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

typedef ItemWidgetBuilder = Widget Function(
    BuildContext context, dynamic item, bool tablet);
typedef IndexedWidgetBuilder = Widget Function(BuildContext context, int index);

class CupertinoMasterDetailController extends StatelessWidget {
  final ItemWidgetBuilder detailBuilder;
  final IndexedWidgetBuilder itemBuilder;
  final Widget? onNull, onEmpty;
  final PreferredSizeWidget? appBar;
  final dynamic selectedItem;
  final ValueChanged<dynamic> itemSelected;
  final List<dynamic> items;

  CupertinoMasterDetailController({
    required this.detailBuilder,
    required this.selectedItem,
    required this.itemSelected,
    required this.itemBuilder,
    required this.items,
    this.appBar,
    this.onNull,
    this.onEmpty,
  });

  Widget _buildMobileLayout(BuildContext context) {
    return Scaffold(
        body: CupertinoPageScaffold(
            child: CustomScrollView(
                semanticChildCount: items.length,
                slivers: <Widget>[
          CupertinoSliverNavigationBar(
            largeTitle: Text("Presidents"),
          ),
          _ItemListing(
            onEmpty: onEmpty,
            onNull: onNull,
            itemBuilder: itemBuilder,
            items: items,
            selectedItem: selectedItem,
            itemSelectedCallback: (item) {
              Navigator.push(
                context,
                MaterialPageRoute(
                    builder: (context) => detailBuilder(context, item, false)),
              );
            },
          ),
        ])));
  }

  Widget _buildTabletLayout(BuildContext context) {
    return OrientationBuilder(builder: (context, orientation) {
      return Row(
        children: <Widget>[
          Flexible(
            flex: orientation == Orientation.landscape ? 1 : 2,
            child: Scaffold(
                appBar: appBar,
                body: CustomScrollView(slivers: [
                  _ItemListing(
                    onEmpty: onEmpty,
                    onNull: onNull,
                    itemBuilder: itemBuilder,
                    items: items,
                    selectedItem: selectedItem,
                    itemSelectedCallback: itemSelected,
                  ),
                ])),
          ),
          Container(
            width: 1.0,
            color: Colors.grey[300],
          ),
          Flexible(
            flex: 3,
            child: detailBuilder(context, selectedItem, true),
          ),
        ],
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    var shortestSide = MediaQuery.of(context).size.shortestSide;
    final bool useMobileLayout = shortestSide < 600;

    if (useMobileLayout) {
      return _buildMobileLayout(context);
    }

    return _buildTabletLayout(context);
  }
}

class _ItemListing extends StatelessWidget {
  _ItemListing({
    required this.itemSelectedCallback,
    this.selectedItem,
    this.itemBuilder,
    this.items,
    this.onNull,
    this.onEmpty,
  });

  final ValueChanged<dynamic> itemSelectedCallback;
  final dynamic selectedItem;
  final IndexedWidgetBuilder? itemBuilder;
  final List<dynamic>? items;
  final Widget? onNull, onEmpty;

  @override
  Widget build(BuildContext context) {
    if (items == null) {
      return onNull ?? Center(child: CircularProgressIndicator());
    }

    if (items!.isEmpty) {
      return onEmpty ?? Center(child: Text("No Items Found"));
    }

    return SliverList(
      delegate: SliverChildBuilderDelegate(
        (BuildContext context, int index) {
          final _child = itemBuilder!(context, index);
          return GestureDetector(
            onTap: () => itemSelectedCallback(items![index]),
            child: _child,
          );
        },
        childCount: items!.length,
      ),
    );
  }
}