# Licensed under a 3-clause BSD style license - see LICENSE.rst

"""
Helper functions for table development, mostly creating useful
tables for testing.
"""

import string
from itertools import cycle

import numpy as np

from astropy.utils.data_info import ParentDtypeInfo

from .table import Column, Table


def simple_table(size=3, cols=None, kinds="ifS", masked=False):
    """
    Return a simple table for testing.

    Example
    --------
    ::

      >>> from astropy.table.table_helpers import simple_table
      >>> print(simple_table(3, 6, masked=True, kinds='ifOS'))
       a   b     c      d   e   f
      --- --- -------- --- --- ---
       -- 1.0 {'c': 2}  --   5 5.0
        2 2.0       --   e   6  --
        3  -- {'e': 4}   f  -- 7.0

    Parameters
    ----------
    size : int
        Number of table rows
    cols : int, optional
        Number of table columns. Defaults to number of kinds.
    kinds : str
        String consisting of the column dtype.kinds.  This string
        will be cycled through to generate the column dtype.
        The allowed values are 'i', 'f', 'S', 'O'.

    Returns
    -------
    out : `Table`
        New table with appropriate characteristics
    """
    if cols is None:
        cols = len(kinds)
    if cols > 26:
        raise ValueError("Max 26 columns in SimpleTable")

    columns = []
    names = [chr(ord("a") + ii) for ii in range(cols)]
    letters = np.array(list(string.ascii_letters))
    for jj, kind in zip(range(cols), cycle(kinds)):
        if kind == "i":
            data = np.arange(1, size + 1, dtype=np.int64) + jj
        elif kind == "f":
            data = np.arange(size, dtype=np.float64) + jj
        elif kind == "S":
            indices = (np.arange(size) + jj) % len(letters)
            data = letters[indices]
        elif kind == "O":
            indices = (np.arange(size) + jj) % len(letters)
            vals = letters[indices]
            data = [{val.item(): index.item()} for val, index in zip(vals, indices)]
        else:
            raise ValueError("Unknown data kind")
        columns.append(Column(data))

    table = Table(columns, names=names, masked=masked)
    if masked:
        for ii, col in enumerate(table.columns.values()):
            mask = np.array((np.arange(size) + ii) % 3, dtype=bool)
            col.mask = ~mask

    return table


def complex_table():
    """
    Return a masked table from the io.votable test set that has a wide variety
    of stressing types.
    """
    import warnings

    from astropy.io.votable.table import parse
    from astropy.utils.data import get_pkg_data_filename

    with warnings.catch_warnings():
        warnings.simplefilter("ignore")
        votable = parse(
            get_pkg_data_filename("../io/votable/tests/data/regression.xml"),
            pedantic=False,
        )
    first_table = votable.get_first_table()
    table = first_table.to_table()

    return table


class ArrayWrapperInfo(ParentDtypeInfo):
    _represent_as_dict_primary_data = "data"

    def _represent_as_dict(self):
        """Represent Column as a dict that can be serialized."""
        col = self._parent
        out = {"data": col.data}
        return out

    def _construct_from_dict(self, map):
        """Construct Column from ``map``."""
        data = map.pop("data")
        out = self._parent_cls(data, **map)
        return out


class ArrayWrapper:
    """
    Minimal mixin using a simple wrapper around a numpy array.

    TODO: think about the future of this class as it is mostly for demonstration
    purposes (of the mixin protocol). Consider taking it out of core and putting
    it into a tutorial. One advantage of having this in core is that it is
    getting tested in the mixin testing though it doesn't work for multidim
    data.
    """

    info = ArrayWrapperInfo()

    def __init__(self, data, copy=True):
        self.data = np.array(data, copy=copy)
        if "info" in getattr(data, "__dict__", ()):
            self.info = data.info

    def __getitem__(self, item):
        if isinstance(item, (int, np.integer)):
            out = self.data[item]
        else:
            out = self.__class__(self.data[item], copy=False)
            if "info" in self.__dict__:
                out.info = self.info
        return out

    def __setitem__(self, item, value):
        self.data[item] = value

    def __len__(self):
        return len(self.data)

    def __eq__(self, other):
        """Minimal equality testing, mostly for mixin unit tests."""
        if isinstance(other, ArrayWrapper):
            return self.data == other.data
        else:
            return self.data == other

    @property
    def dtype(self):
        return self.data.dtype

    @property
    def shape(self):
        return self.data.shape

    def __repr__(self):
        return f"<{self.__class__.__name__} name='{self.info.name}' data={self.data}>"