packets

type FixedHeader struct {
	Remaining int  // the number of remaining bytes in the payload.
	Type      byte // the type of the packet (PUBLISH, SUBSCRIBE, etc) from bits 7 - 4 (byte 1).
	Qos       byte // indicates the quality of service expected.
	Dup       bool // indicates if the packet was already sent at an earlier time.
	Retain    bool // whether the message should be retained.
}

type Packet struct {
	FixedHeader      FixedHeader
	AllowClients     []string // For use with OnMessage event hook.
	Topics           []string
	ReturnCodes      []byte
	ProtocolName     []byte
	Payload          []byte
	Username         []byte
	Password         []byte
	WillMessage      []byte
	ClientIdentifier string
	TopicName        string
	WillTopic        string
	PacketID         uint16
	Keepalive        uint16
	ReturnCode       byte //v5.0 ReasonCode
	ProtocolVersion  byte
	WillQos          byte
	ReservedBit      byte
	CleanSession     bool //v5.0 CleanStart
	WillFlag         bool
	WillRetain       bool
	UsernameFlag     bool
	PasswordFlag     bool
	SessionPresent   bool

	SubOss         []SubOptions
	Properties     *Properties
	WillProperties *Properties
}

type Properties struct {
	// PayloadFormat indicates the format of the payload of the message
	// 0 is unspecified bytes
	// 1 is UTF8 encoded character data
	PayloadFormat *byte `json:"payload_format,omitempty" msg:"payload_format,omitempty"`
	// MessageExpiry is the lifetime of the message in seconds
	MessageExpiry *uint32 `json:"msg_expiry,omitempty" msg:"msg_expiry,omitempty"`
	// ContentType is a UTF8 string describing the content of the message
	// for example it could be a MIME type
	ContentType string `json:"content_type,omitempty" msg:"content_type,omitempty"`
	// ResponseTopic is a UTF8 string indicating the topic name to which any
	// response to this message should be sent
	ResponseTopic string `json:"resp_topic,omitempty" msg:"resp_topic,omitempty"`
	// CorrelationData is binary data used to associate future response
	// messages with the original request message
	CorrelationData []byte `json:"corr_data,omitempty" msg:"corr_data,omitempty"`
	// SubscriptionIdentifier is an identifier of the subscription to which
	// the Publish matched
	SubscriptionIdentifier *int `json:"sub_id,omitempty" msg:"sub_id,omitempty"`
	// SessionExpiryInterval is the time in seconds after a client disconnects
	// that the server should retain the session information (subscriptions etc)
	SessionExpiryInterval *uint32 `json:"sei,omitempty" msg:"sei,omitempty"`
	// AssignedClientID is the server assigned client identifier in the case
	// that a client connected without specifying a clientID the server
	// generates one and returns it in the Connack
	AssignedClientID string `json:"acid,omitempty" msg:"acid,omitempty"`
	// ServerKeepAlive allows the server to specify in the Connack packet
	// the time in seconds to be used as the keep alive value
	ServerKeepAlive *uint16 `json:"ska,omitempty" msg:"ska,omitempty"`
	// AuthMethod is a UTF8 string containing the name of the authentication
	// method to be used for extended authentication
	AuthMethod string `json:"auth_method,omitempty" msg:"auth_method,omitempty"`
	// AuthData is binary data containing authentication data
	AuthData []byte `json:"auth_data,omitempty" msg:"auth_data,omitempty"`
	// RequestProblemInfo is used by the Client to indicate to the server to
	// include the Reason String and/or User Properties in case of failures
	RequestProblemInfo *byte `json:"rpi,omitempty" msg:"rpi,omitempty"`
	// WillDelayInterval is the number of seconds the server waits after the
	// point at which it would otherwise send the will message before sending
	// it. The client reconnecting before that time expires causes the server
	// to cancel sending the will
	WillDelayInterval *uint32 `json:"wdi,omitempty" msg:"wdi,omitempty"`
	// RequestResponseInfo is used by the Client to request the Server provide
	// Response Information in the Connack
	RequestResponseInfo *byte `json:"rri,omitempty" msg:"rri,omitempty"`
	// ResponseInfo is a UTF8 encoded string that can be used as the basis for
	// createing a Response Topic. The way in which the Client creates a
	// Response Topic from the Response Information is not defined. A common
	// use of this is to pass a globally unique portion of the topic tree which
	// is reserved for this Client for at least the lifetime of its Session. This
	// often cannot just be a random name as both the requesting Client and the
	// responding Client need to be authorized to use it. It is normal to use this
	// as the root of a topic tree for a particular Client. For the Server to
	// return this information, it normally needs to be correctly configured.
	// Using this mechanism allows this configuration to be done once in the
	// Server rather than in each Client
	ResponseInfo string `json:"resp_info,omitempty" msg:"resp_info,omitempty"`
	// ServerReference is a UTF8 string indicating another server the client
	// can use
	ServerReference string `json:"server_ref,omitempty" msg:"server_ref,omitempty"`
	// ReasonString is a UTF8 string representing the reason associated with
	// this response, intended to be human readable for diagnostic purposes
	ReasonString string `json:"reason,omitempty" msg:"reason,omitempty"`
	// ReceiveMaximum is the maximum number of QOS1 & 2 messages allowed to be
	// 'inflight' (not having received a PUBACK/PUBCOMP response for)
	ReceiveMaximum *uint16 `json:"rec_max,omitempty" msg:"rec_max,omitempty"`
	// TopicAliasMaximum is the highest value permitted as a Topic Alias
	TopicAliasMaximum *uint16 `json:"tam,omitempty" msg:"tam,omitempty"`
	// TopicAlias is used in place of the topic string to reduce the size of
	// packets for repeated messages on a topic
	TopicAlias *uint16 `json:"topic_alias,omitempty" msg:"topic_alias,omitempty"`
	// MaximumQOS is the highest QOS level permitted for a Publish
	MaximumQOS *byte `json:"max_qos,omitempty" msg:"max_qos,omitempty"`
	// RetainAvailable indicates whether the server supports messages with the
	// retain flag set
	RetainAvailable *byte `json:"retain_ava,omitempty" msg:"retain_ava,omitempty"`
	// User is a slice of user provided properties (key and value)
	User []User `json:"user,omitempty" msg:"user,omitempty"`
	// MaximumPacketSize allows the client or server to specify the maximum packet
	// size in bytes that they support
	MaximumPacketSize *uint32 `json:"mps,omitempty" msg:"mps,omitempty"`
	// WildcardSubAvailable indicates whether wildcard subscriptions are permitted
	WildcardSubAvailable *byte `json:"wsa,omitempty" msg:"wsa,omitempty"`
	// SubIDAvailable indicates whether subscription identifiers are supported
	SubIDAvailable *byte `json:"sid_ava,omitempty" msg:"sid_ava,omitempty"`
	// SharedSubAvailable indicates whether shared subscriptions are supported
	SharedSubAvailable *byte `json:"ssa,omitempty" msg:"ssa,omitempty"`
}

type ReasonCode byte

type SubOptions struct {
	// Qos is the QoS level of the subscription.
	// 0 = At most once delivery
	// 1 = At least once delivery
	// 2 = Exactly once delivery
	QoS byte `json:"qos,omitempty" msg:"qos,omitempty"`
	// RetainHandling specifies whether retained messages are sent when the subscription is established.
	// 0 = Send retained messages at the time of the subscribe
	// 1 = Send retained messages at subscribe only if the subscription does not currently exist
	// 2 = Do not send retained messages at the time of the subscribe
	RetainHandling byte `json:"retain_hd,omitempty" msg:"retain_hd,omitempty"`
	// NoLocal is the No Local option.
	//  If the value is 1, Application Messages MUST NOT be forwarded to a connection with a ClientID equal to the ClientID of the publishing connection
	NoLocal bool `json:"no_local,omitempty" msg:"no_local,omitempty"`
	// RetainAsPublished is the Retain As Published option.
	// If 1, Application Messages forwarded using this subscription keep the RETAIN flag they were published with.
	// If 0, Application Messages forwarded using this subscription have the RETAIN flag set to 0. Retained messages sent when the subscription is established have the RETAIN flag set to 1.
	RetainAsPublished bool `json:"rap,omitempty" msg:"rap,omitempty"`
}

type User struct {
	Key   string `json:"key" msg:"type"`
	Value string `json:"value" msg:"type"`
}