bokeh.models.widgets.DateRangeSlider

def bokeh_main_2():
    import sys
    src = Path(__file__).absolute().parent / 'src'
    sys.path.insert(0, str(src))

    from bokeh.layouts import layout # type: ignore
    from bokeh.models.widgets import Tabs, Panel # type: ignore
    from bokeh.plotting import figure # type: ignore

    from dashboard.core.bokeh import test_scatter_matrix
    import holoviews as hv
    f1 = hv.render(test_scatter_matrix())

    f2 = figure()
    f2.circle([0,0,2],[4,-1,1])

    # todo need something more lazy?
    from dashboard.data import sleep_dataframe
    from dashboard.sleep import plot_sleep
    # TODO would be cool to display logs in the frontend and also currently evaluated function?
    # although pehaps it's easier to just always keep logs open?


    from bokeh.models.widgets import DateRangeSlider # type: ignore
    from datetime import date
    drs = DateRangeSlider(
        title="Date Range: ",
        start=date(2017, 1, 1),
        end=date.today(),
        value=(date(2017, 9, 7), date(2017, 10, 15)),
        step=1,
    )

    def update(attr, old, new):
        print(attr, old, new)

    from bokeh.models import CustomJS # type: ignore
    # todo see https://docs.bokeh.org/en/latest/docs/gallery/slider.html
    update_js = CustomJS(
        args=dict(drs=drs),
        code='''
console.log("HIIII");
'''
    )

    drs.on_change('value', update)
    drs.js_on_change('value', update_js)

    l1 = layout([[f1, drs]], sizing_mode='fixed')
    l2 = layout([[f2]], sizing_mode='fixed')
    tabs = Tabs(tabs=[
        Panel(child=l1            , title='This is Tab 1'  ),
        Panel(child=l2            , title='This is Tab 2'  ),
        # Panel(child=layout([[sp]]), title='Sleep dataframe'),
    ])

    curdoc().add_root(tabs)


def main():

def date_slider(p, *, dates=None, date_column='dt'):
    # todo a bit crap, but kinda works.. not sure what's the proper way?
    # maybe they aren't computed before show()??
    # p.x_range.on_change('start', lambda attr, old, new: print("Start", new))
    # p.x_range.on_change('end', lambda attr, old, new: print("End", new))

    if dates is None:
        graphs = p.renderers
        # todo autodetect by type instead of name?
        dts = np.concatenate([g.data_source.data[date_column] for g in graphs])
        # FFS... apparently no easier way
        sdate = pd.Timestamp(np.min(dts)).to_pydatetime()
        edate = pd.Timestamp(np.max(dts)).to_pydatetime()
    else:
        sdate = min(dates)
        edate = max(dates)
    # todo not sure if should use today?
    edate += timedelta(days=5)

    from bokeh.models.widgets import DateRangeSlider # type: ignore
    ds = DateRangeSlider(
        title="Date Range: ",
        start=sdate,
        end=edate,
        value=(sdate, edate),
        step=1,
    )
    from bokeh.models import CustomJS # type: ignore

    # TODO hmm. so, js won't be able to call into python in Jupyter...
    # see https://docs.bokeh.org/en/latest/docs/gallery/slider.html
    update_js = CustomJS(
        args=dict(ds=ds, xrange=p.x_range),
        code=J('''
    const [ll, rr] = ds.value;
    // didn't work??
    // xrange.set({"start": ll, "end": rr})
    xrange.start = ll;
    xrange.end   = rr;

    // todo hmm, turned out it wasn't necessary??
    // source.trigger('change');
    '''
    ))

    # todo add some quick selectors, e.g. last month, last year, etc like plotly
    ds.js_on_change('value', update_js)
    return ds


def plot_multiple(df, *, columns, **kwargs):

def build_widgets_wb(stock_list):
    # CODE SECTION: setup widgets, widgetbox name = controls_wb
    WIDGET_WIDTH = 250

    # ========== Select Stocks ============= #
    select_stk_1 = Select(width = WIDGET_WIDTH, title='Select Stock 1:', value = stock_list[0], options=stock_list)
    select_stk_2 = Select(width = WIDGET_WIDTH, title='Select Stock 2:', value = stock_list[0], options=stock_list)

    # ========== Strategy Type ============= #
    strategy_list = ['kalman', 'distance', 'cointegration']
    select_strategy = Select(width = WIDGET_WIDTH, title='Select Strategy:', value = strategy_list[0], options=strategy_list)

    # ========== set start/end date ============= #
    # date time variables
    MAX_START = date(2014, 1, 1)
    MAX_END = date(2018, 12, 30)
    DEFAULT_START = date(2016, 5, 1)
    DEFAULT_END = date(2016, 12, 31)
    STEP = 1

    backtest_dates = DateRangeSlider(width = WIDGET_WIDTH, 
                                     start=MAX_START, end=MAX_END, 
                                     value=(DEFAULT_START, DEFAULT_END), 
                                     step=STEP, title="Backtest Date Range:")

    start_bt = Button(label="Backtest", button_type="success", width = WIDGET_WIDTH)

    # controls = column(select_stk_1, select_stk_2, select_strategy, backtest_dates, start_bt)
    controls_wb = widgetbox(select_stk_1, select_stk_2, select_strategy, backtest_dates, start_bt, width=600)
    return controls_wb

def main():

def build_widgets_wb(stock_list, metrics):
    # CODE SECTION: setup buttons, widgetbox name = controls_wb
    WIDGET_WIDTH = 250

    # ========== Select Stocks ============= #
    select_stk_1 = Select(width = WIDGET_WIDTH, title='Select Stock 1:', value = backtest_params["stk_0"], options=stock_list)
    select_stk_2 = Select(width = WIDGET_WIDTH, title='Select Stock 2:', value = backtest_params["stk_1"], options=stock_list)

    # ========== Strategy Type ============= #
    strategy_list = ['kalman', 'distance', 'cointegration', 'reinforcement learning']
    select_strategy = Select(width = WIDGET_WIDTH, title='Select Strategy:', value = backtest_params["strategy_type"], options=strategy_list)

    # ========== set start/end date ============= #
    # date time variables
    MAX_START = datetime.strptime(backtest_params["max_start"], "%Y-%m-%d").date()
    MAX_END = datetime.strptime(backtest_params["max_end"], "%Y-%m-%d").date()
    DEFAULT_START = datetime.strptime(backtest_params["backtest_start"], "%Y-%m-%d").date()
    DEFAULT_END = datetime.strptime(backtest_params["backtest_end"], "%Y-%m-%d").date()
    STEP = 1

    backtest_dates = DateRangeSlider(width = WIDGET_WIDTH, 
                                     start=MAX_START, end=MAX_END, 
                                     value=(DEFAULT_START, DEFAULT_END), 
                                     step=STEP, title="Backtest Date Range:")

    start_bt = Button(label="Backtest", button_type="success", width = WIDGET_WIDTH)

    # controls = column(select_stk_1, select_stk_2, select_strategy, backtest_dates, start_bt)
    controls_wb = widgetbox(select_stk_1, select_stk_2, select_strategy, backtest_dates, start_bt, width=300)

    # CODE SECTION: setup table, widgetbox name = metrics_wb
    master_wb = None
    if metrics is not None:
        metric_source = ColumnDataSource(metrics)
        metric_columns = [
            TableColumn(field="Metrics", title="Metrics"),
            TableColumn(field="Value", title="Performance"),
        ]

        metric_table = DataTable(source=metric_source, columns=metric_columns, width=300)
        master_wb = row(controls_wb, widgetbox(metric_table))
        
    else:
        logging.info("creating controls without table")
        master_wb = row(controls_wb)
    return master_wb, select_stk_1, select_stk_2, select_strategy, backtest_dates, start_bt

if FIRST_ITER[0]: