
+
+
+def terminate_existing_blocker(config: Config) -> None:
+    this_pid = psutil.Process().pid
+    pid_files = [f for f in config.directory if f.endswith(".pid")]
+    for pid_file in pid_files:
+        pid = int(pid_file.replace(".pid", ""))
+        if this_pid == pid:
+            continue
+        try:
+            p = psutil.Process(pid)
+            p.terminate()
+        except psutil.NoSuchProcess:
+            print(f"Could not terminate {p.pid=}.")
+        pid_file = os.path.join(config.directory, pid_file)
+        try:
+            os.remove(pid_file)
+        except PermissionError:
+            print(f"Could not remove {pid_file=}.")
+
+
+def load_blocked_patterns(config: Config) -> List[re.Pattern]:
+    blocked = []
+    for block in config.blocks:
+        for item in block.items:
+            s = "".join([block.prefix, item, block.postfix])
+            r = re.compile(s, re.IGNORECASE)
+            blocked.append(r)
+    return blocked
+
+
+def init(config: Config) -> None:
+    terminate_existing_blocker(config)
+    write_pid_file(config)
+
+
+def run_checks(config: Config) -> None:
+    # shutil.which("xdotool")
+    # That's what we do if anything goes wrong:
+    # xkill --all
+    pass
+
+
+def kill_window_if_blocked(blocked: List[re.Pattern]) -> None:
+    window_name, window_pid = get_active_window_name_and_pid()
+    if is_window_blocked(window_name, blocked):
+        kill_sequence(blocked)
+
+
+def is_process_active(process_name: str) -> bool:
+    for proc in psutil.process_iter():
+        if proc.name() == process_name:
+            return True
+    return False
+
+
+def enforce_aw_commit():
+    def aw_commit_active():
+        return is_process_active("aw-commit")
+
+    def to_display(name: str) -> str:
+        return name if len(name) < 30 else name[:30] + "..."
+
+    if aw_commit_active():
+        return
+
+    for _ in range(10, 0, -1):
+        notify(f"[warning] aw-commit not running")
+        time.sleep(1)
+        if aw_commit_active():
+            return
+
+    if aw_commit_active():
+        return
+
+    window_name, window_pid = get_active_window_name_and_pid()
+    if window_name:
+        notify(f"[kill aw-commit not running] {to_display(window_name)}")
+        p = psutil.Process(int(window_pid))
+        p.terminate()
+    return enforce_aw_commit()
+
+
+def load_window_names(config: Config) -> Set[str]:
+    window_names_file = os.path.join(config.directory, config.window_names)
+    if not os.path.isfile(window_names_file):
+        return set()
+    with open(window_names_file, "r") as f:
+        return {l.strip() for l in f.readlines()}
+
+
+def write_window_names(config: Config, window_names: Set[str]) -> None:
+    window_names_file = os.path.join(config.directory, config.window_names)
+    window_names = "\n".join(sorted(list(window_names)))
+    with open(window_names_file, "w") as f:
+        f.write(window_names)
+
+
+def main() -> None:
+    """ Run main_root as root except while debugging. """
+    config_path = "~/.config/aw-focus/config.json"
+    config = Config.load_config(config_path)
+
+    if config.start_as_user:
+        terminate_existing_blocker(config)
+        main_root(config)
+
+    if os.geteuid() == 0:
+        newpid = os.fork()
+        if newpid == 0:
+            main_root(config)
+    else:
+        cmd = ["sudo", config.aw_focus_cmd] + sys.argv[1:]
+        subprocess.Popen(cmd)
+
+
+def main_root(config: Config) -> None:
+    init(config)
+    blocked = load_blocked_patterns(config)
+    while True:
+        time.sleep(config.sleep_time)
+        run_checks(config)
+        kill_window_if_blocked(blocked)
+        if config.enforce_aw_commit:
+            enforce_aw_commit()
+
+
diff --git a/xwindow.py b/xwindow.py
new file mode 100644
index 0000000..91cb8d9
--- /dev/null
+++ b/xwindow.py
@@ -0,0 +1,47 @@
+import os
+import re
+import subprocess
+import logging
+
+
+class XWindow:
+    def __init__(self):
+        self.window = self._run(["getactivewindow"])
+        if not self.window:
+            self.name = ""
+            self.cls = ""
+            self.pid = ""
+        else:
+            self.name = self._run(["getwindowname", self.window])
+            self.cls = self._run(["getwindowclassname", self.window])
+            self.pid = self._run(["getwindowpid", self.window])
+        self.keywords = list(re.findall("\w+", self.name.lower()))
+
+    def _run(self, cmd) -> str:
+        cmd = ["xdotool"] + cmd
+        p = subprocess.run(cmd, capture_output=True)
+        if p.returncode != 0:
+            return ""
+        return p.stdout.decode().strip()
+
+    def minimize(self):
+        self._run(["windowminimize", self.window])
+
+    def quit(self):
+        self._run(["windowquit", self.window])
+
+
+def notify(message: str) -> None:
+    """ Notify user via the Xorg notify-send command. """
+    logging.debug(f"notify: {message}")
+    env = {
+        **os.environ,
+        "DBUS_SESSION_BUS_ADDRESS": "unix:path=/run/user/1000/bus"
+    }
+    user = env.get("SUDO_USER", None)
+    if user is None:
+        cmd = ["notify-send", message]
+    else:
+        cmd = ["runuser", "-m", "-u", user, "notify-send", message]
+    subprocess.run(cmd, env=env)
+