//     Copyright 2018, Kay Hayen, mailto:kay.hayen@gmail.com
//
//     Part of "Nuitka", an optimizing Python compiler that is compatible and
//     integrates with CPython, but also works on its own.
//
//     Licensed under the Apache License, Version 2.0 (the "License");
//     you may not use this file except in compliance with the License.
//     You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
//     Unless required by applicable law or agreed to in writing, software
//     distributed under the License is distributed on an "AS IS" BASIS,
//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//     See the License for the specific language governing permissions and
//     limitations under the License.
//
#ifndef __NUITKA_HELPER_RAISING_H__
#define __NUITKA_HELPER_RAISING_H__

#if PYTHON_VERSION < 266
#define WRONG_EXCEPTION_TYPE_ERROR_MESSAGE "exceptions must be classes or instances, not %s"
#elif PYTHON_VERSION < 300
#define WRONG_EXCEPTION_TYPE_ERROR_MESSAGE "exceptions must be old-style classes or derived from BaseException, not %s"
#else
#define WRONG_EXCEPTION_TYPE_ERROR_MESSAGE "exceptions must derive from BaseException"
#endif

#if PYTHON_VERSION >= 300
static void CHAIN_EXCEPTION(PyObject *exception_value) {
    // Implicit chain of exception already existing.
    PyThreadState *thread_state = PyThreadState_GET();

    // Normalize existing exception first. TODO: Will normally be done already.
    NORMALIZE_EXCEPTION(&EXC_TYPE(thread_state), &EXC_VALUE(thread_state),
                        (PyTracebackObject **)&EXC_TRACEBACK(thread_state));

    PyObject *old_exc_value = EXC_VALUE(thread_state);

    if (old_exc_value != NULL && old_exc_value != Py_None && old_exc_value != exception_value) {
        PyObject *current = old_exc_value;
        while (true) {
            PyObject *context = PyException_GetContext(current);
            if (!context)
                break;

            CHECK_OBJECT(context);
            Py_DECREF(context);
            CHECK_OBJECT(context);

            if (context == exception_value) {
                PyException_SetContext(current, NULL);
                break;
            }

            current = context;
        }

        CHECK_OBJECT(old_exc_value);
        Py_INCREF(old_exc_value);
        PyException_SetContext(exception_value, old_exc_value);

        CHECK_OBJECT(EXC_TRACEBACK(thread_state));
        PyException_SetTraceback(old_exc_value, EXC_TRACEBACK(thread_state));
    }
}
#endif

NUITKA_MAY_BE_UNUSED static void RAISE_EXCEPTION_WITH_TYPE(PyObject **exception_type, PyObject **exception_value,
                                                           PyTracebackObject **exception_tb) {
    *exception_value = NULL;
    *exception_tb = NULL;

#if PYTHON_VERSION < 300
    // Next, repeatedly, replace a tuple exception with its first item
    while (PyTuple_Check(*exception_type) && PyTuple_Size(*exception_type) > 0) {
        PyObject *tmp = *exception_type;
        *exception_type = PyTuple_GET_ITEM(*exception_type, 0);
        Py_INCREF(*exception_type);
        Py_DECREF(tmp);
    }
#endif

    if (PyExceptionClass_Check(*exception_type)) {
        NORMALIZE_EXCEPTION(exception_type, exception_value, exception_tb);
#if PYTHON_VERSION >= 270
        if (unlikely(!PyExceptionInstance_Check(*exception_value))) {
            PyErr_Format(PyExc_TypeError, "calling %s() should have returned an instance of BaseException, not '%s'",
                         ((PyTypeObject *)*exception_type)->tp_name, Py_TYPE(*exception_value)->tp_name);

            Py_DECREF(*exception_type);
            Py_DECREF(*exception_value);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
            return;
        }
#endif

#if PYTHON_VERSION >= 300
        CHAIN_EXCEPTION(*exception_value);
#endif
        return;
    } else if (PyExceptionInstance_Check(*exception_type)) {
        *exception_value = *exception_type;
        *exception_type = PyExceptionInstance_Class(*exception_type);
        Py_INCREF(*exception_type);

#if PYTHON_VERSION >= 300
        CHAIN_EXCEPTION(*exception_value);

        // Note: Cannot be assigned here.
        assert(*exception_tb == NULL);
        *exception_tb = (PyTracebackObject *)PyException_GetTraceback(*exception_value);
#endif

        return;
    } else {
        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(*exception_type)->tp_name);
        Py_DECREF(*exception_type);

        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        return;
    }
}

#if PYTHON_VERSION >= 300
NUITKA_MAY_BE_UNUSED static void RAISE_EXCEPTION_WITH_CAUSE(PyObject **exception_type, PyObject **exception_value,
                                                            PyTracebackObject **exception_tb,
                                                            PyObject *exception_cause) {
    CHECK_OBJECT(*exception_type);
    CHECK_OBJECT(exception_cause);
    *exception_tb = NULL;

    // None is not a cause.
    if (exception_cause == Py_None) {
        Py_DECREF(exception_cause);
        exception_cause = NULL;
    } else if (PyExceptionClass_Check(exception_cause)) {
        PyObject *old_exception_cause = exception_cause;
        exception_cause = PyObject_CallObject(exception_cause, NULL);
        Py_DECREF(old_exception_cause);

        if (unlikely(exception_cause == NULL)) {
            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_tb);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);

            return;
        }
    }

    if (unlikely(exception_cause != NULL && !PyExceptionInstance_Check(exception_cause))) {
        Py_DECREF(*exception_type);
        Py_XDECREF(*exception_tb);
        Py_XDECREF(exception_cause);

#ifdef _NUITKA_FULL_COMPAT
        PyErr_Format(PyExc_TypeError, "exception causes must derive from BaseException");
#else
        PyErr_Format(PyExc_TypeError, "exception causes must derive from BaseException (%s does not)",
                     Py_TYPE(exception_cause)->tp_name);
#endif
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        return;
    }

    if (PyExceptionClass_Check(*exception_type)) {
        NORMALIZE_EXCEPTION(exception_type, exception_value, exception_tb);

        if (unlikely(!PyExceptionInstance_Check(*exception_value))) {
            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_value);
            Py_DECREF(*exception_tb);
            Py_XDECREF(exception_cause);

            PyErr_Format(PyExc_TypeError, "calling %s() should have returned an instance of BaseException, not '%s'",
                         ((PyTypeObject *)exception_type)->tp_name, Py_TYPE(*exception_value)->tp_name);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
            return;
        }

        PyException_SetCause(*exception_value, exception_cause);

        CHAIN_EXCEPTION(*exception_value);
        return;
    } else if (PyExceptionInstance_Check(*exception_type)) {
        *exception_value = *exception_type;
        *exception_type = PyExceptionInstance_Class(*exception_type);
        Py_INCREF(*exception_type);

        PyException_SetCause(*exception_value, exception_cause);

        CHAIN_EXCEPTION(*exception_value);
        return;
    } else {
        Py_DECREF(*exception_type);
        Py_XDECREF(exception_cause);

        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(exception_type)->tp_name);
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);

        return;
    }
}
#endif

NUITKA_MAY_BE_UNUSED static void RAISE_EXCEPTION_WITH_VALUE(PyObject **exception_type, PyObject **exception_value,
                                                            PyTracebackObject **exception_tb) {
    CHECK_OBJECT(*exception_type);
    CHECK_OBJECT(*exception_value);
    *exception_tb = NULL;

    // Non-empty tuple exceptions are the first element.
    while (unlikely(PyTuple_Check(*exception_type) && PyTuple_Size(*exception_type) > 0)) {
        *exception_type = PyTuple_GET_ITEM(*exception_type, 0);
    }

    if (PyExceptionClass_Check(*exception_type)) {
        NORMALIZE_EXCEPTION(exception_type, exception_value, exception_tb);
#if PYTHON_VERSION >= 270
        if (unlikely(!PyExceptionInstance_Check(*exception_value))) {
            PyErr_Format(PyExc_TypeError, "calling %s() should have returned an instance of BaseException, not '%s'",
                         ((PyTypeObject *)*exception_type)->tp_name, Py_TYPE(*exception_value)->tp_name);

            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_value);
            Py_XDECREF(*exception_tb);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        }
#endif

        return;
    } else if (PyExceptionInstance_Check(*exception_type)) {
        if (unlikely(*exception_value != NULL && *exception_value != Py_None)) {
            PyErr_Format(PyExc_TypeError, "instance exception may not have a separate value");

            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_value);
            Py_XDECREF(*exception_tb);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);

            return;
        }

        // The type is rather a value, so we are overriding it here.
        *exception_value = *exception_type;
        *exception_type = PyExceptionInstance_Class(*exception_type);
        Py_INCREF(*exception_type);

        return;
    } else {
        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(exception_type)->tp_name);
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        return;
    }
}

NUITKA_MAY_BE_UNUSED static void RAISE_EXCEPTION_IMPLICIT(PyObject **exception_type, PyObject **exception_value,
                                                          PyTracebackObject **exception_tb) {
    CHECK_OBJECT(*exception_type);
    CHECK_OBJECT(*exception_value);
    *exception_tb = NULL;

    // Non-empty tuple exceptions are the first element.
    while (unlikely(PyTuple_Check(*exception_type) && PyTuple_Size(*exception_type) > 0)) {
        *exception_type = PyTuple_GET_ITEM(*exception_type, 0);
    }

    if (PyExceptionClass_Check(*exception_type)) {
#if PYTHON_VERSION >= 340
        NORMALIZE_EXCEPTION(exception_type, exception_value, exception_tb);
        CHAIN_EXCEPTION(*exception_value);
#endif

        return;
    } else if (PyExceptionInstance_Check(*exception_type)) {
#if PYTHON_VERSION >= 340
        CHAIN_EXCEPTION(*exception_value);
#endif

        // The type is rather a value, so we are overriding it here.
        *exception_value = *exception_type;
        *exception_type = PyExceptionInstance_Class(*exception_type);
        Py_INCREF(*exception_type);

        return;
    } else {
        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(exception_type)->tp_name);
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);

#if PYTHON_VERSION >= 340
        CHAIN_EXCEPTION(*exception_value);
#endif

        return;
    }
}

NUITKA_MAY_BE_UNUSED static inline void RAISE_EXCEPTION_WITH_TRACEBACK(PyObject **exception_type,
                                                                       PyObject **exception_value,
                                                                       PyTracebackObject **exception_tb) {
    CHECK_OBJECT(*exception_type);
    CHECK_OBJECT(*exception_value);

    if (*exception_tb == (PyTracebackObject *)Py_None) {
        Py_DECREF(*exception_tb);
        *exception_tb = NULL;
    }

    // Non-empty tuple exceptions are the first element.
    while (unlikely(PyTuple_Check(*exception_type) && PyTuple_Size(*exception_type) > 0)) {
        *exception_type = PyTuple_GET_ITEM(*exception_type, 0);
    }

    if (PyExceptionClass_Check(*exception_type)) {
        NORMALIZE_EXCEPTION(exception_type, exception_value, exception_tb);
#if PYTHON_VERSION >= 270
        if (unlikely(!PyExceptionInstance_Check(*exception_value))) {
            PyErr_Format(PyExc_TypeError, "calling %s() should have returned an instance of BaseException, not '%s'",
                         ((PyTypeObject *)*exception_type)->tp_name, Py_TYPE(*exception_value)->tp_name);

            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_value);
            Py_XDECREF(*exception_tb);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        }
#endif

        return;
    } else if (PyExceptionInstance_Check(*exception_type)) {
        if (unlikely(*exception_value != NULL && *exception_value != Py_None)) {
            PyErr_Format(PyExc_TypeError, "instance exception may not have a separate value");

            Py_DECREF(*exception_type);
            Py_XDECREF(*exception_value);
            Py_XDECREF(*exception_tb);

            FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);

            return;
        }

        // The type is rather a value, so we are overriding it here.
        *exception_value = *exception_type;
        *exception_type = PyExceptionInstance_Class(*exception_type);
        Py_INCREF(*exception_type);

        return;
    } else {
        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(exception_type)->tp_name);
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
        return;
    }
}

NUITKA_MAY_BE_UNUSED static bool RERAISE_EXCEPTION(PyObject **exception_type, PyObject **exception_value,
                                                   PyTracebackObject **exception_tb) {
    PyThreadState *tstate = PyThreadState_GET();
    assert(tstate);

    *exception_type = EXC_TYPE(tstate) != NULL ? EXC_TYPE(tstate) : Py_None;
    Py_INCREF(*exception_type);
    *exception_value = EXC_VALUE(tstate);
    Py_XINCREF(*exception_value);
    *exception_tb = (PyTracebackObject *)EXC_TRACEBACK(tstate);
    Py_XINCREF(*exception_tb);

    CHECK_OBJECT(*exception_type);

    if (*exception_type == Py_None) {
#if PYTHON_VERSION >= 300
        Py_DECREF(*exception_type);

        Py_INCREF(PyExc_RuntimeError);
        *exception_type = PyExc_RuntimeError;
        *exception_value = PyUnicode_FromString("No active exception to reraise");
        *exception_tb = NULL;
#else
        PyErr_Format(PyExc_TypeError, WRONG_EXCEPTION_TYPE_ERROR_MESSAGE, Py_TYPE(*exception_type)->tp_name);
        FETCH_ERROR_OCCURRED(exception_type, exception_value, exception_tb);
#endif

        return false;
    }

    return true;
}

#endif
