{
  lib,
  pkgs,
  ...
}:
let
  mockQBittorrent = pkgs.writers.writePython3Bin "mock-qbt" { flakeIgnore = [ "E501" ]; } ''
    import http.server
    import socketserver


    class Handler(http.server.BaseHTTPRequestHandler):
        def log_message(self, fmt, *args):
            print(f"qbt: {fmt % args}")

        def do_GET(self):
            if self.path == "/api/v2/transfer/speedLimitsMode":
                self.send_response(200)
                self.send_header("Content-type", "text/plain")
                self.end_headers()
                self.wfile.write(("1" if getattr(self.server, "alt_speed", False) else "0").encode())
            else:
                self.send_response(404)
                self.end_headers()

        def do_POST(self):
            if self.path == "/api/v2/transfer/toggleSpeedLimitsMode":
                self.server.alt_speed = not getattr(self.server, "alt_speed", False)
                self.send_response(200)
                self.end_headers()
            else:
                self.send_response(404)
                self.end_headers()


    with socketserver.TCPServer(("127.0.0.1", 8080), Handler) as s:
        print("Mock qBittorrent on port 8080")
        s.serve_forever()
  '';

  mockJellyfin = pkgs.writers.writePython3Bin "mock-jellyfin" { flakeIgnore = [ "E501" ]; } ''
    import http.server
    import socketserver
    import json

    DEFAULT = {"streaming": False, "paused": False, "local": False, "media_type": "Movie"}


    class Handler(http.server.BaseHTTPRequestHandler):
        def log_message(self, fmt, *args):
            print(f"jellyfin: {fmt % args}")

        def do_GET(self):
            if self.path == "/Sessions":
                self.send_response(200)
                self.send_header("Content-type", "application/json")
                self.end_headers()
                state = getattr(self.server, "state", DEFAULT.copy())
                sessions = []
                if state["streaming"]:
                    sessions = [{
                        "Id": "test-1",
                        "UserName": "User",
                        "RemoteEndPoint": "192.168.1.100" if state["local"] else "203.0.113.42",
                        "NowPlayingItem": {"Name": f"Test {state['media_type']}", "Type": state["media_type"]},
                        "PlayState": {"IsPaused": state["paused"]}
                    }]
                self.wfile.write(json.dumps(sessions).encode())
            else:
                self.send_response(404)
                self.end_headers()

        def do_POST(self):
            if self.path == "/control/state":
                data = json.loads(self.rfile.read(int(self.headers.get("Content-Length", 0))).decode() or "{}")
                if not hasattr(self.server, "state"):
                    self.server.state = DEFAULT.copy()
                self.server.state.update(data)
                self.send_response(200)
                self.end_headers()
            else:
                self.send_response(404)
                self.end_headers()


    with socketserver.TCPServer(("127.0.0.1", 8096), Handler) as s:
        print("Mock Jellyfin on port 8096")
        s.serve_forever()
  '';
in
pkgs.testers.runNixOSTest {
  name = "jellyfin-qbittorrent-monitor";

  nodes.server = {
    systemd.services.mock-qbittorrent = {
      wantedBy = [ "multi-user.target" ];
      serviceConfig.ExecStart = lib.getExe mockQBittorrent;
    };
    systemd.services.mock-jellyfin = {
      wantedBy = [ "multi-user.target" ];
      serviceConfig.ExecStart = lib.getExe mockJellyfin;
    };
    environment.systemPackages = [ pkgs.curl ];
    networking.firewall.allowedTCPPorts = [
      8096
      8080
    ];
  };

  testScript = ''
    import time, json

    start_all()
    server.wait_for_unit("multi-user.target")
    for svc in ["mock-jellyfin", "mock-qbittorrent"]:
        server.wait_for_unit(f"{svc}.service")
    for port in [8096, 8080]:
        server.wait_for_open_port(port)
    time.sleep(2)

    def set_state(**kwargs):
        server.succeed(f"curl -sX POST -H 'Content-Type: application/json' -d '{json.dumps(kwargs)}' http://localhost:8096/control/state")

    def is_throttled():
        return server.succeed("curl -s http://localhost:8080/api/v2/transfer/speedLimitsMode").strip() == "1"

    # Verify initial state
    assert not is_throttled(), "Should start unthrottled"
    assert "[]" in server.succeed("curl -s http://localhost:8096/Sessions"), "No initial sessions"

    # Start monitor with fast intervals
    python = "${pkgs.python3.withPackages (ps: [ ps.requests ])}/bin/python"
    monitor = "${../services/jellyfin-qbittorrent-monitor.py}"
    server.succeed(f"""
      systemd-run --unit=monitor-test \
        --setenv=JELLYFIN_URL=http://localhost:8096 \
        --setenv=QBITTORRENT_URL=http://localhost:8080 \
        --setenv=CHECK_INTERVAL=1 \
        --setenv=STREAMING_START_DELAY=1 \
        --setenv=STREAMING_STOP_DELAY=1 \
        {python} {monitor}
    """)
    time.sleep(2)

    # Test cases: (streaming, media_type, paused, local, expected_throttle)
    # Throttle only when: external + playing + video content (not audio)
    test_cases: list[tuple[bool, str, bool, bool, bool]] = [
        # Video types, external, playing -> THROTTLE
        (True, "Movie", False, False, True),
        (True, "Episode", False, False, True),
        (True, "Video", False, False, True),
        # Audio external playing -> NO throttle
        (True, "Audio", False, False, False),
        # Paused -> NO throttle
        (True, "Movie", True, False, False),
        # Local -> NO throttle
        (True, "Movie", False, True, False),
        # Local + paused -> NO throttle
        (True, "Movie", True, True, False),
        # No streaming -> NO throttle
        (False, "Movie", False, False, False),
    ]

    for i, (streaming, media_type, paused, local, expected) in enumerate(test_cases, 1):
        desc = f"Test {i}: streaming={streaming}, type={media_type}, paused={paused}, local={local}"
        print(f"\n{desc}")
        set_state(streaming=streaming, media_type=media_type, paused=paused, local=local)
        time.sleep(1.5)
        actual = is_throttled()
        assert actual == expected, f"FAIL {desc}: got {actual}, expected {expected}"

    # Transition tests: pause/unpause while streaming
    print("\nTransition: external movie playing -> paused -> playing")
    set_state(streaming=True, media_type="Movie", paused=False, local=False)
    time.sleep(1.5)
    assert is_throttled(), "Should throttle external movie"

    set_state(streaming=True, media_type="Movie", paused=True, local=False)
    time.sleep(1.5)
    assert not is_throttled(), "Should unthrottle when paused"

    set_state(streaming=True, media_type="Movie", paused=False, local=False)
    time.sleep(1.5)
    assert is_throttled(), "Should re-throttle when unpaused"
  '';
}