add long poller method

.gitignore

@@ -15,4 +15,4 @@
 # vendor/
 data.json
 config.yaml
-telegram-random-image-carousel
+telegram-random-image-carousel*

README.md

@@ -6,4 +6,6 @@
 
 ## Usage
 
-Create `config.yaml` and `data.json` (see example files) and run with `./telegram-random-image-carousel`
+Create `config.yaml` and `data.json` (see example files) and finally run the bot by using `./telegram-random-image-carousel`.
+
+Get the random image by triggering it using `/bucketName` command.

bot.go

@@ -9,16 +9,27 @@ import (
 	tb "gopkg.in/tucnak/telebot.v2"
 )
 
+// RunBot based on the configuration and repository passed
 func RunBot(config *Config, repository *Repository) {
 	settings := tb.Settings{
 		Token: config.BotAPIToken,
-		Poller: &tb.Webhook{
+	}
+
+	// if both port and webhook URL are configured, use webhook
+	if config.Port != "" && config.WebhookURL != "" {
+		settings.Poller = &tb.Webhook{
 			Listen: ":" + config.Port,
 			Endpoint: &tb.WebhookEndpoint{
 				PublicURL: config.WebhookURL,
 			},
-		},
+		}
+		// fallback to long poller
+	} else {
+		settings.Poller = &tb.LongPoller{
+			Timeout: 10 * time.Second,
+		}
 	}
+
 	log.Println("Loading the bot")
 	b, err := tb.NewBot(settings)
 	if err != nil {
@@ -34,6 +45,7 @@ func RunBot(config *Config, repository *Repository) {
 	b.Start()
 }
 
+// SetRepository binds repository data to the bot commands
 func SetRepository(b *tb.Bot, repository *Repository) {
 	rand.Seed(time.Now().UnixNano())
 

config.example.yaml

@@ -1,3 +1,3 @@
 bot_api_token: 1234567890
-webhook_url: https://some_website.com
-port: 3000
+webhook_url: https://some_website.com # Comment this line if you want to use long poller
+port: 3000 # Comment this line if you want to use long poller

config_test.go

@@ -8,7 +8,7 @@ import (
 func TestConfig(t *testing.T) {
 	reference := &Config{
 		BotAPIToken: "1234567890",
-		WebhookURL:  "https://some_website.com/api/telegram",
+		WebhookURL:  "https://some_website.com",
 		Port:        "3000",
 	}
 

repository.go

@@ -35,6 +35,9 @@ func LoadData(filename string) (*Repository, error) {
 
 	repo := Repository{Bucket: b, BucketSize: make(map[string]int)}
 	for k, v := range repo.Bucket {
+		if len(v) == 0 {
+			panic("bucket size must be larger than zero")
+		}
 		repo.BucketSize[k] = len(v)
 	}