# This file is part of Hypothesis, which may be found at
# https://github.com/HypothesisWorks/hypothesis/
#
# Most of this work is copyright (C) 2013-2020 David R. MacIver
# (david@drmaciver.com), but it contains contributions by others. See
# CONTRIBUTING.rst for a full list of people who may hold copyright, and
# consult the git log if you need to determine who owns an individual
# contribution.
#
# This Source Code Form is subject to the terms of the Mozilla Public License,
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/.
#
# END HEADER

from hypothesis.control import note
from hypothesis.errors import InvalidState
from hypothesis.internal.reflection import (
    arg_string,
    convert_positional_arguments,
    nicerepr,
    proxies,
)
from hypothesis.strategies._internal.shared import SharedStrategy
from hypothesis.strategies._internal.strategies import SearchStrategy


class FunctionStrategy(SearchStrategy):
    supports_find = False

    def __init__(self, like, returns, pure):
        super().__init__()
        self.like = like
        self.returns = returns
        self.pure = pure

    def calc_is_empty(self, recur):
        return recur(self.returns)

    def do_draw(self, data):
        @proxies(self.like)
        def inner(*args, **kwargs):
            if data.frozen:
                raise InvalidState(
                    "This generated %s function can only be called within the "
                    "scope of the @given that created it." % (nicerepr(self.like),)
                )
            if self.pure:
                args, kwargs = convert_positional_arguments(self.like, args, kwargs)
                key = (inner, args, frozenset(kwargs.items()))
                val = data.draw(SharedStrategy(base=self.returns, key=key))
            else:
                val = data.draw(self.returns)
            note(
                "Called function: %s(%s) -> %r"
                % (nicerepr(self.like), arg_string(self.like, args, kwargs), val)
            )
            return val

        return inner
