# This file is part of Hypothesis, which may be found at
# https://github.com/HypothesisWorks/hypothesis/
#
# Copyright the Hypothesis Authors.
# Individual contributors are listed in AUTHORS.rst and the git log.
#
# 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/.

import gc
import time

import pytest

from hypothesis import given, settings, strategies as st
from hypothesis.errors import DeadlineExceeded, FlakyFailure, InvalidArgument

from tests.common.utils import assert_falsifying_output, fails_with


def test_raises_deadline_on_slow_test():
    @settings(deadline=500)
    @given(st.integers())
    def slow(i):
        time.sleep(1)

    with pytest.raises(DeadlineExceeded):
        slow()


@pytest.mark.skipif(
    settings.get_profile(settings._current_profile).deadline is None,
    reason="not expected to fail if deadline is disabled",
)
@fails_with(DeadlineExceeded)
@given(st.integers())
def test_slow_tests_are_errors_by_default(i):
    time.sleep(1)


def test_non_numeric_deadline_is_an_error():
    with pytest.raises(InvalidArgument):
        settings(deadline="3 seconds")


@given(st.integers())
@settings(deadline=None)
def test_slow_with_none_deadline(i):
    time.sleep(1)


def test_raises_flaky_if_a_test_becomes_fast_on_rerun():
    once = True

    @settings(deadline=500, backend="hypothesis")
    @given(st.integers())
    def test_flaky_slow(i):
        nonlocal once
        if once:
            once = False
            time.sleep(1)

    with pytest.raises(FlakyFailure):
        test_flaky_slow()


def test_deadlines_participate_in_shrinking():
    @settings(deadline=500, max_examples=1000)
    @given(st.integers(min_value=0))
    def slow_if_large(i):
        if i >= 1000:
            time.sleep(1)

    assert_falsifying_output(
        slow_if_large,
        expected_exception=DeadlineExceeded,
        i=1000,
    )


def test_keeps_you_well_above_the_deadline():
    seen = set()
    failed_once = False

    @settings(deadline=100, backend="hypothesis")
    @given(st.integers(0, 2000))
    def slow(i):
        nonlocal failed_once
        # Make sure our initial failure isn't something that immediately goes flaky.
        if not failed_once:
            if i * 0.9 <= 100:
                return
            else:
                failed_once = True

        t = i / 1000
        if i in seen:
            time.sleep(0.9 * t)
        else:
            seen.add(i)
            time.sleep(t)

    with pytest.raises(DeadlineExceeded):
        slow()


def test_gives_a_deadline_specific_flaky_error_message():
    once = True

    @settings(deadline=100, backend="hypothesis")
    @given(st.integers())
    def slow_once(i):
        nonlocal once
        if once:
            once = False
            time.sleep(0.2)

    with pytest.raises(FlakyFailure) as err:
        slow_once()
    assert "Unreliable test timing" in "\n".join(err.value.__notes__)
    assert "took 2" in "\n".join(err.value.__notes__)


@pytest.mark.parametrize("slow_strategy", [False, True])
@pytest.mark.parametrize("slow_test", [False, True])
def test_should_only_fail_a_deadline_if_the_test_is_slow(slow_strategy, slow_test):
    s = st.integers()
    if slow_strategy:
        s = s.map(lambda x: time.sleep(0.08))

    @settings(deadline=50)
    @given(st.data())
    def test(data):
        data.draw(s)
        if slow_test:
            time.sleep(0.1)

    if slow_test:
        with pytest.raises(DeadlineExceeded):
            test()
    else:
        test()


@pytest.mark.skipif(not hasattr(gc, "callbacks"), reason="CPython specific gc delay")
def test_should_not_fail_deadline_due_to_gc():
    @settings(max_examples=1, deadline=50)
    @given(st.integers())
    def test(i):
        before = time.perf_counter()
        gc.collect()
        assert time.perf_counter() - before >= 0.1  # verify that we're slow

    def delay(phase, _info):
        if phase == "start":
            time.sleep(0.1)

    try:
        gc.callbacks.append(delay)
        test()
    finally:
        gc.callbacks.remove(delay)