from builtins import super

from . import mixin
from . import core


class FieldAncillary(mixin.NetCDFVariable,
                     mixin.PropertiesData,
                     core.FieldAncillary):
    '''A field ancillary construct of the CF data model.

    The field ancillary construct provides metadata which are
    distributed over the same sampling domain as the field itself. For
    example, if a data variable holds a variable retrieved from a
    satellite instrument, a related ancillary data variable might
    provide the uncertainty estimates for those retrievals (varying
    over the same spatiotemporal domain).
    
    The field ancillary construct consists of an array of the
    ancillary data, which is zero-dimensional or which depends on one
    or more of the domain axes, and properties to describe the
    data. It is assumed that the data do not depend on axes of the
    domain which are not spanned by the array, along which the values
    are implicitly propagated. CF-netCDF ancillary data variables
    correspond to field ancillary constructs. Note that a field
    ancillary construct is constrained by the domain definition of the
    parent field construct but does not contribute to the domain's
    definition, unlike, for instance, an auxiliary coordinate
    construct or domain ancillary construct.
    
    **NetCDF interface**
    
    The netCDF variable name of the construct may be accessed with the
    `nc_set_variable`, `nc_get_variable`, `nc_del_variable` and
    `nc_has_variable` methods.
    
    .. versionadded:: 1.7.0

    '''
    def __init__(self, properties=None, data=None, source=None,
                 copy=True, _use_data=True):

        '''**Initialization**

    :Parameters:
    
        properties: `dict`, optional
           Set descriptive properties. The dictionary keys are
           property names, with corresponding values. Ignored if the
           *source* parameter is set.
    
           Properties may also be set after initialisation with the
           `set_properties` and `set_property` methods.
    
           *Parameter example:*
              ``properties={'standard_name': 'altitude'}``
    
        data: `Data`, optional
            Set the data array. Ignored if the *source* parameter is
            set.
    
            The data array may also be set after initialisation with
            the `set_data` method.
    
        source: optional
            Initialize the properties and data from those of *source*.
    
        copy: `bool`, optional
            If False then do not deep copy input parameters prior to
            initialization. By default arguments are deep copied.

        '''
        super().__init__(properties=properties, data=data,
                         source=source, copy=copy,
                         _use_data=_use_data)
        
        self._initialise_netcdf(source)

    
    def dump(self, display=True, _omit_properties=None, _key=None,
             _level=0, _title=None, _axes=None, _axis_names=None):
        '''A full description of the field ancillary construct.

    Returns a description of all properties, including those of
    components, and provides selected values of all data arrays.
    
    .. versionadded:: 1.7.0
    
    :Parameters:
    
        display: `bool`, optional
            If False then return the description as a string. By
            default the description is printed.
    
    :Returns:
    
        `None` or `str`
            The description. If *display* is True then the description
            is printed and `None` is returned. Otherwise the
            description is returned as a string.

        '''
        if _title is None:
            _title = 'Field Ancillary: ' + self.identity(default='')

        return super().dump(display=display, _key=_key,
                            _omit_properties=_omit_properties,
                            _level=_level, _title=_title, _axes=_axes,
                            _axis_names=_axis_names)

    
    def equals(self, other, rtol=None, atol=None, verbose=False,
               ignore_data_type=False, ignore_fill_value=False,
               ignore_properties=(), ignore_compression=True,
               ignore_type=False):
        '''Whether two field ancillary constructs are the same.

    Equality is strict by default. This means that:
    
    * the same descriptive properties must be present, with the same
      values and data types, and vector-valued properties must also have
      same the size and be element-wise equal (see the *ignore_properties*
      and *ignore_data_type* parameters), and
    
    ..
    
    * if there are data arrays then they must have same shape and data
      type, the same missing data mask, and be element-wise equal (see the
      *ignore_data_type* parameter).
    
    Two real numbers ``x`` and ``y`` are considered equal if
    ``|x-y|<=atol+rtol|y|``, where ``atol`` (the tolerance on absolute
    differences) and ``rtol`` (the tolerance on relative differences) are
    positive, typically very small numbers. See the *atol* and *rtol*
    parameters.
    
    Any compression is ignored by default, with only the arrays in
    their uncompressed forms being compared. See the
    *ignore_compression* parameter.
    
    Any type of object may be tested but, in general, equality is only
    possible with another field ancillary construct, or a subclass of
    one. See the *ignore_type* parameter.
    
    NetCDF elements, such as netCDF variable and dimension names, do not
    constitute part of the CF data model and so are not checked.
    
    .. versionadded:: 1.7.0
    
    :Parameters:
    
        other: 
            The object to compare for equality.
    
        atol: float, optional
            The tolerance on absolute differences between real
            numbers. The default value is set by the `cfdm.ATOL` function.
            
        rtol: float, optional
            The tolerance on relative differences between real
            numbers. The default value is set by the `cfdm.RTOL` function.
    
        ignore_fill_value: `bool`, optional
            If True then the "_FillValue" and "missing_value" properties
            are omitted from the comparison.
    
        verbose: `bool`, optional
            If True then print information about differences that lead to
            inequality.
    
        ignore_properties: sequence of `str`, optional
            The names of properties to omit from the comparison.
    
        ignore_data_type: `bool`, optional
            If True then ignore the data types in all numerical 
            comparisons. By default different numerical data types imply
            inequality, regardless of whether the elements are within the
            tolerance for equality.
    
        ignore_compression: `bool`, optional
            If False then the compression type and, if applicable, the
            underlying compressed arrays must be the same, as well as
            the arrays in their uncompressed forms. By default only
            the arrays in their uncompressed forms are compared.
    
        ignore_type: `bool`, optional
            Any type of object may be tested but, in general, equality
            is only possible with another field ancillary construct,
            or a subclass of one. If *ignore_type* is True then
            ``FieldAncillary(source=other)`` is tested, rather than
            the ``other`` defined by the *other* parameter.
    
    :Returns: 
      
        `bool`
            Whether the two field ancillary constructs are equal.
    
    **Examples:**
    
    >>> f.equals(f)
    True
    >>> f.equals(f.copy())
    True
    >>> f.equals('not a field ancillary')
    False
    
    >>> g = f.copy()
    >>> g.set_property('foo', 'bar')
    >>> f.equals(g)
    False
    >>> f.equals(g, verbose=True)
    FieldAncillary: Non-common property name: foo
    FieldAncillary: Different properties
    False

        '''
        return super().equals(other, rtol=rtol, atol=atol,
                              verbose=verbose,
                              ignore_data_type=ignore_data_type,
                              ignore_fill_value=ignore_fill_value,
                              ignore_properties=ignore_properties,
                              ignore_compression=ignore_compression,
                              ignore_type=ignore_type)

    
#--- End: class
