use axum::{
    async_trait,
    extract::{FromRef, FromRequestParts, State},
    http::{request::Parts, StatusCode},
};
use sqlx::SqlitePool;

pub async fn using_connection_pool_extractor(
    State(pool): State<SqlitePool>,
) -> Result<String, (StatusCode, String)> {
    sqlx::query_scalar("select 'hello world from sqlite get'")
        .fetch_one(&pool)
        .await
        .map_err(internal_error)
}

// we can also write a custom extractor that grabs a connection from the pool
// which setup is appropriate depends on your application
pub struct DatabaseConnection(sqlx::pool::PoolConnection<sqlx::Sqlite>);

#[async_trait]
impl<S> FromRequestParts<S> for DatabaseConnection
where
    SqlitePool: FromRef<S>,
    S: Send + Sync,
{
    type Rejection = (StatusCode, String);

    async fn from_request_parts(_parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
        let pool = SqlitePool::from_ref(state);

        let conn = pool.acquire().await.map_err(internal_error)?;

        Ok(Self(conn))
    }
}

pub async fn using_connection_extractor(
    DatabaseConnection(conn): DatabaseConnection,
) -> Result<String, (StatusCode, String)> {
    let mut conn = conn;
    sqlx::query_scalar("select 'hello world from sqlite post'")
        .fetch_one(&mut conn)
        .await
        .map_err(internal_error)
}

/// Utility function for mapping any error into a `500 Internal Server Error`
/// response.
fn internal_error<E>(err: E) -> (StatusCode, String)
where
    E: std::error::Error,
{
    (StatusCode::INTERNAL_SERVER_ERROR, err.to_string())
}