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

import '../core/theme/context_tokens.dart';
import '../core/theme/app_dims.g.dart';
import '../core/responsive/responsive.dart';
import '../core/utils/dialog_util.dart';

/// 年/月/日 滚轮日期选择器（对齐原型 .wheel-pop）。选中返回 DateTime，取消返回 null。
/// 「今天」快速跳到今天；「确定」确认。范围选择由调用方调两次（起/止）拼成。
Future<DateTime?> showWheelDatePicker(
  BuildContext context, {
  DateTime? initial,
  String title = '选择日期',
}) {
  return showAppDialog<DateTime>(
    context: context,
    builder: (_) => _WheelDateDialog(initial: initial ?? DateTime.now(), title: title),
  );
}

class _WheelDateDialog extends StatefulWidget {
  final DateTime initial;
  final String title;
  const _WheelDateDialog({required this.initial, required this.title});

  @override
  State<_WheelDateDialog> createState() => _WheelDateDialogState();
}

class _WheelDateDialogState extends State<_WheelDateDialog> {
  late DateTime _value;

  @override
  void initState() {
    super.initState();
    _value = DateTime(widget.initial.year, widget.initial.month, widget.initial.day);
  }

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    return Dialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(AppDims.rXl)),
      child: SizedBox(
        width: context.dialogWidth(320),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 14, 16, 4),
              child: Row(
                children: [
                  Text(widget.title,
                      style: TextStyle(
                          fontSize: AppDims.fsTitle,
                          fontWeight: FontWeight.w600,
                          color: t.heading)),
                ],
              ),
            ),
            // 三列滚轮（年/月/日），中间高亮行由 CupertinoDatePicker 提供。
            SizedBox(
              height: 200,
              child: CupertinoTheme(
                data: CupertinoThemeData(
                  textTheme: CupertinoTextThemeData(
                    dateTimePickerTextStyle: TextStyle(fontSize: 18, color: t.text),
                  ),
                ),
                child: CupertinoDatePicker(
                  mode: CupertinoDatePickerMode.date,
                  initialDateTime: _value,
                  minimumYear: 2015,
                  maximumYear: 2035,
                  onDateTimeChanged: (d) =>
                      _value = DateTime(d.year, d.month, d.day),
                ),
              ),
            ),
            const Divider(height: 1),
            Padding(
              padding: const EdgeInsets.fromLTRB(12, 8, 12, 10),
              child: Row(
                children: [
                  TextButton(
                    onPressed: () {
                      final now = DateTime.now();
                      setState(() => _value = DateTime(now.year, now.month, now.day));
                    },
                    child: Text('今天', style: TextStyle(color: t.muted)),
                  ),
                  const Spacer(),
                  TextButton(
                    onPressed: () => Navigator.of(context).pop(),
                    child: Text('取消', style: TextStyle(color: t.muted)),
                  ),
                  const SizedBox(width: 4),
                  ElevatedButton(
                    onPressed: () => Navigator.of(context).pop(_value),
                    style: ElevatedButton.styleFrom(
                      backgroundColor: t.primary,
                      foregroundColor: t.onPrimary,
                      elevation: 0,
                    ),
                    child: const Text('确定'),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

/// 范围选择：先选起始日、再选结束日；任一取消则返回 null。
Future<DateTimeRange?> showWheelDateRange(
  BuildContext context, {
  DateTimeRange? initial,
}) async {
  final start = await showWheelDatePicker(context,
      initial: initial?.start, title: '起始日期');
  if (start == null || !context.mounted) return null;
  final end = await showWheelDatePicker(context,
      initial: initial?.end ?? start, title: '结束日期');
  if (end == null) return null;
  // 保证 start <= end
  return end.isBefore(start)
      ? DateTimeRange(start: end, end: start)
      : DateTimeRange(start: start, end: end);
}