import 'package:flutter/material.dart';

import '../../../domain/school_identity.dart';
import '../../../domain/school_term.dart';
import '../../../domain/undergraduate_exam_query.dart';

Future<UndergraduateExamQuery?> showUndergraduateExamQueryPicker(
  BuildContext context, {
  UndergraduateExamQuery? initial,
  required DateTime now,
}) => showDialog<UndergraduateExamQuery>(
  context: context,
  builder: (_) => _ExamPicker(initial: initial, now: now),
);

class _ExamPicker extends StatefulWidget {
  const _ExamPicker({this.initial, required this.now});
  final UndergraduateExamQuery? initial;
  final DateTime now;
  @override
  State<_ExamPicker> createState() => _ExamPickerState();
}

class _ExamPickerState extends State<_ExamPicker> {
  late SchoolTerm _term =
      widget.initial?.term ??
      SchoolTerm(523, school: SupportedSchool.uestcUndergraduate);
  late final Set<UndergraduateExamType> _types = {
    ...?widget.initial?.types,
    if (widget.initial == null) UndergraduateExamType.finalExam,
  };
  @override
  Widget build(BuildContext context) => AlertDialog(
    title: const Text('本科考试查询'),
    content: SingleChildScrollView(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('选择一个学期和需要查询的考试类型'),
          const SizedBox(height: 14),
          DropdownButton<SchoolTerm>(
            isExpanded: true,
            value: _term,
            items: SchoolTerm.undergraduateChoices(widget.now, saved: _term)
                .map((t) => DropdownMenuItem(value: t, child: Text(t.label)))
                .toList(),
            onChanged: (t) {
              if (t != null) setState(() => _term = t);
            },
          ),
          for (final type in UndergraduateExamType.values)
            CheckboxListTile(
              contentPadding: EdgeInsets.zero,
              title: Text(type.label),
              value: _types.contains(type),
              onChanged: (v) => setState(() {
                if (v == true) {
                  _types.add(type);
                } else {
                  _types.remove(type);
                }
              }),
            ),
        ],
      ),
    ),
    actions: [
      TextButton(
        onPressed: () => Navigator.pop(context),
        child: const Text('取消'),
      ),
      FilledButton(
        onPressed: _types.isEmpty
            ? null
            : () => Navigator.pop(
                context,
                UndergraduateExamQuery(term: _term, types: _types),
              ),
        child: const Text('开始查询'),
      ),
    ],
  );
}