upvoters/src/votes/repository.rs

use anyhow::Result;
use sqlx::{PgPool, query, query_as, query_scalar};
use uuid::Uuid;

use crate::votes::model::BestSlugs;

pub async fn insert_new_vote(slug: &str, voter_id: &Uuid, db: &PgPool) -> Result<()> {
    query("insert into votes (slug, voter_id) values ($1, $2)")
        .bind(slug)
        .bind(voter_id)
        .execute(db)
        .await?;
    Ok(())
}

pub async fn get_vote_count_for_slug(slug: &str, db: &PgPool) -> Result<i64> {
    let count: i64 = query_scalar("select count(*) from votes where slug=$1")
        .bind(slug)
        .fetch_one(db)
        .await?;
    Ok(count)
}

pub async fn get_top_n_slugs(n: i64, db: &PgPool) -> Result<Vec<BestSlugs>> {
    if n > 0 {
        let top_slugs = query_as::<_, BestSlugs>(
            r#"select slug, count(*) AS vote_count
               from votes
               group by slug
               order by vote_count desc
               limit $1
            "#,
        )
        .bind(n)
        .fetch_all(db)
        .await?;
        Ok(top_slugs)
    } else {
        Ok(vec![])
    }
}

pub async fn delete_vote(slug: &str, voter_id: &Uuid, db: &PgPool) -> Result<()> {
    query("delete from votes where slug=$1 and voter_id=$2")
        .bind(slug)
        .bind(voter_id)
        .execute(db)
        .await?;
    Ok(())
}

#[cfg(test)]
mod postgres_tests {
    use sqlx::PgPool;
    use uuid::Uuid;

    use crate::{
        test_helpers::db::test_pool,
        votes::repository::{delete_vote, get_top_n_slugs, get_vote_count_for_slug, insert_new_vote},
    };

    fn test_votes() -> [(&'static str, Uuid); 9] {
        [
            ("blog_post1", Uuid::from_u128(0x1)),
            ("blog_post1", Uuid::from_u128(0x2)),
            ("blog_post2", Uuid::from_u128(0x3)),
            ("blog_post2", Uuid::from_u128(0x4)),
            ("blog_post3", Uuid::from_u128(0x5)),
            ("blog_post3", Uuid::from_u128(0x6)),
            ("blog_post1", Uuid::from_u128(0x7)),
            ("blog_post1", Uuid::from_u128(0x8)),
            ("blog_post3", Uuid::from_u128(0x9)),
        ]
    }

    async fn cleanup(db: &PgPool) {
        for (slug, voter_id) in test_votes() {
            delete_vote(slug, &voter_id, db).await.unwrap()
        }
    }

    #[tokio::test]
    #[ignore]
    pub async fn postgres_tests() {
        let db = test_pool().await;
        cleanup(&db).await;
        let votes = test_votes();

        for (slug, voter_id) in votes.iter() {
            insert_new_vote(slug, voter_id, &db)
                .await
                .expect("Insertions to db failed");
        }

        assert_eq!(get_vote_count_for_slug("blog_post1", &db).await.unwrap(), 4);
        assert_eq!(get_vote_count_for_slug("blog_post2", &db).await.unwrap(), 2);
        assert_eq!(get_vote_count_for_slug("blog_post3", &db).await.unwrap(), 3);

        let top_2 = get_top_n_slugs(2, &db).await.unwrap();
        assert_eq!(top_2[0].slug, "blog_post1");
        assert_eq!(top_2[1].slug, "blog_post3");

        delete_vote(votes[4].0, &votes[4].1, &db).await.unwrap();
        delete_vote(votes[5].0, &votes[5].1, &db).await.unwrap();

        assert_eq!(get_vote_count_for_slug("blog_post1", &db).await.unwrap(), 4);
        assert_eq!(get_vote_count_for_slug("blog_post2", &db).await.unwrap(), 2);
        assert_eq!(get_vote_count_for_slug("blog_post3", &db).await.unwrap(), 1);

        let top_2 = get_top_n_slugs(2, &db).await.unwrap();
        assert_eq!(top_2[0].slug, "blog_post1");
        assert_eq!(top_2[1].slug, "blog_post2");

        cleanup(&db).await;
    }
}