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

class DiagnosticsScreen extends ConsumerWidget {
  const DiagnosticsScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final telemetryAsync = ref.watch(telemetryStreamProvider);
    final t = telemetryAsync.value;

    final gpsAccuracy = t?.gpsAccuracy;
    String gpsHealthText = 'No Fix (Unavailable)';
    Color gpsHealthColor = Colors.redAccent;
    if (gpsAccuracy != null) {
      if (gpsAccuracy <= 15.0) {
        gpsHealthText = 'Healthy (${gpsAccuracy.toStringAsFixed(1)}m)';
        gpsHealthColor = Colors.greenAccent;
      } else if (gpsAccuracy <= 35.0) {
        gpsHealthText = 'Degraded (${gpsAccuracy.toStringAsFixed(1)}m)';
        gpsHealthColor = Colors.amberAccent;
      } else {
        gpsHealthText = 'Poor (${gpsAccuracy.toStringAsFixed(1)}m)';
        gpsHealthColor = Colors.redAccent;
      }
    }

    return Scaffold(
      appBar: AppBar(title: const Text('Sensor Diagnostics')),
      body: t == null 
        ? const Center(child: CircularProgressIndicator())
        : ListView(
            padding: const EdgeInsets.all(16.0),
            children: [
              _buildMetric('Timestamp', t.timestamp.toIso8601String()),
              const Divider(),
              const Text('Sensor Health & Signal', style: TextStyle(color: Colors.cyanAccent, fontWeight: FontWeight.bold)),
              _buildHealthMetric('GPS Signal', gpsHealthText, gpsHealthColor),
              _buildHealthMetric('IMU / Accelerometer', t.accelX != null ? 'Active' : 'No Data', t.accelX != null ? Colors.greenAccent : Colors.redAccent),
              _buildHealthMetric('Compass / Gyro', t.heading != null ? 'Active' : 'No Data', t.heading != null ? Colors.greenAccent : Colors.redAccent),
              const Divider(),
              const Text('GPS Data', style: TextStyle(color: Colors.cyanAccent, fontWeight: FontWeight.bold)),
              _buildMetric('GPS Accuracy', gpsAccuracy != null ? '±${gpsAccuracy.toStringAsFixed(1)} m' : 'N/A'),
              _buildMetric('Latitude', t.latitude?.toStringAsFixed(6) ?? 'N/A'),
              _buildMetric('Longitude', t.longitude?.toStringAsFixed(6) ?? 'N/A'),
              _buildMetric('Altitude', t.altitude != null ? '${t.altitude!.toStringAsFixed(1)} m' : 'N/A'),
              _buildMetric('Speed', t.speed != null ? '${t.speed!.toStringAsFixed(1)} MPH' : 'N/A'),
              _buildMetric('Heading', t.heading != null ? '${t.heading!.toStringAsFixed(1)}°' : 'N/A'),
              const Divider(),
              const Text('IMU & G-Force Data', style: TextStyle(color: Colors.cyanAccent, fontWeight: FontWeight.bold)),
              _buildMetric('Accel X (m/s²)', t.accelX?.toStringAsFixed(3) ?? 'N/A'),
              _buildMetric('Accel Y (m/s²)', t.accelY?.toStringAsFixed(3) ?? 'N/A'),
              _buildMetric('Accel Z (m/s²)', t.accelZ?.toStringAsFixed(3) ?? 'N/A'),
              _buildMetric('Longitudinal G', t.longitudinalG != null ? '${t.longitudinalG!.toStringAsFixed(3)} G' : 'N/A'),
              _buildMetric('Lateral G', t.lateralG != null ? '${t.lateralG!.toStringAsFixed(3)} G' : 'N/A'),
              _buildMetric('Lean Angle', t.leanAngle != null ? '${t.leanAngle!.toStringAsFixed(2)}°' : 'N/A'),
              _buildMetric('Pitch Angle', t.pitchAngle != null ? '${t.pitchAngle!.toStringAsFixed(2)}°' : 'N/A'),
            ],
          ),
    );
  }

  Widget _buildHealthMetric(String label, String status, Color statusColor) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4.0),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Text(label, style: const TextStyle(color: Colors.white70)),
          Row(
            children: [
              Icon(Icons.circle, color: statusColor, size: 10),
              const SizedBox(width: 6),
              Text(status, style: TextStyle(fontWeight: FontWeight.bold, color: statusColor)),
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildMetric(String label, String value) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4.0),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Text(label, style: const TextStyle(color: Colors.white70)),
          Text(value, style: const TextStyle(fontWeight: FontWeight.bold, fontFamily: 'monospace')),
        ],
      ),
    );
  }
}