# -*- coding: utf-8 -*-

from __future__ import absolute_import, unicode_literals, division

import re
import operator
import collections
import itertools
import copy
import functools

import six
from jaraco.classes.properties import NonDataProperty
import jaraco.text


class Projection(collections.Mapping):
	"""
	Project a set of keys over a mapping

	>>> sample = {'a': 1, 'b': 2, 'c': 3}
	>>> prj = Projection(['a', 'c', 'd'], sample)
	>>> prj == {'a': 1, 'c': 3}
	True

	Keys should only appear if they were specified and exist in the space.

	>>> sorted(list(prj.keys()))
	['a', 'c']

	Use the projection to update another dict.

	>>> target = {'a': 2, 'b': 2}
	>>> target.update(prj)
	>>> target == {'a': 1, 'b': 2, 'c': 3}
	True

	Also note that Projection keeps a reference to the original dict, so
	if you modify the original dict, that could modify the Projection.

	>>> del sample['a']
	>>> dict(prj)
	{'c': 3}
	"""
	def __init__(self, keys, space):
		self._keys = tuple(keys)
		self._space = space

	def __getitem__(self, key):
		if key not in self._keys:
			raise KeyError(key)
		return self._space[key]

	def __iter__(self):
		return iter(set(self._keys).intersection(self._space))

	def __len__(self):
		return len(tuple(iter(self)))


class DictFilter(object):
	"""
	Takes a dict, and simulates a sub-dict based on the keys.

	>>> sample = {'a': 1, 'b': 2, 'c': 3}
	>>> filtered = DictFilter(sample, ['a', 'c'])
	>>> filtered == {'a': 1, 'c': 3}
	True

	One can also filter by a regular expression pattern

	>>> sample['d'] = 4
	>>> sample['ef'] = 5

	Here we filter for only single-character keys

	>>> filtered = DictFilter(sample, include_pattern='.$')
	>>> filtered == {'a': 1, 'b': 2, 'c': 3, 'd': 4}
	True

	Also note that DictFilter keeps a reference to the original dict, so
	if you modify the original dict, that could modify the filtered dict.

	>>> del sample['d']
	>>> del sample['a']
	>>> filtered == {'b': 2, 'c': 3}
	True

	"""
	def __init__(self, dict, include_keys=[], include_pattern=None):
		self.dict = dict
		self.specified_keys = set(include_keys)
		if include_pattern is not None:
			self.include_pattern = re.compile(include_pattern)
		else:
			# for performance, replace the pattern_keys property
			self.pattern_keys = set()

	def get_pattern_keys(self):
		keys = filter(self.include_pattern.match, self.dict.keys())
		return set(keys)
	pattern_keys = NonDataProperty(get_pattern_keys)

	@property
	def include_keys(self):
		return self.specified_keys.union(self.pattern_keys)

	def keys(self):
		return self.include_keys.intersection(self.dict.keys())

	def values(self):
		keys = self.keys()
		values = map(self.dict.get, keys)
		return values

	def __getitem__(self, i):
		if i not in self.include_keys:
			return KeyError, i
		return self.dict[i]

	def items(self):
		keys = self.keys()
		values = map(self.dict.get, keys)
		return zip(keys, values)

	def __eq__(self, other):
		return dict(self) == other

	def __ne__(self, other):
		return dict(self) != other


def dict_map(function, dictionary):
	"""
	dict_map is much like the built-in function map.  It takes a dictionary
	and applys a function to the values of that dictionary, returning a
	new dictionary with the mapped values in the original keys.

	>>> d = dict_map(lambda x:x+1, dict(a=1, b=2))
	>>> d == dict(a=2,b=3)
	True
	"""
	return dict((key, function(value)) for key, value in dictionary.items())


class RangeMap(dict):
	"""
	A dictionary-like object that uses the keys as bounds for a range.
	Inclusion of the value for that range is determined by the
	key_match_comparator, which defaults to less-than-or-equal.
	A value is returned for a key if it is the first key that matches in
	the sorted list of keys.

	One may supply keyword parameters to be passed to the sort function used
	to sort keys (i.e. cmp [python 2 only], keys, reverse) as sort_params.

	Let's create a map that maps 1-3 -> 'a', 4-6 -> 'b'

	>>> r = RangeMap({3: 'a', 6: 'b'})  # boy, that was easy
	>>> r[1], r[2], r[3], r[4], r[5], r[6]
	('a', 'a', 'a', 'b', 'b', 'b')

	Even float values should work so long as the comparison operator
	supports it.

	>>> r[4.5]
	'b'

	But you'll notice that the way rangemap is defined, it must be open-ended
	on one side.

	>>> r[0]
	'a'
	>>> r[-1]
	'a'

	One can close the open-end of the RangeMap by using undefined_value

	>>> r = RangeMap({0: RangeMap.undefined_value, 3: 'a', 6: 'b'})
	>>> r[0]
	Traceback (most recent call last):
	...
	KeyError: 0

	One can get the first or last elements in the range by using RangeMap.Item

	>>> last_item = RangeMap.Item(-1)
	>>> r[last_item]
	'b'

	.last_item is a shortcut for Item(-1)

	>>> r[RangeMap.last_item]
	'b'

	Sometimes it's useful to find the bounds for a RangeMap

	>>> r.bounds()
	(0, 6)

	RangeMap supports .get(key, default)

	>>> r.get(0, 'not found')
	'not found'

	>>> r.get(7, 'not found')
	'not found'
	"""
	def __init__(self, source, sort_params={}, key_match_comparator=operator.le):
		dict.__init__(self, source)
		self.sort_params = sort_params
		self.match = key_match_comparator

	def __getitem__(self, item):
		sorted_keys = sorted(self.keys(), **self.sort_params)
		if isinstance(item, RangeMap.Item):
			result = self.__getitem__(sorted_keys[item])
		else:
			key = self._find_first_match_(sorted_keys, item)
			result = dict.__getitem__(self, key)
			if result is RangeMap.undefined_value:
				raise KeyError(key)
		return result

	def get(self, key, default=None):
		"""
		Return the value for key if key is in the dictionary, else default.
		If default is not given, it defaults to None, so that this method
		never raises a KeyError.
		"""
		try:
			return self[key]
		except KeyError:
			return default

	def _find_first_match_(self, keys, item):
		is_match = functools.partial(self.match, item)
		matches = list(filter(is_match, keys))
		if matches:
			return matches[0]
		raise KeyError(item)

	def bounds(self):
		sorted_keys = sorted(self.keys(), **self.sort_params)
		return (
			sorted_keys[RangeMap.first_item],
			sorted_keys[RangeMap.last_item],
		)

	# some special values for the RangeMap
	undefined_value = type(str('RangeValueUndefined'), (object,), {})()

	class Item(int):
		"RangeMap Item"
	first_item = Item(0)
	last_item = Item(-1)


def __identity(x):
	return x


def sorted_items(d, key=__identity, reverse=False):
	"""
	Return the items of the dictionary sorted by the keys

	>>> sample = dict(foo=20, bar=42, baz=10)
	>>> tuple(sorted_items(sample))
	(('bar', 42), ('baz', 10), ('foo', 20))

	>>> reverse_string = lambda s: ''.join(reversed(s))
	>>> tuple(sorted_items(sample, key=reverse_string))
	(('foo', 20), ('bar', 42), ('baz', 10))

	>>> tuple(sorted_items(sample, reverse=True))
	(('foo', 20), ('baz', 10), ('bar', 42))
	"""
	# wrap the key func so it operates on the first element of each item
	def pairkey_key(item):
		return key(item[0])
	return sorted(d.items(), key=pairkey_key, reverse=reverse)


class KeyTransformingDict(dict):
	"""
	A dict subclass that transforms the keys before they're used.
	Subclasses may override the default transform_key to customize behavior.
	"""
	@staticmethod
	def transform_key(key):
		return key

	def __init__(self, *args, **kargs):
		super(KeyTransformingDict, self).__init__()
		# build a dictionary using the default constructs
		d = dict(*args, **kargs)
		# build this dictionary using transformed keys.
		for item in d.items():
			self.__setitem__(*item)

	def __setitem__(self, key, val):
		key = self.transform_key(key)
		super(KeyTransformingDict, self).__setitem__(key, val)

	def __getitem__(self, key):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).__getitem__(key)

	def __contains__(self, key):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).__contains__(key)

	def __delitem__(self, key):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).__delitem__(key)

	def get(self, key, *args, **kwargs):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).get(key, *args, **kwargs)

	def setdefault(self, key, *args, **kwargs):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).setdefault(key, *args, **kwargs)

	def pop(self, key, *args, **kwargs):
		key = self.transform_key(key)
		return super(KeyTransformingDict, self).pop(key, *args, **kwargs)

	def matching_key_for(self, key):
		"""
		Given a key, return the actual key stored in self that matches.
		Raise KeyError if the key isn't found.
		"""
		try:
			return next(e_key for e_key in self.keys() if e_key == key)
		except StopIteration:
			raise KeyError(key)


class FoldedCaseKeyedDict(KeyTransformingDict):
	"""
	A case-insensitive dictionary (keys are compared as insensitive
	if they are strings).

	>>> d = FoldedCaseKeyedDict()
	>>> d['heLlo'] = 'world'
	>>> list(d.keys()) == ['heLlo']
	True
	>>> list(d.values()) == ['world']
	True
	>>> d['hello'] == 'world'
	True
	>>> 'hello' in d
	True
	>>> 'HELLO' in d
	True
	>>> print(repr(FoldedCaseKeyedDict({'heLlo': 'world'})).replace("u'", "'"))
	{'heLlo': 'world'}
	>>> d = FoldedCaseKeyedDict({'heLlo': 'world'})
	>>> print(d['hello'])
	world
	>>> print(d['Hello'])
	world
	>>> list(d.keys())
	['heLlo']
	>>> d = FoldedCaseKeyedDict({'heLlo': 'world', 'Hello': 'world'})
	>>> list(d.values())
	['world']
	>>> key, = d.keys()
	>>> key in ['heLlo', 'Hello']
	True
	>>> del d['HELLO']
	>>> d
	{}

	get should work

	>>> d['Sumthin'] = 'else'
	>>> d.get('SUMTHIN')
	'else'
	>>> d.get('OTHER', 'thing')
	'thing'
	>>> del d['sumthin']

	setdefault should also work

	>>> d['This'] = 'that'
	>>> print(d.setdefault('this', 'other'))
	that
	>>> len(d)
	1
	>>> print(d['this'])
	that
	>>> print(d.setdefault('That', 'other'))
	other
	>>> print(d['THAT'])
	other

	Make it pop!

	>>> print(d.pop('THAT'))
	other

	To retrieve the key in its originally-supplied form, use matching_key_for

	>>> print(d.matching_key_for('this'))
	This
	"""
	@staticmethod
	def transform_key(key):
		return jaraco.text.FoldedCase(key)


class DictAdapter(object):
	"""
	Provide a getitem interface for attributes of an object.

	Let's say you want to get at the string.lowercase property in a formatted
	string. It's easy with DictAdapter.

	>>> import string
	>>> print("lowercase is %(ascii_lowercase)s" % DictAdapter(string))
	lowercase is abcdefghijklmnopqrstuvwxyz
	"""
	def __init__(self, wrapped_ob):
		self.object = wrapped_ob

	def __getitem__(self, name):
		return getattr(self.object, name)


class ItemsAsAttributes(object):
	"""
	Mix-in class to enable a mapping object to provide items as
	attributes.

	>>> C = type(str('C'), (dict, ItemsAsAttributes), dict())
	>>> i = C()
	>>> i['foo'] = 'bar'
	>>> i.foo
	'bar'

	Natural attribute access takes precedence

	>>> i.foo = 'henry'
	>>> i.foo
	'henry'

	But as you might expect, the mapping functionality is preserved.

	>>> i['foo']
	'bar'

	A normal attribute error should be raised if an attribute is
	requested that doesn't exist.

	>>> i.missing
	Traceback (most recent call last):
	...
	AttributeError: 'C' object has no attribute 'missing'

	It also works on dicts that customize __getitem__

	>>> missing_func = lambda self, key: 'missing item'
	>>> C = type(
	...     str('C'),
	...     (dict, ItemsAsAttributes),
	...     dict(__missing__ = missing_func),
	... )
	>>> i = C()
	>>> i.missing
	'missing item'
	>>> i.foo
	'missing item'
	"""
	def __getattr__(self, key):
		try:
			return getattr(super(ItemsAsAttributes, self), key)
		except AttributeError as e:
			# attempt to get the value from the mapping (return self[key])
			#  but be careful not to lose the original exception context.
			noval = object()

			def _safe_getitem(cont, key, missing_result):
				try:
					return cont[key]
				except KeyError:
					return missing_result
			result = _safe_getitem(self, key, noval)
			if result is not noval:
				return result
			# raise the original exception, but use the original class
			#  name, not 'super'.
			message, = e.args
			message = message.replace('super', self.__class__.__name__, 1)
			e.args = message,
			raise


def invert_map(map):
	"""
	Given a dictionary, return another dictionary with keys and values
	switched. If any of the values resolve to the same key, raises
	a ValueError.

	>>> numbers = dict(a=1, b=2, c=3)
	>>> letters = invert_map(numbers)
	>>> letters[1]
	'a'
	>>> numbers['d'] = 3
	>>> invert_map(numbers)
	Traceback (most recent call last):
	...
	ValueError: Key conflict in inverted mapping
	"""
	res = dict((v, k) for k, v in map.items())
	if not len(res) == len(map):
		raise ValueError('Key conflict in inverted mapping')
	return res


class IdentityOverrideMap(dict):
	"""
	A dictionary that by default maps each key to itself, but otherwise
	acts like a normal dictionary.

	>>> d = IdentityOverrideMap()
	>>> d[42]
	42
	>>> d['speed'] = 'speedo'
	>>> print(d['speed'])
	speedo
	"""

	def __missing__(self, key):
		return key


class DictStack(list, collections.Mapping):
	"""
	A stack of dictionaries that behaves as a view on those dictionaries,
	giving preference to the last.

	>>> stack = DictStack([dict(a=1, c=2), dict(b=2, a=2)])
	>>> stack['a']
	2
	>>> stack['b']
	2
	>>> stack['c']
	2
	>>> stack.push(dict(a=3))
	>>> stack['a']
	3
	>>> set(stack.keys()) == set(['a', 'b', 'c'])
	True
	>>> d = stack.pop()
	>>> stack['a']
	2
	>>> d = stack.pop()
	>>> stack['a']
	1
	>>> stack.get('b', None)
	"""

	def keys(self):
		return list(set(itertools.chain.from_iterable(c.keys() for c in self)))

	def __getitem__(self, key):
		for scope in reversed(self):
			if key in scope:
				return scope[key]
		raise KeyError(key)

	push = list.append


class BijectiveMap(dict):
	"""
	A Bijective Map (two-way mapping).

	Implemented as a simple dictionary of 2x the size, mapping values back
	to keys.

	Note, this implementation may be incomplete. If there's not a test for
	your use case below, it's likely to fail, so please test and send pull
	requests or patches for additional functionality needed.


	>>> m = BijectiveMap()
	>>> m['a'] = 'b'
	>>> m == {'a': 'b', 'b': 'a'}
	True
	>>> print(m['b'])
	a

	>>> m['c'] = 'd'
	>>> len(m)
	2

	Some weird things happen if you map an item to itself or overwrite a
	single key of a pair, so it's disallowed.

	>>> m['e'] = 'e'
	Traceback (most recent call last):
	ValueError: Key cannot map to itself

	>>> m['d'] = 'e'
	Traceback (most recent call last):
	ValueError: Key/Value pairs may not overlap

	>>> m['e'] = 'd'
	Traceback (most recent call last):
	ValueError: Key/Value pairs may not overlap

	>>> print(m.pop('d'))
	c

	>>> 'c' in m
	False

	>>> m = BijectiveMap(dict(a='b'))
	>>> len(m)
	1
	>>> print(m['b'])
	a

	>>> m = BijectiveMap()
	>>> m.update(a='b')
	>>> m['b']
	'a'

	>>> del m['b']
	>>> len(m)
	0
	>>> 'a' in m
	False
	"""
	def __init__(self, *args, **kwargs):
		super(BijectiveMap, self).__init__()
		self.update(*args, **kwargs)

	def __setitem__(self, item, value):
		if item == value:
			raise ValueError("Key cannot map to itself")
		overlap = (
			item in self and self[item] != value
			or
			value in self and self[value] != item
		)
		if overlap:
			raise ValueError("Key/Value pairs may not overlap")
		super(BijectiveMap, self).__setitem__(item, value)
		super(BijectiveMap, self).__setitem__(value, item)

	def __delitem__(self, item):
		self.pop(item)

	def __len__(self):
		return super(BijectiveMap, self).__len__() // 2

	def pop(self, key, *args, **kwargs):
		mirror = self[key]
		super(BijectiveMap, self).__delitem__(mirror)
		return super(BijectiveMap, self).pop(key, *args, **kwargs)

	def update(self, *args, **kwargs):
		# build a dictionary using the default constructs
		d = dict(*args, **kwargs)
		# build this dictionary using transformed keys.
		for item in d.items():
			self.__setitem__(*item)


class FrozenDict(collections.Mapping, collections.Hashable):
	"""
	An immutable mapping.

	>>> a = FrozenDict(a=1, b=2)
	>>> b = FrozenDict(a=1, b=2)
	>>> a == b
	True

	>>> a == dict(a=1, b=2)
	True
	>>> dict(a=1, b=2) == a
	True

	>>> a['c'] = 3
	Traceback (most recent call last):
	...
	TypeError: 'FrozenDict' object does not support item assignment

	>>> a.update(y=3)
	Traceback (most recent call last):
	...
	AttributeError: 'FrozenDict' object has no attribute 'update'

	Copies should compare equal

	>>> copy.copy(a) == a
	True

	Copies should be the same type

	>>> isinstance(copy.copy(a), FrozenDict)
	True

	FrozenDict supplies .copy(), even though collections.Mapping doesn't
	demand it.

	>>> a.copy() == a
	True
	>>> a.copy() is not a
	True
	"""
	__slots__ = ['__data']

	def __new__(cls, *args, **kwargs):
		self = super(FrozenDict, cls).__new__(cls)
		self.__data = dict(*args, **kwargs)
		return self

	# Container
	def __contains__(self, key):
		return key in self.__data

	# Hashable
	def __hash__(self):
		return hash(tuple(sorted(self.__data.iteritems())))

	# Mapping
	def __iter__(self):
		return iter(self.__data)

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

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

	# override get for efficiency provided by dict
	def get(self, *args, **kwargs):
		return self.__data.get(*args, **kwargs)

	# override eq to recognize underlying implementation
	def __eq__(self, other):
		if isinstance(other, FrozenDict):
			other = other.__data
		return self.__data.__eq__(other)

	def copy(self):
		"Return a shallow copy of self"
		return copy.copy(self)


class Enumeration(ItemsAsAttributes, BijectiveMap):
	"""
	A convenient way to provide enumerated values

	>>> e = Enumeration('a b c')
	>>> e['a']
	0

	>>> e.a
	0

	>>> e[1]
	'b'

	>>> set(e.names) == set('abc')
	True

	>>> set(e.codes) == set(range(3))
	True

	>>> e.get('d') is None
	True

	Codes need not start with 0

	>>> e = Enumeration('a b c', range(1, 4))
	>>> e['a']
	1

	>>> e[3]
	'c'
	"""
	def __init__(self, names, codes=None):
		if isinstance(names, six.string_types):
			names = names.split()
		if codes is None:
			codes = itertools.count()
		super(Enumeration, self).__init__(zip(names, codes))

	@property
	def names(self):
		return (key for key in self if isinstance(key, six.string_types))

	@property
	def codes(self):
		return (self[name] for name in self.names)


class Everything(object):
	"""
	A collection "containing" every possible thing.

	>>> 'foo' in Everything()
	True

	>>> import random
	>>> random.randint(1, 999) in Everything()
	True

	>>> random.choice([None, 'foo', 42, ('a', 'b', 'c')]) in Everything()
	True
	"""
	def __contains__(self, other):
		return True


class InstrumentedDict(six.moves.UserDict):
	"""
	Instrument an existing dictionary with additional
	functionality, but always reference and mutate
	the original dictionary.

	>>> orig = {'a': 1, 'b': 2}
	>>> inst = InstrumentedDict(orig)
	>>> inst['a']
	1
	>>> inst['c'] = 3
	>>> orig['c']
	3
	>>> inst.keys() == orig.keys()
	True
	"""
	def __init__(self, data):
		six.moves.UserDict.__init__(self)
		self.data = data


class Least(object):
	"""
	A value that is always lesser than any other

	>>> least = Least()
	>>> 3 < least
	False
	>>> 3 > least
	True
	>>> least < 3
	True
	>>> least <= 3
	True
	>>> least > 3
	False
	>>> 'x' > least
	True
	>>> None > least
	True
	"""

	def __le__(self, other):
		return True
	__lt__ = __le__

	def __ge__(self, other):
		return False
	__gt__ = __ge__


class Greatest(object):
	"""
	A value that is always greater than any other

	>>> greatest = Greatest()
	>>> 3 < greatest
	True
	>>> 3 > greatest
	False
	>>> greatest < 3
	False
	>>> greatest > 3
	True
	>>> greatest >= 3
	True
	>>> 'x' > greatest
	False
	>>> None > greatest
	False
	"""

	def __ge__(self, other):
		return True
	__gt__ = __ge__

	def __le__(self, other):
		return False
	__lt__ = __le__
