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import 'package:flutter/foundation.dart';
import 'package:mqtt_client/mqtt_client.dart';
import 'package:mqtt_client/mqtt_server_client.dart';
const String brokerHostname = 'sia.xengineering.eu';
const int brokerPort = 1883;
const String topicPrefix = 'sia';
enum MachineState {
init, // user does not want connection MQTT not connected
disconnected, // user wants connection but MQTT not (yet) connected
unreachable, // connected to MQTT broker but Sia server not reachable
reachable, // connected to MQTT and Sia server reachable
}
enum MachineEvent {
connect, // user wants to connect
disconnect, // user does not want an connection anymore
connected, // connection to MQTT broker established
disconnected, // connection to MQTT broker lost
reachable, // Sia server is reachable via MQTT
unreachable, // Sia server not reachable via MQTT
}
class AppState with ChangeNotifier {
static const Map<MachineState, Map<MachineEvent, MachineState>> machine = <MachineState, Map<MachineEvent, MachineState>> {
MachineState.init: <MachineEvent, MachineState> {
MachineEvent.connect: MachineState.disconnected,
},
MachineState.disconnected: <MachineEvent, MachineState> {
MachineEvent.disconnect: MachineState.init,
MachineEvent.connected: MachineState.unreachable,
},
MachineState.unreachable: <MachineEvent, MachineState> {
MachineEvent.disconnect: MachineState.init,
MachineEvent.disconnected: MachineState.disconnected,
MachineEvent.reachable: MachineState.reachable,
},
MachineState.reachable: <MachineEvent, MachineState> {
MachineEvent.disconnect: MachineState.init,
MachineEvent.disconnected: MachineState.disconnected,
MachineEvent.unreachable: MachineState.unreachable,
},
};
MachineState state = MachineState.init;
Map<String, bool> contacts = <String, bool>{};
late MqttServerClient _client;
AppState();
void process(MachineEvent event) {
MachineState lastState = state;
Map<MachineEvent, MachineState>? transitions = machine[lastState];
if (transitions == null) {
return;
}
MachineState? nextState = transitions[event];
if (nextState == null) {
return;
}
if (nextState == lastState) {
return;
}
if (lastState == MachineState.init) {
_initMqtt();
}
if (nextState == MachineState.init) {
_deinitMqtt();
}
state = nextState;
notifyListeners();
}
@override
void dispose() {
_client.disconnect();
super.dispose();
}
void _initMqtt() {
_client = MqttServerClient(
brokerHostname,
'sia_app_${DateTime.now().millisecondsSinceEpoch}',
);
_client.port = brokerPort;
_client.keepAlivePeriod = 2;
_client.autoReconnect = true;
_client.disconnectOnNoResponsePeriod = 1;
_client.logging(on: false);
_client.onConnected = _onConnected;
_client.onDisconnected = _onDisconnected;
_client.onAutoReconnect = _onAutoReconnect;
_client.onAutoReconnected = _onAutoReconnected;
try {
_client.connect();
} catch (e) {
_client.disconnect();
return;
}
_client.updates?.listen(_onMessage);
}
void _deinitMqtt() {
_client.disconnect();
}
void _onConnected() {
_client.subscribe('$topicPrefix/contact/+/state', MqttQos.exactlyOnce);
_client.subscribe('$topicPrefix/server/health', MqttQos.exactlyOnce);
process(MachineEvent.connected);
}
void _onDisconnected() {
process(MachineEvent.disconnected);
}
void _onAutoReconnect() {
process(MachineEvent.disconnected);
}
void _onAutoReconnected() {
process(MachineEvent.connected);
}
void _onMessage(List<MqttReceivedMessage<MqttMessage>> messages) {
for (final MqttReceivedMessage<MqttMessage> message in messages) {
final String topic = message.topic;
final MqttPublishMessage payloadMessage =
message.payload as MqttPublishMessage;
final String payload =
MqttPublishPayload.bytesToStringAsString(payloadMessage.payload.message);
if (topic == '$topicPrefix/server/health') {
if (payload == 'good') {
process(MachineEvent.reachable);
}
if (payload == 'bad') {
process(MachineEvent.unreachable);
}
}
// format <prefix>/contacts/<address>/state
final List<String> parts = topic.split('/');
if (parts.length != 4 || parts[1] != 'contact' || parts[3] != 'state') {
continue;
}
final String address = parts[2];
final bool? parsedState = _parseBool(payload);
if (parsedState != null) {
contacts[address] = parsedState;
notifyListeners();
}
}
}
bool? _parseBool(String payload) {
switch (payload.toLowerCase()) {
case 'open':
return true;
case 'closed':
return false;
default:
return null;
}
}
}
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