import 'dart:math' as math;

import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import '../../../../core/models/units.dart';
import '../../../../core/providers/sensor_history_provider.dart';
import '../../../theme/app_colors.dart';

/// One graph (requirements): line over the selected time window with the
/// window's max/min top-left, current value and name bottom-left, value
/// axis on the right, seconds-ago axis along the bottom, and a touch cursor
/// that reads out the value under the finger.
class SensorGraphPanel extends StatelessWidget {
  final SensorView view;
  final SensorHistory history;
  final int windowSeconds;
  final VoidCallback onRemove;

  const SensorGraphPanel({
    super.key,
    required this.view,
    required this.history,
    required this.windowSeconds,
    required this.onRemove,
  });

  @override
  Widget build(BuildContext context) {
    final c = AppColors.of(context);
    final raw = history.get(view.def.id);
    final now = raw.isEmpty ? 0.0 : raw.last.x;
    // x = seconds before the latest sample (0 at the right edge).
    final spots = [
      for (final s in raw)
        if (now - s.x <= windowSeconds) FlSpot(s.x - now, view.convert(s.y)),
    ];

    double? lo, hi;
    for (final s in spots) {
      lo = lo == null ? s.y : math.min(lo, s.y);
      hi = hi == null ? s.y : math.max(hi, s.y);
    }
    // Y axis follows the data in the window (like the reference), with a
    // margin, and never collapses to zero height for a steady value.
    var minY = view.min, maxY = view.max;
    if (lo != null && hi != null) {
      final pad = math.max((hi - lo) * 0.15, (view.max - view.min) * 0.02);
      minY = lo - pad;
      maxY = hi + pad;
    }
    final muted = TextStyle(color: c.onSurfaceMuted, fontSize: 11);
    String f(double v) => v.toStringAsFixed(view.decimals);

    return Container(
      height: 170,
      margin: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      padding: const EdgeInsets.fromLTRB(8, 6, 4, 4),
      decoration: BoxDecoration(
        color: c.surface,
        borderRadius: BorderRadius.circular(8),
        border: Border.all(color: c.divider),
      ),
      child: Stack(
        children: [
          Padding(
            padding: const EdgeInsets.only(bottom: 4),
            child: spots.length < 2
                ? Center(child: Text('Waiting for data…', style: muted))
                : LineChart(
                    LineChartData(
                      minX: -windowSeconds.toDouble(),
                      maxX: 0,
                      minY: minY,
                      maxY: maxY,
                      clipData: const FlClipData.all(),
                      gridData: FlGridData(
                        show: true,
                        getDrawingHorizontalLine: (_) =>
                            FlLine(color: c.divider, strokeWidth: 1),
                        getDrawingVerticalLine: (_) =>
                            FlLine(color: c.divider, strokeWidth: 1),
                      ),
                      borderData: FlBorderData(show: false),
                      titlesData: FlTitlesData(
                        topTitles: const AxisTitles(),
                        leftTitles: const AxisTitles(),
                        rightTitles: AxisTitles(
                          sideTitles: SideTitles(
                            showTitles: true,
                            reservedSize: 40,
                            getTitlesWidget: (v, meta) => Text(
                              _compact(v),
                              style: muted.copyWith(fontSize: 9),
                            ),
                          ),
                        ),
                        bottomTitles: AxisTitles(
                          sideTitles: SideTitles(
                            showTitles: true,
                            reservedSize: 16,
                            interval: windowSeconds / 6,
                            getTitlesWidget: (v, meta) => Text(
                              (-v).round().toString(),
                              style: muted.copyWith(fontSize: 9),
                            ),
                          ),
                        ),
                      ),
                      lineTouchData: LineTouchData(
                        getTouchedSpotIndicator: (bar, indexes) => [
                          for (final _ in indexes)
                            const TouchedSpotIndicatorData(
                              FlLine(color: Colors.red, strokeWidth: 1.5),
                              FlDotData(show: true),
                            ),
                        ],
                        touchTooltipData: LineTouchTooltipData(
                          getTooltipColor: (_) => Colors.red,
                          tooltipPadding: const EdgeInsets.symmetric(
                              horizontal: 4, vertical: 2),
                          getTooltipItems: (touched) => [
                            for (final t in touched)
                              LineTooltipItem(
                                f(t.y),
                                const TextStyle(
                                    color: Colors.white, fontSize: 11),
                              ),
                          ],
                        ),
                      ),
                      lineBarsData: [
                        LineChartBarData(
                          spots: spots,
                          isCurved: false,
                          color: c.accent,
                          barWidth: 1.5,
                          dotData: const FlDotData(show: false),
                        ),
                      ],
                    ),
                    duration: Duration.zero,
                  ),
          ),
          // Window max / min
          Positioned(
            left: 4,
            top: 0,
            child: IgnorePointer(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(hi == null ? '-' : f(hi), style: muted),
                  Text(lo == null ? '-' : f(lo), style: muted),
                ],
              ),
            ),
          ),
          // Name + current value
          Positioned(
            left: 4,
            bottom: 18,
            child: IgnorePointer(
              child: RichText(
                text: TextSpan(children: [
                  TextSpan(
                    text: '${view.name}  ',
                    style: TextStyle(color: c.accent, fontSize: 14),
                  ),
                  TextSpan(
                    text: raw.isEmpty ? '-' : view.format(raw.last.y),
                    style: TextStyle(
                      color: c.onSurface,
                      fontSize: 20,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                  TextSpan(
                    text: ' ${view.unit}',
                    style: TextStyle(color: c.onSurfaceMuted, fontSize: 12),
                  ),
                ]),
              ),
            ),
          ),
          Positioned(
            right: 0,
            top: 0,
            child: GestureDetector(
              onTap: onRemove,
              child: Icon(Icons.close, size: 16, color: c.onSurfaceMuted),
            ),
          ),
        ],
      ),
    );
  }

  static String _compact(double v) {
    if (v.abs() >= 1000) return '${(v / 1000).toStringAsFixed(1)}k';
    if (v.abs() >= 10 || v == v.roundToDouble()) return v.toStringAsFixed(0);
    return v.toStringAsFixed(1);
  }
}