use async_trait::async_trait;
use dataloader::non_cached::Loader;
use dataloader::BatchFn;
use diesel::prelude::*;
use std::collections::HashMap;
use uuidv7::Uuid;

use crate::{api::models, db};

pub struct UserBatcher;

#[async_trait]
impl BatchFn<Uuid, models::user::User> for UserBatcher {
    async fn load(&mut self, keys: &[Uuid]) -> HashMap<Uuid, models::user::User> {
        let db_conn = &mut db::POOL.get().unwrap();
        let mut map = HashMap::new();
        for row in db::schema::users::table
            .select((db::schema::users::id, db::schema::users::name))
            .filter(db::schema::users::id.eq_any(keys))
            .load::<(Uuid, String)>(db_conn)
            .unwrap()
        {
            let row: (Uuid, String) = row;
            let data = models::user::User {
                id: row.0,
                name: row.1,
            };
            map.insert(data.id, data);
        }

        map
    }
}

pub type UserLoader = Loader<Uuid, models::user::User, UserBatcher>;

pub const YIELD_COUNT: usize = 100;