Improve date and datetime picker functionality (#6152)

panel/dist/css/widgetbox.css

@@ -4,6 +4,4 @@
   border-radius: 4px;
   -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.05);
   box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.05);
-  overflow-x: hidden;
-  overflow-y: hidden;
 }

panel/tests/pane/test_holoviews.py

@@ -743,3 +743,37 @@ def test_holoviews_property_override(document, comm):
 
     assert model.styles["background"] == 'red'
     assert model.children[0].css_classes == ['test_class']
+
+
+@hv_available
+def test_holoviews_date_picker_widget(document, comm):
+    ds = {
+        "time": [np.datetime64("2000-01-01"), np.datetime64("2000-01-02")],
+        "x": [0, 1],
+        "y": [0, 1],
+    }
+    viz = hv.Dataset(ds, ["x", "time"], ["y"])
+    layout = pn.panel(viz.to(
+        hv.Scatter, ["x"], ["y"]), widgets={"time": pn.widgets.DatePicker}
+    )
+    widget_box = layout[0][1]
+    assert isinstance(layout, pn.Row)
+    assert isinstance(widget_box, pn.WidgetBox)
+    assert isinstance(widget_box[0], pn.widgets.DatePicker)
+
+
+@hv_available
+def test_holoviews_datetime_picker_widget(document, comm):
+    ds = {
+        "time": [np.datetime64("2000-01-01"), np.datetime64("2000-01-02")],
+        "x": [0, 1],
+        "y": [0, 1],
+    }
+    viz = hv.Dataset(ds, ["x", "time"], ["y"])
+    layout = pn.panel(viz.to(
+        hv.Scatter, ["x"], ["y"]), widgets={"time": pn.widgets.DatetimePicker}
+    )
+    widget_box = layout[0][1]
+    assert isinstance(layout, pn.Row)
+    assert isinstance(widget_box, pn.WidgetBox)
+    assert isinstance(widget_box[0], pn.widgets.DatetimePicker)

panel/tests/ui/widgets/test_input.py

@@ -1,5 +1,6 @@
 import datetime
 
+import numpy as np
 import pytest
 
 pytest.importorskip("playwright")
@@ -603,6 +604,34 @@ def test_datetimepicker_remove_value(page, datetime_start_end):
     wait_until(lambda: datetime_picker_widget.value is None, page)
 
 
+def test_datetime_picker_start_end_datetime64(page):
+    datetime_picker_widget = DatetimePicker(
+        value=datetime.datetime(2021, 3, 2),
+        start=np.datetime64("2021-03-02"),
+        end=np.datetime64("2021-03-03")
+    )
+
+    serve_component(page, datetime_picker_widget)
+
+    datetime_picker = page.locator('.flatpickr-input')
+    datetime_picker.dblclick()
+
+    # locate by aria label March 1, 2021
+    prev_month_day = page.locator('[aria-label="March 1, 2021"]')
+    # assert class "flatpickr-day flatpickr-disabled"
+    assert "flatpickr-disabled" in prev_month_day.get_attribute("class"), "The date should be disabled"
+
+    # locate by aria label March 3, 2021
+    next_month_day = page.locator('[aria-label="March 3, 2021"]')
+    # assert not class "flatpickr-day flatpickr-disabled"
+    assert "flatpickr-disabled" not in next_month_day.get_attribute("class"), "The date should be enabled"
+
+    # locate by aria label March 4, 2021
+    next_next_month_day = page.locator('[aria-label="March 4, 2021"]')
+    # assert class "flatpickr-day flatpickr-disabled"
+    assert "flatpickr-disabled" in next_next_month_day.get_attribute("class"), "The date should be disabled"
+
+
 def test_text_area_auto_grow_init(page):
     text_area = TextAreaInput(auto_grow=True, value="1\n2\n3\n4\n")
 

panel/tests/widgets/test_input.py

@@ -58,6 +58,16 @@ def test_date_picker(document, comm):
     assert widget.value == '2018-09-04'
 
 
+def test_date_picker_options(document, comm):
+    options = [date(2018, 9, 1), date(2018, 9, 2), date(2018, 9, 3)]
+    datetime_picker = DatePicker(
+        name='DatetimePicker', value=date(2018, 9, 2),
+        options=options
+    )
+    assert datetime_picker.value == date(2018, 9, 2)
+    assert datetime_picker.enabled_dates == options
+
+
 def test_daterange_picker(document, comm):
     date_range_picker = DateRangePicker(name='DateRangePicker',
                                         value=(date(2018, 9, 2), date(2018, 9, 3)),
@@ -130,6 +140,16 @@ def test_datetime_picker(document, comm):
         datetime_picker._process_events({'value': '2018-09-10 00:00:01'})
 
 
+def test_datetime_picker_options(document, comm):
+    options = [datetime(2018, 9, 1), datetime(2018, 9, 2), datetime(2018, 9, 3)]
+    datetime_picker = DatetimePicker(
+        name='DatetimePicker', value=datetime(2018, 9, 2, 1, 5),
+        options=options
+    )
+    assert datetime_picker.value == datetime(2018, 9, 2, 1, 5)
+    assert datetime_picker.enabled_dates == options
+
+
 def test_datetime_range_picker(document, comm):
     datetime_range_picker = DatetimeRangePicker(
         name='DatetimeRangePicker', value=(datetime(2018, 9, 2, 1, 5), datetime(2018, 9, 2, 1, 6)),

panel/util/__init__.py

@@ -479,3 +479,9 @@ def styler_update(styler, new_df):
         todo = tuple(ops)
         todos.append(todo)
     return todos
+
+
+def try_datetime64_to_datetime(value):
+    if isinstance(value, np.datetime64):
+        value = value.astype('datetime64[ms]').astype(datetime)
+    return value

panel/widgets/input.py

@@ -10,7 +10,8 @@
 from base64 import b64decode
 from datetime import date, datetime
 from typing import (
-    TYPE_CHECKING, Any, ClassVar, Dict, Mapping, Optional, Tuple, Type,
+    TYPE_CHECKING, Any, ClassVar, Dict, Iterable, Mapping, Optional, Tuple,
+    Type,
 )
 
 import numpy as np
@@ -30,7 +31,7 @@
 from ..models import (
     DatetimePicker as _bkDatetimePicker, TextAreaInput as _bkTextAreaInput,
 )
-from ..util import param_reprs
+from ..util import param_reprs, try_datetime64_to_datetime
 from .base import CompositeWidget, Widget
 
 if TYPE_CHECKING:
@@ -333,6 +334,20 @@ class DatePicker(Widget):
 
     _widget_type: ClassVar[Type[Model]] = _BkDatePicker
 
+    def __init__(self, **params):
+        # Since options is the standard for other widgets,
+        # it makes sense to also support options here, converting
+        # it to enabled_dates
+        if 'options' in params:
+            options = list(params.pop('options'))
+            params['enabled_dates'] = options
+        if 'value' in params:
+            value = try_datetime64_to_datetime(params['value'])
+            if hasattr(value, "date"):
+                value = value.date()
+            params["value"] = value
+        super().__init__(**params)
+
     def _process_property_change(self, msg):
         msg = super()._process_property_change(msg)
         for p in ('start', 'end', 'value'):
@@ -456,36 +471,65 @@ class _DatetimePickerBase(Widget):
     description = param.String(default=None, doc="""
         An HTML string describing the function of this component.""")
 
+    as_numpy_datetime64 = param.Boolean(default=None, doc="""
+        Whether to return values as numpy.datetime64. If left unset,
+        will be True if value is a numpy.datetime64, else False.""")
+
     _source_transforms: ClassVar[Mapping[str, str | None]] = {
         'value': None, 'start': None, 'end': None, 'mode': None
     }
 
     _rename: ClassVar[Mapping[str, str | None]] = {
-        'start': 'min_date', 'end': 'max_date'
+        'start': 'min_date', 'end': 'max_date', 'as_numpy_datetime64': None,
     }
 
     _widget_type: ClassVar[Type[Model]] = _bkDatetimePicker
 
     __abstract = True
 
     def __init__(self, **params):
+        # Since options is the standard for other widgets,
+        # it makes sense to also support options here, converting
+        # it to enabled_dates
+        if 'options' in params:
+            options = list(params.pop('options'))
+            params['enabled_dates'] = options
+        if params.get('as_numpy_datetime64', None) is None:
+            params['as_numpy_datetime64'] = isinstance(
+                params.get("value"), np.datetime64)
         super().__init__(**params)
         self._update_value_bounds()
 
-    @staticmethod
-    def _convert_to_datetime(v):
+    def _convert_to_datetime(self, v):
+        if v is None:
+            return
+
+        if isinstance(v, Iterable) and not isinstance(v, str):
+            container_type = type(v)
+            return container_type(
+                self._convert_to_datetime(vv)
+                for vv in v
+            )
+
+        v = try_datetime64_to_datetime(v)
         if isinstance(v, datetime):
             return v
         elif isinstance(v, date):
             return datetime(v.year, v.month, v.day)
+        elif isinstance(v, str):
+            return datetime.strptime(v, r'%Y-%m-%d %H:%M:%S')
+        else:
+            raise ValueError(f"Could not convert {v} to datetime")
 
     @param.depends('start', 'end', watch=True)
     def _update_value_bounds(self):
         self.param.value.bounds = (
             self._convert_to_datetime(self.start),
             self._convert_to_datetime(self.end)
         )
-        self.param.value._validate(self.value)
+        self.param.value._validate(
+            self._convert_to_datetime(self.value)
+        )
 
     def _process_property_change(self, msg):
         msg = super()._process_property_change(msg)
@@ -496,7 +540,7 @@ def _process_property_change(self, msg):
     def _process_param_change(self, msg):
         msg = super()._process_param_change(msg)
         if 'value' in msg:
-            msg['value'] = self._deserialize_value(msg['value'])
+            msg['value'] = self._deserialize_value(self._convert_to_datetime(msg['value']))
         if 'min_date' in msg:
             msg['min_date'] = self._convert_to_datetime(msg['min_date'])
         if 'max_date' in msg:
@@ -527,14 +571,15 @@ class DatetimePicker(_DatetimePickerBase):
 
     def _serialize_value(self, value):
         if isinstance(value, str) and value:
-            value = datetime.strptime(value, r'%Y-%m-%d %H:%M:%S')
-
+            if self.as_numpy_datetime64:
+                value = np.datetime64(value)
+            else:
+                value = datetime.strptime(value, r'%Y-%m-%d %H:%M:%S')
         return value
 
     def _deserialize_value(self, value):
         if isinstance(value, (datetime, date)):
             value = value.strftime(r'%Y-%m-%d %H:%M:%S')
-
         return value
 
 
@@ -562,11 +607,11 @@ class DatetimeRangePicker(_DatetimePickerBase):
     def _serialize_value(self, value):
         if isinstance(value, str) and value:
             value = [
-                datetime.strptime(value, r'%Y-%m-%d %H:%M:%S')
+                np.datetime64(value)
+                if self.as_numpy_datetime64
+                else datetime.strptime(value, r'%Y-%m-%d %H:%M:%S')
                 for value in value.split(' to ')
             ]
-
-
             value = tuple(value)
 
         return value