From e09ec92a3bdf9175635d99440c3699897cae3a04 Mon Sep 17 00:00:00 2001
From: lyx0 <66651385+lyx0@users.noreply.github.com>
Date: Tue, 13 Feb 2024 19:13:44 +0100
Subject: [PATCH] add eventsub notifications for channels going live

---
 cmd/nourybot/commands.go | 12 +++++++++++
 cmd/nourybot/eventsub.go | 44 ++++++++++++++++++++++++++++++++++++++
 cmd/nourybot/main.go     |  2 ++
 cmd/nourybot/router.go   | 46 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 104 insertions(+)
 create mode 100644 cmd/nourybot/eventsub.go

diff --git a/cmd/nourybot/commands.go b/cmd/nourybot/commands.go
index 0163cb0..adc7d16 100644
--- a/cmd/nourybot/commands.go
+++ b/cmd/nourybot/commands.go
@@ -122,6 +122,18 @@ func (app *application) handleCommand(message twitch.PrivateMessage) {
 	case "frankerfacez":
 		reply = commands.Ffz(cmdParams[1])
 
+	case "notify":
+		switch cmdParams[1] {
+		case "live":
+			if userLevel >= 100 {
+				reply = app.createLiveSubscription(target, cmdParams[2])
+			}
+		case "offline":
+			if userLevel >= 100 {
+				//reply = app.createFollowSubscription(target, cmdParams[2])
+			}
+		}
+
 	case "ddg":
 		reply = commands.DuckDuckGo(message.Message[6:len(message.Message)])
 
diff --git a/cmd/nourybot/eventsub.go b/cmd/nourybot/eventsub.go
new file mode 100644
index 0000000..4099945
--- /dev/null
+++ b/cmd/nourybot/eventsub.go
@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/lyx0/nourybot/pkg/ivr"
+	"github.com/nicklaw5/helix/v2"
+)
+
+func (app *application) createLiveSubscription(target, channel string) string {
+	client, err := helix.NewClient(&helix.Options{
+		ClientID:       app.Config.twitchClientId,
+		AppAccessToken: app.HelixClient.GetAppAccessToken(),
+	})
+	if err != nil {
+		app.Log.Errorw("Error creating new helix client",
+			"err", err,
+		)
+	}
+
+	uid := ivr.IDByUsername(channel)
+
+	resp, err := client.CreateEventSubSubscription(&helix.EventSubSubscription{
+		Type:    helix.EventSubTypeStreamOnline,
+		Version: "1",
+		Condition: helix.EventSubCondition{
+			BroadcasterUserID: uid,
+		},
+		Transport: helix.EventSubTransport{
+			Method:   "webhook",
+			Callback: "https://bot.noury.li/eventsub",
+			Secret:   app.Config.eventSubSecret,
+		},
+	})
+	if err != nil {
+		app.Log.Errorw("Error creating EvenSub subscription",
+			"resp", resp,
+			"err", err,
+		)
+	}
+
+	app.Log.Infof("%+v\n", resp)
+	return fmt.Sprintf("Created subscription for channel %v; uid=%v", channel, uid)
+}
diff --git a/cmd/nourybot/main.go b/cmd/nourybot/main.go
index 0efe710..d5feef1 100644
--- a/cmd/nourybot/main.go
+++ b/cmd/nourybot/main.go
@@ -25,6 +25,7 @@ type config struct {
 	twitchOauth        string
 	twitchClientId     string
 	twitchClientSecret string
+	eventSubSecret     string
 	twitchID           string
 	wolframAlphaAppID  string
 	commandPrefix      string
@@ -88,6 +89,7 @@ func run(ctx context.Context, w io.Writer, args []string) error {
 	cfg.twitchOauth = os.Getenv("TWITCH_OAUTH")
 	cfg.twitchClientId = os.Getenv("TWITCH_CLIENT_ID")
 	cfg.twitchClientSecret = os.Getenv("TWITCH_CLIENT_SECRET")
+	cfg.eventSubSecret = os.Getenv("EVENTSUB_SECRET")
 	cfg.wolframAlphaAppID = os.Getenv("WOLFRAMALPHA_APP_ID")
 	cfg.twitchID = os.Getenv("TWITCH_ID")
 	cfg.env = os.Getenv("ENV")
diff --git a/cmd/nourybot/router.go b/cmd/nourybot/router.go
index 5c96094..e051ca0 100644
--- a/cmd/nourybot/router.go
+++ b/cmd/nourybot/router.go
@@ -1,8 +1,12 @@
 package main
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"html/template"
+	"io/ioutil"
+	"log"
 	"net/http"
 	"os"
 	"sort"
@@ -10,12 +14,14 @@ import (
 	"github.com/julienschmidt/httprouter"
 	"github.com/lyx0/nourybot/internal/common"
 	"github.com/lyx0/nourybot/internal/data"
+	"github.com/nicklaw5/helix/v2"
 )
 
 func (app *application) startRouter() {
 	router := httprouter.New()
 	router.GET("/", app.homeRoute)
 	router.GET("/status", app.statusPageRoute)
+	router.POST("/eventsub", app.eventsubFollow)
 	router.GET("/commands", app.commandsRoute)
 	router.GET("/commands/:channel", app.channelCommandsRoute)
 	router.GET("/timer", app.timersRoute)
@@ -29,6 +35,46 @@ func (app *application) startRouter() {
 	app.Log.Fatal(http.ListenAndServe(":8080", router))
 }
 
+type eventSubNotification struct {
+	Subscription helix.EventSubSubscription `json:"subscription"`
+	Challenge    string                     `json:"challenge"`
+	Event        json.RawMessage            `json:"event"`
+}
+
+func (app *application) eventsubFollow(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	defer r.Body.Close()
+	// verify that the notification came from twitch using the secret.
+	if !helix.VerifyEventSubNotification(app.Config.eventSubSecret, r.Header, string(body)) {
+		log.Println("no valid signature on subscription")
+		return
+	} else {
+		log.Println("verified signature for subscription")
+	}
+	var vals eventSubNotification
+	err = json.NewDecoder(bytes.NewReader(body)).Decode(&vals)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	// if there's a challenge in the request, respond with only the challenge to verify your eventsub.
+	if vals.Challenge != "" {
+		w.Write([]byte(vals.Challenge))
+		return
+	}
+	var liveEvent helix.EventSubStreamOnlineEvent
+	err = json.NewDecoder(bytes.NewReader(vals.Event)).Decode(&liveEvent)
+
+	log.Printf("got stream online event webhook: %s is live\n", liveEvent.BroadcasterUserName)
+	w.WriteHeader(200)
+	w.Write([]byte("ok"))
+	app.SendNoContext("nouryxd", fmt.Sprintf("%s is now live!", liveEvent.BroadcasterUserName))
+}
+
 type timersRouteData struct {
 	Timers []data.Timer
 }