//! Laying a tree out again has to land where growing it that way would.
//!
//! Every case is one of `scenario`'s, over the trees `iris::random` grows
//! from a seed. The fast test takes a handful of seeds and the ignored one
//! takes as many as it is asked for; both run the same cases the shrinker
//! does over the same trees, so a seed that fails here is reduced by
//!
//!     SHRINK_SEED=<seed> SHRINK_DEPTH=<depth> SHRINK_CASE=<case> \
//!       cargo test --release --test shrink -- --ignored --nocapture
//!
//! `IRIS_GENERATED_SEED`, `IRIS_GENERATED_SEEDS` and `IRIS_GENERATED_DEPTH`
//! select what the long run covers.

#[path = "scenario/mod.rs"]
mod scenario;

use iris::random::{Edits, plan};
use scenario::{ALL, Case, diverges, env, over_seeds};

/// How deep the generator branches. The generator widens two to four ways per
/// level, so depth is exponential in width and a deep narrow tree is not
/// reachable by raising this -- it buys more overlap between dependency
/// paths, not more ancestry.
fn depth() -> usize {
    env("IRIS_GENERATED_DEPTH", 4)
}

/// The seeds the ordinary tests take. Seven that have never failed; 86,
/// which a `Scroll` fixed point once settled differently on; and 20, which
/// caught a locally redrawn widget being placed twice in the box its parent
/// had already placed it in.
const SEEDS: [u64; 10] = [1, 2, 3, 5, 8, 10, 13, 20, 86, 98];

fn check(seed: u64, depth: usize, case: Case) {
    let grown = plan(seed, depth, &Edits::default());
    if let Some(how) = diverges(&grown, case, seed) {
        panic!(
            "seed {seed} at depth {depth} differs after {}: {how}\n\
             reduce it with SHRINK_SEED={seed} SHRINK_DEPTH={depth} \
             SHRINK_CASE={} cargo test --release --test shrink -- --ignored --nocapture",
            case.name(),
            case.name(),
        );
    }
}

macro_rules! case {
    ($name:ident, $case:expr) => {
        #[test]
        fn $name() {
            for seed in SEEDS {
                check(seed, depth(), $case);
            }
        }
    };
}

case!(
    many_widgets_redrawing_at_once_leaves_every_box_where_it_was,
    Case::RepaintSome
);
case!(
    everything_redrawing_at_once_leaves_every_box_where_it_was,
    Case::Repaint
);
case!(
    a_resize_lands_where_starting_at_that_size_would,
    Case::Resize
);
case!(
    a_resize_and_a_repaint_land_where_starting_that_way_would,
    Case::ResizeRepaint
);
case!(
    a_size_change_after_a_resize_lands_the_same_way,
    Case::ResizeSize
);
case!(
    a_size_change_lands_where_growing_it_that_way_would,
    Case::Size
);
case!(
    every_size_changing_at_once_lands_where_growing_it_that_way_would,
    Case::EverySize
);
case!(
    an_alignment_change_lands_where_growing_it_that_way_would,
    Case::Align
);
case!(
    giving_and_taking_a_movable_region_rebuilds_what_resolves_it,
    Case::RegionNode
);
case!(
    reordering_a_span_lands_where_growing_it_that_way_would,
    Case::Reorder
);

#[test]
fn adding_and_removing_span_children_lands_where_growing_it_that_way_would() {
    for case in ALL {
        if matches!(case, Case::Shuffle(_)) {
            for seed in SEEDS {
                check(seed, depth(), case);
            }
        }
    }
}

#[test]
#[ignore = "as many seeds as it is asked for, rather than the nine the others check"]
fn a_long_run_of_seeds_agrees() {
    let depth = depth();
    let seeds: Vec<u64> = match std::env::var("IRIS_GENERATED_SEED")
        .ok()
        .and_then(|v| v.parse().ok())
    {
        Some(seed) => vec![seed],
        None => (1..=env("IRIS_GENERATED_SEEDS", 100_u64)).collect(),
    };
    over_seeds(seeds, |seed| {
        for case in ALL {
            check(seed, depth, case);
        }
    });
}