use sqlite3_ext::{
    Connection, FromValue, Result, ValueRef, ValueType,
    function::Context,
    sqlite3_ext_fn, sqlite3_ext_main,
};

fn add(a: i32, b: i32) -> i32 {
    a + b
}

#[sqlite3_ext_fn(n_args = 2, deterministic)]
fn add_sqlite(ctx: &mut Context, args: &mut [&mut ValueRef]) -> Result<()> {
    if args[0].value_type() != ValueType::Integer || args[1].value_type() != ValueType::Integer {
        return Err(sqlite3_ext::Error::Module(
            "myadd requires both arguments to be an integer".to_string(),
        ));
    }

    let a = args[0].get_i32();
    let b = args[1].get_i32();
    let result = add(a, b);
    ctx.set_result(result)?;
    Ok(())
}

#[sqlite3_ext_main(persistent)]
fn init(db: &Connection) -> Result<()> {
    db.create_scalar_function("myadd", &ADD_SQLITE_OPTS, add_sqlite)?;

    Ok(())
}

#[cfg(all(test, feature = "static"))]
mod test {
    use super::*;
    use sqlite3_ext::{Database, Error, FallibleIterator, FallibleIteratorMut};

    fn setup() -> Result<Database> {
        let conn = Database::open(":memory:")?;
        init(&conn)?;
        Ok(conn)
    }

    #[test]
    fn test_working() -> Result<()> {
        let conn = setup()?;
        let results: Vec<i64> = conn
            .prepare("SELECT myadd(10, 20)")?
            .query(())?
            .map(|row| Ok(row[0].get_i64()))
            .collect()?;
        assert_eq!(results, vec![30]);

        Ok(())
    }

    #[test]
    fn test_wrong_arg_number() -> Result<()> {
        let conn = setup()?;
        let result = conn.prepare("SELECT myadd(10)");
        assert_eq!(
            result.unwrap_err(),
            Error::Sqlite(
                1,
                Some("wrong number of arguments to function myadd()".to_string()),
            )
        );
        Ok(())
    }

    #[test]
    fn test_wrong_arg_type() -> Result<()> {
        let conn = setup()?;
        let mut statement = conn.prepare("SELECT myadd(10, 'hello!')")?;
        let result = statement.query(())?.next();
        assert_eq!(
            result.unwrap_err(),
            Error::Sqlite(
                1,
                Some("myadd requires both arguments to be an integer".to_string()),
            )
        );
        Ok(())
    }
}