// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

#include <stdlib.h>
#include "azure_macro_utils/macro_utils.h"
#include "azure_c_shared_utility/gballoc.h"
#include "azure_c_shared_utility/xlogging.h"
#include "azure_uamqp_c/sasl_mechanism.h"

typedef struct SASL_MECHANISM_INSTANCE_TAG
{
    const SASL_MECHANISM_INTERFACE_DESCRIPTION* sasl_mechanism_interface_description;
    CONCRETE_SASL_MECHANISM_HANDLE concrete_sasl_mechanism_handle;
} SASL_MECHANISM_INSTANCE;

SASL_MECHANISM_HANDLE saslmechanism_create(const SASL_MECHANISM_INTERFACE_DESCRIPTION* sasl_mechanism_interface_description, void* sasl_mechanism_create_parameters)
{
    SASL_MECHANISM_HANDLE result;

    /* Codes_SRS_SASL_MECHANISM_01_004: [If the argument `sasl_mechanism_interface_description` is NULL, `saslmechanism_create` shall return NULL.] */
    if (sasl_mechanism_interface_description == NULL)
    {
        LogError("NULL sasl_mechanism_interface_description");
        result = NULL;
    }
    /* Codes_SRS_SASL_MECHANISM_01_005: [If any `sasl_mechanism_interface_description` member is NULL, `saslmechanism_create` shall fail and return NULL.] */
    else if ((sasl_mechanism_interface_description->concrete_sasl_mechanism_create == NULL) ||
        (sasl_mechanism_interface_description->concrete_sasl_mechanism_destroy == NULL) ||
        (sasl_mechanism_interface_description->concrete_sasl_mechanism_get_init_bytes == NULL) ||
        (sasl_mechanism_interface_description->concrete_sasl_mechanism_get_mechanism_name == NULL))
    {
        LogError("Bad interface, concrete_sasl_mechanism_create = %p, concrete_sasl_mechanism_destroy = %p, concrete_sasl_mechanism_get_init_bytes = %p, concrete_sasl_mechanism_get_mechanism_name = %p",
            sasl_mechanism_interface_description->concrete_sasl_mechanism_create,
            sasl_mechanism_interface_description->concrete_sasl_mechanism_destroy,
            sasl_mechanism_interface_description->concrete_sasl_mechanism_get_init_bytes,
            sasl_mechanism_interface_description->concrete_sasl_mechanism_get_mechanism_name);
        result = NULL;
    }
    else
    {
        result = (SASL_MECHANISM_HANDLE)malloc(sizeof(SASL_MECHANISM_INSTANCE));
        if (result == NULL)
        {
            /* Codes_SRS_SASL_MECHANISM_01_006: [If allocating the memory needed for the SASL mechanism interface fails then `saslmechanism_create` shall fail and return NULL.] */
            LogError("Could not allocate memory for SASL mechanism");
        }
        else
        {
            result->sasl_mechanism_interface_description = sasl_mechanism_interface_description;

            /* Codes_SRS_SASL_MECHANISM_01_002: [In order to instantiate the concrete SASL mechanism implementation the function `concrete_sasl_mechanism_create` from the `sasl_mechanism_interface_description` shall be called, passing the `sasl_mechanism_create_parameters` to it.] */
            result->concrete_sasl_mechanism_handle = result->sasl_mechanism_interface_description->concrete_sasl_mechanism_create((void*)sasl_mechanism_create_parameters);
            if (result->concrete_sasl_mechanism_handle == NULL)
            {
                /* Codes_SRS_SASL_MECHANISM_01_003: [If the underlying `concrete_sasl_mechanism_create` call fails, `saslmechanism_create` shall return NULL.] */
                LogError("concrete_sasl_mechanism_create failed");
                free(result);
                result = NULL;
            }
        }
    }

    /* Codes_SRS_SASL_MECHANISM_01_001: [`saslmechanism_create` shall return on success a non-NULL handle to a new SASL mechanism interface.] */
    return result;
}

void saslmechanism_destroy(SASL_MECHANISM_HANDLE sasl_mechanism)
{
    if (sasl_mechanism == NULL)
    {
        /* Codes_SRS_SASL_MECHANISM_01_009: [If the argument `sasl_mechanism` is NULL, `saslmechanism_destroy` shall do nothing.] */
        LogError("NULL sasl_mechanism");
    }
    else
    {
        /* Codes_SRS_SASL_MECHANISM_01_008: [`saslmechanism_destroy` shall also call the `concrete_sasl_mechanism_destroy` function that is member of the `sasl_mechanism_interface_description` argument passed to `saslmechanism_create`, while passing as argument to `concrete_sasl_mechanism_destroy` the result of the underlying concrete SASL mechanism handle.] */
        sasl_mechanism->sasl_mechanism_interface_description->concrete_sasl_mechanism_destroy(sasl_mechanism->concrete_sasl_mechanism_handle);

        /* Codes_SRS_SASL_MECHANISM_01_007: [`saslmechanism_destroy` shall free all resources associated with the SASL mechanism handle.] */
        free(sasl_mechanism);
    }
}

int saslmechanism_get_init_bytes(SASL_MECHANISM_HANDLE sasl_mechanism, SASL_MECHANISM_BYTES* init_bytes)
{
    int result;

    /* Codes_SRS_SASL_MECHANISM_01_012: [If the argument `sasl_mechanism` is NULL, `saslmechanism_get_init_bytes` shall fail and return a non-zero value.] */
    if (sasl_mechanism == NULL)
    {
        LogError("NULL sasl_mechanism");
        result = MU_FAILURE;
    }
    else
    {
        /* Codes_SRS_SASL_MECHANISM_01_010: [`saslmechanism_get_init_bytes` shall call the specific `concrete_sasl_mechanism_get_init_bytes` function specified in `saslmechanism_create`, passing the `init_bytes` argument to it.] */
        if (sasl_mechanism->sasl_mechanism_interface_description->concrete_sasl_mechanism_get_init_bytes(sasl_mechanism->concrete_sasl_mechanism_handle, init_bytes) != 0)
        {
            /* Codes_SRS_SASL_MECHANISM_01_013: [If the underlying `concrete_sasl_mechanism_get_init_bytes` fails, `saslmechanism_get_init_bytes` shall fail and return a non-zero value.] */
            LogError("concrete_sasl_mechanism_get_init_bytes failed");
            result = MU_FAILURE;
        }
        else
        {
            /* Codes_SRS_SASL_MECHANISM_01_011: [On success, `saslmechanism_get_init_bytes` shall return 0.] */
            result = 0;
        }
    }

    return result;
}

const char* saslmechanism_get_mechanism_name(SASL_MECHANISM_HANDLE sasl_mechanism)
{
    const char* result;

    /* Codes_SRS_SASL_MECHANISM_01_016: [If the argument `sasl_mechanism` is NULL, `saslmechanism_get_mechanism_name` shall fail and return a non-zero value.] */
    if (sasl_mechanism == NULL)
    {
        LogError("NULL sasl_mechanism");
        result = NULL;
    }
    else
    {
        /* Codes_SRS_SASL_MECHANISM_01_014: [`saslmechanism_get_mechanism_name` shall call the specific `concrete_sasl_mechanism_get_mechanism_name` function specified in `saslmechanism_create`.] */
        /* Codes_SRS_SASL_MECHANISM_01_015: [On success, `saslmechanism_get_mechanism_name` shall return a pointer to a string with the mechanism name.] */
        /* Codes_SRS_SASL_MECHANISM_01_017: [If the underlying `concrete_sasl_mechanism_get_mechanism_name` fails, `saslmechanism_get_mechanism_name` shall return NULL.] */
        result = sasl_mechanism->sasl_mechanism_interface_description->concrete_sasl_mechanism_get_mechanism_name(sasl_mechanism->concrete_sasl_mechanism_handle);
        if (result == NULL)
        {
            LogError("concrete_sasl_mechanism_get_mechanism_name failed");
        }
    }

    return result;
}

int saslmechanism_challenge(SASL_MECHANISM_HANDLE sasl_mechanism, const SASL_MECHANISM_BYTES* challenge_bytes, SASL_MECHANISM_BYTES* response_bytes)
{
    int result;

    /* Codes_SRS_SASL_MECHANISM_01_020: [If the argument `sasl_mechanism` is NULL, `saslmechanism_challenge` shall fail and return a non-zero value.] */
    if (sasl_mechanism == NULL)
    {
        LogError("NULL sasl_mechanism");
        result = MU_FAILURE;
    }
    else
    {
        /* Codes_SRS_SASL_MECHANISM_01_018: [`saslmechanism_challenge` shall call the specific `concrete_sasl_mechanism_challenge` function specified in `saslmechanism_create`, while passing the `challenge_bytes` and `response_bytes` arguments to it.] */
        if (sasl_mechanism->sasl_mechanism_interface_description->concrete_sasl_mechanism_challenge(sasl_mechanism->concrete_sasl_mechanism_handle, challenge_bytes, response_bytes) != 0)
        {
            /* Codes_SRS_SASL_MECHANISM_01_021: [If the underlying `concrete_sasl_mechanism_challenge` fails, `saslmechanism_challenge` shall fail and return a non-zero value.] */
            LogError("concrete_sasl_mechanism_challenge failed");
            result = MU_FAILURE;
        }
        else
        {
            /* Codes_SRS_SASL_MECHANISM_01_019: [On success, `saslmechanism_challenge` shall return 0.] */
            result = 0;
        }
    }

    return result;
}