//! Benchmarks for the chase subsystem.
//!
//! These are designed to retroactively validate the semi-naive and Skolem
//! work and catch future regressions. Each workload runs several chase
//! variants over the same input so relative numbers are meaningful.

use criterion::{BatchSize, Criterion, criterion_group, criterion_main};
use query_engine::chase::rule::RuleBuilder;
use query_engine::chase::{ChaseConfig, ChaseVariant, Rule, chase_with_config};
use query_engine::{Atom, Instance, Term};

fn chain_edges(n: usize) -> Instance {
    (0..n)
        .map(|i| {
            Atom::new(
                "Edge",
                vec![
                    Term::constant(format!("n{}", i)),
                    Term::constant(format!("n{}", i + 1)),
                ],
            )
        })
        .collect()
}

fn transitive_closure_rules() -> Vec<Rule> {
    let edge_to_path = RuleBuilder::new()
        .when("Edge", vec![Term::var("X"), Term::var("Y")])
        .then("Path", vec![Term::var("X"), Term::var("Y")])
        .build();
    let extend_path = RuleBuilder::new()
        .when("Path", vec![Term::var("X"), Term::var("Y")])
        .when("Edge", vec![Term::var("Y"), Term::var("Z")])
        .then("Path", vec![Term::var("X"), Term::var("Z")])
        .build();
    vec![edge_to_path, extend_path]
}

fn bench_transitive_closure(c: &mut Criterion) {
    let mut group = c.benchmark_group("transitive_closure_chain_20");
    let instance = chain_edges(20);
    let rules = transitive_closure_rules();

    for (label, variant, semi) in [
        ("restricted_naive", ChaseVariant::Restricted, false),
        ("restricted_semi_naive", ChaseVariant::Restricted, true),
        ("standard_naive", ChaseVariant::Standard, false),
        ("standard_semi_naive", ChaseVariant::Standard, true),
    ] {
        let config = ChaseConfig {
            variant,
            semi_naive: semi,
            ..Default::default()
        };
        group.bench_function(label, |b| {
            b.iter_batched(
                || instance.clone(),
                |inst| chase_with_config(inst, &rules, config.clone()),
                BatchSize::SmallInput,
            );
        });
    }
    group.finish();
}

fn bench_existentials(c: &mut Criterion) {
    let mut group = c.benchmark_group("existentials_50_people");
    let instance: Instance = (0..50)
        .map(|i| Atom::new("Person", vec![Term::constant(format!("p{}", i))]))
        .collect();
    let rule = RuleBuilder::new()
        .when("Person", vec![Term::var("X")])
        .then("HasId", vec![Term::var("X"), Term::var("Y")])
        .build();
    let rules = vec![rule];

    for (label, variant) in [
        ("restricted", ChaseVariant::Restricted),
        ("skolem", ChaseVariant::Skolem),
    ] {
        let config = ChaseConfig {
            variant,
            semi_naive: false,
            ..Default::default()
        };
        group.bench_function(label, |b| {
            b.iter_batched(
                || instance.clone(),
                |inst| chase_with_config(inst, &rules, config.clone()),
                BatchSize::SmallInput,
            );
        });
    }
    group.finish();
}

criterion_group!(benches, bench_transitive_closure, bench_existentials);
criterion_main!(benches);