From bea301dd062128bd84d077fc4e741b2caf0ccdfc Mon Sep 17 00:00:00 2001
From: Alvin Rizki <4lvin.rizki@gmail.com>
Date: Sat, 2 Nov 2019 23:50:16 +0700
Subject: [PATCH 1/2] add token checking expiration checking

---
 jwt.go    | 20 ++++++++++++++++++++
 smooch.go | 20 ++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/jwt.go b/jwt.go
index f8a33a8..79f1b44 100644
--- a/jwt.go
+++ b/jwt.go
@@ -16,3 +16,23 @@ func GenerateJWT(scope string, keyID string, secret string) (string, error) {
 
 	return token.SignedString([]byte(secret))
 }
+
+// isJWTExpired will check whether Smooch JWT is expired or not.
+func isJWTExpired(jwtToken string, secret string) (bool, error) {
+	_, err := jwt.ParseWithClaims(jwtToken, jwt.MapClaims{}, func(t *jwt.Token) (interface{}, error) {
+		return []byte(secret), nil
+	})
+
+	if err == nil {
+		return false, nil
+	}
+
+	switch err.(type) {
+	case *jwt.ValidationError:
+		vErr := err.(*jwt.ValidationError)
+		if vErr.Errors == jwt.ValidationErrorExpired {
+			return true, nil
+		}
+	}
+	return false, err
+}
diff --git a/smooch.go b/smooch.go
index f531871..5dc224c 100644
--- a/smooch.go
+++ b/smooch.go
@@ -17,6 +17,8 @@ import (
 
 var (
 	ErrUserIDEmpty       = errors.New("user id is empty")
+	ErrKeyIDEmpty        = errors.New("key id is empty")
+	ErrSecretEmpty       = errors.New("secret is empty")
 	ErrMessageNil        = errors.New("message is nil")
 	ErrMessageRoleEmpty  = errors.New("message.Role is empty")
 	ErrMessageTypeEmpty  = errors.New("message.Type is empty")
@@ -52,6 +54,7 @@ type WebhookEventHandler func(payload *Payload)
 
 type Client interface {
 	Handler() http.Handler
+	IsJWTExpired() (bool, error)
 	AddWebhookEventHandler(handler WebhookEventHandler)
 	Send(userID string, message *Message) (*ResponsePayload, error)
 	VerifyRequest(r *http.Request) bool
@@ -63,6 +66,8 @@ type Client interface {
 type smoochClient struct {
 	mux                  *http.ServeMux
 	appID                string
+	keyID                string
+	secret               string
 	jwtToken             string
 	verifySecret         string
 	logger               Logger
@@ -72,6 +77,14 @@ type smoochClient struct {
 }
 
 func New(o Options) (*smoochClient, error) {
+	if o.KeyID == "" {
+		return nil, ErrKeyIDEmpty
+	}
+
+	if o.Secret == "" {
+		return nil, ErrSecretEmpty
+	}
+
 	if o.VerifySecret == "" {
 		return nil, ErrVerifySecretEmpty
 	}
@@ -109,6 +122,8 @@ func New(o Options) (*smoochClient, error) {
 	sc := &smoochClient{
 		mux:          o.Mux,
 		appID:        o.AppID,
+		keyID:        o.KeyID,
+		secret:       o.Secret,
 		verifySecret: o.VerifySecret,
 		logger:       o.Logger,
 		region:       region,
@@ -124,6 +139,11 @@ func (sc *smoochClient) Handler() http.Handler {
 	return sc.mux
 }
 
+// IsJWTExpired will check whether Smooch JWT is expired or not.
+func (sc *smoochClient) IsJWTExpired() (bool, error) {
+	return isJWTExpired(sc.jwtToken, sc.secret)
+}
+
 func (sc *smoochClient) AddWebhookEventHandler(handler WebhookEventHandler) {
 	sc.webhookEventHandlers = append(sc.webhookEventHandlers, handler)
 }

From 0f402017863a33fa53ed1ce624c54d0327e18fc6 Mon Sep 17 00:00:00 2001
From: Alvin Rizki <4lvin.rizki@gmail.com>
Date: Sun, 3 Nov 2019 00:01:11 +0700
Subject: [PATCH 2/2] add RenewToken()

---
 smooch.go | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/smooch.go b/smooch.go
index 5dc224c..4fe2276 100644
--- a/smooch.go
+++ b/smooch.go
@@ -13,6 +13,7 @@ import (
 	"os"
 	"path"
 	"strings"
+	"sync"
 )
 
 var (
@@ -55,6 +56,7 @@ type WebhookEventHandler func(payload *Payload)
 type Client interface {
 	Handler() http.Handler
 	IsJWTExpired() (bool, error)
+	RenewToken() (string, error)
 	AddWebhookEventHandler(handler WebhookEventHandler)
 	Send(userID string, message *Message) (*ResponsePayload, error)
 	VerifyRequest(r *http.Request) bool
@@ -74,6 +76,7 @@ type smoochClient struct {
 	region               string
 	webhookEventHandlers []WebhookEventHandler
 	httpClient           *http.Client
+	mtx                  sync.Mutex
 }
 
 func New(o Options) (*smoochClient, error) {
@@ -144,6 +147,20 @@ func (sc *smoochClient) IsJWTExpired() (bool, error) {
 	return isJWTExpired(sc.jwtToken, sc.secret)
 }
 
+// RenewToken will generate new Smooch JWT token.
+func (sc *smoochClient) RenewToken() (string, error) {
+	sc.mtx.Lock()
+	defer sc.mtx.Unlock()
+
+	jwtToken, err := GenerateJWT("app", sc.keyID, sc.secret)
+	if err != nil {
+		return "", err
+	}
+
+	sc.jwtToken = jwtToken
+	return jwtToken, nil
+}
+
 func (sc *smoochClient) AddWebhookEventHandler(handler WebhookEventHandler) {
 	sc.webhookEventHandlers = append(sc.webhookEventHandlers, handler)
 }