/*
    tests/test_call_policies.cpp -- keep_alive and call_guard

    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>

    All rights reserved. Use of this source code is governed by a
    BSD-style license that can be found in the LICENSE file.
*/

#include "pybind11_tests.h"

struct CustomGuard
{
    static bool enabled;

    CustomGuard()
    {
        enabled = true;
    }
    ~CustomGuard()
    {
        enabled = false;
    }

    static const char* report_status()
    {
        return enabled ? "guarded" : "unguarded";
    }
};
bool CustomGuard::enabled = false;

struct DependentGuard
{
    static bool enabled;

    DependentGuard()
    {
        enabled = CustomGuard::enabled;
    }
    ~DependentGuard()
    {
        enabled = false;
    }

    static const char* report_status()
    {
        return enabled ? "guarded" : "unguarded";
    }
};
bool DependentGuard::enabled = false;

TEST_SUBMODULE(call_policies, m)
{
    // Parent/Child are used in:
    // test_keep_alive_argument, test_keep_alive_return_value, test_alive_gc_derived,
    // test_alive_gc_multi_derived, test_return_none, test_keep_alive_constructor
    class Child
    {
        public:
            Child()
            {
                py::print("Allocating child.");
            }
            Child(const Child&) = default;
            Child(Child&&) = default;
            ~Child()
            {
                py::print("Releasing child.");
            }
    };
    py::class_<Child>(m, "Child").def(py::init<>());

    class Parent
    {
        public:
            Parent()
            {
                py::print("Allocating parent.");
            }
            Parent(const Parent& parent) = default;
            ~Parent()
            {
                py::print("Releasing parent.");
            }
            void addChild(Child*) {}
            Child* returnChild()
            {
                return new Child();
            }
            Child* returnNullChild()
            {
                return nullptr;
            }
            static Child* staticFunction(Parent*)
            {
                return new Child();
            }
    };
    py::class_<Parent>(m, "Parent")
    .def(py::init<>())
    .def(py::init([](Child*)
    {
        return new Parent();
    }), py::keep_alive<1, 2>())
    .def("addChild", &Parent::addChild)
    .def("addChildKeepAlive", &Parent::addChild, py::keep_alive<1, 2>())
    .def("returnChild", &Parent::returnChild)
    .def("returnChildKeepAlive", &Parent::returnChild, py::keep_alive<1, 0>())
    .def("returnNullChildKeepAliveChild", &Parent::returnNullChild, py::keep_alive<1, 0>())
    .def("returnNullChildKeepAliveParent", &Parent::returnNullChild, py::keep_alive<0, 1>())
    .def_static("staticFunction", &Parent::staticFunction, py::keep_alive<1, 0>());

    m.def("free_function", [](Parent*, Child*) {}, py::keep_alive<1, 2>());
    m.def("invalid_arg_index", [] {}, py::keep_alive<0, 1>());

#if !defined(PYPY_VERSION)
    // test_alive_gc
    class ParentGC : public Parent
    {
        public:
            using Parent::Parent;
    };
    py::class_<ParentGC, Parent>(m, "ParentGC", py::dynamic_attr()).def(py::init<>());
#endif

    // test_call_guard
    m.def("unguarded_call", &CustomGuard::report_status);
    m.def("guarded_call", &CustomGuard::report_status, py::call_guard<CustomGuard>());

    m.def(
        "multiple_guards_correct_order",
        []()
    {
        return CustomGuard::report_status() + std::string(" & ")
               + DependentGuard::report_status();
    },
    py::call_guard<CustomGuard, DependentGuard>());

    m.def(
        "multiple_guards_wrong_order",
        []()
    {
        return DependentGuard::report_status() + std::string(" & ")
               + CustomGuard::report_status();
    },
    py::call_guard<DependentGuard, CustomGuard>());

#if !defined(PYPY_VERSION)
    // `py::call_guard<py::gil_scoped_release>()` should work in PyPy as well,
    // but it's unclear how to test it without `PyGILState_GetThisThreadState`.
    auto report_gil_status = []()
    {
        auto is_gil_held = false;

        if (auto* tstate = py::detail::get_thread_state_unchecked())
        {
            is_gil_held = (tstate == PyGILState_GetThisThreadState());
        }

        return is_gil_held ? "GIL held" : "GIL released";
    };

    m.def("with_gil", report_gil_status);
    m.def("without_gil", report_gil_status, py::call_guard<py::gil_scoped_release>());
#endif
}