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/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 ConsumerWidget {
  const RawFrameDebugScreen({super.key});

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

    return Scaffold(
      appBar: AppBar(
        title: const Text('ECU Frame Debug'),
        actions: [
          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('Frames', bt.frameCount.toString()),
              _RowData('Dropped', bt.droppedFrames.toString()),
              _RowData('Last frame bytes', frame?.length.toString() ?? 'none'),
              if (frame != null)
                _RowData('Checksum', validateFrame(frame) ? 'valid' : 'bad'),
            ],
          ),
          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', s.vss.toStringAsFixed(2)),
        _RowData('MAP', 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)),
      ];

  List<_RowData> _s300CandidateRows(Uint8List f) {
    final rpmBe = _u16be(f, 3);
    final rpmLe = _u16le(f, 3);
    final vssBe = _u16be(f, 5);
    final vssLe = _u16le(f, 5);
    final mapBe = _u16be(f, 7);
    final mapLe = _u16le(f, 7);

    return [
      _RowData('Header bytes', '${_b(f, 0)} ${_b(f, 1)} ${_b(f, 2)}'),
      _RowData('RPM @3 BE / LE', '$rpmBe / $rpmLe'),
      _RowData('VSS raw @5 BE / LE', '$vssBe / $vssLe'),
      _RowData('VSS current BE km/h', _s300Vss(vssBe).toStringAsFixed(2)),
      _RowData('VSS alternate LE km/h', _s300Vss(vssLe).toStringAsFixed(2)),
      _RowData('MAP raw @7 BE / LE', '$mapBe / $mapLe'),
      _RowData('MAP /10 BE / LE',
          '${(mapBe / 10).toStringAsFixed(2)} / ${(mapLe / 10).toStringAsFixed(2)}'),
      _RowData('TPS raw @9', f[9].toString()),
      _RowData('TPS current', _s300Tps(f[9]).toStringAsFixed(2)),
      _RowData('ECT raw @45', f[0x2D].toString()),
      _RowData('IAT raw @46', f[0x2E].toString()),
      _RowData('BAT raw @48', f[0x30].toString()),
      _RowData('ERR bytes @49-52',
          '${_b(f, 0x31)} ${_b(f, 0x32)} ${_b(f, 0x33)} ${_b(f, 0x34)}'),
    ];
  }

  static int _u16be(Uint8List f, int o) => (f[o] << 8) | f[o + 1];
  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 double _s300Vss(int raw) {
    return (raw < 893 || raw == 0xFFFF) ? 0.0 : 228480.0 / raw;
  }

  static double _s300Tps(int raw) {
    return raw < 25 ? 0.0 : raw * 51.0 / 46.0;
  }

  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(' ');
  }
}

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);
}