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

import '../../api/health_api.dart';
import '../../models/health.dart';
import '../../providers/health_provider.dart';
import '../../utils/toast.dart';
import '../../widgets/state_views.dart';
import 'widgets/weight_line_chart.dart';

/// 体重页面：记体重 + 看折线图 + 看历史。
///
/// 顶部一个「记一下」输入区放着不动，下面依次是图表和历史 ——
/// 这个页面最高频的动作就是「记一次」，它必须在第一屏、不用滚动就能点到。
class WeightPage extends ConsumerStatefulWidget {
  const WeightPage({super.key});

  @override
  ConsumerState<WeightPage> createState() => _WeightPageState();
}

class _WeightPageState extends ConsumerState<WeightPage> {
  final _ctrl = TextEditingController();
  final _noteCtrl = TextEditingController();

  bool _saving = false;
  DateTime _date = DateTime.now();

  @override
  void initState() {
    super.initState();
    // 预填最近一次体重 —— 大部分时候体重变化很小，改一下比重新敲快
    Future.microtask(() async {
      try {
        final chart = await ref.read(healthApiProvider).weightChart();
        if (!mounted) return;
        final current = chart.currentWeight;
        if (current != null) {
          setState(() => _ctrl.text = _fmt(current));
        }
      } catch (_) {
        // 拿不到就留空手填
      }
    });
  }

  @override
  void dispose() {
    _ctrl.dispose();
    _noteCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final chartAsync = ref.watch(weightChartProvider);
    final goalAsync = ref.watch(weightGoalProvider);

    return Scaffold(
      backgroundColor: const Color(0xFFF7F4F1),
      appBar: AppBar(
        title: const Text('体重记录'),
        backgroundColor: const Color(0xFFF7F4F1),
        elevation: 0,
        scrolledUnderElevation: 0,
        foregroundColor: const Color(0xFF5D4037),
      ),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(14, 6, 14, 24),
        children: [
          _inputCard(),
          const SizedBox(height: 12),
          _chartCard(chartAsync, goalAsync.value),
          const SizedBox(height: 12),
          _historyCard(),
        ],
      ),
    );
  }

  // ---------------- 输入区 ----------------

  Widget _inputCard() {
    return Container(
      padding: const EdgeInsets.fromLTRB(16, 14, 16, 14),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              const Text('记录体重',
                  style: TextStyle(
                    fontSize: 15,
                    fontWeight: FontWeight.w600,
                    color: Color(0xFF5D4037),
                  )),
              const Spacer(),
              // 日期默认今天，要补记以前的就点这里改
              GestureDetector(
                onTap: _pickDate,
                child: Row(
                  children: [
                    Text(
                      _isToday(_date) ? '今天' : _dateText(_date),
                      style: const TextStyle(
                          fontSize: 12.5, color: Color(0xFFC8956E)),
                    ),
                    const Icon(Icons.chevron_right,
                        size: 16, color: Color(0xFFC8956E)),
                  ],
                ),
              ),
            ],
          ),
          const SizedBox(height: 6),
          Row(
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              Expanded(
                child: TextField(
                  controller: _ctrl,
                  keyboardType:
                      const TextInputType.numberWithOptions(decimal: true),
                  style: const TextStyle(
                    fontSize: 34,
                    fontWeight: FontWeight.bold,
                    color: Color(0xFF5D4037),
                  ),
                  decoration: const InputDecoration(
                    hintText: '65.0',
                    hintStyle: TextStyle(
                        fontSize: 34,
                        fontWeight: FontWeight.bold,
                        color: Color(0xFFEFE5DC)),
                    suffixText: 'kg',
                    suffixStyle:
                        TextStyle(fontSize: 14, color: Color(0xFF8D6E63)),
                    isDense: true,
                    contentPadding: EdgeInsets.symmetric(vertical: 8),
                    border: InputBorder.none,
                  ),
                ),
              ),
              const SizedBox(width: 10),
              ElevatedButton(
                onPressed: _saving ? null : _save,
                style: ElevatedButton.styleFrom(
                  backgroundColor: const Color(0xFFC8956E),
                  foregroundColor: Colors.white,
                  padding: const EdgeInsets.symmetric(
                      horizontal: 22, vertical: 12),
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(22),
                  ),
                ),
                child: Text(_saving ? '…' : '记录'),
              ),
            ],
          ),
          const SizedBox(height: 4),
          TextField(
            controller: _noteCtrl,
            style: const TextStyle(fontSize: 13, color: Color(0xFF5D4037)),
            decoration: const InputDecoration(
              hintText: '备注（可选），比如「早上空腹」',
              hintStyle: TextStyle(fontSize: 12.5, color: Color(0xFFBCAAA4)),
              isDense: true,
              contentPadding: EdgeInsets.symmetric(vertical: 6),
              border: InputBorder.none,
            ),
          ),
        ],
      ),
    );
  }

  Future<void> _pickDate() async {
    final picked = await showDatePicker(
      context: context,
      initialDate: _date,
      firstDate: DateTime(2020),
      lastDate: DateTime.now(),
    );
    if (picked != null) setState(() => _date = picked);
  }

  Future<void> _save() async {
    final weight = double.tryParse(_ctrl.text.trim());
    if (weight == null) {
      showToast(context, '请输入体重', error: true);
      return;
    }
    if (weight < 20 || weight > 300) {
      showToast(context, '体重需在 20 ~ 300 kg 之间', error: true);
      return;
    }

    setState(() => _saving = true);
    try {
      await ref.read(healthApiProvider).saveWeight(
            weight: weight,
            date: _date,
            note: _noteCtrl.text.trim().isEmpty
                ? null
                : _noteCtrl.text.trim(),
          );
      if (!mounted) return;
      ref.invalidate(weightChartProvider);
      ref.invalidate(weightHistoryProvider);
      ref.invalidate(weightGoalProvider);
      FocusScope.of(context).unfocus();
      setState(() => _noteCtrl.clear());
      showToast(context, '已记录', icon: 'check');
    } catch (e) {
      if (!mounted) return;
      showToast(context, e.toString(), error: true);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  // ---------------- 图表 ----------------

  Widget _chartCard(AsyncValue<WeightChart> chartAsync, WeightGoal? goal) {
    final chart = chartAsync.value;

    return Container(
      padding: const EdgeInsets.fromLTRB(10, 14, 16, 10),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Padding(
            padding: EdgeInsets.only(left: 6),
            child: Text('体重变化',
                style: TextStyle(
                  fontSize: 15,
                  fontWeight: FontWeight.w600,
                  color: Color(0xFF5D4037),
                )),
          ),
          if (chart != null && chart.hasData && goal != null && goal.hasGoal)
            Padding(
              padding: const EdgeInsets.only(left: 6, top: 6),
              child: Row(
                children: [
                  _legend(const Color(0xFFC8956E), '实测'),
                  const SizedBox(width: 14),
                  _legend(const Color(0xFF4FA98A), '理想'),
                ],
              ),
            ),
          const SizedBox(height: 8),
          if (chartAsync.isLoading)
            const SizedBox(height: 220, child: LoadingView(tip: ''))
          else if (chartAsync.hasError)
            SizedBox(
              height: 220,
              child: Center(
                child: ErrorView(
                  message: '图表加载失败',
                  onRetry: () => ref.invalidate(weightChartProvider),
                ),
              ),
            )
          else
            WeightLineChart(
              points: chart?.points ?? const [],
              idealCurve: goal?.idealCurve ?? const [],
            ),
        ],
      ),
    );
  }

  Widget _legend(Color color, String label) {
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Container(
          width: 14,
          height: 2.5,
          decoration: BoxDecoration(
            color: color,
            borderRadius: BorderRadius.circular(2),
          ),
        ),
        const SizedBox(width: 5),
        Text(label,
            style: const TextStyle(
                fontSize: 11.5, color: Color(0xFF8D6E63))),
      ],
    );
  }

  // ---------------- 历史 ----------------

  Widget _historyCard() {
    final async = ref.watch(weightHistoryProvider);

    return Container(
      padding: const EdgeInsets.fromLTRB(16, 14, 16, 8),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('历史记录',
              style: TextStyle(
                fontSize: 15,
                fontWeight: FontWeight.w600,
                color: Color(0xFF5D4037),
              )),
          const SizedBox(height: 8),
          switch (async) {
            AsyncValue(hasError: true) => const Padding(
                padding: EdgeInsets.symmetric(vertical: 20),
                child: Text('加载失败',
                    style: TextStyle(
                        fontSize: 13, color: Color(0xFFBCAAA4))),
              ),
            AsyncValue(:final value?) when value.isEmpty => const Padding(
                padding: EdgeInsets.symmetric(vertical: 20),
                child: Text('还没有记录',
                    style: TextStyle(
                        fontSize: 13, color: Color(0xFFBCAAA4))),
              ),
            AsyncValue(:final value?) => _historyList(value),
            _ => const SizedBox(
                height: 60,
                child: Center(
                  child: SizedBox(
                    width: 20,
                    height: 20,
                    child: CircularProgressIndicator(
                        strokeWidth: 2, color: Color(0xFFC8956E)),
                  ),
                ),
              ),
          },
        ],
      ),
    );
  }

  Widget _historyList(List<WeightRecordItem> items) {
    // 相邻两条的差值，让「掉了多少」一眼可见
    return Column(
      children: [
        for (var i = 0; i < items.length; i++)
          _historyRow(items, i),
      ],
    );
  }

  Widget _historyRow(List<WeightRecordItem> items, int index) {
    final item = items[index];
    // 历史是倒序的，所以「上一次」是后面那条
    final previous = index + 1 < items.length ? items[index + 1] : null;
    final diff = previous == null ? null : item.weight - previous.weight;

    return Padding(
      padding: const EdgeInsets.only(bottom: 10),
      child: Row(
        children: [
          SizedBox(
            width: 74,
            child: Text(
              item.date == null ? '--' : _dateShort(item.date!),
              style: const TextStyle(
                  fontSize: 12.5, color: Color(0xFF8D6E63)),
            ),
          ),
          Expanded(
            child: Row(
              children: [
                Text(
                  '${_fmt(item.weight)} kg',
                  style: const TextStyle(
                    fontSize: 14,
                    fontWeight: FontWeight.w600,
                    color: Color(0xFF5D4037),
                  ),
                ),
                if (diff != null && diff.abs() >= 0.05) ...[
                  const SizedBox(width: 8),
                  Text(
                    // 掉了给绿色，涨了给红 —— 这个模块的语境界定了颜色方向
                    '${diff > 0 ? '+' : ''}${diff.toStringAsFixed(1)}',
                    style: TextStyle(
                      fontSize: 11.5,
                      color: diff > 0
                          ? const Color(0xFFE0725C)
                          : const Color(0xFF4FA98A),
                    ),
                  ),
                ],
              ],
            ),
          ),
          if (item.note.isNotEmpty)
            Flexible(
              child: Text(
                item.note,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: const TextStyle(
                    fontSize: 11.5, color: Color(0xFFBCAAA4)),
              ),
            ),
          IconButton(
            onPressed: () => _confirmDelete(item),
            icon: const Icon(Icons.close, size: 16),
            color: const Color(0xFFD7CCC8),
            visualDensity: VisualDensity.compact,
            padding: EdgeInsets.zero,
            constraints: const BoxConstraints(minWidth: 30, minHeight: 30),
          ),
        ],
      ),
    );
  }

  Future<void> _confirmDelete(WeightRecordItem item) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('删除这条记录？'),
        content: Text(
            '${item.date == null ? '' : _dateShort(item.date!)} · ${_fmt(item.weight)} kg'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(false),
            child: const Text('取消'),
          ),
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(true),
            style: TextButton.styleFrom(
                foregroundColor: const Color(0xFFE53935)),
            child: const Text('删除'),
          ),
        ],
      ),
    );
    if (ok != true) return;

    try {
      await ref.read(healthApiProvider).deleteWeight(item.id);
      if (!mounted) return;
      ref.invalidate(weightHistoryProvider);
      ref.invalidate(weightChartProvider);
      ref.invalidate(weightGoalProvider);
      showToast(context, '已删除', icon: 'check');
    } catch (e) {
      if (!mounted) return;
      showToast(context, e.toString(), error: true);
    }
  }
}

// ==================================================================

String _fmt(num value) {
  if (value == value.roundToDouble()) return value.round().toString();
  return value.toStringAsFixed(1);
}

bool _isToday(DateTime date) {
  final now = DateTime.now();
  return date.year == now.year &&
      date.month == now.month &&
      date.day == now.day;
}

String _dateText(DateTime date) =>
    '${date.year}-${date.month.toString().padLeft(2, '0')}-${date.day.toString().padLeft(2, '0')}';

String _dateShort(DateTime date) =>
    '${date.month.toString().padLeft(2, '0')}-${date.day.toString().padLeft(2, '0')}';