# Source code for django_tables2.columns.checkboxcolumn

    from django.utils.safestring import mark_safe

    from django_tables2.utils import Accessor, AttributeDict, computed_values

    from .base import Column, library

    @library.register
    class CheckBoxColumn(Column):
        """
        A subclass of `.Column` that renders as a checkbox form input.

        This column allows a user to *select* a set of rows. The selection
        information can then be used to apply some operation (e.g. "delete") onto
        the set of objects that correspond to the selected rows.

        The value that is extracted from the :term:`table data` for this column is
        used as the value for the checkbox, i.e. ``<input type="checkbox"
        value="..." />``

        This class implements some sensible defaults:

        - HTML input's ``name`` attribute is the :term:`column name` (can override
          via *attrs* argument).
        - ``orderable`` defaults to `False`.

        Arguments:
            attrs (dict): In addition to *attrs* keys supported by `~.Column`, the
                following are available:

                 - ``input``     -- ``<input>`` elements in both ``<td>`` and ``<th>``.
                 - ``th__input`` -- Replaces ``input`` attrs in header cells.
                 - ``td__input`` -- Replaces ``input`` attrs in body cells.

            checked (`~.Accessor`, bool, callable): Allow rendering the checkbox as
                checked. If it resolves to a truthy value, the checkbox will be
                rendered as checked.

        .. note::

            You might expect that you could select multiple checkboxes in the
            rendered table and then *do something* with that. This functionality
            is not implemented. If you want something to actually happen, you will
            need to implement that yourself.
        """

        def __init__(self, attrs=None, checked=None, **extra):
            self.checked = checked
            kwargs = {"orderable": False, "attrs": attrs}
            kwargs.update(extra)
            super().__init__(**kwargs)

        @property
        def header(self):
            default = {"type": "checkbox"}
            general = self.attrs.get("input")
            specific = self.attrs.get("th__input")
            attrs = AttributeDict(default, **(specific or general or {}))
            return mark_safe(f"<input {attrs.as_html()} />")

        def render(self, value, bound_column, record):
            default = {"type": "checkbox", "name": bound_column.name, "value": value}
            if self.is_checked(value, record):
                default.update({"checked": "checked"})

            general = self.attrs.get("input")
            specific = self.attrs.get("td__input")

            attrs = dict(default, **(specific or general or {}))
            attrs = computed_values(attrs, kwargs={"record": record, "value": value})
            return mark_safe(f"<input {AttributeDict(attrs).as_html()} />")

        def is_checked(self, value, record):
            """Determine if the checkbox should be checked."""
            if self.checked is None:
                return False
            if self.checked is True:
                return True

            if callable(self.checked):
                return bool(self.checked(value, record))

            checked = Accessor(self.checked)
            if checked in record:
                return bool(record[checked])
            return False