import itertools

from jinja2 import Template
from jinja2.runtime import LoopContext

TEST_IDX_TEMPLATE_STR_1 = (
    "[{% for i in lst|reverse %}(len={{ loop.length }},"
    " revindex={{ loop.revindex }}, index={{ loop.index }}, val={{ i }}){% endfor %}]"
)
TEST_IDX0_TEMPLATE_STR_1 = (
    "[{% for i in lst|reverse %}(len={{ loop.length }},"
    " revindex0={{ loop.revindex0 }}, index0={{ loop.index0 }}, val={{ i }})"
    "{% endfor %}]"
)


def test_loop_idx():
    t = Template(TEST_IDX_TEMPLATE_STR_1)
    lst = [10]
    excepted_render = "[(len=1, revindex=1, index=1, val=10)]"
    assert excepted_render == t.render(lst=lst)


def test_loop_idx0():
    t = Template(TEST_IDX0_TEMPLATE_STR_1)
    lst = [10]
    excepted_render = "[(len=1, revindex0=0, index0=0, val=10)]"
    assert excepted_render == t.render(lst=lst)


def test_loopcontext0():
    in_lst = []
    lc = LoopContext(reversed(in_lst), None)
    assert lc.length == len(in_lst)


def test_loopcontext1():
    in_lst = [10]
    lc = LoopContext(reversed(in_lst), None)
    assert lc.length == len(in_lst)


def test_loopcontext2():
    in_lst = [10, 11]
    lc = LoopContext(reversed(in_lst), None)
    assert lc.length == len(in_lst)


def test_iterator_not_advanced_early():
    t = Template("{% for _, g in gs %}{{ loop.index }} {{ g|list }}\n{% endfor %}")
    out = t.render(
        gs=itertools.groupby([(1, "a"), (1, "b"), (2, "c"), (3, "d")], lambda x: x[0])
    )
    # groupby groups depend on the current position of the iterator. If
    # it was advanced early, the lists would appear empty.
    assert out == "1 [(1, 'a'), (1, 'b')]\n2 [(2, 'c')]\n3 [(3, 'd')]\n"


def test_mock_not_contextfunction():
    """If a callable class has a ``__getattr__`` that returns True-like
    values for arbitrary attrs, it should not be incorrectly identified
    as a ``contextfunction``.
    """

    class Calc:
        def __getattr__(self, item):
            return object()

        def __call__(self, *args, **kwargs):
            return len(args) + len(kwargs)

    t = Template("{{ calc() }}")
    out = t.render(calc=Calc())
    # Would be "1" if context argument was passed.
    assert out == "0"