//! End-to-end: load rows into [`MemoryStorage`], scan as a [`Table`],
//! run [`scan_atom`] against it.
//!
//! Demonstrates that `query-ops` operators can consume from a storage backend
//! through the [`scan_as_table`] bridge, with no changes to `query-ops` itself.

use query_ops::atom::{AtomPattern, Term, scan_atom};
use query_storage::table::Table;
use query_storage::value::Value;
use query_storage::{MemoryStorage, Storage, StorageError, scan_as_table};

fn i(x: i64) -> Value {
    Value::Int(x)
}

fn var(name: &str) -> Term {
    Term::Var(name.to_string())
}

#[test]
fn scan_atom_consumes_from_memory_backend() -> Result<(), StorageError> {
    let mut storage = MemoryStorage::new();
    storage.create_relation("edge", 2)?;
    storage.insert("edge", vec![i(1), i(2)])?;
    storage.insert("edge", vec![i(2), i(2)])?;
    storage.insert("edge", vec![i(3), i(3)])?;
    storage.insert("edge", vec![i(4), i(5)])?;

    let edge_table: Table = scan_as_table(&storage, "edge")?;
    let self_loops = scan_atom(
        &edge_table,
        &AtomPattern {
            columns: vec![var("X"), var("X")],
        },
    );

    assert_eq!(self_loops.columns, vec!["X".to_string()]);
    assert_eq!(self_loops.rows, vec![vec![i(2)], vec![i(3)]]);
    Ok(())
}