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

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

  @override
  State<EventAdder> createState() => _EventAdderState();
}

class _EventAdderState extends State<EventAdder> {
  final _customEventNameController = TextEditingController();
  final _customEventCodeController = TextEditingController();
  List<String> customEventNames = [];
  List<String> customEventCodes = [];
  final _formKey = GlobalKey<FormState>();

  @override
  void initState() {
    super.initState();
    _loadEvents();
  }

  Future<void> _loadEvents() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    setState(() {
      customEventNames = prefs.getStringList('custom_event_names') ?? [];
      customEventCodes = prefs.getStringList('custom_event_codes') ?? [];
    });
  }

  Future<void> _saveEvent() async {
    if (!_formKey.currentState!.validate()) {
      return;
    }

    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final String eventName = _customEventNameController.text;
    String eventCode;

    if (_customEventCodeController.text.isEmpty) {
      eventCode = '${DateTime.now().year.toString()}${eventName.replaceAll(' ', '').substring(0,4)}';
    } else {
      eventCode = _customEventCodeController.text;
    }

    customEventNames.add(eventName);
    customEventCodes.add(eventCode);

    await prefs.setStringList('custom_event_names', customEventNames);
    await prefs.setStringList('custom_event_codes', customEventCodes);

    _customEventNameController.clear();
    _customEventCodeController.clear();
    setState(() {});

    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Added Event: $eventName - $eventCode'),
          behavior: SnackBarBehavior.floating,
          margin: const EdgeInsets.all(16.0),
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Add Event')),
      body: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
          Padding(
            padding: const EdgeInsets.only(top: 16.0),
            child: Text('Add Custom Event', style: Theme.of(context).textTheme.titleLarge)
          ),
          Padding(
            padding: const EdgeInsets.only(top: 16.0),
            child: ListView(
              shrinkWrap: true,
              padding: const EdgeInsets.symmetric(horizontal: 16.0),
              children: [
                const SizedBox(height: 16),
                TextFormField(
                  controller: _customEventNameController,
                  decoration: const InputDecoration(
                    labelText: 'Event Name',
                    hintText: 'gm_construct Regional',
                    border: OutlineInputBorder()
                  ),
                  validator: (value) {
                    if (value == null || value.isEmpty) {
                      return 'Please enter a event name';
                    }
                    return null;
                  },
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _customEventCodeController,
                  decoration: const InputDecoration(
                    labelText: 'Event Code',
                    hintText: '2026gmct',
                    border: OutlineInputBorder()
                  )
                ),
                Text('Leave this field EMPTY unless you NEED a custom code.'),
                const SizedBox(height: 16.0),
                ElevatedButton(
                  onPressed: () { _saveEvent(); },
                  child: const Text('Create Event'),
                ),
              ],
            )
          ),
          Divider(),
          Text('Custom Events', style: Theme.of(context).textTheme.titleLarge),
          ListView.builder(
              shrinkWrap: true,
              itemCount: customEventNames.length,
              itemBuilder: (context, index) {
                return ListTile(
                    title: Text('${customEventNames[index]} - ${customEventCodes[index]}')
                );
              }
            )
          ],
        )
      )
    );
  }
}