# util/_collections.py
# Copyright (C) 2005-2018 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""Collection classes and helpers."""

from __future__ import absolute_import
import weakref
import operator
from .compat import threading, itertools_filterfalse, string_types, \
    binary_types
from . import py2k
import types
import collections

EMPTY_SET = frozenset()


class AbstractKeyedTuple(tuple):
    __slots__ = ()

    def keys(self):
        """Return a list of string key names for this :class:`.KeyedTuple`.

        .. seealso::

            :attr:`.KeyedTuple._fields`

        """

        return list(self._fields)


class KeyedTuple(AbstractKeyedTuple):
    """``tuple`` subclass that adds labeled names.

    E.g.::

        >>> k = KeyedTuple([1, 2, 3], labels=["one", "two", "three"])
        >>> k.one
        1
        >>> k.two
        2

    Result rows returned by :class:`.Query` that contain multiple
    ORM entities and/or column expressions make use of this
    class to return rows.

    The :class:`.KeyedTuple` exhibits similar behavior to the
    ``collections.namedtuple()`` construct provided in the Python
    standard library, however is architected very differently.
    Unlike ``collections.namedtuple()``, :class:`.KeyedTuple` is
    does not rely on creation of custom subtypes in order to represent
    a new series of keys, instead each :class:`.KeyedTuple` instance
    receives its list of keys in place.   The subtype approach
    of ``collections.namedtuple()`` introduces significant complexity
    and performance overhead, which is not necessary for the
    :class:`.Query` object's use case.

    .. versionchanged:: 0.8
        Compatibility methods with ``collections.namedtuple()`` have been
        added including :attr:`.KeyedTuple._fields` and
        :meth:`.KeyedTuple._asdict`.

    .. seealso::

        :ref:`ormtutorial_querying`

    """

    def __new__(cls, vals, labels=None):
        t = tuple.__new__(cls, vals)
        if labels:
            t.__dict__.update(zip(labels, vals))
        else:
            labels = []
        t.__dict__['_labels'] = labels
        return t

    @property
    def _fields(self):
        """Return a tuple of string key names for this :class:`.KeyedTuple`.

        This method provides compatibility with ``collections.namedtuple()``.

        .. versionadded:: 0.8

        .. seealso::

            :meth:`.KeyedTuple.keys`

        """
        return tuple([l for l in self._labels if l is not None])

    def __setattr__(self, key, value):
        raise AttributeError("Can't set attribute: %s" % key)

    def _asdict(self):
        """Return the contents of this :class:`.KeyedTuple` as a dictionary.

        This method provides compatibility with ``collections.namedtuple()``,
        with the exception that the dictionary returned is **not** ordered.

        .. versionadded:: 0.8

        """
        return {key: self.__dict__[key] for key in self.keys()}


class _LW(AbstractKeyedTuple):
    __slots__ = ()

    def __new__(cls, vals):
        return tuple.__new__(cls, vals)

    def __reduce__(self):
        # for pickling, degrade down to the regular
        # KeyedTuple, thus avoiding anonymous class pickling
        # difficulties
        return KeyedTuple, (list(self), self._real_fields)

    def _asdict(self):
        """Return the contents of this :class:`.KeyedTuple` as a dictionary."""

        d = dict(zip(self._real_fields, self))
        d.pop(None, None)
        return d


class ImmutableContainer(object):
    def _immutable(self, *arg, **kw):
        raise TypeError("%s object is immutable" % self.__class__.__name__)

    __delitem__ = __setitem__ = __setattr__ = _immutable


class immutabledict(ImmutableContainer, dict):

    clear = pop = popitem = setdefault = \
        update = ImmutableContainer._immutable

    def __new__(cls, *args):
        new = dict.__new__(cls)
        dict.__init__(new, *args)
        return new

    def __init__(self, *args):
        pass

    def __reduce__(self):
        return immutabledict, (dict(self), )

    def union(self, d):
        if not d:
            return self
        elif not self:
            if isinstance(d, immutabledict):
                return d
            else:
                return immutabledict(d)
        else:
            d2 = immutabledict(self)
            dict.update(d2, d)
            return d2

    def __repr__(self):
        return "immutabledict(%s)" % dict.__repr__(self)


class Properties(object):
    """Provide a __getattr__/__setattr__ interface over a dict."""

    __slots__ = '_data',

    def __init__(self, data):
        object.__setattr__(self, '_data', data)

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

    def __iter__(self):
        return iter(list(self._data.values()))

    def __add__(self, other):
        return list(self) + list(other)

    def __setitem__(self, key, object):
        self._data[key] = object

    def __getitem__(self, key):
        return self._data[key]

    def __delitem__(self, key):
        del self._data[key]

    def __setattr__(self, key, obj):
        self._data[key] = obj

    def __getstate__(self):
        return {'_data': self._data}

    def __setstate__(self, state):
        object.__setattr__(self, '_data', state['_data'])

    def __getattr__(self, key):
        try:
            return self._data[key]
        except KeyError:
            raise AttributeError(key)

    def __contains__(self, key):
        return key in self._data

    def as_immutable(self):
        """Return an immutable proxy for this :class:`.Properties`."""

        return ImmutableProperties(self._data)

    def update(self, value):
        self._data.update(value)

    def get(self, key, default=None):
        if key in self:
            return self[key]
        else:
            return default

    def keys(self):
        return list(self._data)

    def values(self):
        return list(self._data.values())

    def items(self):
        return list(self._data.items())

    def has_key(self, key):
        return key in self._data

    def clear(self):
        self._data.clear()


class OrderedProperties(Properties):
    """Provide a __getattr__/__setattr__ interface with an OrderedDict
    as backing store."""

    __slots__ = ()

    def __init__(self):
        Properties.__init__(self, OrderedDict())


class ImmutableProperties(ImmutableContainer, Properties):
    """Provide immutable dict/object attribute to an underlying dictionary."""

    __slots__ = ()


class OrderedDict(dict):
    """A dict that returns keys/values/items in the order they were added."""

    __slots__ = '_list',

    def __reduce__(self):
        return OrderedDict, (self.items(),)

    def __init__(self, ____sequence=None, **kwargs):
        self._list = []
        if ____sequence is None:
            if kwargs:
                self.update(**kwargs)
        else:
            self.update(____sequence, **kwargs)

    def clear(self):
        self._list = []
        dict.clear(self)

    def copy(self):
        return self.__copy__()

    def __copy__(self):
        return OrderedDict(self)

    def sort(self, *arg, **kw):
        self._list.sort(*arg, **kw)

    def update(self, ____sequence=None, **kwargs):
        if ____sequence is not None:
            if hasattr(____sequence, 'keys'):
                for key in ____sequence.keys():
                    self.__setitem__(key, ____sequence[key])
            else:
                for key, value in ____sequence:
                    self[key] = value
        if kwargs:
            self.update(kwargs)

    def setdefault(self, key, value):
        if key not in self:
            self.__setitem__(key, value)
            return value
        else:
            return self.__getitem__(key)

    def __iter__(self):
        return iter(self._list)

    def keys(self):
        return list(self)

    def values(self):
        return [self[key] for key in self._list]

    def items(self):
        return [(key, self[key]) for key in self._list]

    if py2k:
        def itervalues(self):
            return iter(self.values())

        def iterkeys(self):
            return iter(self)

        def iteritems(self):
            return iter(self.items())

    def __setitem__(self, key, object):
        if key not in self:
            try:
                self._list.append(key)
            except AttributeError:
                # work around Python pickle loads() with
                # dict subclass (seems to ignore __setstate__?)
                self._list = [key]
        dict.__setitem__(self, key, object)

    def __delitem__(self, key):
        dict.__delitem__(self, key)
        self._list.remove(key)