shinespark/src/fighter/attack/reaction.rs

use bevy::prelude::*;
use bevy_ggrs::prelude::GgrsSchedule;

use super::*;
use crate::{
    fighter::{
        Fighter, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole, FighterPendingHitReaction, FighterStaleMoveQueue, errors::FighterErrors, manifest::FighterManifest, state::FighterState,
    }, game_settings::GameSettings, math::{int::FGi32}, player::Player, schedule::GameplaySet, scripting::FighterAttackScript,
};

pub fn resolve_fighter_hits(
    mut pending_hits: ResMut<FighterPendingHits>,
    mut attacker: Query<(
        &FighterStaleMoveQueue,
        &FighterFacingDirection,
        &FighterHitboxes,
        &Player,
        &mut FighterHitstop,
        &mut FighterHitstopShake,
    )>,
    mut receiver: Query<(&mut FighterDamage, &Fighter, &mut FighterPendingHitReaction, &FighterState)>,
    attack_scripts: Res<Assets<FighterAttackScript>>,
    game_settings: Res<GameSettings>,
    fighter_manifests: Res<Assets<FighterManifest>>,
) -> Result {
    let hits = std::mem::take(&mut pending_hits.0);
    let mut hit_offset = 0;

    while hit_offset < hits.len() {
        let defender = hits[hit_offset].defender;
        let next_defender = hits[hit_offset..]
            .iter()
            .position(|hit| hit.defender != defender)
            .map_or(hits.len(), |offset| hit_offset + offset);

        let Ok((mut receiver_damage, fighter, mut pending_reaction, receiver_state)) = receiver.get_mut(defender)
        else {
            hit_offset = next_defender;
            continue;
        };

        let damage_data = hits[hit_offset..next_defender]
            .iter()
            .filter_map(|hit| {
                let Ok((stale_move_queue, facing_dir, _hitboxes, player, _, _)) =
                    attacker.get(hit.attacker)
                else {
                    return None;
                };
                let attack_script = attack_scripts.get(&hit.attack_script)?;
                let hitbox = attack_script.hitboxes.get(hit.hitbox_index)?;
                let damage_received = stale_move_queue
                    .get_attack_damage_multiplier(hit.attack_kind)
                    * hitbox.damage.0;

                Some((
                    hit.attacker,
                    damage_received,
                    hitbox,
                    matches!(facing_dir, FighterFacingDirection::Left),
                    player.handle,
                ))
            })
            .collect::<Vec<_>>();

        let total_damage_received_this_frame = damage_data
            .iter()
            .map(|(_, damage, ..)| damage)
            .sum::<FGi32>();
        let fighter_manifest = fighter_manifests
            .get(&fighter.manifest)
            .ok_or(FighterErrors::FighterManifestNotFound)?;
        let mut reactions = Vec::with_capacity(damage_data.len());

        for (attacker_entity, attack_damage, hitbox, facing_left, attacker_slot) in damage_data {
            let knockback = hitbox.calculate_knockback(
                &fighter_manifest.attributes,
                *receiver_damage,
                FighterDamage(total_damage_received_this_frame),
                false,
                false,
            );
            let angle = match &hitbox.angle {
                AttackAngle::Normal(angle) => *angle,
                AttackAngle::Sakurai => FGi32::lit("32.0"),
            };
            let launch_angle = if facing_left {
                FGi32::lit("180.0") - angle
            } else {
                angle
            };

            let hitstop = HitStop::calculate(FighterDamage(attack_damage), false);
            reactions.push((
                attacker_entity,
                attacker_slot,
                FighterHitReaction {
                    launch_velocity: knockback.get_launch_speed(&game_settings),
                    launch_angle,
                    hitstun_frames: knockback.get_hitstun_frames(&game_settings),
                    hitstop_frames: hitstop,
                    kind: HitReactionKind::Flinch,
                },
            ));
        }

        receiver_damage.0 += total_damage_received_this_frame;

        for (attacker_entity, _, reaction) in &reactions {
            let Ok((.., mut hitstop, mut hitstop_shake)) = attacker.get_mut(*attacker_entity) else {
                continue;
            };

            if hitstop.remaining_frames < reaction.hitstop_frames.0 {
                let shake_kind = if receiver_state.is_visually_grounded() {
                    FighterHitstopShakeKind::Horizontal
                } else {
                    FighterHitstopShakeKind::Vertical
                };
                hitstop.remaining_frames = reaction.hitstop_frames.0;
                let shake_frames = reaction.hitstop_frames.calculate_shake_frames(&game_settings);
                hitstop_shake.total_frames = shake_frames;
                hitstop_shake.remaining_frames = shake_frames;
                hitstop_shake.kind = shake_kind;
                hitstop_shake.role = FighterHitstopShakeRole::Attacker;
            }
        }

        pending_reaction.0 = reactions
            .into_iter()
            .min_by(|(_, port_a, _), (_, port_b, _)| port_a.cmp(port_b))
            .map(|(_, _, reaction)| reaction);

        hit_offset = next_defender;
    }

    Ok(())
}

pub struct FighterReactionPlugin;

impl Plugin for FighterReactionPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(
            GgrsSchedule,
            resolve_fighter_hits
                .in_set(GameplaySet::Attacks)
                .after(super::intersect_attacks_with_hurtboxes),
        );
    }
}