"""

Originally from https://github.com/naiquevin/lookupy

The library is provided as-is under the MIT License

Copyright (c) 2013 Vineet Naik (naikvin@gmail.com)

Permission is hereby granted, free of charge, to any person obtaining

a copy of this software and associated documentation files (the

"Software"), to deal in the Software without restriction, including

without limitation the rights to use, copy, modify, merge, publish,

distribute, sublicense, and/or sell copies of the Software, and to

permit persons to whom the Software is furnished to do so, subject to

the following conditions:

The above copyright notice and this permission notice shall be

included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

"""

import re

from typing import TYPE_CHECKING

if TYPE_CHECKING:

from ... import Document

import re

from functools import partial

PLACEHOLDER_PATTERN = re.compile(r'\{\s*([a-zA-Z0-9_]*)\s*}')

def lookup(key, val, doc: 'Document') -> bool:

"""Checks if key-val pair exists in doc using various lookup types

The lookup types are derived from the `key` and then used to check

if the lookup holds true for the document::

>>> lookup('text__exact', 'hello', doc)

The above will return True if doc.text == 'hello' else False. And

>>> lookup('text_exact', '{tags__name}', doc)

will return True if doc.text == doc.tags['name'] else False

:param key : the field name to find

:param val : object to match the value in the document against

:param doc : the document to match

"""

get_key, last = dunder_partition(key)

if isinstance(val, str) and val.startswith('{'):

r = PLACEHOLDER_PATTERN.findall(val)

if r and len(r) == 1:

val = doc._get_attributes(r[0])

else:

raise ValueError(f'The placeholder "{val}" is illegal')

value = doc._get_attributes(get_key)

if last == 'exact':

return value == val

elif last == 'neq':

return value != val

elif last == 'contains':

val = guard_str(val)

return iff_not_none(value, lambda y: val in y)

elif last == 'icontains':

val = guard_str(val)

return iff_not_none(value, lambda y: val.lower() in y.lower())

elif last == 'in':

val = guard_iter(val)

return value in val

elif last == 'nin':

val = guard_iter(val)

return not (value in val)

elif last == 'startswith':

val = guard_str(val)

return iff_not_none(value, lambda y: y.startswith(val))

elif last == 'istartswith':

val = guard_str(val)

return iff_not_none(value, lambda y: y.lower().startswith(val.lower()))

elif last == 'endswith':

val = guard_str(val)

return iff_not_none(value, lambda y: y.endswith(val))

elif last == 'iendswith':

val = guard_str(val)

return iff_not_none(value, lambda y: y.lower().endswith(val.lower()))

elif last == 'gt':

return iff_not_none(value, lambda y: y > val)

elif last == 'gte':

return iff_not_none(value, lambda y: y >= val)

elif last == 'lt':

return iff_not_none(value, lambda y: y < val)

elif last == 'lte':

return iff_not_none(value, lambda y: y <= val)

elif last == 'regex':

return iff_not_none(value, lambda y: re.search(val, y) is not None)

elif last == 'size':

return iff_not_none(value, lambda y: len(y) == val)

else:

# return value == val

raise ValueError(

f'The given compare operator "{last}" (derived from "{key}") is not supported'

)

## Classes to compose compound lookups (Q object)

class LookupTreeElem(object):

"""Base class for a child in the lookup expression tree"""

def __init__(self):

self.negate = False

def evaluate(self, item):

raise NotImplementedError

def __or__(self, other):

node = LookupNode()

node.op = 'or'

node.add_child(self)

node.add_child(other)

return node

def __and__(self, other):

node = LookupNode()

node.add_child(self)

node.add_child(other)

return node

class LookupNode(LookupTreeElem):

"""A node (element having children) in the lookup expression tree

Typically it's any object composed of two ``Q`` objects eg::

>>> Q(language__neq='Ruby') | Q(framework__startswith='S')

>>> ~Q(language__exact='PHP')

"""

def __init__(self, op: str = 'and', negate: bool = False):

super(LookupNode, self).__init__()

self.children = []

self.op = op

self.negate = negate

def add_child(self, child):

self.children.append(child)

def evaluate(self, doc: 'Document'):

"""Evaluates the expression represented by the object for the document

:param doc : the document to match

:return: returns true if lookup passed

"""

results = map(lambda x: x.evaluate(doc), self.children)

result = any(results) if self.op == 'or' else all(results)

return not result if self.negate else result

def __invert__(self):

newnode = LookupNode()

for c in self.children:

newnode.add_child(c)

newnode.negate = not self.negate

return newnode

def __repr__(self):

return f'{self.op}: [{self.children}]'

class LookupLeaf(LookupTreeElem):

"""Class for a leaf in the lookup expression tree"""

def __init__(self, **kwargs):

super(LookupLeaf, self).__init__()

self.lookups = kwargs

def evaluate(self, doc: 'Document'):

"""Evaluates the expression represented by the object for the document

:param doc : the document to match

:return: returns true if lookup passed

"""

result = all(lookup(k, v, doc) for k, v in self.lookups.items())

return not result if self.negate else result

def __invert__(self):

newleaf = LookupLeaf(**self.lookups)

newleaf.negate = not self.negate

return newleaf

def __repr__(self):

return f'{self.lookups}'

# alias LookupLeaf to Q

Q = LookupLeaf

## Exceptions

class LookupyError(Exception):

"""Base exception class for all exceptions raised by lookupy"""

pass

## utility functions

def dunder_partition(key):

"""Splits a dunderkey into 2 parts

The first part is everything before the final double underscore

The second part is after the final double underscore

>>> dunder_partition('a__b__c')

>>> ('a__b', 'c')

"""

parts = key.rsplit('__', 1)

return tuple(parts) if len(parts) > 1 else (parts[0], None)

def iff(precond, val, f):

"""If and only if the precond is True

Shortcut function for precond(val) and f(val). It is mainly used

to create partial functions for commonly required preconditions

:param precond : (function) represents the precondition

:param val : (mixed) value to which the functions are applied

:param f : (function) the actual function

"""

return False if not precond(val) else f(val)

iff_not_none = partial(iff, lambda x: x is not None)

def guard_type(classinfo, val):

if not isinstance(val, classinfo):

raise LookupyError('Value not a {classinfo}'.format(classinfo=classinfo))

return val

guard_str = partial(guard_type, str)

guard_list = partial(guard_type, list)

guard_Q = partial(guard_type, Q)

def guard_iter(val):

try:

iter(val)

except TypeError:

raise LookupyError('Value not an iterable')

else:

return val