class MonthlyProductSales(ReportView):
    report_title = _("Product Sales Monthly")
    report_description = _("Breaks product sales into one column per month using a Time Series, "
                           "also demonstrates defining a reusable ComputationField.")
    report_model = SalesTransaction
    date_field = "date"
    group_by = "product"
    columns = ["name", "sku"]

    time_series_pattern = "monthly"
    time_series_columns = [
        SumValueComputationField,
    ]

    chart_settings = [
        Chart(
            _("Total Sales Monthly"),
            Chart.PIE,
            data_source=["my_value_sum"],
            title_source=["name"],
            plot_total=True,
        ),
        Chart(
            _("Sales Monthly [Bar]"),
            Chart.COLUMN,
            data_source=["my_value_sum"],
            title_source=["name"],
        ),
    ]