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(
        r#"insert into votes (slug, voter_id) 
             values ($1, $2) 
             on conflict (slug, voter_id) do nothing"#,
    )
    .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,
        },
    };

    async fn cleanup(db: &PgPool, votes: &[(String, Uuid)]) {
        for (slug, voter_id) in votes {
            delete_vote(slug, voter_id, db).await.unwrap()
        }
    }

    #[tokio::test]
    pub async fn postgres_tests() {
        let db = test_pool().await;
        let votes = vec![
            (
                "postgres_tests_blog_post1".to_string(),
                Uuid::from_u128(0x1),
            ),
            (
                "postgres_tests_blog_post1".to_string(),
                Uuid::from_u128(0x2),
            ),
            (
                "postgres_tests_blog_post2".to_string(),
                Uuid::from_u128(0x3),
            ),
            (
                "postgres_tests_blog_post2".to_string(),
                Uuid::from_u128(0x4),
            ),
            (
                "postgres_tests_blog_post3".to_string(),
                Uuid::from_u128(0x5),
            ),
            (
                "postgres_tests_blog_post3".to_string(),
                Uuid::from_u128(0x6),
            ),
            (
                "postgres_tests_blog_post1".to_string(),
                Uuid::from_u128(0x7),
            ),
            (
                "postgres_tests_blog_post1".to_string(),
                Uuid::from_u128(0x8),
            ),
            (
                "postgres_tests_blog_post3".to_string(),
                Uuid::from_u128(0x9),
            ),
        ];
        cleanup(&db, &votes).await;

        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("postgres_tests_blog_post1", &db)
                .await
                .unwrap(),
            4
        );
        assert_eq!(
            get_vote_count_for_slug("postgres_tests_blog_post2", &db)
                .await
                .unwrap(),
            2
        );
        assert_eq!(
            get_vote_count_for_slug("postgres_tests_blog_post3", &db)
                .await
                .unwrap(),
            3
        );

        let top_2 = get_top_n_slugs(2, &db).await.unwrap();
        assert_eq!(top_2[0].slug, "postgres_tests_blog_post1");
        assert_eq!(top_2[1].slug, "postgres_tests_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("postgres_tests_blog_post1", &db)
                .await
                .unwrap(),
            4
        );
        assert_eq!(
            get_vote_count_for_slug("postgres_tests_blog_post2", &db)
                .await
                .unwrap(),
            2
        );
        assert_eq!(
            get_vote_count_for_slug("postgres_tests_blog_post3", &db)
                .await
                .unwrap(),
            1
        );

        let top_2 = get_top_n_slugs(2, &db).await.unwrap();
        assert_eq!(top_2[0].slug, "postgres_tests_blog_post1");
        assert_eq!(top_2[1].slug, "postgres_tests_blog_post2");

        cleanup(&db, &votes).await;
    }

    #[tokio::test]
    pub async fn insert_idempotency_test() {
        let db = test_pool().await;
        let votes = vec![(
            "insert_idempotency_test_blog_post1".to_string(),
            Uuid::from_u128(0x1),
        )];
        cleanup(&db, &votes).await;

        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();
        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();
        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();
        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();
        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();
        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();

        let votes_count = get_vote_count_for_slug(&votes[0].0, &db).await.unwrap();

        assert_eq!(votes_count, 1);

        cleanup(&db, &votes).await;
    }

    #[tokio::test]
    pub async fn delete_idempotency_test() {
        let db = test_pool().await;
        let votes = vec![(
            "delete_idempotency_test_blog_post1".to_string(),
            Uuid::from_u128(0x1),
        )];
        cleanup(&db, &votes).await;

        insert_new_vote(&votes[0].0, &votes[0].1, &db)
            .await
            .unwrap();

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

        let votes_count = get_vote_count_for_slug(&votes[0].0, &db).await.unwrap();

        assert_eq!(votes_count, 0);

        cleanup(&db, &votes).await;
    }
}