import 'dart:async';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:sendtrain/services/functional/debouncer.dart';
import 'package:sendtrain/widgets/generic/elements/form_text_input.dart';

class Suggestion<T> {
  T type;

  Suggestion(this.type);
}

class FormSearchInput extends StatefulWidget {
  const FormSearchInput(
      {super.key,
      required this.sessionController,
      required this.service,
      this.title,
      this.callback,
      this.optionalPayload});

  final String? title;
  final TextEditingController sessionController;
  final dynamic service;
  final Function? callback;
  final dynamic optionalPayload;

  @override
  State<FormSearchInput> createState() => _FormSearchInputState();
}

class _FormSearchInputState extends State<FormSearchInput> {
  String? _currentQuery;

  late final service = widget.service;
  late final callback = widget.callback;
  // The most recent suggestions received from the API.
  late Iterable<Widget> _lastOptions = <Widget>[];
  late final Debouncer debouncer;

  // @override
  // initState() {
  //   service = widget.service;
  // }

  // Calls the "remote" API to search with the given query. Returns null when
  // the call has been made obsolete.
  Future<Iterable<Suggestion>?> _search(String query) async {
    _currentQuery = query;

    // In a real application, there should be some error handling here.
    // final Iterable<String> options = await _FakeAPI.search(_currentQuery!);
    if (query.isNotEmpty) {
      final List<Suggestion>? suggestions =
          await service.fetchSuggestions(_currentQuery!, 'en');

      // If another search happened after this one, throw away these options.
      if (_currentQuery != query) {
        return null;
      }
      _currentQuery = null;

      return suggestions?.map((suggestion) => suggestion);
    } else {
      return null;
    }
  }

  @override
  void initState() {
    super.initState();
    debouncer = Debouncer(Duration(milliseconds: 50), _search);
  }

  @override
  Widget build(BuildContext context) {
    return SearchAnchor(
        builder: (BuildContext context, SearchController controller) {
      return FormTextInput(
          controller: widget.sessionController,
          title: widget.title ?? "",
          icon: Icon(Icons.search_rounded),
          maxLines: 2,
          requiresValidation: false,
          onTap: () {
            controller.openView();
          });
    }, suggestionsBuilder:
            (BuildContext context, SearchController controller) async {
      final List<Suggestion>? options =
          (await debouncer.process(controller.text))?.toList();
      if (options == null) {
        return _lastOptions;
      }
      _lastOptions = List<ListTile>.generate(options.length, (int index) {
        final Suggestion item = options[index];
        final dynamic content = item.type;
        return ListTile(
          title: Text(content.description),
          onTap: () async {
            if (callback != null) {
              callback!(content, service);
            }

            controller.closeView(null);
          },
        );
      });

      return _lastOptions;
    });
  }
}