import 'package:flutter/material.dart';
import 'dart:async';
import 'package:flutter/services.dart';
import 'package:multi_image_picker/multi_image_picker.dart';
import 'dart:typed_data';
import 'dart:io';
import 'package:image/image.dart' as v3;
//import 'package:flutter/widgets.dart' as v2;

void main() => runApp(new MyApp());


class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {
  List<Asset> images = List<Asset>();

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

  Widget buildGridView() {
    return GridView.count(
      crossAxisCount: 3, //images.length
      children: List.generate(images.length, (index) {
        Asset asset1 = images[index];
        var x = asset1.identifier;
        print("The asset's name is $x");
        //print("The string rep is $grayScaleImage(asset1).toString()");
        return AssetThumb(
          asset: asset1,
          width: 300,
          height: 300,
        );

      }), // displays the selected images in a grid view
    );
  }

  Future<AssetThumb> assetThumbMaker(Asset asset1) async {
    await saveImage(asset1);
    return await assetThumbMaker2(asset1);
  }

  Future<AssetThumb> assetThumbMaker2(Asset asset1) async {
    await Future.delayed(const Duration(seconds: 5), (){});
    print("got here 3");
    return AssetThumb(
      asset: asset1,
      width: 300,
      height: 300,
    );
  }

  Future<void> saveImage(Asset asset1) async {
    var z = await grayScaleImage(asset1);
    v3.Image image1 = v3.decodeJpg(z);
    v3.Image thumbnail = v3.copyResize(image1, width: 120);
    File('assets/thumbnail-test.jpeg').writeAsBytesSync(v3.encodeJpg(thumbnail));
    print("got here");
    //Image.memory(z);
  }

  Future<void> deleteAssets() async {
    await MultiImagePicker.deleteImages(assets: images);
    setState(() {
      images = List<Asset>();
    });
  }

  Future<Uint8List> grayScaleImage(Asset asset) async {
    print("here 1");
    ByteData bd = await asset.requestThumbnail(
        asset.originalWidth, asset.originalHeight,
        quality: 100); // width and height
    var a2 = bd.buffer.asUint8List();
    var input1 =
        v3.Image.fromBytes(asset.originalWidth, asset.originalHeight, a2);
    v3.Image grayImage = v3.grayscale(input1);
    print("here 2");
    return Uint8List.fromList(v3.encodeJpg(grayImage));
    //return v3.encodeJpg(grayImage);
    // Image(image: MemoryImage(listaU8L[0]));
  }

  Future<void> loadAssets() async {
    List<Asset> resultList = List<Asset>();
    String error = 'No Error Dectected';

    try {
      resultList = await MultiImagePicker.pickImages(
          maxImages: 300,
          enableCamera: true,
          selectedAssets: images,
          cupertinoOptions: CupertinoOptions(takePhotoIcon: "chat"),
          materialOptions: MaterialOptions(
            allViewTitle: "All Photos",
          ));
    } on PlatformException catch (e) {
      error = e.message;
      print(error);
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      images = resultList;
      print(error);
    });
  }

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      home: new Scaffold(
        appBar: new AppBar(
          title: const Text('GrayScale Maker'),
          centerTitle: true,
          backgroundColor: Colors.deepOrangeAccent,
        ),
        body: Stack(
          children: <Widget>[
            new Container(
              decoration: new BoxDecoration(
                image: new DecorationImage(
                  image: new AssetImage("assets/background.jpg"),
                  fit: BoxFit.cover,
                ), // adds background image
              ),
            ),
            Column(
              children: <Widget>[
                RaisedButton(
                  child: Text("Pick images"),
                  onPressed: loadAssets,
                ),
                images.length > 0
                    ? RaisedButton(
                        child: Text("Remove All Images"),
                        onPressed: deleteAssets,
                      )
                    : Container(),
                Expanded(
                  child: buildGridView(),
                )
              ],
            ),
          ],
        ),
      ),
    );
  }
}