text: /*
   * Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License").
   * You may not use this file except in compliance with the License.
   * A copy of the License is located at
   *
   *  http://aws.amazon.com/apache2.0
   *
   * or in the "license" file accompanying this file. This file 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.
   */
  
  // Based on Eclipse Paho.
  /*******************************************************************************
   * Copyright (c) 2014 IBM Corp.
   *
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * and Eclipse Distribution License v1.0 which accompany this distribution.
   *
   * The Eclipse Public License is available at
   *    http://www.eclipse.org/legal/epl-v10.html
   * and the Eclipse Distribution License is available at
   *   http://www.eclipse.org/org/documents/edl-v10.php.
   *
   * Contributors:
   *    Ian Craggs - initial API and implementation and/or initial documentation
   *    Xiang Rong - 442039 Add makefile to Embedded C client
   *******************************************************************************/
  
  /**
   * @file aws_iot_mqtt_client.h
   * @brief Client definition for MQTT
   */
  
  #ifndef AWS_IOT_SDK_SRC_IOT_MQTT_CLIENT_H
  #define AWS_IOT_SDK_SRC_IOT_MQTT_CLIENT_H
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /* Library Header files */
  #include "stdio.h"
  #include "stdbool.h"
  #include "stdint.h"
  #include "stddef.h"
  
  /* AWS Specific header files */
  #include "aws_iot_error.h"
  #include "aws_iot_config.h"
  
  /* Platform specific implementation header files */
  #include "network_interface.h"
  #include "timer_interface.h"
  
  #ifdef _ENABLE_THREAD_SUPPORT_
  #include "threads_interface.h"
  #endif
  
  #define MAX_PACKET_ID 65535
  
  typedef struct _Client AWS_IoT_Client;
  
  /**
   * @brief Quality of Service Type
   *
   * Defining a QoS type.
   * @note QoS 2 is \b NOT supported by the AWS IoT Service at the time of this SDK release.
   *
   */
  typedef enum QoS {
  	QOS0 = 0,
  	QOS1 = 1
  } QoS;
  
  /**
   * @brief Publish Message Parameters Type
   *
   * Defines a type for MQTT Publish messages. Used for both incoming and out going messages
   *
   */
  typedef struct {
  	QoS qos;		///< Message Quality of Service
  	uint8_t isRetained;	///< Retained messages are \b NOT supported by the AWS IoT Service at the time of this SDK release.
  	uint8_t isDup;		///< Is this message a duplicate QoS > 0 message?  Handled automatically by the MQTT client.
  	uint16_t id;		///< Message sequence identifier.  Handled automatically by the MQTT client.
  	void *payload;		///< Pointer to MQTT message payload (bytes).
  	size_t payloadLen;	///< Length of MQTT payload.
  } IoT_Publish_Message_Params;
  
  /**
   * @brief MQTT Version Type
   *
   * Defining an MQTT version type. Only 3.1.1 is supported at this time
   *
   */
  typedef enum {
  	MQTT_3_1_1 = 4    ///< MQTT 3.1.1 (protocol message byte = 4)
  } MQTT_Ver_t;
  
  /**
   * @brief Last Will and Testament Definition
   *
   * Defining a type for the MQTT "Last Will and Testament" (LWT) parameters.
   * @note Retained messages are \b NOT supported by the AWS IoT Service at the time of this SDK release.
   *
   */
  typedef struct {
  	char struct_id[4];		///< The eyecatcher for this structure.  must be MQTW
  	char *pTopicName;		///< The LWT topic to which the LWT message will be published
  	uint16_t topicNameLen;		///< The length of the LWT topic, 16 bit unsinged integer
  	char *pMessage;			///< Message to be delivered as LWT
  	uint16_t msgLen;		///< The length of the Message, 16 bit unsinged integer
  	bool isRetained;		///< NOT supported. The retained flag for the LWT message (see MQTTAsync_message.retained)
  	QoS qos;			///< QoS of LWT message
  } IoT_MQTT_Will_Options;
  extern const IoT_MQTT_Will_Options iotMqttWillOptionsDefault;
  
  #define IoT_MQTT_Will_Options_Initializer { {'M', 'Q', 'T', 'W'}, NULL, 0, NULL, 0, false, QOS0 }
  
  /**
   * @brief MQTT Connection Parameters
   *
   * Defining a type for MQTT connection parameters.  Passed into client when establishing a connection.
   *
   */
  typedef struct {
  	char struct_id[4];			///< The eyecatcher for this structure.  must be MQTC
  	MQTT_Ver_t MQTTVersion;			///< Desired MQTT version used during connection
  	char *pClientID;                	///< Pointer to a string defining the MQTT client ID (this needs to be unique \b per \b device across your AWS account)
  	uint16_t clientIDLen;			///< Client Id Length. 16 bit unsigned integer
  	uint16_t keepAliveIntervalInSec;	///< MQTT keep alive interval in seconds.  Defines inactivity time allowed before determining the connection has been lost.
  	bool isCleanSession;			///< MQTT clean session.  True = this session is to be treated as clean.  Previous server state is cleared and no stated is retained from this connection.
  	bool isWillMsgPresent;			///< Is there a LWT associated with this connection?
  	IoT_MQTT_Will_Options will;		///< MQTT LWT parameters.
  	char *pUsername;			///< Not used in the AWS IoT Service, will need to be cstring if used
  	uint16_t usernameLen;			///< Username Length. 16 bit unsigned integer
  	char *pPassword;			///< Not used in the AWS IoT Service, will need to be cstring if used
  	uint16_t passwordLen;			///< Password Length. 16 bit unsigned integer
  } IoT_Client_Connect_Params;
  extern const IoT_Client_Connect_Params iotClientConnectParamsDefault;
  
  #define IoT_Client_Connect_Params_initializer { {'M', 'Q', 'T', 'C'}, MQTT_3_1_1, NULL, 0, 60, true, false, \
          IoT_MQTT_Will_Options_Initializer, NULL, 0, NULL, 0 }
  
  /**
   * @brief Disconnect Callback Handler Type
   *
   * Defining a TYPE for definition of disconnect callback function pointers.
   *
   */
  typedef void (*iot_disconnect_handler)(AWS_IoT_Client *, void *);
  
  /**
   * @brief MQTT Initialization Parameters
   *
   * Defining a type for MQTT initialization parameters.
   * Passed into client when to initialize the client
   *
   */
  typedef struct {
  	bool enableAutoReconnect;			///< Set to true to enable auto reconnect
  	char *pHostURL;					///< Pointer to a string defining the endpoint for the MQTT service
  	uint16_t port;					///< MQTT service listening port
  	char *pRootCALocation;				///< Pointer to a string defining the Root CA file (full file, not path)
  	char *pDeviceCertLocation;			///< Pointer to a string defining the device identity certificate file (full file, not path)
  	char *pDevicePrivateKeyLocation;        	///< Pointer to a string defining the device private key file (full file, not path)
  	uint32_t mqttPacketTimeout_ms;			///< Timeout for reading a complete MQTT packet. In milliseconds
  	uint32_t mqttCommandTimeout_ms;			///< Timeout for MQTT blocking calls. In milliseconds
  	uint32_t tlsHandshakeTimeout_ms;		///< TLS handshake timeout.  In milliseconds
  	bool isSSLHostnameVerify;			///< Client should perform server certificate hostname validation
  	iot_disconnect_handler disconnectHandler;	///< Callback to be invoked upon connection loss
  	void *disconnectHandlerData;			///< Data to pass as argument when disconnect handler is called
  #ifdef _ENABLE_THREAD_SUPPORT_
  	bool isBlockOnThreadLockEnabled;		///< Timeout for Thread blocking calls. Set to 0 to block until lock is obtained. In milliseconds
  #endif
  } IoT_Client_Init_Params;
  extern const IoT_Client_Init_Params iotClientInitParamsDefault;
  
  #ifdef _ENABLE_THREAD_SUPPORT_
  #define IoT_Client_Init_Params_initializer { true, NULL, 0, NULL, NULL, NULL, 2000, 20000, 5000, true, NULL, NULL, false }
  #else
  #define IoT_Client_Init_Params_initializer { true, NULL, 0, NULL, NULL, NULL, 2000, 20000, 5000, true, NULL, NULL }
  #endif
  
  /**
   * @brief MQTT Client State Type
   *
   * Defining a type for MQTT Client State
   *
   */
  typedef enum _ClientState {
  	CLIENT_STATE_INVALID = 0,
  	CLIENT_STATE_INITIALIZED = 1,
  	CLIENT_STATE_CONNECTING = 2,
  	CLIENT_STATE_CONNECTED_IDLE = 3,
  	CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS = 4,
  	CLIENT_STATE_CONNECTED_PUBLISH_IN_PROGRESS = 5,
  	CLIENT_STATE_CONNECTED_SUBSCRIBE_IN_PROGRESS = 6,
  	CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS = 7,
  	CLIENT_STATE_CONNECTED_RESUBSCRIBE_IN_PROGRESS = 8,
  	CLIENT_STATE_CONNECTED_WAIT_FOR_CB_RETURN = 9,
  	CLIENT_STATE_DISCONNECTING = 10,
  	CLIENT_STATE_DISCONNECTED_ERROR = 11,
  	CLIENT_STATE_DISCONNECTED_MANUALLY = 12,
  	CLIENT_STATE_PENDING_RECONNECT = 13
  } ClientState;
  
  /**
   * @brief Application Callback Handler Type
   *
   * Defining a TYPE for definition of application callback function pointers.
   * Used to send incoming data to the application
   *
   */
  typedef void (*pApplicationHandler_t)(AWS_IoT_Client *pClient, char *pTopicName, uint16_t topicNameLen,
  									  IoT_Publish_Message_Params *pParams, void *pClientData);
  
  /**
   * @brief MQTT Message Handler
   *
   * Defining a type for MQTT Message Handlers.
   * Used to pass incoming data back to the application
   *
   */
  typedef struct _MessageHandlers {
  	const char *topicName;
  	uint16_t topicNameLen;
  	QoS qos;
  	pApplicationHandler_t pApplicationHandler;
  	void *pApplicationHandlerData;
  } MessageHandlers;   /* Message handlers are indexed by subscription topic */
  
  /**
   * @brief MQTT Client Status
   *
   * Defining a type for MQTT Client Status
   * Contains information about the state of the MQTT Client
   *
   */
  typedef struct _ClientStatus {
  	ClientState clientState;
  	bool isPingOutstanding;
  	bool isAutoReconnectEnabled;
  } ClientStatus;
  
  /**
   * @brief MQTT Client Data
   *
   * Defining a type for MQTT Client Data
   * Contains data used by the MQTT Client
   *
   */
  typedef struct _ClientData {
  	uint16_t nextPacketId;
  
  	uint32_t packetTimeoutMs;
  	uint32_t commandTimeoutMs;
  	uint16_t keepAliveInterval;
  	uint32_t currentReconnectWaitInterval;
  	uint32_t counterNetworkDisconnected;
  
  	/* The below values are initialized with the
  	 * lengths of the TX/RX buffers and never modified
  	 * afterwards */
  	size_t writeBufSize;
  	size_t readBufSize;
      size_t readBufIndex;
  	unsigned char writeBuf[AWS_IOT_MQTT_TX_BUF_LEN];
  	unsigned char readBuf[AWS_IOT_MQTT_RX_BUF_LEN];
  
  #ifdef _ENABLE_THREAD_SUPPORT_
  	bool isBlockOnThreadLockEnabled;
  	IoT_Mutex_t state_change_mutex;
  	IoT_Mutex_t tls_read_mutex;
  	IoT_Mutex_t tls_write_mutex;
  #endif
  
  	IoT_Client_Connect_Params options;
  
  	MessageHandlers messageHandlers[AWS_IOT_MQTT_NUM_SUBSCRIBE_HANDLERS];
  	iot_disconnect_handler disconnectHandler;
  
  	void *disconnectHandlerData;
  } ClientData;
  
  /**
   * @brief MQTT Client
   *
   * Defining a type for MQTT Client
   *
   */
  struct _Client {
  	Timer pingTimer;
  	Timer reconnectDelayTimer;
  
  	ClientStatus clientStatus;
  	ClientData clientData;
  	Network networkStack;
  };
  
  /**
   * @brief What is the next available packet Id
   *
   * Called to retrieve the next packet id to be used for outgoing packets.
   * Automatically increments the last sent packet id variable
   *
   * @param pClient Reference to the IoT Client
   *
   * @return next packet id as a 16 bit unsigned integer
   */
  uint16_t aws_iot_mqtt_get_next_packet_id(AWS_IoT_Client *pClient);
  
  /**
   * @brief Set the connection parameters for the IoT Client
   *
   * Called to set the connection parameters for the IoT Client.
   * Used to update the connection parameters provided before the last connect.
   * Won't take effect until the next time connect is called
   *
   * @param pClient Reference to the IoT Client
   * @param pNewConnectParams Reference to the new Connection Parameters structure
   *
   * @return IoT_Error_t Type defining successful/failed API call
   */
  IoT_Error_t aws_iot_mqtt_set_connect_params(AWS_IoT_Client *pClient, IoT_Client_Connect_Params *pNewConnectParams);
  
  /**
   * @brief Is the MQTT client currently connected?
   *
   * Called to determine if the MQTT client is currently connected.  Used to support logic
   * in the device application around reconnecting and managing offline state.
   *
   * @param pClient Reference to the IoT Client
   *
   * @return true = connected, false = not currently connected
   */
  bool aws_iot_mqtt_is_client_connected(AWS_IoT_Client *pClient);
  
  /**
   * @brief Get the current state of the client
   *
   * Called to get the current state of the client
   *
   * @param pClient Reference to the IoT Client
   *
   * @return ClientState value equal to the current state of the client
   */
  ClientState aws_iot_mqtt_get_client_state(AWS_IoT_Client *pClient);
  
  /**
   * @brief Is the MQTT client set to reconnect automatically?
   *
   * Called to determine if the MQTT client is set to reconnect automatically.
   * Used to support logic in the device application around reconnecting
   *
   * @param pClient Reference to the IoT Client
   *
   * @return true = enabled, false = disabled
   */
  bool aws_iot_is_autoreconnect_enabled(AWS_IoT_Client *pClient);
  
  /**
   * @brief Set the IoT Client disconnect handler
   *
   * Called to set the IoT Client disconnect handler
   * The disconnect handler is called whenever the client disconnects with error
   *
   * @param pClient Reference to the IoT Client
   * @param pConnectHandler Reference to the new Disconnect Handler
   * @param pDisconnectHandlerData Reference to the data to be passed as argument when disconnect handler is called
   *
   * @return IoT_Error_t Type defining successful/failed API call
   */
  IoT_Error_t aws_iot_mqtt_set_disconnect_handler(AWS_IoT_Client *pClient, iot_disconnect_handler pDisconnectHandler,
  												void *pDisconnectHandlerData);
  
  /**
   * @brief Enable or Disable AutoReconnect on Network Disconnect
   *
   * Called to enable or disabled the auto reconnect features provided with the SDK
   *
   * @param pClient Reference to the IoT Client
   * @param newStatus set to true for enabling and false for disabling
   *
   * @return IoT_Error_t Type defining successful/failed API call
   */
  IoT_Error_t aws_iot_mqtt_autoreconnect_set_status(AWS_IoT_Client *pClient, bool newStatus);
  
  /**
   * @brief Get count of Network Disconnects
   *
   * Called to get the number of times a network disconnect occurred due to errors
   *
   * @param pClient Reference to the IoT Client
   *
   * @return uint32_t the disconnect count
   */
  uint32_t aws_iot_mqtt_get_network_disconnected_count(AWS_IoT_Client *pClient);
  
  /**
   * @brief Reset Network Disconnect conter
   *
   * Called to reset the Network Disconnect counter to zero
   *
   * @param pClient Reference to the IoT Client
   */
  void aws_iot_mqtt_reset_network_disconnected_count(AWS_IoT_Client *pClient);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif
  