import unittest

from test import test_support

from itertools import *

from weakref import proxy

import sys

import operator

import random

maxsize = test_support.MAX_Py_ssize_t

minsize = -maxsize-1

def onearg(x):

    'Test function of one argument'

    return 2*x

def errfunc(*args):

    'Test function that raises an error'

    raise ValueError

def gen3():

    'Non-restartable source sequence'

    for i in (0, 1, 2):

        yield i

def isEven(x):

    'Test predicate'

    return x%2==0

def isOdd(x):

    'Test predicate'

    return x%2==1

class StopNow:

    'Class emulating an empty iterable.'

    def __iter__(self):

        return self

    def next(self):

        raise StopIteration

def take(n, seq):

    'Convenience function for partially consuming a long of infinite iterable'

    return list(islice(seq, n))

def prod(iterable):

    return reduce(operator.mul, iterable, 1)

def fact(n):

    'Factorial'

    return prod(range(1, n+1))

class TestBasicOps(unittest.TestCase):

    def test_chain(self):

        def chain2(*iterables):

            'Pure python version in the docs'

            for it in iterables:

                for element in it:

                    yield element

        for c in (chain, chain2):

            self.assertEqual(list(c('abc', 'def')), list('abcdef'))

            self.assertEqual(list(c('abc')), list('abc'))

            self.assertEqual(list(c('')), [])

            self.assertEqual(take(4, c('abc', 'def')), list('abcd'))

            self.assertRaises(TypeError, list,c(2, 3))

    def test_chain_from_iterable(self):

        self.assertEqual(list(chain.from_iterable(['abc', 'def'])), list('abcdef'))

        self.assertEqual(list(chain.from_iterable(['abc'])), list('abc'))

        self.assertEqual(list(chain.from_iterable([''])), [])

        self.assertEqual(take(4, chain.from_iterable(['abc', 'def'])), list('abcd'))

        self.assertRaises(TypeError, list, chain.from_iterable([2, 3]))

    def test_combinations(self):

        self.assertRaises(TypeError, combinations, 'abc')   # missing r argument

        self.assertRaises(TypeError, combinations, 'abc', 2, 1) # too many arguments

        self.assertRaises(TypeError, combinations, None)        # pool is not iterable

        self.assertRaises(ValueError, combinations, 'abc', -2)  # r is negative

        self.assertRaises(ValueError, combinations, 'abc', 32)  # r is too big

        self.assertEqual(list(combinations(range(4), 3)),

                                           [(0,1,2), (0,1,3), (0,2,3), (1,2,3)])

        def combinations1(iterable, r):

            'Pure python version shown in the docs'

            pool = tuple(iterable)

            n = len(pool)

            indices = range(r)

            yield tuple(pool[i] for i in indices)

            while 1:

                for i in reversed(range(r)):

                    if indices[i] != i + n - r:

                        break

                else:

                    return

                indices[i] += 1

                for j in range(i+1, r):

                    indices[j] = indices[j-1] + 1

                yield tuple(pool[i] for i in indices)

        def combinations2(iterable, r):

            'Pure python version shown in the docs'

            pool = tuple(iterable)

            n = len(pool)

            for indices in permutations(range(n), r):

                if sorted(indices) == list(indices):

                    yield tuple(pool[i] for i in indices)

        for n in range(7):

            values = [5*x-12 for x in range(n)]

            for r in range(n+1):

                result = list(combinations(values, r))

                self.assertEqual(len(result), fact(n) / fact(r) / fact(n-r)) # right number of combs

                self.assertEqual(len(result), len(set(result)))         # no repeats

                self.assertEqual(result, sorted(result))                # lexicographic order

                for c in result:

                    self.assertEqual(len(c), r)                         # r-length combinations

                    self.assertEqual(len(set(c)), r)                    # no duplicate elements

                    self.assertEqual(list(c), sorted(c))                # keep original ordering

                    self.assert_(all(e in values for e in c))           # elements taken from input iterable

                    self.assertEqual(list(c),

                                     [e for e in values if e in c])      # comb is a subsequence of the input iterable

                self.assertEqual(result, list(combinations1(values, r))) # matches first pure python version

                self.assertEqual(result, list(combinations2(values, r))) # matches first pure python version

        # Test implementation detail:  tuple re-use

        self.assertEqual(len(set(map(id, combinations('abcde', 3)))), 1)

        self.assertNotEqual(len(set(map(id, list(combinations('abcde', 3))))), 1)

    def test_permutations(self):

        self.assertRaises(TypeError, permutations)              # too few arguments

        self.assertRaises(TypeError, permutations, 'abc', 2, 1) # too many arguments

        self.assertRaises(TypeError, permutations, None)        # pool is not iterable

        self.assertRaises(ValueError, permutations, 'abc', -2)  # r is negative

        self.assertRaises(ValueError, permutations, 'abc', 32)  # r is too big

        self.assertRaises(TypeError, permutations, 'abc', 's')  # r is not an int or None

        self.assertEqual(list(permutations(range(3), 2)),

                                           [(0,1), (0,2), (1,0), (1,2), (2,0), (2,1)])

        def permutations1(iterable, r=None):

            'Pure python version shown in the docs'

            pool = tuple(iterable)

            n = len(pool)

            r = n if r is None else r

            indices = range(n)

            cycles = range(n, n-r, -1)

            yield tuple(pool[i] for i in indices[:r])

            while n:

                for i in reversed(range(r)):

                    cycles[i] -= 1

                    if cycles[i] == 0:

                        indices[i:] = indices[i+1:] + indices[i:i+1]

                        cycles[i] = n - i

                    else:

                        j = cycles[i]

                        indices[i], indices[-j] = indices[-j], indices[i]

                        yield tuple(pool[i] for i in indices[:r])

                        break

                else:

                    return

        def permutations2(iterable, r=None):

            'Pure python version shown in the docs'

            pool = tuple(iterable)

            n = len(pool)

            r = n if r is None else r

            for indices in product(range(n), repeat=r):

                if len(set(indices)) == r:

                    yield tuple(pool[i] for i in indices)

        for n in range(7):

            values = [5*x-12 for x in range(n)]

            for r in range(n+1):

                result = list(permutations(values, r))

                self.assertEqual(len(result), fact(n) / fact(n-r))      # right number of perms

                self.assertEqual(len(result), len(set(result)))         # no repeats

                self.assertEqual(result, sorted(result))                # lexicographic order

                for p in result:

                    self.assertEqual(len(p), r)                         # r-length permutations

                    self.assertEqual(len(set(p)), r)                    # no duplicate elements

                    self.assert_(all(e in values for e in p))           # elements taken from input iterable

                self.assertEqual(result, list(permutations1(values, r))) # matches first pure python version

                self.assertEqual(result, list(permutations2(values, r))) # matches first pure python version

                if r == n:

                    self.assertEqual(result, list(permutations(values, None))) # test r as None

                    self.assertEqual(result, list(permutations(values)))       # test default r

        # Test implementation detail:  tuple re-use

        self.assertEqual(len(set(map(id, permutations('abcde', 3)))), 1)

        self.assertNotEqual(len(set(map(id, list(permutations('abcde', 3))))), 1)

    def test_count(self):

        self.assertEqual(zip('abc',count()), [('a', 0), ('b', 1), ('c', 2)])

        self.assertEqual(zip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)])

        self.assertEqual(take(2, zip('abc',count(3))), [('a', 3), ('b', 4)])

        self.assertEqual(take(2, zip('abc',count(-1))), [('a', -1), ('b', 0)])

        self.assertEqual(take(2, zip('abc',count(-3))), [('a', -3), ('b', -2)])

        self.assertRaises(TypeError, count, 2, 3)

        self.assertRaises(TypeError, count, 'a')

        self.assertEqual(list(islice(count(maxsize-5), 10)), range(maxsize-5, maxsize+5))

        self.assertEqual(list(islice(count(-maxsize-5), 10)), range(-maxsize-5, -maxsize+5))

        c = count(3)

        self.assertEqual(repr(c), 'count(3)')

        c.next()

        self.assertEqual(repr(c), 'count(4)')

        c = count(-9)

        self.assertEqual(repr(c), 'count(-9)')

        c.next()

        self.assertEqual(c.next(), -8)

        for i in (-sys.maxint-5, -sys.maxint+5 ,-10, -1, 0, 10, sys.maxint-5, sys.maxint+5):

            # Test repr (ignoring the L in longs)

            r1 = repr(count(i)).replace('L', '')

            r2 = 'count(%r)'.__mod__(i).replace('L', '')

            self.assertEqual(r1, r2)

    def test_cycle(self):

        self.assertEqual(take(10, cycle('abc')), list('abcabcabca'))

        self.assertEqual(list(cycle('')), [])

        self.assertRaises(TypeError, cycle)

        self.assertRaises(TypeError, cycle, 5)

        self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0])

    def test_groupby(self):

        # Check whether it accepts arguments correctly

        self.assertEqual([], list(groupby([])))

        self.assertEqual([], list(groupby([], key=id)))

        self.assertRaises(TypeError, list, groupby('abc', []))

        self.assertRaises(TypeError, groupby, None)

        self.assertRaises(TypeError, groupby, 'abc', lambda x:x, 10)

        # Check normal input

        s = [(0, 10, 20), (0, 11,21), (0,12,21), (1,13,21), (1,14,22),

             (2,15,22), (3,16,23), (3,17,23)]

        dup = []

        for k, g in groupby(s, lambda r:r[0]):

            for elem in g:

                self.assertEqual(k, elem[0])

                dup.append(elem)

        self.assertEqual(s, dup)

        # Check nested case

        dup = []

        for k, g in groupby(s, lambda r:r[0]):

            for ik, ig in groupby(g, lambda r:r[2]):

                for elem in ig:

                    self.assertEqual(k, elem[0])

                    self.assertEqual(ik, elem[2])

                    dup.append(elem)

        self.assertEqual(s, dup)

        # Check case where inner iterator is not used

        keys = [k for k, g in groupby(s, lambda r:r[0])]

        expectedkeys = set([r[0] for r in s])

        self.assertEqual(set(keys), expectedkeys)

        self.assertEqual(len(keys), len(expectedkeys))

        # Exercise pipes and filters style

        s = 'abracadabra'

        # sort s | uniq

        r = [k for k, g in groupby(sorted(s))]

        self.assertEqual(r, ['a', 'b', 'c', 'd', 'r'])

        # sort s | uniq -d

        r = [k for k, g in groupby(sorted(s)) if list(islice(g,1,2))]

        self.assertEqual(r, ['a', 'b', 'r'])

        # sort s | uniq -c

        r = [(len(list(g)), k) for k, g in groupby(sorted(s))]

        self.assertEqual(r, [(5, 'a'), (2, 'b'), (1, 'c'), (1, 'd'), (2, 'r')])

        # sort s | uniq -c | sort -rn | head -3

        r = sorted([(len(list(g)) , k) for k, g in groupby(sorted(s))], reverse=True)[:3]

        self.assertEqual(r, [(5, 'a'), (2, 'r'), (2, 'b')])

        # iter.next failure

        class ExpectedError(Exception):

            pass

        def delayed_raise(n=0):

            for i in range(n):

                yield 'yo'

            raise ExpectedError

        def gulp(iterable, keyp=None, func=list):

            return [func(g) for k, g in groupby(iterable, keyp)]

        # iter.next failure on outer object

        self.assertRaises(ExpectedError, gulp, delayed_raise(0))

        # iter.next failure on inner object

        self.assertRaises(ExpectedError, gulp, delayed_raise(1))

        # __cmp__ failure

        class DummyCmp:

            def __cmp__(self, dst):

                raise ExpectedError

        s = [DummyCmp(), DummyCmp(), None]

        # __cmp__ failure on outer object

        self.assertRaises(ExpectedError, gulp, s, func=id)

        # __cmp__ failure on inner object

        self.assertRaises(ExpectedError, gulp, s)

        # keyfunc failure

        def keyfunc(obj):

            if keyfunc.skip > 0:

                keyfunc.skip -= 1

                return obj

            else:

                raise ExpectedError

        # keyfunc failure on outer object

        keyfunc.skip = 0

        self.assertRaises(ExpectedError, gulp, [None], keyfunc)

        keyfunc.skip = 1

        self.assertRaises(ExpectedError, gulp, [None, None], keyfunc)

    def test_ifilter(self):

        self.assertEqual(list(ifilter(isEven, range(6))), [0,2,4])

        self.assertEqual(list(ifilter(None, [0,1,0,2,0])), [1,2])

        self.assertEqual(list(ifilter(bool, [0,1,0,2,0])), [1,2])

        self.assertEqual(take(4, ifilter(isEven, count())), [0,2,4,6])

        self.assertRaises(TypeError, ifilter)

        self.assertRaises(TypeError, ifilter, lambda x:x)

        self.assertRaises(TypeError, ifilter, lambda x:x, range(6), 7)

        self.assertRaises(TypeError, ifilter, isEven, 3)

        self.assertRaises(TypeError, ifilter(range(6), range(6)).next)

    def test_ifilterfalse(self):

        self.assertEqual(list(ifilterfalse(isEven, range(6))), [1,3,5])

        self.assertEqual(list(ifilterfalse(None, [0,1,0,2,0])), [0,0,0])

        self.assertEqual(list(ifilterfalse(bool, [0,1,0,2,0])), [0,0,0])

        self.assertEqual(take(4, ifilterfalse(isEven, count())), [1,3,5,7])

        self.assertRaises(TypeError, ifilterfalse)

        self.assertRaises(TypeError, ifilterfalse, lambda x:x)

        self.assertRaises(TypeError, ifilterfalse, lambda x:x, range(6), 7)

        self.assertRaises(TypeError, ifilterfalse, isEven, 3)

        self.assertRaises(TypeError, ifilterfalse(range(6), range(6)).next)

    def test_izip(self):

        ans = [(x,y) for x, y in izip('abc',count())]

        self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)])

        self.assertEqual(list(izip('abc', range(6))), zip('abc', range(6)))

        self.assertEqual(list(izip('abcdef', range(3))), zip('abcdef', range(3)))

        self.assertEqual(take(3,izip('abcdef', count())), zip('abcdef', range(3)))

        self.assertEqual(list(izip('abcdef')), zip('abcdef'))

        self.assertEqual(list(izip()), zip())

        self.assertRaises(TypeError, izip, 3)

        self.assertRaises(TypeError, izip, range(3), 3)

        # Check tuple re-use (implementation detail)

        self.assertEqual([tuple(list(pair)) for pair in izip('abc', 'def')],

                         zip('abc', 'def'))

        self.assertEqual([pair for pair in izip('abc', 'def')],

                         zip('abc', 'def'))

        ids = map(id, izip('abc', 'def'))

        self.assertEqual(min(ids), max(ids))

        ids = map(id, list(izip('abc', 'def')))

        self.assertEqual(len(dict.fromkeys(ids)), len(ids))

    def test_iziplongest(self):

        for args in [

                ['abc', range(6)],

                [range(6), 'abc'],

                [range(1000), range(2000,2100), range(3000,3050)],

                [range(1000), range(0), range(3000,3050), range(1200), range(1500)],

                [range(1000), range(0), range(3000,3050), range(1200), range(1500), range(0)],

            ]:

            target = map(None, *args)

            self.assertEqual(list(izip_longest(*args)), target)

            self.assertEqual(list(izip_longest(*args, **{})), target)

            target = [tuple((e is None and 'X' or e) for e in t) for t in target]   # Replace None fills with 'X'

            self.assertEqual(list(izip_longest(*args, **dict(fillvalue='X'))), target)

        self.assertEqual(take(3,izip_longest('abcdef', count())), zip('abcdef', range(3))) # take 3 from infinite input

        self.assertEqual(list(izip_longest()), zip())

        self.assertEqual(list(izip_longest([])), zip([]))

        self.assertEqual(list(izip_longest('abcdef')), zip('abcdef'))

        self.assertEqual(list(izip_longest('abc', 'defg', **{})), map(None, 'abc', 'defg')) # empty keyword dict

        self.assertRaises(TypeError, izip_longest, 3)

        self.assertRaises(TypeError, izip_longest, range(3), 3)

        for stmt in [

            "izip_longest('abc', fv=1)",

            "izip_longest('abc', fillvalue=1, bogus_keyword=None)",

        ]:

            try:

                eval(stmt, globals(), locals())

            except TypeError:

                pass

            else:

                self.fail('Did not raise Type in:  ' + stmt)

        # Check tuple re-use (implementation detail)

        self.assertEqual([tuple(list(pair)) for pair in izip_longest('abc', 'def')],

                         zip('abc', 'def'))

        self.assertEqual([pair for pair in izip_longest('abc', 'def')],

                         zip('abc', 'def'))

        ids = map(id, izip_longest('abc', 'def'))

        self.assertEqual(min(ids), max(ids))

        ids = map(id, list(izip_longest('abc', 'def')))

        self.assertEqual(len(dict.fromkeys(ids)), len(ids))

    def test_product(self):

        for args, result in [

            ([], [()]),                     # zero iterables

            (['ab'], [('a',), ('b',)]),     # one iterable

            ([range(2), range(3)], [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2)]),     # two iterables

            ([range(0), range(2), range(3)], []),           # first iterable with zero length

            ([range(2), range(0), range(3)], []),           # middle iterable with zero length

            ([range(2), range(3), range(0)], []),           # last iterable with zero length

            ]:

            self.assertEqual(list(product(*args)), result)

            for r in range(4):

                self.assertEqual(list(product(*(args*r))),

                                 list(product(*args, **dict(repeat=r))))

        self.assertEqual(len(list(product(*[range(7)]*6))), 7**6)

        self.assertRaises(TypeError, product, range(6), None)

        def product1(*args, **kwds):

            pools = map(tuple, args) * kwds.get('repeat', 1)

            n = len(pools)

            if n == 0:

                yield ()

                return

            if any(len(pool) == 0 for pool in pools):

                return

            indices = [0] * n

            yield tuple(pool[i] for pool, i in zip(pools, indices))

            while 1:

                for i in reversed(range(n)):  # right to left

                    if indices[i] == len(pools[i]) - 1:

                        continue

                    indices[i] += 1

                    for j in range(i+1, n):

                        indices[j] = 0

                    yield tuple(pool[i] for pool, i in zip(pools, indices))

                    break

                else:

                    return

        def product2(*args, **kwds):

            'Pure python version used in docs'

            pools = map(tuple, args) * kwds.get('repeat', 1)

            result = [[]]

            for pool in pools:

                result = [x+[y] for x in result for y in pool]

            for prod in result:

                yield tuple(prod)

        argtypes = ['', 'abc', '', xrange(0), xrange(4), dict(a=1, b=2, c=3),

                    set('abcdefg'), range(11), tuple(range(13))]

        for i in range(100):

            args = [random.choice(argtypes) for j in range(random.randrange(5))]

            expected_len = prod(map(len, args))

            self.assertEqual(len(list(product(*args))), expected_len)

            self.assertEqual(list(product(*args)), list(product1(*args)))

            self.assertEqual(list(product(*args)), list(product2(*args)))

            args = map(iter, args)

            self.assertEqual(len(list(product(*args))), expected_len)

        # Test implementation detail:  tuple re-use

        self.assertEqual(len(set(map(id, product('abc', 'def')))), 1)

        self.assertNotEqual(len(set(map(id, list(product('abc', 'def'))))), 1)

    def test_repeat(self):

        self.assertEqual(zip(xrange(3),repeat('a')),

                         [(0, 'a'), (1, 'a'), (2, 'a')])

        self.assertEqual(list(repeat('a', 3)), ['a', 'a', 'a'])

        self.assertEqual(take(3, repeat('a')), ['a', 'a', 'a'])

        self.assertEqual(list(repeat('a', 0)), [])

        self.assertEqual(list(repeat('a', -3)), [])

        self.assertRaises(TypeError, repeat)

        self.assertRaises(TypeError, repeat, None, 3, 4)

        self.assertRaises(TypeError, repeat, None, 'a')

        r = repeat(1+0j)

        self.assertEqual(repr(r), 'repeat((1+0j))')

        r = repeat(1+0j, 5)

        self.assertEqual(repr(r), 'repeat((1+0j), 5)')

        list(r)

        self.assertEqual(repr(r), 'repeat((1+0j), 0)')

    def test_imap(self):

        self.assertEqual(list(imap(operator.pow, range(3), range(1,7))),

                         [0**1, 1**2, 2**3])

        self.assertEqual(list(imap(None, 'abc', range(5))),

                         [('a',0),('b',1),('c',2)])

        self.assertEqual(list(imap(None, 'abc', count())),

                         [('a',0),('b',1),('c',2)])

        self.assertEqual(take(2,imap(None, 'abc', count())),

                         [('a',0),('b',1)])

        self.assertEqual(list(imap(operator.pow, [])), [])

        self.assertRaises(TypeError, imap)

        self.assertRaises(TypeError, imap, operator.neg)

        self.assertRaises(TypeError, imap(10, range(5)).next)

        self.assertRaises(ValueError, imap(errfunc, [4], [5]).next)

        self.assertRaises(TypeError, imap(onearg, [4], [5]).next)

    def test_starmap(self):

        self.assertEqual(list(starmap(operator.pow, zip(range(3), range(1,7)))),

                         [0**1, 1**2, 2**3])

        self.assertEqual(take(3, starmap(operator.pow, izip(count(), count(1)))),

                         [0**1, 1**2, 2**3])

        self.assertEqual(list(starmap(operator.pow, [])), [])

        self.assertEqual(list(starmap(operator.pow, [iter([4,5])])), [4**5])

        self.assertRaises(TypeError, list, starmap(operator.pow, [None]))

        self.assertRaises(TypeError, starmap)

        self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra')

        self.assertRaises(TypeError, starmap(10, [(4,5)]).next)

        self.assertRaises(ValueError, starmap(errfunc, [(4,5)]).next)

        self.assertRaises(TypeError, starmap(onearg, [(4,5)]).next)

    def test_islice(self):

        for args in [          # islice(args) should agree with range(args)

                (10, 20, 3),

                (10, 3, 20),

                (10, 20),

                (10, 3),

                (20,)

                ]:

            self.assertEqual(list(islice(xrange(100), *args)), range(*args))

        for args, tgtargs in [  # Stop when seqn is exhausted

                ((10, 110, 3), ((10, 100, 3))),

                ((10, 110), ((10, 100))),

                ((110,), (100,))

                ]:

            self.assertEqual(list(islice(xrange(100), *args)), range(*tgtargs))

        # Test stop=None

        self.assertEqual(list(islice(xrange(10), None)), range(10))

        self.assertEqual(list(islice(xrange(10), None, None)), range(10))

        self.assertEqual(list(islice(xrange(10), None, None, None)), range(10))

        self.assertEqual(list(islice(xrange(10), 2, None)), range(2, 10))

        self.assertEqual(list(islice(xrange(10), 1, None, 2)), range(1, 10, 2))