class ProductSales(ReportView):
    report_title = _("Product Sales")
    report_description = _("Given a typical 'Sale Item' model, this report demonstrate a total of product sold. "
                           "With a bar and a pie charts.")
    report_model = SalesTransaction
    date_field = "date"
    group_by = "product"

    columns = [
        "name",
        ComputationField.create(
            method=Sum,
            field="value",
            name="value__sum",
            verbose_name="Total sold $",
            is_summable=True,
        ),
    ]

    # Charts
    chart_settings = [
        Chart(
            "Total sold $",
            Chart.BAR,
            data_source=["value__sum"],
            title_source=["name"],
        ),
    ]