{
  config,
  lib,
  pkgs,
  ...
}:
let
  testPkgs = pkgs.appendOverlays [ (import ../modules/overlays.nix) ];
in
testPkgs.testers.runNixOSTest {
  name = "ntfy-alerts";

  nodes.machine =
    { pkgs, ... }:
    {
      imports = [
        ../modules/ntfy-alerts.nix
      ];

      system.stateVersion = config.system.stateVersion;

      virtualisation.memorySize = 2048;

      environment.systemPackages = with pkgs; [
        curl
        jq
      ];

      # Create test topic file
      systemd.tmpfiles.rules = [
        "f /run/ntfy-test-topic 0644 root root - test-alerts"
      ];

      # Mock ntfy server that records POST requests
      systemd.services.mock-ntfy =
        let
          mockNtfyScript = pkgs.writeScript "mock-ntfy.py" ''
            import json
            import os
            from http.server import HTTPServer, BaseHTTPRequestHandler
            from datetime import datetime

            REQUESTS_FILE = "/tmp/ntfy-requests.json"

            class MockNtfy(BaseHTTPRequestHandler):
                def _respond(self, code=200, body=b"Ok"):
                    self.send_response(code)
                    self.send_header("Content-Type", "application/json")
                    self.end_headers()
                    self.wfile.write(body if isinstance(body, bytes) else body.encode())

                def do_GET(self):
                    self._respond()

                def do_POST(self):
                    content_length = int(self.headers.get("Content-Length", 0))
                    body = self.rfile.read(content_length).decode() if content_length > 0 else ""

                    request_data = {
                        "timestamp": datetime.now().isoformat(),
                        "path": self.path,
                        "headers": dict(self.headers),
                        "body": body,
                    }

                    # Load existing requests or start new list
                    requests = []
                    if os.path.exists(REQUESTS_FILE):
                        try:
                            with open(REQUESTS_FILE, "r") as f:
                                requests = json.load(f)
                        except:
                            requests = []

                    requests.append(request_data)

                    with open(REQUESTS_FILE, "w") as f:
                        json.dump(requests, f, indent=2)

                    self._respond()

                def log_message(self, format, *args):
                    pass

            HTTPServer(("0.0.0.0", 8080), MockNtfy).serve_forever()
          '';
        in
        {
          description = "Mock ntfy server";
          wantedBy = [ "multi-user.target" ];
          before = [ "ntfy-alert@test-fail.service" ];
          serviceConfig = {
            ExecStart = "${pkgs.python3}/bin/python3 ${mockNtfyScript}";
            Type = "simple";
          };
        };

      # Test service that will fail
      systemd.services.test-fail = {
        description = "Test service that fails";
        serviceConfig = {
          Type = "oneshot";
          ExecStart = "${pkgs.coreutils}/bin/false";
        };
      };

      # Configure ntfy-alerts to use mock server
      services.ntfyAlerts = {
        enable = true;
        serverUrl = "http://localhost:8080";
        topicFile = "/run/ntfy-test-topic";

      };
    };

  testScript = ''
    import json
    import time

    start_all()

    # Wait for mock ntfy server to be ready
    machine.wait_for_unit("mock-ntfy.service")
    machine.wait_until_succeeds("curl -sf http://localhost:8080/", timeout=30)

    # Verify the ntfy-alert@ template service exists
    machine.succeed("systemctl list-unit-files | grep ntfy-alert@")

    # Verify the global OnFailure drop-in is configured
    machine.succeed("cat /etc/systemd/system/service.d/onfailure.conf | grep -q 'OnFailure=ntfy-alert@%p.service'")

    # Trigger the test-fail service
    machine.succeed("systemctl start test-fail.service || true")

    # Wait a moment for the failure notification to be sent
    time.sleep(2)

    # Verify the ntfy-alert@test-fail service ran
    machine.succeed("systemctl is-active ntfy-alert@test-fail.service || systemctl is-failed ntfy-alert@test-fail.service || true")

    # Check that the mock server received a POST request
    machine.wait_until_succeeds("test -f /tmp/ntfy-requests.json", timeout=30)

    # Verify the request content
    result = machine.succeed("cat /tmp/ntfy-requests.json")
    requests = json.loads(result)

    assert len(requests) >= 1, f"Expected at least 1 request, got {len(requests)}"

    # Check the first request
    req = requests[0]
    assert "/test-alerts" in req["path"], f"Expected path to contain /test-alerts, got {req['path']}"
    assert "Title" in req["headers"], "Expected Title header"
    assert "test-fail" in req["headers"]["Title"], f"Expected Title to contain 'test-fail', got {req['headers']['Title']}"
    assert req["headers"]["Priority"] == "high", f"Expected Priority 'high', got {req['headers'].get('Priority')}"
    assert req["headers"]["Tags"] == "warning", f"Expected Tags 'warning', got {req['headers'].get('Tags')}"

    print(f"Received notification: Title={req['headers']['Title']}, Body={req['body'][:100]}...")

    # Idempotency test: trigger failure again
    machine.succeed("rm /tmp/ntfy-requests.json")
    machine.succeed("systemctl reset-failed test-fail.service || true")
    machine.succeed("systemctl start test-fail.service || true")
    time.sleep(2)

    # Verify another notification was sent
    machine.wait_until_succeeds("test -f /tmp/ntfy-requests.json", timeout=30)
    result = machine.succeed("cat /tmp/ntfy-requests.json")
    requests = json.loads(result)
    assert len(requests) >= 1, f"Expected at least 1 request after second failure, got {len(requests)}"

    print("All tests passed!")
  '';
}