use async_trait::async_trait;
use grammers_client::{Client, Update};
use rand::seq::IteratorRandom;

use crate::bot::handlers::base::Handler;

lazy_static::lazy_static! {
    static ref GREETINGS: &'static [&'static str] = &[
        "Привет!",
        "Добрый день!",
        "Здравствуйте.",
        "Приетствую.",
        "Доброго времени суток.",
    ];
}

/// Greeter just replies to greeting messages.
#[derive(Clone)]
pub struct Greeter;

#[async_trait]
impl Handler for Greeter {
    async fn react(&self, client: &Client, update: &Update) -> anyhow::Result<()> {
        let Update::NewMessage(message) = update else {return Ok(())};

        // Check if chat has less than 100 participants.
        let participants = client.iter_participants(message.chat()).total().await?;
        if participants >= 100 {
            return Ok(());
        }

        // Choose random greeting from the list of greetings.
        let reply_text = GREETINGS.iter().choose(&mut rand::thread_rng()).copied();

        if let Some(text) = reply_text {
            message.reply(text).await?;
        }

        Ok(())
    }
}