#-----------------------------------------------------------------------------
# Copyright (c) Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
#-----------------------------------------------------------------------------
''' Various kinds of data table (data grid) widgets.

'''

#-----------------------------------------------------------------------------
# Boilerplate
#-----------------------------------------------------------------------------
from __future__ import annotations

import logging # isort:skip
log = logging.getLogger(__name__)

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

# Bokeh imports
from ...core.enums import (
    AutosizeMode,
    DateFormat,
    NumeralLanguage,
    RoundingFunction,
)
from ...core.has_props import abstract
from ...core.properties import (
    Bool,
    ColorSpec,
    Either,
    Enum,
    Float,
    FontStyleSpec,
    Instance,
    InstanceDefault,
    Int,
    List,
    Nullable,
    Override,
    Required,
    String,
    TextAlignSpec,
)
from ...core.property.singletons import Intrinsic
from ...model import Model
from ..sources import CDSView, ColumnDataSource, DataSource
from .widget import Widget

#-----------------------------------------------------------------------------
# Globals and constants
#-----------------------------------------------------------------------------

__all__ = (
    'AvgAggregator',
    'BooleanFormatter',
    'CellFormatter',
    'CellEditor',
    'CheckboxEditor',
    'DataCube',
    'DataTable',
    'DateEditor',
    'DateFormatter',
    'GroupingInfo',
    'HTMLTemplateFormatter',
    'IntEditor',
    'MaxAggregator',
    'MinAggregator',
    'NumberEditor',
    'NumberFormatter',
    'PercentEditor',
    'ScientificFormatter',
    'SelectEditor',
    'StringEditor',
    'StringFormatter',
    'SumAggregator',
    'TableColumn',
    'TableWidget',
    'TextEditor',
    'TimeEditor',
)

#-----------------------------------------------------------------------------
# Dev API
#-----------------------------------------------------------------------------

@abstract
class CellFormatter(Model):
    ''' Abstract base class for data table's cell formatters.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

@abstract
class CellEditor(Model):
    ''' Abstract base class for data table's cell editors.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

@abstract
class RowAggregator(Model):
    ''' Abstract base class for data cube's row formatters.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    field_ = String('', help="""
    Refers to the table column being aggregated
    """)

#-----------------------------------------------------------------------------
# General API
#-----------------------------------------------------------------------------

class StringFormatter(CellFormatter):
    ''' Basic string cell formatter.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    font_style = FontStyleSpec(default="normal", help="""
    An optional text font style, e.g. bold, italic.
    """)

    text_align = TextAlignSpec(default="left", help="""
    An optional text align, i.e. left, center or right.
    """)

    text_color = ColorSpec(default=None, help="""
    An optional text color.
    """)

    background_color = ColorSpec(default=None, help="""
    An optional background color.
    """)

    nan_format = String("-", help="""
    Formatting to apply to NaN and None values.
    """)



class ScientificFormatter(StringFormatter):
    ''' Display numeric values from continuous ranges as "basic numbers",
    using scientific notation when appropriate by default.
    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    precision = Int(10, help="""
    How many digits of precision to display.
    """)

    power_limit_high = Int(5, help="""
    Limit the use of scientific notation to when::
        log(x) >= power_limit_high
    """)

    power_limit_low = Int(-3, help="""
    Limit the use of scientific notation to when::
        log(x) <= power_limit_low
    """)

class NumberFormatter(StringFormatter):
    ''' Number cell formatter.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    format = String("0,0", help="""
    The number format, as defined in the following tables:

    **NUMBERS**:

    ============ ============== ===============
    Number       Format         String
    ============ ============== ===============
    10000        '0,0.0000'     10,000.0000
    10000.23     '0,0'          10,000
    10000.23     '+0,0'         +10,000
    -10000       '0,0.0'        -10,000.0
    10000.1234   '0.000'        10000.123
    10000.1234   '0[.]00000'    10000.12340
    -10000       '(0,0.0000)'   (10,000.0000)
    -0.23        '.00'          -.23
    -0.23        '(.00)'        (.23)
    0.23         '0.00000'      0.23000
    0.23         '0.0[0000]'    0.23
    1230974      '0.0a'         1.2m
    1460         '0 a'          1 k
    -104000      '0a'           -104k
    1            '0o'           1st
    52           '0o'           52nd
    23           '0o'           23rd
    100          '0o'           100th
    ============ ============== ===============

    **CURRENCY**:

    =========== =============== =============
    Number      Format          String
    =========== =============== =============
    1000.234    '$0,0.00'       $1,000.23
    1000.2      '0,0[.]00 $'    1,000.20 $
    1001        '$ 0,0[.]00'    $ 1,001
    -1000.234   '($0,0)'        ($1,000)
    -1000.234   '$0.00'         -$1000.23
    1230974     '($ 0.00 a)'    $ 1.23 m
    =========== =============== =============

    **BYTES**:

    =============== =========== ============
    Number          Format      String
    =============== =========== ============
    100             '0b'        100B
    2048            '0 b'       2 KB
    7884486213      '0.0b'      7.3GB
    3467479682787   '0.000 b'   3.154 TB
    =============== =========== ============

    **PERCENTAGES**:

    ============= ============= ===========
    Number        Format        String
    ============= ============= ===========
    1             '0%'          100%
    0.974878234   '0.000%'      97.488%
    -0.43         '0 %'         -43 %
    0.43          '(0.000 %)'   43.000 %
    ============= ============= ===========

    **TIME**:

    ============ ============== ============
    Number       Format         String
    ============ ============== ============
    25           '00:00:00'     0:00:25
    238          '00:00:00'     0:03:58
    63846        '00:00:00'     17:44:06
    ============ ============== ============

    For the complete specification, see http://numbrojs.com/format.html
    """)

    language = Enum(NumeralLanguage, default="en", help="""
    The language to use for formatting language-specific features (e.g. thousands separator).
    """)

    rounding = Enum(RoundingFunction, help="""
    Rounding functions (round, floor, ceil) and their synonyms (nearest, rounddown, roundup).
    """)

class BooleanFormatter(CellFormatter):
    ''' Boolean (check mark) cell formatter.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    icon = Enum('check', 'check-circle', 'check-circle-o', 'check-square', 'check-square-o', help="""
    The icon visualizing the check mark.
    """)

class DateFormatter(StringFormatter):
    ''' Date cell formatter.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    format = Either(Enum(DateFormat), String, default='ISO-8601', help="""
    The date format can be any standard `strftime`_ format string, as well
    as any of the following predefined format names:

    ================================================ ================== ===================
    Format name(s)                                   Format string      Example Output
    ================================================ ================== ===================
    ``ATOM`` / ``W3C`` / ``RFC-3339`` / ``ISO-8601`` ``"%Y-%m-%d"``     2014-03-01
    ``COOKIE``                                       ``"%a, %d %b %Y"`` Sat, 01 Mar 2014
    ``RFC-850``                                      ``"%A, %d-%b-%y"`` Saturday, 01-Mar-14
    ``RFC-1123`` / ``RFC-2822``                      ``"%a, %e %b %Y"`` Sat, 1 Mar 2014
    ``RSS`` / ``RFC-822`` / ``RFC-1036``             ``"%a, %e %b %y"`` Sat, 1 Mar 14
    ``TIMESTAMP``                                    (ms since epoch)   1393632000000
    ================================================ ================== ===================

    Note that in the table some of the format names are synonymous, with
    identical format names separated by slashes.

    This list of supported `strftime`_ format codes is reproduced below.

    %a
        The abbreviated name of the day of the week according to the
        current locale.

    %A
        The full name of the day of the week according to the current
        locale.

    %b
        The abbreviated month name according to the current locale.

    %B
        The full month name according to the current locale.

    %c
        The preferred date and time representation for the current
        locale.

    %C
        The century number (year/100) as a 2-digit integer.

    %d
        The day of the month as a decimal number (range 01 to 31).

    %D
        Equivalent to %m/%d/%y. (Americans should note that in many
        other countries %d/%m/%y is rather common. This means that in
        international context this format is ambiguous and should not
        be used.)

    %e
        Like %d, the day of the month as a decimal number, but a
        leading zero is replaced by a space.

    %f
        Microsecond as a decimal number, zero-padded on the left (range
        000000-999999). This is an extension to the set of directives
        available to `timezone`_.

    %F
        Equivalent to %Y-%m-%d (the ISO 8601 date format).

    %G
        The ISO 8601 week-based year with century as a decimal number.
        The 4-digit year corresponding to the ISO week number (see %V).
        This has the same format and value as %Y, except that if the
        ISO week number belongs to the previous or next year, that year
        is used instead.

    %g
        Like %G, but without century, that is, with a 2-digit year (00-99).

    %h
        Equivalent to %b.

    %H
        The hour as a decimal number using a 24-hour clock (range 00
        to 23).

    %I
        The hour as a decimal number using a 12-hour clock (range 01
        to 12).

    %j
        The day of the year as a decimal number (range 001 to 366).

    %k
        The hour (24-hour clock) as a decimal number (range 0 to 23).
        Single digits are preceded by a blank. (See also %H.)

    %l
        The hour (12-hour clock) as a decimal number (range 1 to 12).
        Single digits are preceded by a blank. (See also %I.) (TZ)

    %m
        The month as a decimal number (range 01 to 12).

    %M
        The minute as a decimal number (range 00 to 59).

    %n
        A newline character. Bokeh text does not currently support
        newline characters.

    %N
        Nanosecond as a decimal number, zero-padded on the left (range
        000000000-999999999). Supports a padding width specifier, i.e.
        %3N displays 3 leftmost digits. However, this is only accurate
        to the millisecond level of precision due to limitations of
        `timezone`_.

    %p
        Either "AM" or "PM" according to the given time value, or the
        corresponding strings for the current locale. Noon is treated
        as "PM" and midnight as "AM".

    %P
        Like %p but in lowercase: "am" or "pm" or a corresponding
        string for the current locale.

    %r
        The time in a.m. or p.m. notation. In the POSIX locale this
        is equivalent to %I:%M:%S %p.

    %R
        The time in 24-hour notation (%H:%M). For a version including
        the seconds, see %T below.

    %s
        The number of seconds since the Epoch, 1970-01-01 00:00:00
        +0000 (UTC).

    %S
        The second as a decimal number (range 00 to 60). (The range
        is up to 60 to allow for occasional leap seconds.)

    %t
        A tab character. Bokeh text does not currently support tab
        characters.

    %T
        The time in 24-hour notation (%H:%M:%S).

    %u
        The day of the week as a decimal, range 1 to 7, Monday being 1.
        See also %w.

    %U
        The week number of the current year as a decimal number, range
        00 to 53, starting with the first Sunday as the first day of
        week 01. See also %V and %W.

    %V
        The ISO 8601 week number (see NOTES) of the current year as a
        decimal number, range 01 to 53, where week 1 is the first week
        that has at least 4 days in the new year. See also %U and %W.

    %w
        The day of the week as a decimal, range 0 to 6, Sunday being 0.
        See also %u.

    %W
        The week number of the current year as a decimal number, range
        00 to 53, starting with the first Monday as the first day of
        week 01.

    %x
        The preferred date representation for the current locale
        without the time.

    %X
        The preferred time representation for the current locale
        without the date.

    %y
        The year as a decimal number without a century (range 00 to 99).

    %Y
        The year as a decimal number including the century.

    %z
        The +hhmm or -hhmm numeric timezone (that is, the hour and
        minute offset from UTC).

    %Z
        The timezone name or abbreviation.

    %%
        A literal '%' character.

    .. warning::
        The client library BokehJS uses the `timezone`_ library to
        format datetimes. The inclusion of the list below is based on the
        claim that `timezone`_ makes to support "the full compliment
        of GNU date format specifiers." However, this claim has not
        been tested exhaustively against this list. If you find formats
        that do not function as expected, please submit a `github issue`_,
        so that the documentation can be updated appropriately.

    .. _strftime: http://man7.org/linux/man-pages/man3/strftime.3.html
    .. _timezone: http://bigeasy.github.io/timezone/
    .. _github issue: https://github.com/bokeh/bokeh/issues

    """)


class HTMLTemplateFormatter(CellFormatter):
    ''' HTML formatter using a template.
    This uses Underscore's `template` method and syntax. http://underscorejs.org/#template
    The formatter has access other items in the row via the `dataContext` object passed to the formatter.
    So, for example, if another column in the datasource was named `url`, the template could access it as:

    .. code-block:: jinja

        <a href="<%= url %>"><%= value %></a>

    To use a different set of template delimiters, pass the appropriate values for `evaluate`, `interpolate`,
    or `escape`. See the Underscore `template` documentation for more information. http://underscorejs.org/#template

    Example: Simple HTML template to format the column value as code.

    .. code-block:: python

        HTMLTemplateFormatter(template='<code><%= value %></code>')

    Example: Use values from other columns (`manufacturer` and `model`) to build a hyperlink.

    .. code-block:: python

        HTMLTemplateFormatter(template=
            '<a href="https:/www.google.com/search?q=<%= manufacturer %>+<%= model %>" target="_blank"><%= value %></a>'
        )

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    template = String('<%= value %>', help="""
    Template string to be used by Underscore's template method.
    """)

class StringEditor(CellEditor):
    ''' Basic string cell editor with auto-completion.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    completions = List(String, help="""
    An optional list of completion strings.
    """)

class TextEditor(CellEditor):
    ''' Multi-line string cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class SelectEditor(CellEditor):
    ''' Select cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    options = List(String, help="""
    The list of options to select from.
    """)

class PercentEditor(CellEditor):
    ''' ``IntEditor`` optimized for editing percentages.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class CheckboxEditor(CellEditor):
    ''' Boolean value cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class IntEditor(CellEditor):
    ''' Spinner-based integer cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    step = Int(1, help="""
    The major step value.
    """)

class NumberEditor(CellEditor):
    ''' Spinner-based number cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    step = Float(0.01, help="""
    The major step value.
    """)

class TimeEditor(CellEditor):
    ''' Spinner-based time cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class DateEditor(CellEditor):
    ''' Calendar-based date cell editor.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class AvgAggregator(RowAggregator):
    ''' Simple average across multiple rows.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class MinAggregator(RowAggregator):
    ''' Smallest value across multiple rows.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class MaxAggregator(RowAggregator):
    ''' Largest value across multiple rows.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class SumAggregator(RowAggregator):
    ''' Simple sum across multiple rows.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

class TableColumn(Model):
    ''' Table column widget.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    field = Required(String, help="""
    The name of the field mapping to a column in the data source.
    """)

    title = Nullable(String, help="""
    The title of this column. If not set, column's data field is
    used instead.
    """)

    width = Int(300, help="""
    The width or maximum width (depending on data table's configuration)
    in pixels of this column.
    """)

    formatter = Instance(CellFormatter, InstanceDefault(StringFormatter), help="""
    The cell formatter for this column. By default, a simple string
    formatter is used.
    """)

    editor = Instance(CellEditor, InstanceDefault(StringEditor), help="""
    The cell editor for this column. By default, a simple string editor
    is used.
    """)

    sortable = Bool(True, help="""
    Whether this column is sortable or not. Note that data table has
    to have sorting enabled to allow sorting in general.
    """)

    default_sort = Enum("ascending", "descending", help="""
    The default sorting order. By default ``ascending`` order is used.
    """)

    visible = Bool(True, help="""
    Whether this column shold be displayed or not.
    """)

@abstract
class TableWidget(Widget):
    ''' Abstract base class for data table (data grid) widgets.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    source = Instance(DataSource, default=InstanceDefault(ColumnDataSource), help="""
    The source of data for the widget.
    """)

    view = Instance(CDSView, default=InstanceDefault(CDSView), help="""
    A view into the data source to use when rendering table rows. A default view
    of the entire data source is created if a view is not passed in during
    initialization.
    """)

class DataTable(TableWidget):
    ''' Two-dimensional grid for visualization and editing large amounts
    of data.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    autosize_mode = Enum(AutosizeMode, default="force_fit", help="""
    Describes the column autosizing mode with one of the following options:

    ``"fit_columns"``
        Compute column widths based on cell contents but ensure the
        table fits into the available viewport. This results in no
        horizontal scrollbar showing up, but data can get unreadable
        if there is not enough space available.

    ``"fit_viewport"``
        Adjust the viewport size after computing columns widths based
        on cell contents.

    ``"force_fit"``
        Fit columns into available space dividing the table width across
        the columns equally (equivalent to `fit_columns=True`).
        This results in no horizontal scrollbar showing up, but data
        can get unreadable if there is not enough space available.

    ``"none"``
        Do not automatically compute column widths.
    """)

    auto_edit = Bool(False, help="""
    When enabled editing mode is enabled after a single click on a
    table cell.
    """)

    columns = List(Instance(TableColumn), help="""
    The list of child column widgets.
    """)

    fit_columns = Nullable(Bool, help="""
    **This is a legacy parameter.** For new development, use the
    ``autosize_mode`` parameter.

    Whether columns should be fit to the available width. This results in
    no horizontal scrollbar showing up, but data can get unreadable if there
    is not enough space available. If set to True, each column's width is
    understood as maximum width.
    """)

    frozen_columns = Nullable(Int, help="""
    Integer indicating the number of columns to freeze. If set the first N
    columns will be frozen which prevents them from scrolling out of frame.
    """)

    frozen_rows = Nullable(Int, help="""
    Integer indicating the number of rows to freeze. If set the first N
    rows will be frozen which prevents them from scrolling out of frame,
    if set to a negative value last N rows will be frozen.
    """)

    sortable = Bool(True, help="""
    Allows to sort table's contents. By default natural order is preserved.
    To sort a column, click on it's header. Clicking one more time changes
    sort direction. Use Ctrl + click to return to natural order. Use
    Shift + click to sort multiple columns simultaneously.
    """)

    reorderable = Bool(True, help="""
    Allows the reordering of a table's columns. To reorder a column,
    click and drag a table's header to the desired location in the table.
    The columns on either side will remain in their previous order.
    """)

    editable = Bool(False, help="""
    Allows to edit table's contents. Needs cell editors to be configured on
    columns that are required to be editable.
    """)

    selectable = Either(Bool(True), Enum("checkbox"), help="""
    Whether a table's rows can be selected or not. Using ``checkbox`` is
    equivalent to True, but makes selection visible through a checkbox
    for each row, instead of highlighting rows. Multiple selection is
    allowed and can be achieved by either clicking multiple checkboxes (if
    enabled) or using Shift + click on rows.
    """)

    index_position = Nullable(Int, default=0, help="""
    Where among the list of columns to insert a column displaying the row
    index. Negative indices are supported, and specify an index position
    from the end of the list of columns (i.e. standard Python behaviour).

    To prevent the index column from being added, set to None.

    If the absolute value of index_position is larger than the length of
    the columns, then the index will appear at the beginning or end, depending
    on the sign.
    """)

    index_header = String("#", help="""
    The column header to display for the index column, if it is present.
    """)

    index_width = Int(40, help="""
    The width of the index column, if present.
    """)

    scroll_to_selection = Bool(True, help="""
    Whenever a selection is made on the data source, scroll the selected
    rows into the table's viewport if none of the selected rows are already
    in the viewport.
    """)

    header_row = Bool(True, help="""
    Whether to show a header row with column names at the top of the table.
    """)

    width = Override(default=600)

    height = Override(default=400)

    row_height = Int(25, help="""
    The height of each row in pixels.
    """)

    @staticmethod
    def from_data(data, columns=None, formatters={}, **kwargs) -> DataTable:
        """ Create a simple table from a pandas dataframe, dictionary or ColumnDataSource.

        Args:
            data (DataFrame or dict or ColumnDataSource) :
                The data to create the table from. If the data is a dataframe
                or dictionary, a ColumnDataSource will be created from it.

            columns (list, optional) :
                A list of column names to use from the input data.
                If None, use all columns. (default: None)

            formatters (dict, optional) :
                A mapping of column names and corresponding Formatters to
                apply to each column. (default: None)

        Keyword arguments:
            Any additional keyword arguments will be passed to DataTable.

        Returns:
            DataTable

        Raises:
            ValueError
                If the provided data is not a ColumnDataSource
                or a data source that a ColumnDataSource can be created from.

        """

        if isinstance(data, ColumnDataSource):
            source = data.clone()
        else:
            try:
                source = ColumnDataSource(data)
            except ValueError as e:
                raise ValueError("Expected a ColumnDataSource or something a ColumnDataSource can be created from like a dict or a DataFrame") from e

        if columns is not None:
            source.data = {col: source.data[col] for col in columns}

        table_columns = []
        for c in source.data.keys():
            formatter = formatters.get(c, Intrinsic)
            table_columns.append(TableColumn(field=c, title=c, formatter=formatter))

        return DataTable(source=source, columns=table_columns, index_position=None, **kwargs)

class GroupingInfo(Model):
    '''Describes how to calculate totals and sub-totals

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    getter = String('', help="""
    References the column which generates the unique keys of this sub-total (groupby).
    """)

    aggregators = List(Instance(RowAggregator), help="""
    Describes how to aggregate the columns which will populate this sub-total.
    """)

    collapsed = Bool(False, help="""
    Whether the corresponding sub-total is expanded or collapsed by default.
    """)

class DataCube(DataTable):
    '''Specialized DataTable with collapsing groups, totals, and sub-totals.

    '''

    # explicit __init__ to support Init signatures
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    grouping = List(Instance(GroupingInfo), help="""
    Describe what aggregation operations used to define sub-totals and totals
    """)

    target = Instance(DataSource, help="""
    Two column datasource (row_indices & labels) describing which rows of the
    data cubes are expanded or collapsed
    """)

#-----------------------------------------------------------------------------
# Private API
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------
