add-slash-command

name	add-slash-command
description	Register a /slash_command (BotCommands derive) with permission check, dispatcher wiring, and i18n help text. Use for /verify, /ban, /unban, /stats, /help and similar.

Add Slash Command (Vixen server)

Read first:

• server/docs/bot.md — slash-command table, dispatcher topology.
• server/docs/rules/telegram-handlers.md — handler conventions.

Steps

1. Add a variant to the Command enum in server/src/telegram/commands.rs (with description attr — feeds the menu UI).
2. Implement handle_{cmd} in server/src/telegram/handlers/commands.rs.
3. Permission check via state.moderation.is_moderator(chat_id, user_id).await? inside the handler, before any side effect.
4. Register dptree::case![Command::X] in dispatcher.rs under the commands branch.
5. Update the slash-command table in server/docs/bot.md.
6. Push setMyCommands via the ops endpoint or one-shot CLI on next deploy.

Skeleton

#[derive(BotCommands, Clone)]
#[command(rename_rule = "lowercase")]
pub enum Command {
    #[command(description = "Verify a user (reply or by id).")]
    Verify { user_id: Option<i64> },
    #[command(description = "Ban a user.")]
    Ban { user_id: Option<i64> },
}

Gotchas

• User ID is i64. Always.
• Permission check inside the handler, not the dispatcher. BotCommands derive doesn't enforce moderator scope. Don't trust the message just because the dispatcher routed it.
• Optional args (Option<i64>) let /verify work both as a reply (no args) and with an explicit id. Resolve in this order: explicit arg → msg.reply_to_message().from.id → reject with help text.
• setMyCommands is not automatic. Add the new entry to the deploy-time push, or moderators won't see it in the Telegram menu.
• description is mandatory for menu UX. A missing description hides the command from the slash menu.
• Reply-mode vs id-mode is a single handler — branch on args.user_id then msg.reply_to_message().

Verification

• cargo build — derive macro errors out at compile time.
• Manual: type the command in a dev chat with both moderator and non-moderator accounts.

Related

• add-telegram-handler — non-command updates.
• per-chat-config — commands that mutate config (transactional update).