// Sometimes we need a global state, for example to be able to use
// a database, that way we can have an active connection all time,
// without having to reopen every time

use panda::{events::GuildMemberAdd, HandlerResult, Session};
use std::{collections::HashMap, error::Error};

// We use futures Mutex to prevent lock the thread
use futures::lock::Mutex;

#[derive(Default)]
struct State {
    guild_members: Mutex<HashMap<String, u64>>,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let mut client = panda::new_with_state("your token here", State::default()).await?;

    client.on_guild_member_add(member_add_handler);
    client.start().await?;

    Ok(())
}

async fn member_add_handler(session: Session<State>, member: GuildMemberAdd) -> HandlerResult {
    // guild_id it's an Option<String>
    let guild_id = member.guild_id.as_ref().unwrap();

    // Get the state
    let mut counter = session.state.guild_members.lock().await;

    // Get count, set default to 0, we use .to_owned() to be able to use it later in println!
    let guild_count = counter.entry(guild_id.to_owned()).or_insert(0);

    println!(
        "A new member joined server {}, current count: {}",
        guild_id, guild_count
    );

    Ok(())
}