156 lines
4.2 KiB
Dart
156 lines
4.2 KiB
Dart
import 'dart:async';
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import 'dart:typed_data';
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import '../protocol/neg8.dart';
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import 'bt_service.dart';
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enum EcuType { s300, kpro }
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/// Sends the ECU request byte every [pollingInterval] ms,
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/// accumulates raw bytes into 128-byte frames, validates NEG8,
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/// and emits the newest usable frame on [frameStream].
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class BtPoller {
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final BtService _service;
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EcuType ecuType;
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final Duration pollingInterval;
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// S300 request: [0x1B, 0x00, 0xE5]
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static final Uint8List _s300Request = Uint8List.fromList([0x1B, 0x00, 0xE5]);
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// KPro request: [0x1B, 0x01, 0xE4]
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static final Uint8List _kproRequest = Uint8List.fromList([0x1B, 0x01, 0xE4]);
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final StreamController<Uint8List> _frameController =
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StreamController<Uint8List>.broadcast();
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Stream<Uint8List> get frameStream => _frameController.stream;
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final List<int> _rxBuf = [];
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Timer? _pollTimer;
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StreamSubscription<Uint8List>? _rxSub;
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int droppedFrames = 0;
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int validFrames = 0;
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BtPoller(
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this._service, {
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this.ecuType = EcuType.s300,
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this.pollingInterval = const Duration(milliseconds: 50),
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});
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void start() {
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_rxBuf.clear();
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// Listen to raw bytes from BT and accumulate into 128-byte frames
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_rxSub = _service.rawStream.listen(
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(Uint8List chunk) {
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_rxBuf.addAll(chunk);
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_processBuffer();
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},
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onError: (Object e) {
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_frameController.addError(e);
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stop();
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},
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);
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// Send request at polling interval
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_pollTimer = Timer.periodic(pollingInterval, (_) async {
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if (_service.isConnected) {
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await _service.write(
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ecuType == EcuType.s300 ? _s300Request : _kproRequest,
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);
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}
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});
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}
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void _processBuffer() {
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// Extract as many 128-byte frames as possible.
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// Frame start sync: first byte should be 0x1B (header marker).
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// If we have a misaligned buffer, scan forward.
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Uint8List? latestUsableFrame;
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while (_rxBuf.length >= 128) {
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// Scan for 0x1B frame header
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int startIdx = 0;
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while (startIdx < _rxBuf.length && _rxBuf[startIdx] != 0x1B) {
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startIdx++;
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}
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// Not enough data after sync byte
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if (_rxBuf.length - startIdx < 128) {
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// Discard bytes before potential header
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if (startIdx > 0) {
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_rxBuf.removeRange(0, startIdx);
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}
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break;
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}
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final Uint8List frame =
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Uint8List.fromList(_rxBuf.sublist(startIdx, startIdx + 128));
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if (ecuType == EcuType.s300 && _isS300PlaceholderFrame(frame)) {
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droppedFrames++;
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_rxBuf.removeRange(0, startIdx + 128);
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continue;
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}
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final checksumOk = validateFrame(frame);
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final canUseFrame = checksumOk || ecuType == EcuType.s300;
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if (canUseFrame) {
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if (!checksumOk) droppedFrames++;
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validFrames++;
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latestUsableFrame = frame;
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_rxBuf.removeRange(0, startIdx + 128);
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} else {
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// Bad checksum — skip this byte and try again
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droppedFrames++;
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_rxBuf.removeRange(0, startIdx + 1);
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}
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}
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if (latestUsableFrame != null) {
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_frameController.add(latestUsableFrame);
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}
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}
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void stop() {
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_pollTimer?.cancel();
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_pollTimer = null;
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_rxSub?.cancel();
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_rxSub = null;
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_rxBuf.clear();
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}
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void dispose() {
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stop();
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_frameController.close();
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}
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bool _isS300PlaceholderFrame(Uint8List frame) {
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if (frame.length != 128) return false;
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// The S300 Bluetooth stream can interleave a valid-checksum placeholder
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// frame that is not the SManager live sensor frame. It has a fixed header
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// and zero/overflow values for speed, TPS, injection and ignition, then it
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// overwrites the dashboard with stale/empty values. Filter only this exact
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// signature so true idle/stopped live frames can still pass.
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return frame[0] == 0x1B &&
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frame[1] == 0x00 &&
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frame[2] == 0x14 &&
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frame[3] == 0x00 &&
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frame[4] == 0x00 &&
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frame[5] == 0xFF &&
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frame[6] == 0xFF &&
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frame[7] == 0xF2 &&
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frame[8] == 0x03 &&
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frame[9] == 0x18 &&
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frame[10] == 0x00 &&
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frame[11] == 0x00 &&
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frame[12] == 0x10 &&
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frame[13] == 0x00 &&
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frame[14] == 0x00 &&
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frame[15] == 0x00 &&
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frame[16] == 0xC4;
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}
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}
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