class BusinessAvailableProductsDisplay extends StatefulWidget {
  const BusinessAvailableProductsDisplay(this._ownerID, {Key? key})
      : super(key: key);

  final String _ownerID;

  @override
  State<BusinessAvailableProductsDisplay> createState() => _BusinessAvailableProductsDisplayState();
}

class _BusinessAvailableProductsDisplayState extends State<BusinessAvailableProductsDisplay> {

  bool _nextPageAvailable = true;
  int _curPage = 1;
  String? _lastUsedID;

  Future<CategorySelectionButton> _createProductCategoryButton(String productID) async {

    DocumentReference doc = await GetData.document('products', productID);
    DocumentSnapshot snapshot = await doc.get();
    String name = await snapshot.get('productName');

    String imageName = await snapshot.get('productImage');
    await FirebaseAuth.instance.signInAnonymously();
    String downloadSource = await FirebaseStorage.instance.ref(imageName).getDownloadURL();
    Image image = Image.network(
      downloadSource,
      width: 30.0,
      height:30.0,
    );

    CategorySelectionButton newButton = CategorySelectionButton(name, image.image, ProductDisplay(productID));
    return newButton;
  }

  Future<List<Widget>> _getProducts(BuildContext context) async {
    List<Widget> productWidgets = [];

    if (_curPage == 1) {
      _lastUsedID = null;
    }

    List<String> products = await FilterCollection.limitNumberByField(
      'products',
      'owner',
      widget._ownerID,
      numProductsDisplayedPerPage,
      _lastUsedID,
    );

    _lastUsedID = products.last;

    if (products.isEmpty) {
      productWidgets.add(_noProductsFoundDisplay(context));
      return productWidgets;
    }

    int totalProducts = await FilterCollection.sizeOfQuery('products', 'owner', widget._ownerID);
    _nextPageAvailable = totalProducts > _curPage * numProductsDisplayedPerPage;

    for (int i = (_curPage - 1) * numProductsDisplayedPerPage; i < _curPage * numProductsDisplayedPerPage && i < totalProducts; i++) {
      productWidgets.add(await _createProductCategoryButton(products[i]));
    }

    return productWidgets;
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _getProducts(context),
      builder: (context, snapshot) {
        if (!snapshot.hasData && snapshot.connectionState == ConnectionState.done) {
          return const Text(
            'ERROR: Could not load data',
          );
        } else if (snapshot.hasData) {
          return Column(
            children: [
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  _curPage > 1 ? LeftArrow(callback: () => setState(() {
                    _curPage--;
                  })) : Container(),
                  _nextPageAvailable ? RightArrow(callback: () => setState(() {
                    _curPage++;
                  })) : Container(),
                ],
              ),
              Padding(
                padding: const EdgeInsets.all(10.0),
                child: Container(
                  padding: const EdgeInsets.all(8.0),
                  width: double.infinity,
                  height: 400,
                  decoration: _boxDecoration(),
                  child: SingleChildScrollView(
                    scrollDirection: Axis.vertical,
                    child: Column(
                      children: [
                        SectionLabel(AppLocalizations.of(context)!.availableProducts),
                        Column(
                          children: snapshot.data!,
                        ),
                      ],
                    ),
                  ),
                ),
              ),
            ],
          );
        } else {
          return const CircularProgressIndicator();
        }
      }
    );
  }
}