//-----------------------------------------------------------------------------
// Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// cxoUtils.c
//   Utility functions used in cx_Oracle.
//-----------------------------------------------------------------------------

#include "cxoModule.h"

//-----------------------------------------------------------------------------
// cxoUtils_convertOciAttrToPythonValue()
//   Convert the OCI attribute value to an equivalent Python value using the
// specified type.
//-----------------------------------------------------------------------------
PyObject *cxoUtils_convertOciAttrToPythonValue(unsigned attrType,
        dpiDataBuffer *value, uint32_t valueLength, const char *encoding)
{
    switch (attrType) {
        case CXO_OCI_ATTR_TYPE_STRING:
            if (!value->asString) {
                Py_RETURN_NONE;
            }
            return PyUnicode_Decode(value->asString, valueLength, encoding,
                    NULL);
        case CXO_OCI_ATTR_TYPE_BOOLEAN:
            if (value->asBoolean) {
                Py_RETURN_TRUE;
            }
            Py_RETURN_FALSE;
        case CXO_OCI_ATTR_TYPE_UINT8:
            return PyLong_FromUnsignedLong(value->asUint8);
        case CXO_OCI_ATTR_TYPE_UINT16:
            return PyLong_FromUnsignedLong(value->asUint16);
        case CXO_OCI_ATTR_TYPE_UINT32:
            return PyLong_FromUnsignedLong(value->asUint32);
        case CXO_OCI_ATTR_TYPE_UINT64:
            return PyLong_FromUnsignedLongLong(value->asUint64);
    }

    return cxoError_raiseFromString(cxoProgrammingErrorException,
            "invalid attribute type specified");
}


//-----------------------------------------------------------------------------
// cxoUtils_convertPythonValueToOciAttr()
//   Convert the Python value to an equivalent OCI attribute value using the
// specified type.
//-----------------------------------------------------------------------------
int cxoUtils_convertPythonValueToOciAttr(PyObject *value, unsigned attrType,
        cxoBuffer *buffer, dpiDataBuffer *ociBuffer, void **ociValue,
        uint32_t *ociValueLength, const char *encoding)
{
    unsigned long tempValue;

    switch (attrType) {
        case CXO_OCI_ATTR_TYPE_STRING:
            if (cxoBuffer_fromObject(buffer, value, encoding) < 0)
                return -1;
            *ociValue = (void*) buffer->ptr;
            *ociValueLength = (uint32_t) buffer->size;
            break;
        case CXO_OCI_ATTR_TYPE_BOOLEAN:
            ociBuffer->asBoolean = PyObject_IsTrue(value);
            if (PyErr_Occurred())
                return -1;
            *ociValue = &ociBuffer->asBoolean;
            *ociValueLength = sizeof(ociBuffer->asBoolean);
            break;
        case CXO_OCI_ATTR_TYPE_UINT8:
            tempValue = PyLong_AsUnsignedLong(value);
            if (PyErr_Occurred())
                return -1;
            if (tempValue > UINT8_MAX) {
                PyErr_SetString(PyExc_OverflowError,
                        "Python int too large to convert to uint8_t");
                return -1;
            }
            ociBuffer->asUint8 = (uint8_t) tempValue;
            *ociValue = &ociBuffer->asUint8;
            *ociValueLength = sizeof(ociBuffer->asUint8);
            break;
        case CXO_OCI_ATTR_TYPE_UINT16:
            tempValue = PyLong_AsUnsignedLong(value);
            if (PyErr_Occurred())
                return -1;
            if (tempValue > UINT16_MAX) {
                PyErr_SetString(PyExc_OverflowError,
                        "Python int too large to convert to uint16_t");
                return -1;
            }
            ociBuffer->asUint16 = (uint16_t) tempValue;
            *ociValue = &ociBuffer->asUint16;
            *ociValueLength = sizeof(ociBuffer->asUint16);
            break;
        case CXO_OCI_ATTR_TYPE_UINT32:
            tempValue = PyLong_AsUnsignedLong(value);
            if (PyErr_Occurred())
                return -1;
            if (tempValue > UINT32_MAX) {
                PyErr_SetString(PyExc_OverflowError,
                        "Python int too large to convert to uint32_t");
                return -1;
            }
            ociBuffer->asUint32 = (uint32_t) tempValue;
            *ociValue = &ociBuffer->asUint32;
            *ociValueLength = sizeof(ociBuffer->asUint32);
            break;
        case CXO_OCI_ATTR_TYPE_UINT64:
            ociBuffer->asUint64 = (uint64_t) PyLong_AsUnsignedLongLong(value);
            if (PyErr_Occurred())
                return -1;
            *ociValue = &ociBuffer->asUint64;
            *ociValueLength = sizeof(ociBuffer->asUint64);
            break;
        default:
            cxoError_raiseFromString(cxoProgrammingErrorException,
                    "invalid attribute type specified");
            return -1;
    }

    return 0;
}


//-----------------------------------------------------------------------------
// cxoUtils_formatString()
//   Return a Python string formatted using the given format string and
// arguments. The arguments have a reference taken from them after they have
// been used (which should mean that they are destroyed).
//-----------------------------------------------------------------------------
PyObject *cxoUtils_formatString(const char *format, PyObject *args)
{
    PyObject *formatObj, *result;

    // assume that a NULL value for arguments implies building the arguments
    // failed and a Python exception has already been raised
    if (!args)
        return NULL;

    // convert string format to Python object
    formatObj = PyUnicode_DecodeASCII(format, strlen(format), NULL);
    if (!formatObj) {
        Py_DECREF(args);
        return NULL;
    }

    // create formatted result
    result = PyUnicode_Format(formatObj, args);
    Py_DECREF(args);
    Py_DECREF(formatObj);
    return result;
}


//-----------------------------------------------------------------------------
// cxoUtils_getAdjustedEncoding()
//   Return the adjusted encoding to use when encoding and decoding strings
// that are passed to and from the Oracle database. The Oracle client interface
// does not support the inclusion of a BOM in the encoded string but assumes
// native endian order for UTF-16. Python generates a BOM at the beginning of
// the encoded string if plain UTF-16 is specified. For this reason, the
// correct byte order must be determined and used inside Python so that the
// Oracle client receives the data it expects.
//-----------------------------------------------------------------------------
const char *cxoUtils_getAdjustedEncoding(const char *encoding)
{
    static const union {
        unsigned char bytes[4];
        uint32_t value;
    } hostOrder = { { 0, 1, 2, 3 } };

    if (!encoding || strcmp(encoding, "UTF-16") != 0)
        return encoding;
    return (hostOrder.value == 0x03020100) ? "UTF-16LE" : "UTF-16BE";
}


//-----------------------------------------------------------------------------
// cxoUtils_getModuleAndName()
//   Return the module and name for the type.
//-----------------------------------------------------------------------------
int cxoUtils_getModuleAndName(PyTypeObject *type, PyObject **module,
        PyObject **name)
{
    *module = PyObject_GetAttrString( (PyObject*) type, "__module__");
    if (!*module)
        return -1;
    *name = PyObject_GetAttrString( (PyObject*) type, "__name__");
    if (!*name) {
        Py_DECREF(*module);
        return -1;
    }
    return 0;
}


//-----------------------------------------------------------------------------
// cxoUtils_initializeDPI()
//   Initialize the ODPI-C library. This is done when the first standalone
// connection or session pool is created, rather than when the module is first
// imported so that manipulating environment variables such as NLS_LANG will
// work as expected. It also has the additional benefit of reducing the number
// of errors that can take place when the module is imported.
//-----------------------------------------------------------------------------
int cxoUtils_initializeDPI(dpiContextCreateParams *params)
{
    dpiContextCreateParams localParams;
    dpiErrorInfo errorInfo;
    dpiContext *context;

    // if already initialized and parameters were passed, raise an exception;
    // otherwise do nothing as this is implicitly called when creating a
    // standalone connection or session pool and when getting the Oracle Client
    // library version
    if (cxoDpiContext) {
        if (!params)
            return 0;
        cxoError_raiseFromString(cxoProgrammingErrorException,
                "Oracle Client library has already been initialized");
        return -1;
    }

    // set up parameters used for initializing ODPI-C
    if (params) {
        memcpy(&localParams, params, sizeof(dpiContextCreateParams));
    } else {
        memset(&localParams, 0, sizeof(dpiContextCreateParams));
    }
    localParams.defaultEncoding = "UTF-8";
    if (!localParams.defaultDriverName)
        localParams.defaultDriverName = CXO_DRIVER_NAME;
    if (!localParams.loadErrorUrl)
        localParams.loadErrorUrl = "https://cx-oracle.readthedocs.io/en/"
                "latest/user_guide/installation.html";

    // create ODPI-C context with the specified parameters
    if (dpiContext_createWithParams(DPI_MAJOR_VERSION, DPI_MINOR_VERSION,
            &localParams, &context, &errorInfo) < 0)
        return cxoError_raiseFromInfo(&errorInfo);
    if (dpiContext_getClientVersion(context, &cxoClientVersionInfo) < 0) {
        cxoError_raiseAndReturnInt();
        dpiContext_destroy(context);
        return -1;
    }

    cxoDpiContext = context;
    return 0;
}


//-----------------------------------------------------------------------------
// cxoUtils_processJsonArg()
//   Process the argument which is expected to be either a string or bytes, or
// a dictionary or list which is converted to a string via the json.dumps()
// method. All strings are encoded to UTF-8 which is what SODA expects.
//-----------------------------------------------------------------------------
int cxoUtils_processJsonArg(PyObject *arg, cxoBuffer *buffer)
{
    int converted = 0;

    if (arg && (PyDict_Check(arg) || PyList_Check(arg))) {
        arg = PyObject_CallFunctionObjArgs(cxoJsonDumpFunction, arg, NULL);
        if (!arg)
            return -1;
        converted = 1;
    }
    if (cxoBuffer_fromObject(buffer, arg, "UTF-8") < 0)
        return -1;
    if (converted)
        Py_DECREF(arg);

    return 0;
}


//-----------------------------------------------------------------------------
// cxoUtils_processSodaDocArg()
//   Process a SODA document argument. This is expectd to be an actual SODA
// document object or a dictionary. If the argument refers to a dictionary or
// list, a new SODA document will be created with the given content and without
// a key or media type specified.
//-----------------------------------------------------------------------------
int cxoUtils_processSodaDocArg(cxoSodaDatabase *db, PyObject *arg,
        dpiSodaDoc **handle)
{
    cxoBuffer buffer;
    cxoSodaDoc *doc;

    if (PyObject_TypeCheck(arg, &cxoPyTypeSodaDoc)) {
        doc = (cxoSodaDoc*) arg;
        if (dpiSodaDoc_addRef(doc->handle) < 0)
            return cxoError_raiseAndReturnInt();
        *handle = doc->handle;
    } else if (PyDict_Check(arg) || PyList_Check(arg)) {
        arg = PyObject_CallFunctionObjArgs(cxoJsonDumpFunction, arg, NULL);
        if (!arg)
            return -1;
        if (cxoBuffer_fromObject(&buffer, arg, "UTF-8") < 0) {
            Py_DECREF(arg);
            return -1;
        }
        Py_DECREF(arg);
        if (dpiSodaDb_createDocument(db->handle, NULL, 0, buffer.ptr,
                buffer.size, NULL, 0, DPI_SODA_FLAGS_DEFAULT, handle) < 0) {
            cxoBuffer_clear(&buffer);
            return cxoError_raiseAndReturnInt();
        }
        cxoBuffer_clear(&buffer);
    } else {
        PyErr_SetString(PyExc_TypeError,
                "value must be a SODA document or a dictionary or list");
        return -1;
    }

    return 0;
}