#
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# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
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#    http://www.apache.org/licenses/LICENSE-2.0
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from typing import Any, Callable, List, Optional, Union, cast, no_type_check

import pandas as pd
from pandas.api.types import is_hashable, CategoricalDtype  # type: ignore[attr-defined]

from pyspark import pandas as ps
from pyspark.pandas.indexes.base import Index
from pyspark.pandas.internal import InternalField
from pyspark.pandas.series import Series
from pyspark.sql.types import StructField


class CategoricalIndex(Index):
    """
    Index based on an underlying `Categorical`.

    CategoricalIndex can only take on a limited,
    and usually fixed, number of possible values (`categories`). Also,
    it might have an order, but numerical operations
    (additions, divisions, ...) are not possible.

    Parameters
    ----------
    data : array-like (1-dimensional)
        The values of the categorical. If `categories` are given, values not in
        `categories` will be replaced with NaN.
    categories : index-like, optional
        The categories for the categorical. Items need to be unique.
        If the categories are not given here (and also not in `dtype`), they
        will be inferred from the `data`.
    ordered : bool, optional
        Whether or not this categorical is treated as an ordered
        categorical. If not given here or in `dtype`, the resulting
        categorical will be unordered.
    dtype : CategoricalDtype or "category", optional
        If :class:`CategoricalDtype`, cannot be used together with
        `categories` or `ordered`.
    copy : bool, default False
        Make a copy of input ndarray.
    name : object, optional
        Name to be stored in the index.

    See Also
    --------
    Index : The base pandas-on-Spark Index type.

    Examples
    --------
    >>> ps.CategoricalIndex(["a", "b", "c", "a", "b", "c"])  # doctest: +NORMALIZE_WHITESPACE
    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
                     categories=['a', 'b', 'c'], ordered=False, dtype='category')

    ``CategoricalIndex`` can also be instantiated from a ``Categorical``:

    >>> c = pd.Categorical(["a", "b", "c", "a", "b", "c"])
    >>> ps.CategoricalIndex(c)  # doctest: +NORMALIZE_WHITESPACE
    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
                     categories=['a', 'b', 'c'], ordered=False, dtype='category')

    Ordered ``CategoricalIndex`` can have a min and max value.

    >>> ci = ps.CategoricalIndex(
    ...     ["a", "b", "c", "a", "b", "c"], ordered=True, categories=["c", "b", "a"]
    ... )
    >>> ci  # doctest: +NORMALIZE_WHITESPACE
    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
                     categories=['c', 'b', 'a'], ordered=True, dtype='category')

    From a Series:

    >>> s = ps.Series(["a", "b", "c", "a", "b", "c"], index=[10, 20, 30, 40, 50, 60])
    >>> ps.CategoricalIndex(s)  # doctest: +NORMALIZE_WHITESPACE
    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
                     categories=['a', 'b', 'c'], ordered=False, dtype='category')

    From an Index:

    >>> idx = ps.Index(["a", "b", "c", "a", "b", "c"])
    >>> ps.CategoricalIndex(idx)  # doctest: +NORMALIZE_WHITESPACE
    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
                     categories=['a', 'b', 'c'], ordered=False, dtype='category')
    """

    @no_type_check
    def __new__(cls, data=None, categories=None, ordered=None, dtype=None, copy=False, name=None):
        if not is_hashable(name):
            raise TypeError("Index.name must be a hashable type")

        if isinstance(data, (Series, Index)):
            if dtype is None:
                dtype = "category"
            return Index(data, dtype=dtype, copy=copy, name=name)

        return ps.from_pandas(
            pd.CategoricalIndex(
                data=data, categories=categories, ordered=ordered, dtype=dtype, name=name
            )
        )

    @property
    def dtype(self) -> CategoricalDtype:
        return cast(CategoricalDtype, super().dtype)

    @property
    def codes(self) -> Index:
        """
        The category codes of this categorical.

        Codes are an Index of integers which are the positions of the actual
        values in the categories Index.

        There is no setter, use the other categorical methods and the normal item
        setter to change values in the categorical.

        Returns
        -------
        Index
            A non-writable view of the `codes` Index.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.codes
        Index([0, 1, 1, 2, 2, 2], dtype='int8')
        """
        return self._with_new_scol(
            self.spark.column,
            field=InternalField.from_struct_field(
                StructField(
                    name=self._internal.index_spark_column_names[0],
                    dataType=self.spark.data_type,
                    nullable=self.spark.nullable,
                )
            ),
        ).rename(None)

    @property
    def categories(self) -> pd.Index:
        """
        The categories of this categorical.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.categories
        Index(['a', 'b', 'c'], dtype='object')
        """
        return self.dtype.categories

    @categories.setter
    def categories(self, categories: Union[pd.Index, List]) -> None:
        dtype = CategoricalDtype(categories, ordered=self.ordered)

        if len(self.categories) != len(dtype.categories):
            raise ValueError(
                "new categories need to have the same number of items as the old categories!"
            )

        internal = self._psdf._internal.copy(
            index_fields=[self._internal.index_fields[0].copy(dtype=dtype)]
        )
        self._psdf._update_internal_frame(internal)

    @property
    def ordered(self) -> bool:
        """
        Whether the categories have an ordered relationship.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.ordered
        False
        """
        return self.dtype.ordered

    def add_categories(
        self, new_categories: Union[pd.Index, Any, List]
    ) -> Optional["CategoricalIndex"]:
        """
        Add new categories.

        `new_categories` will be included at the last/highest place in the
        categories and will be unused directly after this call.

        Parameters
        ----------
        new_categories : category or list-like of category
           The new categories to be included.

        Returns
        -------
        CategoricalIndex
            Categorical with new categories added

        Raises
        ------
        ValueError
            If the new categories include old categories or do not validate as
            categories

        See Also
        --------
        rename_categories : Rename categories.
        reorder_categories : Reorder categories.
        remove_categories : Remove the specified categories.
        remove_unused_categories : Remove categories which are not used.
        set_categories : Set the categories to the specified ones.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.add_categories('x')  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c', 'x'], ordered=False, dtype='category')
        """
        return CategoricalIndex(
            self.to_series().cat.add_categories(new_categories=new_categories)
        ).rename(self.name)

    def as_ordered(self) -> Optional["CategoricalIndex"]:
        """
        Set the Categorical to be ordered.

        Returns
        -------
        CategoricalIndex
            Ordered Categorical

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.as_ordered()  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=True, dtype='category')
        """
        return CategoricalIndex(self.to_series().cat.as_ordered()).rename(self.name)

    def as_unordered(self) -> Optional["CategoricalIndex"]:
        """
        Set the Categorical to be unordered.

        Returns
        -------
        CategoricalIndex
            Unordered Categorical

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc")).as_ordered()
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=True, dtype='category')

        >>> idx.as_unordered()  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')
        """
        return CategoricalIndex(self.to_series().cat.as_unordered()).rename(self.name)

    def remove_categories(
        self, removals: Union[pd.Index, Any, List]
    ) -> Optional["CategoricalIndex"]:
        """
        Remove the specified categories.

        `removals` must be included in the old categories. Values which were in
        the removed categories will be set to NaN

        Parameters
        ----------
        removals : category or list of categories
           The categories which should be removed.

        Returns
        -------
        CategoricalIndex
            Categorical with removed categories

        Raises
        ------
        ValueError
            If the removals are not contained in the categories

        See Also
        --------
        rename_categories : Rename categories.
        reorder_categories : Reorder categories.
        add_categories : Add new categories.
        remove_unused_categories : Remove categories which are not used.
        set_categories : Set the categories to the specified ones.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.remove_categories('b')  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', nan, nan, 'c', 'c', 'c'],
                         categories=['a', 'c'], ordered=False, dtype='category')
        """
        return CategoricalIndex(self.to_series().cat.remove_categories(removals)).rename(self.name)

    def remove_unused_categories(self) -> Optional["CategoricalIndex"]:
        """
        Remove categories which are not used.

        Returns
        -------
        cat : CategoricalIndex
            Categorical with unused categories dropped

        See Also
        --------
        rename_categories : Rename categories.
        reorder_categories : Reorder categories.
        add_categories : Add new categories.
        remove_categories : Remove the specified categories.
        set_categories : Set the categories to the specified ones.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"), categories=['a', 'b', 'c', 'd'])
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c', 'd'], ordered=False, dtype='category')

        >>> idx.remove_unused_categories()  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')
        """
        return CategoricalIndex(self.to_series().cat.remove_unused_categories()).rename(self.name)

    def rename_categories(
        self, new_categories: Union[list, dict, Callable]
    ) -> Optional["CategoricalIndex"]:
        """
        Rename categories.

        Parameters
        ----------
        new_categories : list-like, dict-like or callable

            New categories which will replace old categories.

            * list-like: all items must be unique and the number of items in
              the new categories must match the existing number of categories.

            * dict-like: specifies a mapping from
              old categories to new. Categories not contained in the mapping
              are passed through and extra categories in the mapping are
              ignored.

            * callable : a callable that is called on all items in the old
              categories and whose return values comprise the new categories.

        Returns
        -------
        cat : CategoricalIndex
            Categorical with removed categories or None

        Raises
        ------
        ValueError
            If new categories are list-like and do not have the same number of
            items than the current categories or do not validate as categories

        See Also
        --------
        reorder_categories : Reorder categories.
        add_categories : Add new categories.
        remove_categories : Remove the specified categories.
        remove_unused_categories : Remove categories which are not used.
        set_categories : Set the categories to the specified ones.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(["a", "a", "b"])
        >>> idx.rename_categories([0, 1])
        CategoricalIndex([0, 0, 1], categories=[0, 1], ordered=False, dtype='category')

        For dict-like ``new_categories``, extra keys are ignored and
        categories not in the dictionary are passed through

        >>> idx.rename_categories({'a': 'A', 'c': 'C'})
        CategoricalIndex(['A', 'A', 'b'], categories=['A', 'b'], ordered=False, dtype='category')

        You may also provide a callable to create the new categories

        >>> idx.rename_categories(lambda x: x.upper())
        CategoricalIndex(['A', 'A', 'B'], categories=['A', 'B'], ordered=False, dtype='category')
        """
        return CategoricalIndex(self.to_series().cat.rename_categories(new_categories)).rename(
            self.name
        )

    def reorder_categories(
        self,
        new_categories: Union[pd.Index, Any, List],
        ordered: Optional[bool] = None,
    ) -> Optional["CategoricalIndex"]:
        """
        Reorder categories as specified in new_categories.

        `new_categories` needs to include all old categories and no new category
        items.

        Parameters
        ----------
        new_categories : Index-like
           The categories in new order.
        ordered : bool, optional
           Whether or not the categorical is treated as an ordered categorical.
           If not given, do not change the ordered information.

        Returns
        -------
        cat : CategoricalIndex
            Categorical with removed categories

        Raises
        ------
        ValueError
            If the new categories do not contain all old category items or any
            new ones

        See Also
        --------
        rename_categories : Rename categories.
        add_categories : Add new categories.
        remove_categories : Remove the specified categories.
        remove_unused_categories : Remove categories which are not used.
        set_categories : Set the categories to the specified ones.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.reorder_categories(['c', 'b', 'a'])  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['c', 'b', 'a'], ordered=False, dtype='category')
        """
        return CategoricalIndex(
            self.to_series().cat.reorder_categories(new_categories=new_categories, ordered=ordered)
        ).rename(self.name)

    def set_categories(
        self,
        new_categories: Union[pd.Index, List],
        ordered: Optional[bool] = None,
        rename: bool = False,
    ) -> Optional["CategoricalIndex"]:
        """
        Set the categories to the specified new_categories.

        `new_categories` can include new categories (which will result in
        unused categories) or remove old categories (which results in values
        set to NaN). If `rename==True`, the categories will simply be renamed
        (less or more items than in old categories will result in values set to
        NaN or in unused categories respectively).

        This method can be used to perform more than one action of adding,
        removing, and reordering simultaneously and is therefore faster than
        performing the individual steps via the more specialised methods.

        On the other hand this methods does not do checks (e.g., whether the
        old categories are included in the new categories on a reorder), which
        can result in surprising changes, for example when using special string
        dtypes, which does not consider a S1 string equal to a single char
        python string.

        Parameters
        ----------
        new_categories : Index-like
           The categories in new order.
        ordered : bool, default False
           Whether or not the categorical is treated as an ordered categorical.
           If not given, do not change the ordered information.
        rename : bool, default False
           Whether or not the new_categories should be considered as a rename
           of the old categories or as reordered categories.

        Returns
        -------
        CategoricalIndex with reordered categories

        Raises
        ------
        ValueError
            If new_categories does not validate as categories

        See Also
        --------
        rename_categories : Rename categories.
        reorder_categories : Reorder categories.
        add_categories : Add new categories.
        remove_categories : Remove the specified categories.
        remove_unused_categories : Remove categories which are not used.

        Examples
        --------
        >>> idx = ps.CategoricalIndex(list("abbccc"))
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'b', 'c', 'c', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.set_categories(['b', 'c'])  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex([nan, 'b', 'b', 'c', 'c', 'c'],
                         categories=['b', 'c'], ordered=False, dtype='category')

        >>> idx.set_categories([1, 2, 3], rename=True)
        CategoricalIndex([1, 2, 2, 3, 3, 3], categories=[1, 2, 3], ordered=False, dtype='category')

        >>> idx.set_categories([1, 2, 3], rename=True, ordered=True)
        CategoricalIndex([1, 2, 2, 3, 3, 3], categories=[1, 2, 3], ordered=True, dtype='category')
        """
        return CategoricalIndex(
            self.to_series().cat.set_categories(new_categories, ordered=ordered, rename=rename)
        ).rename(self.name)

    def map(  # type: ignore[override]
        self, mapper: Union[dict, Callable[[Any], Any], pd.Series]
    ) -> "Index":
        """
        Map values using input correspondence (a dict, Series, or function).

        Maps the values (their categories, not the codes) of the index to new
        categories. If the mapping correspondence is one-to-one the result is a
        `CategoricalIndex` which has the same order property as the original,
        otherwise an `Index` is returned.

        If a `dict` or `Series` is used any unmapped category is mapped to missing values.
        Note that if this happens an `Index` will be returned.

        Parameters
        ----------
        mapper : function, dict, or Series
            Mapping correspondence.

        Returns
        -------
        CategoricalIndex or Index
            Mapped index.

        See Also
        --------
        Index.map : Apply a mapping correspondence on an `Index`.
        Series.map : Apply a mapping correspondence on a `Series`
        Series.apply : Apply more complex functions on a `Series`

        Examples
        --------
        >>> idx = ps.CategoricalIndex(['a', 'b', 'c'])
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'c'],
                         categories=['a', 'b', 'c'], ordered=False, dtype='category')

        >>> idx.map(lambda x: x.upper())  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['A', 'B', 'C'],
                         categories=['A', 'B', 'C'], ordered=False, dtype='category')

        >>> pser = pd.Series([1, 2, 3], index=pd.CategoricalIndex(['a', 'b', 'c'], ordered=True))
        >>> idx.map(pser)  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex([1, 2, 3],
                         categories=[1, 2, 3], ordered=False, dtype='category')

        >>> idx.map({'a': 'first', 'b': 'second', 'c': 'third'})  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['first', 'second', 'third'],
                         categories=['first', 'second', 'third'], ordered=False, dtype='category')

        If the mapping is one-to-one the ordering of the categories is preserved:

        >>> idx = ps.CategoricalIndex(['a', 'b', 'c'], ordered=True)
        >>> idx  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex(['a', 'b', 'c'],
                         categories=['a', 'b', 'c'], ordered=True, dtype='category')

        >>> idx.map({'a': 3, 'b': 2, 'c': 1})  # doctest: +NORMALIZE_WHITESPACE
        CategoricalIndex([3, 2, 1],
                         categories=[3, 2, 1], ordered=True, dtype='category')

        If the mapping is not one-to-one an `Index` is returned:

        >>> idx.map({'a': 'first', 'b': 'second', 'c': 'first'})
        Index(['first', 'second', 'first'], dtype='object')

        If a `dict` is used, all unmapped categories are mapped to None and
        the result is an `Index`:

        >>> idx.map({'a': 'first', 'b': 'second'})
        Index(['first', 'second', None], dtype='object')
        """
        return super().map(mapper)

    @no_type_check
    def all(self, *args, **kwargs) -> None:
        raise TypeError("Cannot perform 'all' with this index type: %s" % type(self).__name__)


def _test() -> None:
    import os
    import doctest
    import sys
    from pyspark.sql import SparkSession
    import pyspark.pandas.indexes.category

    os.chdir(os.environ["SPARK_HOME"])

    globs = pyspark.pandas.indexes.category.__dict__.copy()
    globs["ps"] = pyspark.pandas
    spark = (
        SparkSession.builder.master("local[4]")
        .appName("pyspark.pandas.indexes.category tests")
        .getOrCreate()
    )
    (failure_count, test_count) = doctest.testmod(
        pyspark.pandas.indexes.category,
        globs=globs,
        optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE,
    )
    spark.stop()
    if failure_count:
        sys.exit(-1)


if __name__ == "__main__":
    _test()