make Client an interface, make Message a plain structv0.0.3

3 files changed, 54 insertions, 41 deletions

diff --git a/api.go b/api.go
new file mode 100644
index 0000000..8397cb9
--- /dev/null
+++ b/api.go
@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: 2020 Ethel Morgan
+//
+// SPDX-License-Identifier: MIT
+
+// Package catbus is a convenience wrapper around MQTT for use with Catbus.
+package catbus
+
+type (
+	MessageHandler func(Client, Message)
+
+	Message struct {
+		Payload   string
+		Retention Retention
+		Topic     string
+	}
+
+	Client interface {
+		Connect() error
+		Subscribe(topic string, f MessageHandler) error
+		Publish(topic string, retention Retention, payload string) error
+	}
+
+	// Retention is whether or not the MQTT broker should retain the message.
+	Retention bool
+)
+
+const (
+	Retain     = Retention(true)
+	DontRetain = Retention(false)
+)
diff --git a/catbus.go b/catbus.go
index c2af247..a3eb115 100644
--- a/catbus.go
+++ b/catbus.go
@@ -2,7 +2,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-// Package catbus is a convenience wrapper around MQTT for use with Catbus.
 package catbus
 
 import (
@@ -14,13 +13,7 @@ import (
 )
 
 type (
-	MessageHandler func(*Client, Message)
-
-	Message struct {
-		message mqtt.Message
-	}
-
-	Client struct {
+	client struct {
 		mqtt mqtt.Client
 
 		payloadByTopicMu sync.Mutex
@@ -34,8 +27,8 @@ type (
 	}
 
 	ClientOptions struct {
-		DisconnectHandler func(*Client, error)
-		ConnectHandler    func(*Client)
+		DisconnectHandler func(Client, error)
+		ConnectHandler    func(Client)
 
 		// Publish previously seen or default values on connecting after OnconnectDelay ± [0,OnconnectJitter).
 		OnconnectDelay  time.Duration
@@ -45,9 +38,6 @@ type (
 		// E.g. unless we've been told otherwise, assume a device is off.
 		DefaultPayloadByTopic map[string]string
 	}
-
-	// Retention is whether or not the MQTT broker should retain the message.
-	Retention bool
 )
 
 const (
@@ -57,17 +47,12 @@ const (
 )
 
 const (
-	Retain     = Retention(true)
-	DontRetain = Retention(false)
-)
-
-const (
 	DefaultOnconnectDelay  = 1 * time.Minute
 	DefaultOnconnectJitter = 15 * time.Second
 )
 
-func NewClient(brokerURI string, options ClientOptions) *Client {
-	client := &Client{
+func NewClient(brokerURI string, options ClientOptions) Client {
+	client := &client{
 		payloadByTopic:        map[string]string{},
 		onconnectTimerByTopic: map[string]*time.Timer{},
 
@@ -88,7 +73,7 @@ func NewClient(brokerURI string, options ClientOptions) *Client {
 	mqttOpts := mqtt.NewClientOptions()
 	mqttOpts.AddBroker(brokerURI)
 	mqttOpts.SetAutoReconnect(true)
-	mqttOpts.SetOnConnectHandler(func(c mqtt.Client) {
+	mqttOpts.SetOnConnectHandler(func(_ mqtt.Client) {
 		client.stopAllTimers()
 		client.startAllTimers()
 
@@ -96,7 +81,7 @@ func NewClient(brokerURI string, options ClientOptions) *Client {
 			options.ConnectHandler(client)
 		}
 	})
-	mqttOpts.SetConnectionLostHandler(func(c mqtt.Client, err error) {
+	mqttOpts.SetConnectionLostHandler(func(_ mqtt.Client, err error) {
 		client.stopAllTimers()
 
 		if options.DisconnectHandler != nil {
@@ -109,7 +94,7 @@ func NewClient(brokerURI string, options ClientOptions) *Client {
 }
 
 // Connect connects to the Catbus MQTT broker and blocks forever.
-func (c *Client) Connect() error {
+func (c *client) Connect() error {
 	if err := c.mqtt.Connect().Error(); err != nil {
 		return err
 	}
@@ -117,22 +102,22 @@ func (c *Client) Connect() error {
 }
 
 // Subscribe subscribes to a Catbus MQTT topic.
-func (c *Client) Subscribe(topic string, f MessageHandler) error {
+func (c *client) Subscribe(topic string, f MessageHandler) error {
 	return c.mqtt.Subscribe(topic, atLeastOnce, func(_ mqtt.Client, msg mqtt.Message) {
 		c.storePayload(msg.Topic(), Retention(msg.Retained()), string(msg.Payload()))
 
-		f(c, Message{msg})
+		f(c, messageFromMQTTMessage(msg))
 	}).Error()
 }
 
 // Publish publishes to a Catbus MQTT topic.
-func (c *Client) Publish(topic string, retention Retention, payload string) error {
+func (c *client) Publish(topic string, retention Retention, payload string) error {
 	c.storePayload(topic, retention, payload)
 
 	return c.mqtt.Publish(topic, atLeastOnce, bool(retention), payload).Error()
 }
 
-func (c *Client) jitteredOnconnectDelay() time.Duration {
+func (c *client) jitteredOnconnectDelay() time.Duration {
 	jitter := time.Duration(rand.Intn(int(c.onconnectJitter)))
 	if rand.Intn(2) == 0 {
 		return c.onconnectDelay + jitter
@@ -140,7 +125,7 @@ func (c *Client) jitteredOnconnectDelay() time.Duration {
 	return c.onconnectDelay - jitter
 }
 
-func (c *Client) storePayload(topic string, retention Retention, payload string) {
+func (c *client) storePayload(topic string, retention Retention, payload string) {
 	c.payloadByTopicMu.Lock()
 	defer c.payloadByTopicMu.Unlock()
 
@@ -157,7 +142,7 @@ func (c *Client) storePayload(topic string, retention Retention, payload string)
 	}
 	c.payloadByTopic[topic] = payload
 }
-func (c *Client) stopTimer(topic string) {
+func (c *client) stopTimer(topic string) {
 	c.onconnectTimerByTopicMu.Lock()
 	defer c.onconnectTimerByTopicMu.Unlock()
 
@@ -165,7 +150,7 @@ func (c *Client) stopTimer(topic string) {
 		_ = timer.Stop()
 	}
 }
-func (c *Client) stopAllTimers() {
+func (c *client) stopAllTimers() {
 	c.onconnectTimerByTopicMu.Lock()
 	defer c.onconnectTimerByTopicMu.Unlock()
 
@@ -173,7 +158,7 @@ func (c *Client) stopAllTimers() {
 		_ = timer.Stop()
 	}
 }
-func (c *Client) startAllTimers() {
+func (c *client) startAllTimers() {
 	c.payloadByTopicMu.Lock()
 	defer c.payloadByTopicMu.Unlock()
 
@@ -193,12 +178,10 @@ func (c *Client) startAllTimers() {
 	}
 }
 
-func (m Message) Topic() string {
-	return m.message.Topic()
-}
-func (m Message) Payload() string {
-	return string(m.message.Payload())
-}
-func (m Message) Retained() bool {
-	return m.message.Retained()
+func messageFromMQTTMessage(msg mqtt.Message) Message {
+	return Message{
+		Payload:   string(msg.Payload()),
+		Retention: Retention(msg.Retained()),
+		Topic:     msg.Topic(),
+	}
 }
diff --git a/catbus_test.go b/catbus_test.go
index cc22ebb..b345c48 100644
--- a/catbus_test.go
+++ b/catbus_test.go
@@ -105,7 +105,7 @@ func TestOnConnect(t *testing.T) {
 			payloadByTopic:  map[string]string{},
 		}
 
-		catbus := &Client{
+		catbus := &client{
 			mqtt:                  fakeMQTT,
 			payloadByTopic:        map[string]string{},
 			onconnectTimerByTopic: map[string]*time.Timer{},
@@ -117,7 +117,7 @@ func TestOnConnect(t *testing.T) {
 		}
 
 		for _, topic := range tt.subscribe {
-			catbus.Subscribe(topic, func(_ *Client, _ Message) {})
+			catbus.Subscribe(topic, func(_ Client, _ Message) {})
 		}
 		for topic, message := range tt.receive {
 			fakeMQTT.send(topic, message.retention, message.payload)