water-management-system/mobile/lib/pages/patrol/track_page.dart

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

/// GPS 轨迹记录页面
class TrackPage extends StatefulWidget {
  final String taskId;
  final String taskName;

  const TrackPage({super.key, required this.taskId, required this.taskName});

  @override
  State<TrackPage> createState() => _TrackPageState();
}

class _TrackPageState extends State<TrackPage> {
  final PatrolService _service = PatrolService.instance;
  List<TrackPoint> _trackPoints = [];
  bool _loading = true;
  bool _recording = false;

  @override
  void initState() {
    super.initState();
    _loadTrackPoints();
  }

  Future<void> _loadTrackPoints() async {
    setState(() => _loading = true);
    final points = await _service.getTrackPoints(widget.taskId);
    if (mounted) {
      setState(() {
        _trackPoints = points;
        _loading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GPS轨迹 - ${widget.taskName}'),
        actions: [
          IconButton(
            icon: Icon(
              _recording ? Icons.stop : Icons.play_arrow,
              color: _recording ? Colors.red : null,
            ),
            tooltip: _recording ? '停止记录' : '开始记录',
            onPressed: _toggleRecording,
          ),
        ],
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : Column(
              children: [
                _buildStatsBar(),
                Expanded(child: _buildTrackMap()),
                _buildPointList(),
              ],
            ),
    );
  }

  Widget _buildStatsBar() {
    final totalDistance = _calculateDistance();
    final duration = _trackPoints.isNotEmpty
        ? _trackPoints.last.timestamp.difference(_trackPoints.first.timestamp)
        : Duration.zero;

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
      color: Theme.of(context).colorScheme.surfaceContainerHighest,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: [
          _StatItem(
            icon: Icons.straighten,
            label: '总距离',
            value: '${totalDistance.toStringAsFixed(1)} km',
          ),
          _StatItem(
            icon: Icons.access_time,
            label: '用时',
            value:
                '${duration.inHours}h ${duration.inMinutes.remainder(60)}min',
          ),
          _StatItem(
            icon: Icons.location_on,
            label: '轨迹点',
            value: '${_trackPoints.length}',
          ),
          _StatItem(
            icon: Icons.speed,
            label: '平均速度',
            value: duration.inMinutes > 0
                ? '${(totalDistance / (duration.inMinutes / 60)).toStringAsFixed(1)} km/h'
                : '-',
          ),
        ],
      ),
    );
  }

  Widget _buildTrackMap() {
    // 使用简化的轨迹可视化（实际项目可集成高德/百度地图）
    return Card(
      margin: const EdgeInsets.all(12),
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      child: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(12),
            child: Row(
              children: [
                const Icon(Icons.map, size: 20, color: Colors.blue),
                const SizedBox(width: 8),
                Text('轨迹地图', style: Theme.of(context).textTheme.titleMedium),
                const Spacer(),
                if (_recording)
                  Container(
                    padding: const EdgeInsets.symmetric(
                        horizontal: 8, vertical: 2),
                    decoration: BoxDecoration(
                      color: Colors.red.shade100,
                      borderRadius: BorderRadius.circular(4),
                    ),
                    child: const Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Icon(Icons.fiber_manual_record,
                            size: 8, color: Colors.red),
                        SizedBox(width: 4),
                        Text('记录中',
                            style: TextStyle(fontSize: 11, color: Colors.red)),
                      ],
                    ),
                  ),
              ],
            ),
          ),
          Expanded(
            child: Container(
              margin: const EdgeInsets.fromLTRB(12, 0, 12, 12),
              decoration: BoxDecoration(
                color: Colors.grey.shade100,
                borderRadius: BorderRadius.circular(8),
              ),
              child: CustomPaint(
                size: Size.infinite,
                painter: _TrackPainter(
                  points: _trackPoints,
                  color: Theme.of(context).colorScheme.primary,
                ),
                child: Stack(
                  children: [
                    // 起点标记
                    if (_trackPoints.isNotEmpty)
                      Positioned(
                        left: 12,
                        top: 12,
                        child: Container(
                          padding: const EdgeInsets.symmetric(
                              horizontal: 8, vertical: 4),
                          decoration: BoxDecoration(
                            color: Colors.green,
                            borderRadius: BorderRadius.circular(12),
                          ),
                          child: const Text(
                            '起点',
                            style: TextStyle(
                                color: Colors.white,
                                fontSize: 11,
                                fontWeight: FontWeight.w600),
                          ),
                        ),
                      ),
                    // 终点标记
                    if (_trackPoints.isNotEmpty)
                      Positioned(
                        right: 12,
                        bottom: 12,
                        child: Container(
                          padding: const EdgeInsets.symmetric(
                              horizontal: 8, vertical: 4),
                          decoration: BoxDecoration(
                            color: Colors.red,
                            borderRadius: BorderRadius.circular(12),
                          ),
                          child: const Text(
                            '终点',
                            style: TextStyle(
                                color: Colors.white,
                                fontSize: 11,
                                fontWeight: FontWeight.w600),
                          ),
                        ),
                      ),
                  ],
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildPointList() {
    return Container(
      height: 200,
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surface,
        border: Border(
          top: BorderSide(color: Colors.grey.shade300),
        ),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
            child: Text(
              '轨迹点详情',
              style: Theme.of(context).textTheme.titleSmall,
            ),
          ),
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.symmetric(horizontal: 12),
              itemCount: _trackPoints.length,
              itemBuilder: (ctx, i) {
                final point = _trackPoints[i];
                return _TrackPointTile(point: point, index: i + 1);
              },
            ),
          ),
        ],
      ),
    );
  }

  double _calculateDistance() {
    if (_trackPoints.length < 2) return 0;
    double total = 0;
    for (int i = 1; i < _trackPoints.length; i++) {
      total += _haversine(
        _trackPoints[i - 1].lat,
        _trackPoints[i - 1].lng,
        _trackPoints[i].lat,
        _trackPoints[i].lng,
      );
    }
    return total;
  }

  double _haversine(double lat1, double lng1, double lat2, double lng2) {
    const r = 6371.0; // Earth radius in km
    final dLat = (lat2 - lat1) * 3.14159265 / 180;
    final dLng = (lng2 - lng1) * 3.14159265 / 180;
    final a = (dLat / 2).sin() * (dLat / 2).sin() +
        (lat1 * 3.14159265 / 180).cos() *
            (lat2 * 3.14159265 / 180).cos() *
            (dLng / 2).sin() *
            (dLng / 2).sin();
    return 2 * r * a.sqrt().asin();
  }

  void _toggleRecording() {
    setState(() => _recording = !_recording);
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(_recording ? 'GPS轨迹记录已开始' : 'GPS轨迹记录已停止'),
        duration: const Duration(seconds: 2),
      ),
    );
  }
}

// 扩展方法用于三角函数计算
extension _MathExt on double {
  double sin() => _sin(this);
  double cos() => _cos(this);
  double sqrt() => _sqrt(this);
  double asin() => _asin(this);

  static double _sin(double x) {
    // Taylor approximation
    double result = x;
    double term = x;
    for (int i = 1; i <= 10; i++) {
      term *= -x * x / ((2 * i + 1) * (2 * i + 2));
      result += term / (2 * i + 1);
    }
    return result;
  }

  static double _cos(double x) {
    double result = 1;
    double term = 1;
    for (int i = 1; i <= 10; i++) {
      term *= -x * x / ((2 * i - 1) * (2 * i));
      result += term;
    }
    return result;
  }

  static double _sqrt(double x) {
    if (x < 0) return double.nan;
    double guess = x / 2;
    for (int i = 0; i < 20; i++) {
      guess = (guess + x / guess) / 2;
    }
    return guess;
  }

  static double _asin(double x) {
    if (x < -1 || x > 1) return double.nan;
    // Use Taylor series: asin(x) ≈ x + x³/6 + 3x⁵/40 + ...
    // Better approximation using atan
    return _atan(x / _sqrt(1 - x * x));
  }

  static double _atan(double x) {
    // atan approximation
    if (x.abs() > 1) {
      return 3.14159265 / 2 * (x > 0 ? 1 : -1) - _atanSmall(1 / x);
    }
    return _atanSmall(x);
  }

  static double _atanSmall(double x) {
    // Polynomial approximation for |x| <= 1
    final x2 = x * x;
    return x * (1 - x2 / 3 + x2 * x2 / 5 - x2 * x2 * x2 / 7 +
        x2 * x2 * x2 * x2 / 9);
  }
}

class _TrackPainter extends CustomPainter {
  final List<TrackPoint> points;
  final Color color;

  _TrackPainter({required this.points, required this.color});

  @override
  void paint(Canvas canvas, Size size) {
    if (points.length < 2) return;

    // Find bounds
    double minLat = points.first.lat;
    double maxLat = points.first.lat;
    double minLng = points.first.lng;
    double maxLng = points.first.lng;

    for (final p in points) {
      if (p.lat < minLat) minLat = p.lat;
      if (p.lat > maxLat) maxLat = p.lat;
      if (p.lng < minLng) minLng = p.lng;
      if (p.lng > maxLng) maxLng = p.lng;
    }

    final latRange = maxLat - minLat;
    final lngRange = maxLng - minLng;
    final padding = 20.0;
    final drawWidth = size.width - padding * 2;
    final drawHeight = size.height - padding * 2;

    Offset toScreen(TrackPoint p) {
      final x = lngRange > 0
          ? padding + (p.lng - minLng) / lngRange * drawWidth
          : size.width / 2;
      final y = latRange > 0
          ? padding + (1 - (p.lat - minLat) / latRange) * drawHeight
          : size.height / 2;
      return Offset(x, y);
    }

    // Draw track line
    final paint = Paint()
      ..color = color
      ..strokeWidth = 3
      ..style = PaintingStyle.stroke
      ..strokeCap = StrokeCap.round;

    final path = Path();
    final first = toScreen(points.first);
    path.moveTo(first.dx, first.dy);
    for (int i = 1; i < points.length; i++) {
      final p = toScreen(points[i]);
      path.lineTo(p.dx, p.dy);
    }
    canvas.drawPath(path, paint);

    // Draw points
    final pointPaint = Paint()..style = PaintingStyle.fill;
    for (int i = 0; i < points.length; i++) {
      final p = toScreen(points[i]);
      pointPaint.color = i == 0
          ? Colors.green
          : i == points.length - 1
              ? Colors.red
              : color;
      canvas.drawCircle(p, i == 0 || i == points.length - 1 ? 6 : 4, pointPaint);
      canvas.drawCircle(
          p, i == 0 || i == points.length - 1 ? 8 : 5,
          Paint()
            ..color = Colors.white
            ..style = PaintingStyle.stroke
            ..strokeWidth = 1.5);
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
}

class _StatItem extends StatelessWidget {
  final IconData icon;
  final String label;
  final String value;

  const _StatItem({
    required this.icon,
    required this.label,
    required this.value,
  });

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        Icon(icon, size: 18, color: Theme.of(context).colorScheme.primary),
        const SizedBox(height: 4),
        Text(value,
            style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 13)),
        const SizedBox(height: 2),
        Text(label, style: TextStyle(fontSize: 11, color: Colors.grey.shade600)),
      ],
    );
  }
}

class _TrackPointTile extends StatelessWidget {
  final TrackPoint point;
  final int index;

  const _TrackPointTile({required this.point, required this.index});

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(vertical: 6, horizontal: 8),
      margin: const EdgeInsets.only(bottom: 4),
      decoration: BoxDecoration(
        color: index == 1
            ? Colors.green.shade50
            : Colors.grey.shade50,
        borderRadius: BorderRadius.circular(6),
      ),
      child: Row(
        children: [
          CircleAvatar(
            radius: 14,
            backgroundColor:
                index == 1 ? Colors.green : Colors.grey.shade300,
            child: Text(
              '$index',
              style: TextStyle(
                fontSize: 11,
                color: index == 1 ? Colors.white : Colors.grey.shade700,
              ),
            ),
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  point.address,
                  style: const TextStyle(fontSize: 13, fontWeight: FontWeight.w500),
                ),
                Text(
                  '${point.lat.toStringAsFixed(4)}, ${point.lng.toStringAsFixed(4)} | 海拔 ${point.altitude.toStringAsFixed(1)}m',
                  style: TextStyle(fontSize: 11, color: Colors.grey.shade600),
                ),
              ],
            ),
          ),
          Column(
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              Text(
                '${point.timestamp.hour.toString().padLeft(2, '0')}:'
                '${point.timestamp.minute.toString().padLeft(2, '0')}',
                style: const TextStyle(fontSize: 12, fontWeight: FontWeight.w500),
              ),
              if (point.speed > 0)
                Text(
                  '${point.speed.toStringAsFixed(1)} km/h',
                  style: TextStyle(fontSize: 11, color: Colors.grey.shade600),
                ),
            ],
          ),
        ],
      ),
    );
  }
}