text: // Copyright (c) Microsoft. All rights reserved.
  // Licensed under the MIT license. See LICENSE file in the project root for full license information.
  
  /** @file iothub_device_client_ll.h
  *    @brief     APIs that allow a user (usually a device) to communicate
  *             with an Azure IoTHub.
  *
  *    @details IoTHubDeviceClient_LL is a module that allows a user (usually a
  *             device) to communicate with an Azure IoTHub. It can send events
  *             and receive messages. At any given moment in time there can only
  *             be at most 1 message callback function.
  *
  *             This API surface contains a set of APIs that allows the user to
  *             interact with the lower layer portion of the IoTHubClient. These APIs
  *             contain @c _LL_ in their name, but retain the same functionality like the
  *             @c IoTHubDeviceClient_... APIs, with one difference. If the @c _LL_ APIs are
  *             used then the user is responsible for scheduling when the actual work done
  *             by the IoTHubClient happens (when the data is sent/received on/from the wire).
  *             This is useful for constrained devices where spinning a separate thread is
  *             often not desired.
  */
  
  #ifndef IOTHUB_DEVICE_CLIENT_LL_H
  #define IOTHUB_DEVICE_CLIENT_LL_H
  
  #include <stddef.h>
  #include <stdint.h>
  
  #include "azure_c_shared_utility/macro_utils.h"
  #include "azure_c_shared_utility/umock_c_prod.h"
  
  #include "iothub_transport_ll.h"
  #include "iothub_client_core_ll.h"
  
  #ifdef __cplusplus
  extern "C"
  {
  #endif
  
  typedef struct IOTHUB_CLIENT_CORE_LL_HANDLE_DATA_TAG* IOTHUB_DEVICE_CLIENT_LL_HANDLE;
  
  
      /**
      * @brief    Creates a IoT Hub client for communication with an existing
      *           IoT Hub using the specified connection string parameter.
      *
      * @param    connectionString    Pointer to a character string
      * @param    protocol            Function pointer for protocol implementation
      *
      *            Sample connection string:
      *                <blockquote>
      *                    <pre>HostName=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net];DeviceId=[Device ID goes here];SharedAccessKey=[Device key goes here];</pre>
      *                </blockquote>
      *
      * @return    A non-NULL @c IOTHUB_DEVICE_CLIENT_LL_HANDLE value that is used when
      *             invoking other functions for IoT Hub client and @c NULL on failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_DEVICE_CLIENT_LL_HANDLE, IoTHubDeviceClient_LL_CreateFromConnectionString, const char*, connectionString, IOTHUB_CLIENT_TRANSPORT_PROVIDER, protocol);
  
      /**
      * @brief    Creates a IoT Hub client for communication with an existing IoT
      *           Hub using the specified parameters.
      *
      * @param    config    Pointer to an @c IOTHUB_CLIENT_CONFIG structure
      *
      *           The API does not allow sharing of a connection across multiple
      *           devices. This is a blocking call.
      *
      * @return    A non-NULL @c IOTHUB_DEVICE_CLIENT_LL_HANDLE value that is used when
      *            invoking other functions for IoT Hub client and @c NULL on failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_DEVICE_CLIENT_LL_HANDLE, IoTHubDeviceClient_LL_Create, const IOTHUB_CLIENT_CONFIG*, config);
  
      /**
      * @brief    Creates a IoT Hub client for communication with an existing IoT
      *           Hub using an existing transport.
      *
      * @param    config    Pointer to an @c IOTHUB_CLIENT_DEVICE_CONFIG structure
      *
      *           The API *allows* sharing of a connection across multiple
      *           devices. This is a blocking call.
      *
      * @return   A non-NULL @c IOTHUB_DEVICE_CLIENT_LL_HANDLE value that is used when
      *           invoking other functions for IoT Hub client and @c NULL on failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_DEVICE_CLIENT_LL_HANDLE, IoTHubDeviceClient_LL_CreateWithTransport, const IOTHUB_CLIENT_DEVICE_CONFIG*, config);
  
       /**
       * @brief    Creates a IoT Hub client for communication with an existing IoT
       *           Hub using the device auth module.
       *
       * @param    iothub_uri             Pointer to an ioThub hostname received in the registration process
       * @param    device_id              Pointer to the device Id of the device
       * @param    device_auth_handle     A device auth handle used to generate the connection string
       * @param    protocol               Function pointer for protocol implementation
       *
       * @return   A non-NULL @c IOTHUB_DEVICE_CLIENT_LL_HANDLE value that is used when
       *           invoking other functions for IoT Hub client and @c NULL on failure.
       */
       MOCKABLE_FUNCTION(, IOTHUB_DEVICE_CLIENT_LL_HANDLE, IoTHubDeviceClient_LL_CreateFromDeviceAuth, const char*, iothub_uri, const char*, device_id, IOTHUB_CLIENT_TRANSPORT_PROVIDER, protocol);
  
      /**
      * @brief    Disposes of resources allocated by the IoT Hub client. This is a
      *           blocking call.
      *
      * @param    iotHubClientHandle    The handle created by a call to the create function.
      */
       MOCKABLE_FUNCTION(, void, IoTHubDeviceClient_LL_Destroy, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle);
  
      /**
      * @brief    Asynchronous call to send the message specified by @p eventMessageHandle.
      *
      * @param    iotHubClientHandle              The handle created by a call to the create function.
      * @param    eventMessageHandle              The handle to an IoT Hub message.
      * @param    eventConfirmationCallback       The callback specified by the device for receiving
      *                                           confirmation of the delivery of the IoT Hub message.
      *                                           This callback can be expected to invoke the
      *                                           ::IoTHubDeviceClient_LL_SendEventAsync function for the
      *                                           same message in an attempt to retry sending a failing
      *                                           message. The user can specify a @c NULL value here to
      *                                           indicate that no callback is required.
      * @param    userContextCallback             User specified context that will be provided to the
      *                                           callback. This can be @c NULL.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SendEventAsync, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_MESSAGE_HANDLE, eventMessageHandle, IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK, eventConfirmationCallback, void*, userContextCallback);
  
      /**
      * @brief    This function returns the current sending status for IoTHubClient.
      *
      * @param    iotHubClientHandle        The handle created by a call to the create function.
      * @param    iotHubClientStatus        The sending state is populated at the address pointed
      *                                     at by this parameter. The value will be set to
      *                                     @c IOTHUBCLIENT_SENDSTATUS_IDLE if there is currently
      *                                     no item to be sent and @c IOTHUBCLIENT_SENDSTATUS_BUSY
      *                                     if there are.
      *
      * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_GetSendStatus, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_STATUS*, iotHubClientStatus);
  
      /**
      * @brief    Sets up the message callback to be invoked when IoT Hub issues a
      *           message to the device. This is a blocking call.
      *
      * @param    iotHubClientHandle              The handle created by a call to the create function.
      * @param    messageCallback                 The callback specified by the device for receiving
      *                                           messages from IoT Hub.
      * @param    userContextCallback             User specified context that will be provided to the
      *                                           callback. This can be @c NULL.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetMessageCallback, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_MESSAGE_CALLBACK_ASYNC, messageCallback, void*, userContextCallback);
  
      /**
      * @brief    Sets up the connection status callback to be invoked representing the status of
      * the connection to IOT Hub. This is a blocking call.
      *
      * @param    iotHubClientHandle              The handle created by a call to the create function.
      * @param    connectionStatusCallback        The callback specified by the device for receiving
      *                                           updates about the status of the connection to IoT Hub.
      * @param    userContextCallback             User specified context that will be provided to the
      *                                           callback. This can be @c NULL.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetConnectionStatusCallback, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_CONNECTION_STATUS_CALLBACK, connectionStatusCallback, void*, userContextCallback);
  
      /**
      * @brief    Sets up the connection status callback to be invoked representing the status of
      * the connection to IOT Hub. This is a blocking call.
      *
      * @param    iotHubClientHandle              The handle created by a call to the create function.
      * @param    retryPolicy                     The policy to use to reconnect to IoT Hub when a
      *                                           connection drops.
      * @param    retryTimeoutLimitInSeconds      Maximum amount of time(seconds) to attempt reconnection when a
      *                                           connection drops to IOT Hub.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetRetryPolicy, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_RETRY_POLICY, retryPolicy, size_t, retryTimeoutLimitInSeconds);
  
  
      /**
      * @brief    Sets up the connection status callback to be invoked representing the status of
      * the connection to IOT Hub. This is a blocking call.
      *
      * @param    iotHubClientHandle                  The handle created by a call to the create function.
      * @param    retryPolicy                         Out parameter containing the policy to use to reconnect to IoT Hub.
      * @param    retryTimeoutLimitInSeconds          Out parameter containing maximum amount of time in seconds to attempt reconnection
                                                      to IOT Hub.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_GetRetryPolicy, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_RETRY_POLICY*, retryPolicy, size_t*, retryTimeoutLimitInSeconds);
  
      /**
      * @brief    This function returns in the out parameter @p lastMessageReceiveTime
      *           what was the value of the @c time function when the last message was
      *           received at the client.
      *
      * @param    iotHubClientHandle          The handle created by a call to the create function.
      * @param    lastMessageReceiveTime      Out parameter containing the value of @c time function
      *                                       when the last message was received.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_GetLastMessageReceiveTime, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, time_t*, lastMessageReceiveTime);
  
      /**
      * @brief    This function is meant to be called by the user when work
      *           (sending/receiving) can be done by the IoTHubClient.
      *
      * @param    iotHubClientHandle    The handle created by a call to the create function.
      *
      *           All IoTHubClient interactions (in regards to network traffic
      *           and/or user level callbacks) are the effect of calling this
      *           function and they take place synchronously inside _DoWork.
      */
       MOCKABLE_FUNCTION(, void, IoTHubDeviceClient_LL_DoWork, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle);
  
      /**
      * @brief    This API sets a runtime option identified by parameter @p optionName
      *           to a value pointed to by @p value. @p optionName and the data type
      *           @p value is pointing to are specific for every option.
      *
      * @param    iotHubClientHandle      The handle created by a call to the create function.
      * @param    optionName              Name of the option.
      * @param    value                   The value.
      *
      *           The options that can be set via this API are:
      *                - @b timeout - the maximum time in milliseconds a communication is
      *                  allowed to use. @p value is a pointer to an @c unsigned @c int with
      *                  the timeout value in milliseconds. This is only supported for the HTTP
      *                  protocol as of now. When the HTTP protocol uses CURL, the meaning of
      *                  the parameter is <em>total request time</em>. When the HTTP protocol uses
      *                  winhttp, the meaning is the same as the @c dwSendTimeout and
      *                  @c dwReceiveTimeout parameters of the
      *                  <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa384116(v=vs.85).aspx">
      *                  WinHttpSetTimeouts</a> API.
      *                - @b CURLOPT_LOW_SPEED_LIMIT - only available for HTTP protocol and only
      *                  when CURL is used. It has the same meaning as CURL's option with the same
      *                  name. @p value is pointer to a long.
      *                - @b CURLOPT_LOW_SPEED_TIME - only available for HTTP protocol and only
      *                  when CURL is used. It has the same meaning as CURL's option with the same
      *                  name. @p value is pointer to a long.
      *                - @b CURLOPT_FORBID_REUSE - only available for HTTP protocol and only
      *                  when CURL is used. It has the same meaning as CURL's option with the same
      *                  name. @p value is pointer to a long.
      *                - @b CURLOPT_FRESH_CONNECT - only available for HTTP protocol and only
      *                  when CURL is used. It has the same meaning as CURL's option with the same
      *                  name. @p value is pointer to a long.
      *                - @b CURLOPT_VERBOSE - only available for HTTP protocol and only
      *                  when CURL is used. It has the same meaning as CURL's option with the same
      *                  name. @p value is pointer to a long.
      *              - @b keepalive - available for MQTT protocol.  Integer value that sets the
      *                interval in seconds when pings are sent to the server.
      *              - @b logtrace - available for MQTT protocol.  Boolean value that turns on and
      *                off the diagnostic logging.
      *              - @b sas_token_lifetime - available for MQTT & AMQP protocol.  size_t value that that determines the
      *                sas token timeout length.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetOption, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, const char*, optionName, const void*, value);
  
      /**
      * @brief   This API specifies a callback to be used when the device receives a desired state update.
      *
      * @param   iotHubClientHandle        The handle created by a call to the create function.
      * @param   deviceTwinCallback        The callback specified by the device client to be used for updating
      *                                    the desired state. The callback will be called in response to patch
      *                                    request send by the IoTHub services. The payload will be passed to the
      *                                    callback, along with two version numbers:
      *                                        - Desired:
      *                                        - LastSeenReported:
      * @param   userContextCallback       User specified context that will be provided to the
      *                                    callback. This can be @c NULL.
      *
      *           @b NOTE: The application behavior is undefined if the user calls
      *           the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetDeviceTwinCallback, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_DEVICE_TWIN_CALLBACK, deviceTwinCallback, void*, userContextCallback);
  
      /**
      * @brief    This API sends a report of the device's properties and their current values.
      *
      * @param    iotHubClientHandle        The handle created by a call to the create function.
      * @param    reportedState             The current device property values to be 'reported' to the IoTHub.
      * @param    reportedStateCallback     The callback specified by the device client to be called with the
      *                                     result of the transaction.
      * @param    userContextCallback       User specified context that will be provided to the
      *                                     callback. This can be @c NULL.
      *
      *            @b NOTE: The application behavior is undefined if the user calls
      *            the ::IoTHubDeviceClient_LL_Destroy function from within any callback.
      *
      * @return    IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SendReportedState, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, const unsigned char*, reportedState, size_t, size, IOTHUB_CLIENT_REPORTED_STATE_CALLBACK, reportedStateCallback, void*, userContextCallback);
       /**
       * @brief    This API sets the callback for async cloud to device method calls.
       *
       * @param    iotHubClientHandle                 The handle created by a call to the create function.
       * @param    inboundDeviceMethodCallback        The callback which will be called by IoTHub.
       * @param    userContextCallback                User specified context that will be provided to the
       *                                              callback. This can be @c NULL.
       *
       * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
       */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_SetDeviceMethodCallback, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, IOTHUB_CLIENT_DEVICE_METHOD_CALLBACK_ASYNC, deviceMethodCallback, void*, userContextCallback);
  
       /**
       * @brief    This API responds to an asnyc method callback identified the methodId.
       *
       * @param    iotHubClientHandle      The handle created by a call to the create function.
       * @param    methodId                The methodId of the Device Method callback.
       * @param    response                The response data for the method callback.
       * @param    response_size           The size of the response data buffer.
       * @param    status_response         The status response of the method callback.
       *
       * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
       */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_DeviceMethodResponse, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, METHOD_HANDLE, methodId, const unsigned char*, response, size_t, respSize, int, statusCode);
  
  #ifndef DONT_USE_UPLOADTOBLOB
      /**
      * @brief    This API uploads to Azure Storage the content pointed to by @p source having the size @p size
      *           under the blob name devicename/@pdestinationFileName
      *
      * @param    iotHubClientHandle      The handle created by a call to the create function.
      * @param    destinationFileName     name of the file.
      * @param    source                  pointer to the source for file content (can be NULL)
      * @param    size                    the size of the source in memory (if @p source is NULL then size needs to be 0).
      *
      * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
      */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_UploadToBlob, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, const char*, destinationFileName, const unsigned char*, source, size_t, size);
  
       /**
       * @brief    This API uploads to Azure Storage the content provided block by block by @p getDataCallback
       *           under the blob name devicename/@pdestinationFileName
       *
       * @param    iotHubClientHandle      The handle created by a call to the create function.
       * @param    destinationFileName     name of the file.
       * @param    getDataCallbackEx       A callback to be invoked to acquire the file chunks to be uploaded, as well as to indicate the status of the upload of the previous block.
       * @param    context                 Any data provided by the user to serve as context on getDataCallback.
       *
       * @return   IOTHUB_CLIENT_OK upon success or an error code upon failure.
       */
       MOCKABLE_FUNCTION(, IOTHUB_CLIENT_RESULT, IoTHubDeviceClient_LL_UploadMultipleBlocksToBlob, IOTHUB_DEVICE_CLIENT_LL_HANDLE, iotHubClientHandle, const char*, destinationFileName, IOTHUB_CLIENT_FILE_UPLOAD_GET_DATA_CALLBACK_EX, getDataCallbackEx, void*, context);
  
  #endif /*DONT_USE_UPLOADTOBLOB*/
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* IOTHUB_DEVICE_CLIENT_LL_H */
  