# Source code for django_tables2.rows

    from django.core.exceptions import FieldDoesNotExist
    from django.db import models

    from .columns.linkcolumn import BaseLinkColumn
    from .columns.manytomanycolumn import ManyToManyColumn
    from .utils import A, AttributeDict, call_with_appropriate, computed_values

    class CellAccessor:
        """Access cell contents on a row object (see `BoundRow`)."""

        def __init__(self, row):
            self.row = row

        def __getitem__(self, key):
            return self.row.get_cell(key)

        def __getattr__(self, name):
            return self.row.get_cell(name)

    class BoundRow:
        """
        Represents a *specific* row in a table.

        `.BoundRow` objects are a container that make it easy to access the
        final 'rendered' values for cells in a row. You can simply iterate over a
        `.BoundRow` object and it will take care to return values rendered
        using the correct method (e.g. :ref:`table.render_FOO`)

        To access the rendered value of each cell in a row, just iterate over it::

            >>> import django_tables2 as tables
            >>> class SimpleTable(tables.Table):
            ...     a = tables.Column()
            ...     b = tables.CheckBoxColumn(attrs={'name': 'my_chkbox'})
            ...
            >>> table = SimpleTable([{'a': 1, 'b': 2}])
            >>> row = table.rows[0]  # we only have one row, so let's use it
            >>> for cell in row:
            ...     print(cell)
            ...
            1
            <input type="checkbox" name="my_chkbox" value="2" />

        Alternatively you can use row.cells[0] to retrieve a specific cell::

            >>> row.cells[0]
            1
            >>> row.cells[1]
            '<input type="checkbox" name="my_chkbox" value="2" />'
            >>> row.cells[2]
            ...
            IndexError: list index out of range

        Finally you can also use the column names to retrieve a specific cell::

            >>> row.cells.a
            1
            >>> row.cells.b
            '<input type="checkbox" name="my_chkbox" value="2" />'
            >>> row.cells.c
            ...
            KeyError: "Column with name 'c' does not exist; choices are: ['a', 'b']"

        If you have the column name in a variable, you can also treat the `cells`
        property like a `dict`::

            >>> key = 'a'
            >>> row.cells[key]
            1

        Arguments:
            table: The `.Table` in which this row exists.
            record: a single record from the :term:`table data` that is used to
                populate the row. A record could be a `~django.db.Model` object, a
                `dict`, or something else.

        """

        def __init__(self, record, table):
            self._record = record
            self._table = table

            self.row_counter = next(table._counter)

            # support accessing cells from a template: {{ row.cells.column_name }}
            self.cells = CellAccessor(self)

        @property
        def table(self):
            """The `.Table` this row is part of."""
            return self._table

        def get_even_odd_css_class(self):
            """
            Return css class, alternating for odd and even records.

            Return:
                string: `even` for even records, `odd` otherwise.
            """
            return "odd" if self.row_counter % 2 else "even"

        @property
        def attrs(self):
            """Return the attributes for a certain row."""
            cssClass = self.get_even_odd_css_class()

            row_attrs = computed_values(
                self._table.row_attrs, kwargs=dict(table=self._table, record=self._record)
            )

            if "class" in row_attrs and row_attrs["class"]:
                row_attrs["class"] += " " + cssClass
            else:
                row_attrs["class"] = cssClass

            return AttributeDict(row_attrs)

        @property
        def record(self):
            """The data record from the data source which is used to populate this row with data."""
            return self._record

        def __iter__(self):
            """
            Iterate over the rendered values for cells in the row.

            Under the hood this method just makes a call to
            `.BoundRow.__getitem__` for each cell.
            """
            for column, value in self.items():
                # this uses __getitem__, using the name (rather than the accessor)
                # is correct – it's what __getitem__ expects.
                yield value

        def _get_and_render_with(self, bound_column, render_func, default):
            value = None
            accessor = A(bound_column.accessor)
            column = bound_column.column

            # We need to take special care here to allow get_FOO_display()
            # methods on a model to be used if available. See issue #30.
            penultimate, remainder = accessor.penultimate(self.record)

            # If the penultimate is a model and the remainder is a field
            # using choices, use get_FOO_display().
            if isinstance(penultimate, models.Model):
                try:
                    field = accessor.get_field(self.record)
                    display_fn = getattr(penultimate, f"get_{remainder}_display", None)
                    if getattr(field, "choices", ()) and display_fn:
                        value = display_fn()
                        remainder = None
                except FieldDoesNotExist:
                    pass

            # Fall back to just using the original accessor
            if remainder:
                try:
                    value = accessor.resolve(self.record)
                except Exception:
                    # we need to account for non-field based columns (issue #257)
                    if isinstance(column, BaseLinkColumn) and column.text is not None:
                        return render_func(bound_column)

            is_manytomanycolumn = isinstance(column, ManyToManyColumn)
            if value in column.empty_values or (is_manytomanycolumn and not value.exists()):
                return default

            return render_func(bound_column, value)

        def _optional_cell_arguments(self, bound_column, value):
            """Arguments that will optionally be passed while rendering cells."""
            return {
                "value": value,
                "record": self.record,
                "column": bound_column.column,
                "bound_column": bound_column,
                "bound_row": self,
                "table": self._table,
            }

        def get_cell(self, name):
            """Return the final rendered html for a cell in the row, given the name of a column."""
            bound_column = self.table.columns[name]

            return self._get_and_render_with(
                bound_column, render_func=self._call_render, default=bound_column.default
            )

        def _call_render(self, bound_column, value=None):
            """Call the column's render method with appropriate kwargs."""
            render_kwargs = self._optional_cell_arguments(bound_column, value)
            content = call_with_appropriate(bound_column.render, render_kwargs)

            return bound_column.link(content, **render_kwargs) if bound_column.link else content

        def get_cell_value(self, name):
            """Return the final rendered value (excluding any html) for a cell in the row, given the name of a column."""
            return self._get_and_render_with(
                self.table.columns[name], render_func=self._call_value, default=None
            )

        def _call_value(self, bound_column, value=None):
            """Call the column's value method with appropriate kwargs."""
            return call_with_appropriate(
                bound_column.value, self._optional_cell_arguments(bound_column, value)
            )

        def __contains__(self, item):
            """Check by both row object and column name."""
            return item in (self.table.columns if isinstance(item, str) else self)

        def items(self):
            """
            Return an iterator yielding ``(bound_column, cell)`` pairs.

            *cell* is ``row[name]`` -- the rendered unicode value that should be
            ``rendered within ``<td>``.
            """
            for column in self.table.columns:
                # column gets some attributes relevant only relevant in this iteration,
                # used to allow passing the value/record to a callable Column.attrs /
                # Table.attrs item.
                column.current_value = self.get_cell(column.name)
                column.current_record = self.record
                yield (column, column.current_value)

    class BoundPinnedRow(BoundRow):
        """A *pinned* row in a table."""

        @property
        def attrs(self):
            """
            Return the attributes for a certain pinned row.

            Add CSS classes `pinned-row` and `odd` or `even` to `class` attribute.

            Return:
                AttributeDict: Attributes for pinned rows.
            """
            row_attrs = computed_values(self._table.pinned_row_attrs, kwargs={"record": self._record})
            css_class = " ".join(
                [self.get_even_odd_css_class(), "pinned-row", row_attrs.get("class", "")]
            )
            row_attrs["class"] = css_class
            return AttributeDict(row_attrs)

    class BoundRows:
        """
        Container for spawning `.BoundRow` objects.

        Arguments:
            data: iterable of records
            table: the `~.Table` in which the rows exist
            pinned_data: dictionary with iterable of records for top and/or
             bottom pinned rows.

        Example:
            >>> pinned_data = {
            ...    'top': iterable,      # or None value
            ...    'bottom': iterable,   # or None value
            ... }

        This is used for `~.Table.rows`.
        """

        def __init__(self, data, table, pinned_data=None):
            self.data = data
            self.table = table
            self.pinned_data = pinned_data or {}

        def generator_pinned_row(self, data):
            """
            Top and bottom pinned rows generator.

            Arguments:
                data: Iterable data for all records for top or bottom pinned rows.

            Yields:
                BoundPinnedRow: Top or bottom `BoundPinnedRow` object for single pinned record.
            """
            if data is not None:
                if hasattr(data, "__iter__") is False:
                    raise ValueError("The data for pinned rows must be iterable")

                for pinned_record in data:
                    yield BoundPinnedRow(pinned_record, table=self.table)

        def __iter__(self):
            # Top pinned rows
            yield from self.generator_pinned_row(self.pinned_data.get("top"))

            for record in self.data:
                yield BoundRow(record, table=self.table)

            # Bottom pinned rows
            yield from self.generator_pinned_row(self.pinned_data.get("bottom"))

        def __len__(self):
            length = len(self.data)
            pinned_top = self.pinned_data.get("top")
            pinned_bottom = self.pinned_data.get("bottom")
            length += 0 if pinned_top is None else len(pinned_top)
            length += 0 if pinned_bottom is None else len(pinned_bottom)
            return length

        def __getitem__(self, key):
            """Return a new `~.BoundRows` instance for a slice, a single `~.BoundRow` instance for an index."""
            if isinstance(key, slice):
                return BoundRows(data=self.data[key], table=self.table, pinned_data=self.pinned_data)
            else:
                return BoundRow(record=self.data[key], table=self.table)