# 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 pytest

from hypothesis import HealthCheck, Verbosity, assume, example, given, reject, settings
from hypothesis.core import StateForActualGivenExecution
from hypothesis.errors import Flaky, FlakyFailure, Unsatisfiable, UnsatisfiedAssumption
from hypothesis.internal.conjecture.engine import MIN_TEST_CALLS
from hypothesis.internal.scrutineer import Tracer
from hypothesis.strategies import booleans, composite, integers, lists, random_module

from tests.common.utils import no_shrink


class Nope(Exception):
    pass


def test_fails_only_once_is_flaky():
    first_call = True

    @given(integers())
    def rude(x):
        nonlocal first_call
        if first_call:
            first_call = False
            raise Nope

    with pytest.raises(FlakyFailure, match="Falsified on the first call but") as e:
        rude()
    exceptions = e.value.exceptions
    assert len(exceptions) == 1
    assert isinstance(exceptions[0], Nope)


def test_gives_flaky_error_if_assumption_is_flaky():
    seen = set()

    @given(integers())
    @settings(verbosity=Verbosity.quiet, database=None)
    def oops(s):
        assume(s not in seen)
        seen.add(s)
        raise AssertionError

    with pytest.raises(FlakyFailure, match="Inconsistent results from replaying") as e:
        oops()
    exceptions = e.value.exceptions
    assert len(exceptions) == 2
    assert isinstance(exceptions[0], AssertionError)
    assert isinstance(exceptions[1], UnsatisfiedAssumption)


def test_flaky_with_context_when_fails_only_under_tracing(monkeypatch):
    # make anything fail under tracing
    monkeypatch.setattr(Tracer, "can_trace", staticmethod(lambda: True))
    monkeypatch.setattr(Tracer, "__enter__", lambda *_: 1 / 0)
    # ensure tracing is always entered inside _execute_once_for_engine
    monkeypatch.setattr(StateForActualGivenExecution, "_should_trace", lambda _: True)

    @given(integers())
    def test(x):
        pass

    with pytest.raises(
        FlakyFailure, match="failed on the first run but now succeeds"
    ) as e:
        test()
    exceptions = e.value.exceptions
    assert len(exceptions) == 1
    assert isinstance(exceptions[0], ZeroDivisionError)


def test_does_not_attempt_to_shrink_flaky_errors():
    values = []

    @settings(database=None)
    @given(integers())
    def test(x):
        values.append(x)
        assert len(values) != 1

    with pytest.raises(FlakyFailure):
        test()
    # We try a total of ten calls in the generation phase, each usually a
    # unique value, looking briefly (and unsuccessfully) for another bug.
    assert 1 < len(set(values)) <= MIN_TEST_CALLS
    # We don't try any new values while shrinking, just execute the test
    # twice more (to check for flakiness and to raise the bug to the user).
    assert set(values) == set(values[:-2])


class SatisfyMe(Exception):
    pass


@composite
def single_bool_lists(draw):
    n = draw(integers(0, 20))
    result = [False] * (n + 1)
    result[n] = True
    return result


@example([True, False, False, False], [3], None)
@example([False, True, False, False], [3], None)
@example([False, False, True, False], [3], None)
@example([False, False, False, True], [3], None)
@settings(deadline=None)
@given(lists(booleans()) | single_bool_lists(), lists(integers(1, 3)), random_module())
def test_failure_sequence_inducing(building, testing, rnd):
    buildit = iter(building)
    testit = iter(testing)

    def build(x):
        try:
            assume(not next(buildit))
        except StopIteration:
            pass
        return x

    @given(integers().map(build))
    @settings(
        verbosity=Verbosity.quiet,
        database=None,
        suppress_health_check=list(HealthCheck),
        phases=no_shrink,
    )
    def test(x):
        try:
            i = next(testit)
        except StopIteration:
            return
        if i == 1:
            return
        elif i == 2:
            reject()
        else:
            raise Nope

    try:
        test()
    except (Nope, Flaky, Unsatisfiable):
        pass
    except UnsatisfiedAssumption:
        raise SatisfyMe from None