import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'dart:io';

class ActivitySubmitPage extends StatefulWidget {
  const ActivitySubmitPage({super.key});

  @override
  State<ActivitySubmitPage> createState() => _ActivitySubmitPageState();
}

class _ActivitySubmitPageState extends State<ActivitySubmitPage> {
  final _formKey = GlobalKey<FormState>();
  final _titleController = TextEditingController();
  final _locationController = TextEditingController();
  final _descriptionController = TextEditingController();
  DateTime? _startDate;
  DateTime? _endDate;
  String _needRegister = '否';
  String _repeatOption = 'none';
  int _repeatCount = 1;
  File? _poster;

  Future<void> _selectDateTime(bool isStart) async {
    final now = DateTime.now();
    final date = await showDatePicker(
      context: context,
      initialDate: now,
      firstDate: now,
      lastDate: DateTime(now.year + 2),
    );
    if (date == null) return;

    final time = await showTimePicker(
      context: context,
      initialTime: TimeOfDay.fromDateTime(now),
    );
    if (time == null) return;

    final selected = DateTime(
      date.year,
      date.month,
      date.day,
      time.hour,
      time.minute,
    );
    setState(() {
      if (isStart) {
        _startDate = selected;
      } else {
        _endDate = selected;
      }
    });
  }

  void _submitForm() {
    if (!_formKey.currentState!.validate()) return;

    if (_startDate == null || _endDate == null) {
      _showAlert('請選擇開始與結束時間');
      return;
    }

    if (_endDate!.isBefore(_startDate!)) {
      _showAlert('結束時間必須晚於開始時間！');
      return;
    }

    final formatter = DateFormat('yyyy-MM-dd HH:mm');
    final message =
        StringBuffer()
          ..writeln('活動申請已送出')
          ..writeln('名稱：${_titleController.text}')
          ..writeln('開始時間：${formatter.format(_startDate!)}')
          ..writeln('結束時間：${formatter.format(_endDate!)}')
          ..writeln('地點：${_locationController.text}')
          ..writeln('描述：${_descriptionController.text}')
          ..writeln('需報名統計：$_needRegister');

    if (_repeatOption != 'none') {
      final map = {'weekly': '每週', 'biweekly': '每兩週', 'monthly': '每月'};
      message.writeln('重複設定：${map[_repeatOption]}，共重複 $_repeatCount 次');
    }

    if (_poster != null) {
      message.writeln('檔案名稱：${_poster!.path.split('/').last}');
    }

    _showAlert(message.toString());
  }

  void _showAlert(String text) {
    // print('Submit button pressed'); // ← Debug 用
    showDialog(
      context: context,
      builder:
          (_) => AlertDialog(
            title: const Text('訊息'),
            content: Text(text),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(context),
                child: const Text('確定'),
              ),
            ],
          ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('提交活動申請'),
        backgroundColor: const Color(0xFF9eaf9f),
        foregroundColor: Colors.white,
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16),
        child: Form(
          key: _formKey,
          child: Column(
            children: [
              TextFormField(
                controller: _titleController,
                decoration: const InputDecoration(labelText: '活動名稱'),
                validator: (value) => value!.isEmpty ? '必填' : null,
              ),
              const SizedBox(height: 12),
              _buildDateField('開始時間', _startDate, () => _selectDateTime(true)),
              const SizedBox(height: 12),
              _buildDateField('結束時間', _endDate, () => _selectDateTime(false)),
              const SizedBox(height: 12),
              TextFormField(
                controller: _locationController,
                decoration: const InputDecoration(labelText: '地點'),
                validator: (value) => value!.isEmpty ? '必填' : null,
              ),
              const SizedBox(height: 12),
              TextFormField(
                controller: _descriptionController,
                decoration: const InputDecoration(labelText: '活動描述'),
                maxLines: 4,
                validator: (value) => value!.isEmpty ? '必填' : null,
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<String>(
                value: _needRegister,
                decoration: const InputDecoration(labelText: '是否需統計報名人數？'),
                items:
                    ['否', '是']
                        .map((v) => DropdownMenuItem(value: v, child: Text(v)))
                        .toList(),
                onChanged: (v) => setState(() => _needRegister = v!),
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<String>(
                value: _repeatOption,
                decoration: const InputDecoration(labelText: '是否重複舉辦'),
                items: const [
                  DropdownMenuItem(value: 'none', child: Text('否')),
                  DropdownMenuItem(value: 'weekly', child: Text('每週一次')),
                  DropdownMenuItem(value: 'biweekly', child: Text('每兩週一次')),
                  DropdownMenuItem(value: 'monthly', child: Text('每月一次')),
                ],
                onChanged: (v) => setState(() => _repeatOption = v!),
              ),
              if (_repeatOption != 'none') ...[
                const SizedBox(height: 12),
                TextFormField(
                  decoration: const InputDecoration(labelText: '重複次數（不含首次）'),
                  keyboardType: TextInputType.number,
                  initialValue: '1',
                  onChanged:
                      (v) =>
                          _repeatCount =
                              int.tryParse(v) != null ? int.parse(v) : 1,
                ),
              ],
              const SizedBox(height: 24),
              ElevatedButton.icon(
                onPressed: () {
                  // 檔案選取功能：日後可整合 `file_picker` 套件
                  _showAlert('尚未實作檔案選擇功能，請整合 file_picker 或 image_picker');
                },
                icon: const Icon(Icons.upload_file),
                label: const Text('上傳活動海報'),
              ),
              const SizedBox(height: 24),
              ElevatedButton(
                onPressed: _submitForm,
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.green,
                  padding: const EdgeInsets.symmetric(
                    vertical: 12,
                    horizontal: 32,
                  ),
                ),
                child: const Text(
                  '送出申請',
                  style: TextStyle(color: Colors.white),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildDateField(String label, DateTime? value, VoidCallback onTap) {
    final formatter = DateFormat('yyyy-MM-dd HH:mm');
    return Row(
      children: [
        Expanded(
          child: Text(
            '$label：${value != null ? formatter.format(value) : '未選擇'}',
          ),
        ),
        TextButton(onPressed: onTap, child: const Text('選擇')),
      ],
    );
  }
}