Add repository commands for handling votes

src/votes/repository.rs

@@ -1,3 +1,161 @@
-use sqlx::PgPool;
+use anyhow::Result;
+use sqlx::{PgPool, query, query_as, query_scalar};
+use uuid::Uuid;
+
+use crate::votes::model::BestSlugs;
 
 use super::model::Vote;
+
+pub async fn insert_new_vote(vote: &Vote, db: &PgPool) -> Result<()> {
+    query("insert into votes (slug, voter_id) values ($1, $2)")
+        .bind(vote.slug.clone())
+        .bind(vote.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::{
+            model::Vote,
+            repository::{delete_vote, get_top_n_slugs, get_vote_count_for_slug, insert_new_vote},
+        },
+    };
+
+    async fn cleanup(db: &PgPool) {
+        for vote in test_votes() {
+            delete_vote(&vote.slug, &vote.voter_id, db).await.unwrap()
+        }
+    }
+
+    fn test_votes() -> [Vote; 9] {
+        [
+            Vote {
+                slug: "blog_post1".into(),
+                voter_id: Uuid::from_u128(0x1),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post1".into(),
+                voter_id: Uuid::from_u128(0x2),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post2".into(),
+                voter_id: Uuid::from_u128(0x3),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post2".into(),
+                voter_id: Uuid::from_u128(0x4),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post3".into(),
+                voter_id: Uuid::from_u128(0x5),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post3".into(),
+                voter_id: Uuid::from_u128(0x6),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post1".into(),
+                voter_id: Uuid::from_u128(0x7),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post1".into(),
+                voter_id: Uuid::from_u128(0x8),
+                created_at: chrono::Utc::now(),
+            },
+            Vote {
+                slug: "blog_post3".into(),
+                voter_id: Uuid::from_u128(0x9),
+                created_at: chrono::Utc::now(),
+            },
+        ]
+    }
+
+    #[tokio::test]
+    #[ignore]
+    pub async fn postgres_tests() {
+        let db = test_pool().await;
+        cleanup(&db).await;
+        let votes = test_votes();
+
+        for vote in votes.iter() {
+            insert_new_vote(vote, &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].slug, &votes[4].voter_id, &db)
+            .await
+            .unwrap();
+        delete_vote(&votes[5].slug, &votes[5].voter_id, &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;
+    }
+}