import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/bluetooth/bt_poller.dart';
import '../../../core/logging/app_log.dart';
import '../../../core/providers/bt_provider.dart';
import '../../../core/providers/sensor_provider.dart';
import '../../../core/providers/settings_provider.dart';
import '../../../core/protocol/neg8.dart';
import '../../../core/protocol/sensor_state.dart';

class RawFrameDebugScreen extends ConsumerStatefulWidget {
  const RawFrameDebugScreen({super.key});

  @override
  ConsumerState<RawFrameDebugScreen> createState() =>
      _RawFrameDebugScreenState();
}

class _RawFrameDebugScreenState extends ConsumerState<RawFrameDebugScreen> {
  Uint8List? _probeResult;
  bool _probing = false;

  Future<void> _runProbe() async {
    setState(() {
      _probing = true;
      _probeResult = null;
    });
    final result =
        await ref.read(btProvider.notifier).probeOfficialProtocol();
    if (!mounted) return;
    setState(() {
      _probing = false;
      _probeResult = result;
    });
  }

  @override
  Widget build(BuildContext context) {
    final bt = ref.watch(btProvider);
    final settings = ref.watch(settingsProvider);
    final sensorAsync = ref.watch(sensorStateProvider);
    final state = ref.watch(latestSensorProvider);
    final decodeStats = ref.watch(decodeStatsProvider);
    final frame = bt.lastFrame;
    final hex = frame == null ? '' : _hex(frame);

    return Scaffold(
      appBar: AppBar(
        title: const Text('ECU Frame Debug'),
        actions: [
          IconButton(
            tooltip: 'Copy app log',
            icon: const Icon(Icons.description_outlined),
            onPressed: () async {
              await Clipboard.setData(ClipboardData(text: AppLog.dump()));
              if (context.mounted) {
                ScaffoldMessenger.of(context).showSnackBar(
                  SnackBar(
                      content: Text(
                          'App log copied (${AppLog.length} lines) — paste it into an email/message')),
                );
              }
            },
          ),
          IconButton(
            tooltip: 'Copy raw frame',
            icon: const Icon(Icons.copy),
            onPressed: frame == null
                ? null
                : () async {
                    await Clipboard.setData(ClipboardData(text: hex));
                    if (context.mounted) {
                      ScaffoldMessenger.of(context).showSnackBar(
                        const SnackBar(content: Text('Raw frame copied')),
                      );
                    }
                  },
          ),
        ],
      ),
      body: ListView(
        padding: const EdgeInsets.all(12),
        children: [
          _Section(
            title: 'Connection',
            rows: [
              _RowData('Protocol', settings.ecuType.name.toUpperCase()),
              _RowData('Link status', bt.status.name),
              _RowData('ECU data', bt.dataStatus.name),
              _RowData('Poll interval', '${settings.pollingInterval.inMilliseconds} ms'),
              _RowData('Requests sent', bt.requestsSent.toString()),
              _RowData('Valid replies', bt.frameCount.toString()),
              _RowData('  live ECU frames', bt.liveFrames.toString()),
              _RowData('  adapter default frames', bt.defaultFrames.toString()),
              _RowData('Timeouts (no reply)', bt.timeouts.toString()),
              _RowData('Dropped (bad checksum)', bt.droppedFrames.toString()),
              _RowData('Last reply time', bt.lastResponseMs == null ? '-' : '${bt.lastResponseMs} ms'),
              _RowData('Auto-reconnects', bt.reconnects.toString()),
              _RowData('Last frame bytes', frame?.length.toString() ?? 'none'),
              if (frame != null)
                _RowData(
                  'Checksum',
                  validateFrame(frame) ? 'valid' : 'bad',
                ),
            ],
          ),
          const SizedBox(height: 12),
          _ProtocolProbeCard(
            connected: bt.isConnected,
            probing: _probing,
            result: _probeResult,
            onProbe: _runProbe,
          ),
          const SizedBox(height: 12),
          _Section(
            title: 'Decode Pipeline',
            rows: [
              _RowData('Decoded -> UI', decodeStats.decoded.toString()),
              _RowData('Skipped (decode error)', decodeStats.decodeErrors.toString()),
              _RowData(
                'sensorStateProvider raw',
                sensorAsync.when(
                  data: (s) =>
                      'data(rpm=${s.rpm.toStringAsFixed(0)}, age=${DateTime.now().difference(s.timestamp).inMilliseconds}ms)',
                  loading: () => 'loading (no frame yet)',
                  error: (e, st) => 'error: $e',
                ),
              ),
              _RowData(
                'latestSensorProvider age',
                '${DateTime.now().difference(state.timestamp).inMilliseconds}ms since decode',
              ),
            ],
          ),
          const SizedBox(height: 12),
          _Section(
            title: 'Current App Decode',
            rows: _decodedRows(state),
          ),
          const SizedBox(height: 12),
          if (frame == null)
            const Center(
              child: Padding(
                padding: EdgeInsets.all(24),
                child: Text(
                  'No ECU frame received yet.',
                  style: TextStyle(color: Colors.grey),
                ),
              ),
            )
          else ...[
            if (settings.ecuType == EcuType.s300) ...[
              _Section(
                title: 'S300 Raw Candidates',
                rows: _s300CandidateRows(frame),
              ),
              const SizedBox(height: 12),
            ],
            _RawHexBlock(hex: hex),
          ],
        ],
      ),
    );
  }

  List<_RowData> _decodedRows(SensorState s) => [
        _RowData('RPM', s.rpm.toStringAsFixed(0)),
        _RowData('Speed km/h', s.vss.toStringAsFixed(2)),
        _RowData('MAP kPa', s.map.toStringAsFixed(2)),
        _RowData('TPS', s.tps.toStringAsFixed(2)),
        _RowData('ECT', s.ect.toStringAsFixed(2)),
        _RowData('IAT', s.iat.toStringAsFixed(2)),
        _RowData('Battery', s.bat.toStringAsFixed(2)),
        _RowData('O2', s.o2.toStringAsFixed(2)),
        _RowData('AFR', s.afr.toStringAsFixed(2)),
        _RowData('MIL (unverified)', s.mil.toString()),
        _RowData('Fuel Pump', s.fuelPump.toString()),
        _RowData('Fan Out (unverified)', s.fanOut.toString()),
        _RowData('VTEC (unverified)', s.vtec.toString()),
        _RowData('Knock', s.knock.toString()),
        _RowData('Rev Limit (unverified)', s.revLimit.toString()),
        _RowData('Launch (unverified)', s.launch.toString()),
      ];

  List<_RowData> _s300CandidateRows(Uint8List f) {
    final rpmLe = _u16le(f, 3);
    final vssLe = _u16le(f, 5);
    final mapLe = _u16le(f, 7);

    return [
      _RowData('Header bytes', '${_b(f, 0)} ${_b(f, 1)} ${_b(f, 2)}'),
      _RowData('RPM raw @3 LE', rpmLe.toString()),
      _RowData('VSS raw @5 LE', vssLe.toString()),
      _RowData('VSS current km/h', _s300Vss(vssLe).toStringAsFixed(2)),
      _RowData('MAP raw @7 LE', mapLe.toString()),
      _RowData('MAP current kPa', _s300Map(mapLe).toStringAsFixed(2)),
      _RowData('TPS raw @9', f[9].toString()),
      _RowData('TPS current', _s300Tps(f[9]).toStringAsFixed(2)),
      _RowData('Gear raw @27 (decimal)', f[27].toString()),
      _RowData('INJ raw @10 LE', _u16le(f, 10).toString()),
      _RowData('IGN raw @12', f[12].toString()),
      _RowData('O2 raw @16', f[16].toString()),
      _RowData('Strim raw @29 / Ltrim raw @31', '${f[29]} / ${f[31]}'),
      _RowData('PA raw @32', f[32].toString()),
      _RowData('ECT raw @33', f[33].toString()),
      _RowData('IAT raw @34', f[34].toString()),
      _RowData('BAT raw @36', f[36].toString()),
      _RowData('ERR00-03 @37-40',
          '${_b(f, 37)} ${_b(f, 38)} ${_b(f, 39)} ${_b(f, 40)}'),
      _RowData('Eth raw @41', f[41].toString()),
      _RowData('AF raw @55', f[55].toString()),
      _RowData('SW1 @17 (bit7..0)', '${_b(f, 17)}  ${_bin(f, 17)}'),
      _RowData('SW2 @18 (bit7..0)', '${_b(f, 18)}  ${_bin(f, 18)}'),
      _RowData('SW3 @19 (bit7..0)', '${_b(f, 19)}  ${_bin(f, 19)}'),
      _RowData('SW5 @49 (bit7..0)', '${_b(f, 49)}  ${_bin(f, 49)}'),
      _RowData('SW6 @50 (bit7..0)', '${_b(f, 50)}  ${_bin(f, 50)}'),
    ];
  }

  static int _u16le(Uint8List f, int o) => f[o] | (f[o + 1] << 8);
  static String _b(Uint8List f, int o) =>
      f[o].toRadixString(16).padLeft(2, '0');
  static String _bin(Uint8List f, int o) =>
      f[o].toRadixString(2).padLeft(8, '0');

  static double _s300Vss(int raw) {
    return (raw < 893 || raw == 0xFFFF) ? 0.0 : 228480.0 / raw;
  }

  static double _s300Map(int raw) {
    return raw / 10.0;
  }

  static double _s300Tps(int raw) {
    return (raw * 100.0 / 255.0).clamp(0.0, 100.0);
  }

  static String _hex(Uint8List frame) {
    final parts = <String>[];
    for (var i = 0; i < frame.length; i++) {
      if (i > 0 && i % 16 == 0) parts.add('\n');
      parts.add(frame[i].toRadixString(16).padLeft(2, '0'));
    }
    return parts.join(' ');
  }
}

/// Step 1 of the data-layer review: checks whether this device/firmware
/// understands the official, self-describing Hondata Bluetooth protocol
/// (Bluetooth.pdf) rather than only the legacy fixed-offset frame format
/// this app currently speaks. A real reply here (Protocol=0x00, ID=0x02,
/// with a recognizable DeviceType byte) means migrating to that protocol is
/// on the table; silence means this hardware is legacy-only.
class _ProtocolProbeCard extends StatelessWidget {
  final bool connected;
  final bool probing;
  final Uint8List? result;
  final VoidCallback onProbe;

  const _ProtocolProbeCard({
    required this.connected,
    required this.probing,
    required this.result,
    required this.onProbe,
  });

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Official Protocol Probe',
              style: TextStyle(fontWeight: FontWeight.bold, fontSize: 13),
            ),
            const SizedBox(height: 4),
            const Text(
              'Sends DL_DeviceInfo (00 02 04 00). Pauses normal polling for '
              'the duration of the probe.',
              style: TextStyle(color: Colors.grey, fontSize: 11),
            ),
            const SizedBox(height: 8),
            SizedBox(
              width: double.infinity,
              child: ElevatedButton(
                onPressed: (connected && !probing) ? onProbe : null,
                child: Text(probing ? 'Probing…' : 'Send Probe'),
              ),
            ),
            if (result != null) ...[
              const SizedBox(height: 8),
              for (final row in _interpret(result!)) _InfoRow(row),
            ],
          ],
        ),
      ),
    );
  }

  List<_RowData> _interpret(Uint8List r) {
    if (r.isEmpty) {
      return const [
        _RowData('Result', 'No response — likely legacy protocol only'),
      ];
    }

    final hex = r.map((b) => b.toRadixString(16).padLeft(2, '0')).join(' ');
    final rows = [_RowData('Raw bytes', hex)];
    if (r.length >= 4) {
      final size = r[2] | (r[3] << 8); // little-endian per TDLHeader.Size
      rows.add(_RowData('Protocol / ID / Size', '${r[0]} / ${r[1]} / $size'));
    }
    if (r.length >= 6) {
      final deviceType = switch (r[4]) {
        0xC0 => 'S300',
        0xC1 => 'KPro',
        0xC2 => 'FlashPro',
        _ => 'unknown (0x${r[4].toRadixString(16)})',
      };
      rows.add(_RowData('Device type', deviceType));
      rows.add(_RowData('Ignition', r[5] != 0 ? 'On' : 'Off'));
    }
    return rows;
  }
}

class _Section extends StatelessWidget {
  final String title;
  final List<_RowData> rows;

  const _Section({required this.title, required this.rows});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              title,
              style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 13),
            ),
            const SizedBox(height: 8),
            for (final row in rows) _InfoRow(row),
          ],
        ),
      ),
    );
  }
}

class _InfoRow extends StatelessWidget {
  final _RowData row;

  const _InfoRow(this.row);

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 3),
      child: Row(
        children: [
          Expanded(
            child: Text(
              row.label,
              style: const TextStyle(color: Colors.grey, fontSize: 12),
            ),
          ),
          const SizedBox(width: 12),
          Flexible(
            child: Text(
              row.value,
              textAlign: TextAlign.right,
              style: const TextStyle(
                fontSize: 12,
                fontFamily: 'monospace',
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _RawHexBlock extends StatelessWidget {
  final String hex;

  const _RawHexBlock({required this.hex});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: SelectableText(
          hex,
          style: const TextStyle(fontFamily: 'monospace', fontSize: 11),
        ),
      ),
    );
  }
}

class _RowData {
  final String label;
  final String value;

  const _RowData(this.label, this.value);
}