// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';
import 'dart:ui_web' as ui_web;

import 'package:flutter/material.dart';
import 'package:web/web.dart' as web;

import 'recorder.dart';

const String benchmarkViewType = 'benchmark_element';

void _registerFactory() {
  ui_web.platformViewRegistry.registerViewFactory(benchmarkViewType, (int viewId) {
    final web.HTMLElement htmlElement = web.document.createElement('div') as web.HTMLDivElement;
    htmlElement.id = '${benchmarkViewType}_$viewId';
    htmlElement.innerText = 'Google';
    htmlElement.style
      ..setProperty('width', '100%')
      ..setProperty('height', '100%')
      ..setProperty('color', 'black')
      ..setProperty('backgroundColor', 'rgba(0, 255, 0, .5)')
      ..setProperty('textAlign', 'center')
      ..setProperty('border', '1px solid black');
    return htmlElement;
  });
}

/// Creates an infinite list of Link widgets and scrolls it.
class BenchPlatformViewInfiniteScroll extends WidgetRecorder {
  BenchPlatformViewInfiniteScroll.forward()
    : initialOffset = 0.0,
      finalOffset = 30000.0,
      super(name: benchmarkName) {
    _registerFactory();
  }

  BenchPlatformViewInfiniteScroll.backward()
    : initialOffset = 30000.0,
      finalOffset = 0.0,
      super(name: benchmarkNameBackward) {
    _registerFactory();
  }

  static const String benchmarkName = 'bench_platform_view_infinite_scroll';
  static const String benchmarkNameBackward = 'bench_platform_view_infinite_scroll_backward';

  final double initialOffset;
  final double finalOffset;

  @override
  Widget createWidget() => MaterialApp(
    title: 'Infinite Platform View Scroll Benchmark',
    home: _InfiniteScrollPlatformViews(initialOffset, finalOffset),
  );
}

class _InfiniteScrollPlatformViews extends StatefulWidget {
  const _InfiniteScrollPlatformViews(this.initialOffset, this.finalOffset);

  final double initialOffset;
  final double finalOffset;

  @override
  State<_InfiniteScrollPlatformViews> createState() => _InfiniteScrollPlatformViewsState();
}

class _InfiniteScrollPlatformViewsState extends State<_InfiniteScrollPlatformViews> {
  static const Duration stepDuration = Duration(seconds: 20);

  late ScrollController scrollController;
  late double offset;

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

    offset = widget.initialOffset;

    scrollController = ScrollController(initialScrollOffset: offset);

    // Without the timer the animation doesn't begin.
    Timer.run(() async {
      await scrollController.animateTo(
        widget.finalOffset,
        curve: Curves.linear,
        duration: stepDuration,
      );
    });
  }

  @override
  void dispose() {
    scrollController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      controller: scrollController,
      itemExtent: 100.0,
      itemBuilder: (BuildContext context, int index) {
        return const SizedBox(height: 100.0, child: HtmlElementView(viewType: benchmarkViewType));
      },
    );
  }
}