initial working version based on a medium article

.env.example

@@ -0,0 +1,3 @@
+SLACK_AUTH_TOKEN=""
+SLACK_CHANNEL_ID=""
+SLACK_APP_TOKEN=""

go.mod

@@ -0,0 +1,9 @@
+module rodleyserverbot/slack-bot
+
+go 1.13
+
+require (
+	github.com/gorilla/websocket v1.5.0 // indirect
+	github.com/joho/godotenv v1.4.0 // indirect
+	github.com/slack-go/slack v0.11.0 // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
+github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/joho/godotenv v1.4.0 h1:3l4+N6zfMWnkbPEXKng2o2/MR5mSwTrBih4ZEkkz1lg=
+github.com/joho/godotenv v1.4.0/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/slack-go/slack v0.11.0 h1:sBBjQz8LY++6eeWhGJNZpRm5jvLRNnWBFZ/cAq58a6k=
+github.com/slack-go/slack v0.11.0/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

main.go

@@ -0,0 +1,168 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/joho/godotenv"
+	"github.com/slack-go/slack"
+	"github.com/slack-go/slack/slackevents"
+	"github.com/slack-go/slack/socketmode"
+)
+
+func main() {
+
+	// Load Env variables from .dot file
+	godotenv.Load(".env")
+
+	token := os.Getenv("SLACK_AUTH_TOKEN")
+	appToken := os.Getenv("SLACK_APP_TOKEN")
+	// Create a new client to slack by giving token
+	// Set debug to true while developing
+	// Also add a ApplicationToken option to the client
+	client := slack.New(token, slack.OptionDebug(true), slack.OptionAppLevelToken(appToken))
+	// go-slack comes with a SocketMode package that we need to use that accepts a Slack client and outputs a Socket mode client instead
+	socketClient := socketmode.New(
+		client,
+		socketmode.OptionDebug(true),
+		// Option to set a custom logger
+		socketmode.OptionLog(log.New(os.Stdout, "socketmode: ", log.Lshortfile|log.LstdFlags)),
+	)
+
+	// Create a context that can be used to cancel goroutine
+	ctx, cancel := context.WithCancel(context.Background())
+	// Make this cancel called properly in a real program , graceful shutdown etc
+	defer cancel()
+
+	go func(ctx context.Context, client *slack.Client, socketClient *socketmode.Client) {
+		// Create a for loop that selects either the context cancellation or the events incomming
+		for {
+			select {
+			// inscase context cancel is called exit the goroutine
+			case <-ctx.Done():
+				log.Println("Shutting down socketmode listener")
+				return
+			case event := <-socketClient.Events:
+				// We have a new Events, let's type switch the event
+				// Add more use cases here if you want to listen to other events.
+				switch event.Type {
+				// handle EventInteractive events
+				case socketmode.EventTypeInteractive:
+					fmt.Println("Recivimos un Interactive!", event)
+					eventsInteractive, ok := event.Data.(slackevents.EventsAPICallbackEvent)
+					if !ok {
+						log.Printf("Could not type cast the event to the EventsAPICallbackEvent: %v\n", event)
+						continue
+					}
+					fmt.Println("Se pudo castear!!", eventsInteractive)
+				// handle EventAPI events
+				case socketmode.EventTypeEventsAPI:
+					// The Event sent on the channel is not the same as the EventAPI events so we need to type cast it
+					eventsAPIEvent, ok := event.Data.(slackevents.EventsAPIEvent)
+					if !ok {
+						log.Printf("Could not type cast the event to the EventsAPIEvent: %v\n", event)
+						continue
+					}
+					// We need to send an Acknowledge to the slack server
+					socketClient.Ack(*event.Request)
+					// Now we have an Events API event, but this event type can in turn be many types, so we actually need another type switch
+					log.Println(eventsAPIEvent)
+					err := handleEventMessage(eventsAPIEvent, client)
+					if err != nil {
+						// Replace with actual err handeling
+						log.Fatal(err)
+					}
+				}
+
+			}
+		}
+	}(ctx, client, socketClient)
+
+	socketClient.Run()
+}
+
+// handleEventMessage will take an event and handle it properly based on the type of event
+func handleEventMessage(event slackevents.EventsAPIEvent, client *slack.Client) error {
+	switch event.Type {
+	// First we check if this is an CallbackEvent
+	case slackevents.CallbackEvent:
+
+		innerEvent := event.InnerEvent
+		fmt.Println("We received an event!", innerEvent)
+		// Yet Another Type switch on the actual Data to see if its an AppMentionEvent
+		switch ev := innerEvent.Data.(type) {
+		case *slackevents.AppMentionEvent:
+			// The application has been mentioned since this Event is a Mention event
+			log.Println(ev)
+			handleAppMentionEvent(ev, client)
+		}
+	default:
+		return errors.New("unsupported event type")
+	}
+	return nil
+}
+
+// handleAppMentionEvent is used to take care of the AppMentionEvent when the bot is mentioned
+func handleAppMentionEvent(event *slackevents.AppMentionEvent, client *slack.Client) error {
+
+	// Grab the user name based on the ID of the one who mentioned the bot
+	user, err := client.GetUserInfo(event.User)
+	if err != nil {
+		return err
+	}
+	// Check if the user said Hello to the bot
+	text := strings.ToLower(event.Text)
+
+	// Create the attachment and assigned based on the message
+	attachment := slack.Attachment{}
+	// Add Some default context like user who mentioned the bot
+	// attachment.Fields = []slack.AttachmentField{
+	// 	{
+	// 		Title: "Date",
+	// 		Value: time.Now().String(),
+	// 	}, {
+	// 		Title: "Initializer",
+	// 		Value: user.Name,
+	// 	},
+	// }
+	attachment.CallbackID = "server_action"
+	if strings.Contains(text, "hello") {
+		// Greet the user
+		attachment.Text = fmt.Sprintf("Hello %s", user.Name)
+		attachment.Pretext = "Greetings"
+		attachment.Color = "#4af030"
+	} else {
+		// Send a message to the user
+		attachment.Text = "Por el momento esto es lo que se hacer"
+		attachment.Pretext = fmt.Sprintf("Como te puedo ayudar %s?", user.Name)
+		attachment.Color = "#3d3d3d"
+		powerOnAction := slack.AttachmentAction{}
+		powerOnAction.Name = "poweron"
+		powerOnAction.Text = "Encender"
+		powerOnAction.Value = "poweron"
+		powerOnAction.Type = "button"
+
+		powerOffAction := slack.AttachmentAction{}
+		powerOffAction.Name = "poweroff"
+		powerOffAction.Text = "Apagar"
+		powerOffAction.Value = "poweroff"
+		powerOffAction.Type = "button"
+		powerOffAction.Style = "danger"
+
+		actions := []slack.AttachmentAction{powerOnAction, powerOffAction}
+		fmt.Println(actions)
+		attachment.Actions = actions
+
+	}
+	// Send the message to the channel
+	// The Channel is available in the event message
+	_, _, err = client.PostMessage(event.Channel, slack.MsgOptionAttachments(attachment))
+	if err != nil {
+		return fmt.Errorf("failed to post message: %w", err)
+	}
+	return nil
+}