import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:path_provider/path_provider.dart';
import "package:dslink_schedule/ical.dart";
import 'package:rxdart/rxdart.dart';
import 'package:flutter/services.dart';
import 'package:flutter_stream_friends/flutter_stream_friends.dart';

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'MAH Schema',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'MAH Schema'),
    );
  }
}


class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}


class _MyHomePageState extends State<MyHomePage> {
  final ValueChangedStreamCallback<String> onTextChanged = new ValueChangedStreamCallback<String>();
  dynamic searchResults;
  bool hasError = false;
  bool isLoading = false;

  _MyHomePageState() {
    new Observable<String>(onTextChanged)
        // Use distinct() to ignore all keystrokes that don't have an impact on the input field's value (brake, ctrl, shift, ..)
        .distinct((String prev, String next) => prev == next)
        // Use debounce() to prevent calling the server on fast following keystrokes
        .debounce(const Duration(milliseconds: 250))
        // Use call(onData) to clear the previous results / errors and begin showing the loading state
        .doOnEach((var _) {
          setState(() {
            hasError = false;
            isLoading = true;
            searchResults = null;
          });
        })
        .flatMapLatest((String value) => fetchAutoComplete(value))
        .listen((dynamic latestResult) {
          debugPrint(latestResult.toString());
        // If a result has been returned, disable the loading and error states and save the latest result
          setState(() {
            isLoading = false;
            hasError = false;
            searchResults = latestResult;
          });
        }, onError: (dynamic e) {
          debugPrint("ERROR: ${e.toString()}");
          setState(() {
            isLoading = false;
            hasError = true;
            searchResults = null;
          });
        }, cancelOnError: false);
  }

  Observable<dynamic> fetchAutoComplete(String searchString) {
    var httpClient = createHttpClient();
    return  new Observable<String>.fromFuture(
        httpClient.read("https://kronox.mah.se/ajax/ajax_autocompleteResurser.jsp?typ=program&term=${searchString}")
    )
    .map((String response) => JSON.decode(response));
  }

  @override
  Widget build(BuildContext context) {

    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: buildSearch(),
    );
  }

  Widget buildSearch() {
    return new IconTheme(
        data: new IconThemeData(color: Theme.of(context).accentColor),
        child: new Container(
          margin: const EdgeInsets.symmetric(horizontal: 8.0),
          child: new Column(
            children: <Widget>[
              new Row(
                  children: <Widget>[
                    new Flexible(
                      child: new TextField(
                        onChanged: onTextChanged,
                        decoration: new InputDecoration.collapsed(
                            hintText: "Search for program or course"),
                      ),
                    ),
                    new Container(
                        margin: new EdgeInsets.symmetric(horizontal: 4.0),
                        child: new Icon(Icons.search)
                    ),
                  ]
              ),
              new Text(
                searchResults == null ? "Nothing..." : searchResults.length == 0 ? "No results" : searchResults[0]["value"]
              )
            ],
          )
        )
    );
  }
}