# 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 contextlib import contextmanager

from hypothesis import HealthCheck, settings
from hypothesis.internal.conjecture import engine as engine_module
from hypothesis.internal.conjecture.data import Status
from hypothesis.internal.conjecture.engine import ConjectureRunner
from hypothesis.internal.conjecture.utils import calc_label_from_name
from hypothesis.internal.entropy import deterministic_PRNG

SOME_LABEL = calc_label_from_name("some label")


TEST_SETTINGS = settings(
    max_examples=5000, database=None, suppress_health_check=HealthCheck.all()
)


def run_to_data(f):
    with deterministic_PRNG():
        runner = ConjectureRunner(f, settings=TEST_SETTINGS)
        runner.run()
        assert runner.interesting_examples
        (last_data,) = runner.interesting_examples.values()
        return last_data


def run_to_buffer(f):
    return bytes(run_to_data(f).buffer)


@contextmanager
def buffer_size_limit(n):
    original = engine_module.BUFFER_SIZE
    try:
        engine_module.BUFFER_SIZE = n
        yield
    finally:
        engine_module.BUFFER_SIZE = original


def shrinking_from(start):
    def accept(f):
        with deterministic_PRNG():
            runner = ConjectureRunner(
                f,
                settings=settings(
                    max_examples=5000,
                    database=None,
                    suppress_health_check=HealthCheck.all(),
                ),
            )
            runner.cached_test_function(start)
            assert runner.interesting_examples
            (last_data,) = runner.interesting_examples.values()
            return runner.new_shrinker(
                last_data, lambda d: d.status == Status.INTERESTING
            )

    return accept