feat: Add option to delete join/leave messages for failed verifications

.gitignore

@@ -3,3 +3,4 @@ dist/
 bot
 
 dist/
+tg-captcha-bot

README.md

@@ -31,10 +31,59 @@ This bot has been tested on several supergroups (2000+ people) for a long time a
 
 `/healthz` - check that the bot is working correctly
 
-## Сustomization
+## Configuration
 
-You can change several bot's settings (welcome message, ban duration, socks5 proxy server) through the configuration file `config.toml`
+The bot uses a TOML configuration file and environment variables.
 
-## Alternatives / Forks
+### Environment Variables
 
-- [momai/tg-captcha-bot](https://github.com/momai/tg-captcha-bot) - fork of `tg-captcha-bot` with interesting additional features.
+| Variable | Required | Description |
+|----------|----------|-------------|
+| `TGTOKEN` | Yes | Telegram bot token from [@BotFather](https://t.me/BotFather) |
+| `CONFIG_PATH` | No | Directory path containing `config.toml`. Defaults to current directory |
+
+### Configuration File Options
+
+Create a `config.toml` file with the following options:
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `button_text` | string | `"I'm not a robot!"` | Text displayed on the captcha button |
+| `welcome_message` | string | `"Hello! This is the spam protection system..."` | Message sent to new users |
+| `after_success_message` | string | `"User passed the validation."` | Message shown after successful verification |
+| `after_fail_message` | string | `"User didn't pass the validation and was banned."` | Message shown after failed verification |
+| `success_message_strategy` | string | `"show"` | Action after success: `"show"` (edit message) or `"del"` (delete message) |
+| `fail_message_strategy` | string | `"del"` | Action after failure: `"show"` (edit message) or `"del"` (delete message) |
+| `welcome_timeout` | string | `"30"` | Seconds user has to press the button |
+| `ban_duration` | string | `"forever"` | Ban duration: `"forever"` or number of minutes (e.g., `"10"`) |
+| `delete_join_message_on_fail` | string | `"no"` | Delete system join/leave messages for failed users: `"yes"` or `"no"` |
+| `use_socks5_proxy` | string | `"no"` | Enable SOCKS5 proxy: `"yes"` or `"no"` |
+| `socks5_address` | string | `"1.1.1.1"` | SOCKS5 proxy IP address |
+| `socks5_port` | string | `"1080"` | SOCKS5 proxy port |
+| `socks5_login` | string | `"login"` | SOCKS5 proxy username |
+| `socks5_password` | string | `"password"` | SOCKS5 proxy password |
+
+### Example Configuration
+
+```toml
+button_text = "I'm not a robot!"
+welcome_message = "Hello! Please press the button within 30 seconds or you will be banned!"
+after_success_message = "User passed the validation."
+after_fail_message = "User didn't pass the validation and was banned."
+success_message_strategy = "show"
+fail_message_strategy = "del"
+welcome_timeout = "30"
+ban_duration = "forever"
+delete_join_message_on_fail = "no"
+use_socks5_proxy = "no"
+```
+
+### Default behavior
+
+With the default configuration:
+
+1. New user joins the group
+2. Bot restricts the user and sends a welcome message with "I'm not a robot!" button
+3. User has 30 seconds to press the button
+4. **If user passes**: Challenge message is edited to show "User passed the validation."
+5. **If user fails**: User is banned forever, challenge message is deleted

config.toml

@@ -12,15 +12,26 @@ after_success_message = "User passed the validation."
 # Edit welcome message with this text if user failed validation
 after_fail_message = "User didn't pass the validation and was banned."
 
-# Show success and failure messages or delete them. Pick "show" or "del"
-print_success_and_fail_messages_strategy = "show"
+# What to do with challenge message when user passes verification. Pick "show" or "del"
+# "show" - edit message with after_success_message text
+# "del" - delete the challenge message
+success_message_strategy = "show"
+
+# What to do with challenge message when user fails verification. Pick "show" or "del"
+# "show" - edit message with after_fail_message text
+# "del" - delete the challenge message
+fail_message_strategy = "del"
 
 # During this time in seconds, the new user have to press the captha button
 welcome_timeout = "30"
 
 # If the new user does not press the button, the bot will ban the user for this duration of time. Can be "forever" or number of minutes ("10")
 ban_duration = "forever"
 
+# Delete the "user joined the group" system message when verification fails. Can be "yes" or "no"
+# This helps prevent spam advertising via usernames in join messages
+delete_join_message_on_fail = "no"
+
 # Do you want to use a socks5 proxy server? Can be "yes" or "no"
 use_socks5_proxy = "no"
 

main.go

@@ -22,22 +22,25 @@ import (
 
 // Config struct for toml config file
 type Config struct {
-	ButtonText          string `mapstructure:"button_text"`
-	WelcomeMessage      string `mapstructure:"welcome_message"`
-	AfterSuccessMessage string `mapstructure:"after_success_message"`
-	AfterFailMessage    string `mapstructure:"after_fail_message"`
-	PrintSuccessAndFail string `mapstructure:"print_success_and_fail_messages_strategy"`
-	WelcomeTimeout      string `mapstructure:"welcome_timeout"`
-	BanDurations        string `mapstructure:"ban_duration"`
-	UseSocks5Proxy      string `mapstructure:"use_socks5_proxy"`
-	Socks5Address       string `mapstructure:"socks5_address"`
-	Socks5Port          string `mapstructure:"socks5_port"`
-	Socks5Login         string `mapstructure:"socks5_login"`
-	Socks5Password      string `mapstructure:"socks5_password"`
+	ButtonText             string `mapstructure:"button_text"`
+	WelcomeMessage         string `mapstructure:"welcome_message"`
+	AfterSuccessMessage    string `mapstructure:"after_success_message"`
+	AfterFailMessage       string `mapstructure:"after_fail_message"`
+	SuccessMessageStrategy string `mapstructure:"success_message_strategy"`
+	FailMessageStrategy    string `mapstructure:"fail_message_strategy"`
+	WelcomeTimeout         string `mapstructure:"welcome_timeout"`
+	BanDurations           string `mapstructure:"ban_duration"`
+	DeleteJoinMsgOnFail    string `mapstructure:"delete_join_message_on_fail"`
+	UseSocks5Proxy         string `mapstructure:"use_socks5_proxy"`
+	Socks5Address          string `mapstructure:"socks5_address"`
+	Socks5Port             string `mapstructure:"socks5_port"`
+	Socks5Login            string `mapstructure:"socks5_login"`
+	Socks5Password         string `mapstructure:"socks5_password"`
 }
 
 var config Config
 var passedUsers = sync.Map{}
+var bannedUsers = sync.Map{} // tracks users banned by the bot for join message cleanup
 var bot *tb.Bot
 var tgtoken = "TGTOKEN"
 var configPath = "CONFIG_PATH"
@@ -76,6 +79,7 @@ func main() {
 
 	bot.Handle(tb.OnUserJoined, challengeUser)
 	bot.Handle(tb.OnCallback, passChallenge)
+	bot.Handle(tb.OnUserLeft, handleUserLeft)
 
 	bot.Handle("/healthz", func(m *tb.Message) {
 		msg := "I'm OK"
@@ -138,23 +142,30 @@ func challengeUser(m *tb.Message) {
 				log.Println(e)
 			}
 			chatMember := tb.ChatMember{User: m.UserJoined, RestrictedUntil: banDuration}
+			// Mark user as banned for cleanup of "removed" message
+			if config.DeleteJoinMsgOnFail == "yes" {
+				bannedUsers.Store(m.UserJoined.ID, struct{}{})
+			}
 			err := bot.Ban(m.Chat, &chatMember)
 			if err != nil {
 				log.Println(err)
 			}
 
-			switch config.PrintSuccessAndFail {
+			switch config.FailMessageStrategy {
 			case "show":
 				_, err := bot.Edit(challengeMsg, config.AfterFailMessage)
 				if err != nil {
 					log.Println(err)
 				}
 			case "del":
-				err := bot.Delete(m)
+				err := bot.Delete(challengeMsg)
 				if err != nil {
 					log.Println(err)
 				}
-				err = bot.Delete(challengeMsg)
+			}
+			// Delete join message if configured (prevents spam advertising via usernames)
+			if config.DeleteJoinMsgOnFail == "yes" {
+				err = bot.Delete(m)
 				if err != nil {
 					log.Println(err)
 				}
@@ -177,7 +188,7 @@ func passChallenge(c *tb.Callback) {
 	}
 	passedUsers.Store(c.Sender.ID, struct{}{})
 
-	switch config.PrintSuccessAndFail {
+	switch config.SuccessMessageStrategy {
 	case "show":
 		_, err := bot.Edit(c.Message, config.AfterSuccessMessage)
 		if err != nil {
@@ -202,6 +213,22 @@ func passChallenge(c *tb.Callback) {
 	}
 }
 
+// handleUserLeft deletes the "bot removed user" message for banned users
+func handleUserLeft(m *tb.Message) {
+	if m.UserLeft == nil {
+		return
+	}
+	// Check if this user was banned by the bot
+	_, wasBanned := bannedUsers.Load(m.UserLeft.ID)
+	if wasBanned {
+		bannedUsers.Delete(m.UserLeft.ID)
+		err := bot.Delete(m)
+		if err != nil {
+			log.Println(err)
+		}
+	}
+}
+
 func readConfig() (err error) {
 	v := viper.New()
 	path, ok := os.LookupEnv(configPath)