shinespark/src/fighter/state/hitstun.rs

use crate::{
    fighter::{
        animation::AnimKind,
        attack::FighterHitReaction,
        state::{
            CollisionContext, EnterContext, ExitContext, FighterState, FighterStateImpl,
            InterruptContext, UpdateContext, air,
            fall::FallState,
            ground::{GroundedMotionResult, GroundedStateCommon, collide_with_stage_grounded},
            land::{LandingState, LandingType},
            wait::WaitState,
        },
    },
    math::int::FGi32,
};

#[derive(Clone, Debug, Hash)]
pub enum HitstopStateKind {
    Grounded(GroundedStateCommon),
    Airborne,
}

#[derive(Clone, Debug, Hash)]
pub struct HitstunState {
    pub hit_reaction: FighterHitReaction,
    pub hitstop_kind: HitstopStateKind,
}

impl FighterStateImpl for HitstunState {
    const NAME: &'static str = "Hitstun";

    fn name(&self) -> String {
        let hitstop_kind = match self.hitstop_kind {
            HitstopStateKind::Grounded(_) => "Grounded",
            HitstopStateKind::Airborne => "Airborne",
        };

        let hit_reaction_type = match &self.hit_reaction.kind {
            crate::fighter::attack::HitReactionKind::Flinch => "Flinch",
            crate::fighter::attack::HitReactionKind::Tumble => "Tumble",
        };

        format!("Hitstun ({hitstop_kind}, {hit_reaction_type})")
    }

    fn check_interrupt(&self, state_context: &mut InterruptContext) -> Option<FighterState> {
        if state_context.get_current_animation_frame() > self.hit_reaction.hitstun_frames {
            match &self.hitstop_kind {
                HitstopStateKind::Grounded(grounded_state_common) => {
                    Some(FighterState::Wait(WaitState {
                        grounded_common: grounded_state_common.clone(),
                    }))
                }
                HitstopStateKind::Airborne => Some(FighterState::Fall(FallState)),
            }
        } else {
            None
        }
    }

    fn update(&mut self, ctx: &mut UpdateContext) {
        air::integrate_gravity(ctx.velocity, ctx.fighter_attributes);

        let speed = ctx.knockback_velocity.length();
        let next_speed = speed
            .saturating_sub(ctx.game_settings.fighter_common.knockback_decay_per_frame)
            .max(FGi32::ZERO);

        ctx.knockback_velocity.0 = ctx.knockback_velocity.normalize_or_zero() * next_speed;

        ctx.translation.0 += ctx.velocity.0 + ctx.knockback_velocity.0;
    }

    fn on_enter(&mut self, state_context: &mut EnterContext) {
        let animation = match self.hitstop_kind {
            HitstopStateKind::Grounded(_) => AnimKind::FlinchGround,
            HitstopStateKind::Airborne => AnimKind::FlinchAir,
        };
        state_context.play_animation(animation, false);
        state_context.knockback_velocity.0 = self.hit_reaction.launch_velocity;
    }

    fn on_exit(&mut self, _state_context: &mut ExitContext) {}

    fn check_collision_interrupt(
        &mut self,
        state_context: &mut CollisionContext,
    ) -> Option<FighterState> {
        match &mut self.hitstop_kind {
            HitstopStateKind::Grounded(grounded_state_common) => {
                if let GroundedMotionResult::InAir =
                    collide_with_stage_grounded(state_context, grounded_state_common, true)
                {
                    Some(FighterState::Fall(FallState {}))
                } else {
                    None
                }
            }
            HitstopStateKind::Airborne => {
                if let Some(res) = state_context.air_collide_with_stage() {
                    // Adjust translation
                    state_context.translation.0 =
                        res.hit_position - state_context.ecb.get_bottom_point();
                    let grounded_common = GroundedStateCommon {
                        current_line_id: res.line_id,
                    };
                    Some(FighterState::Land(LandingState::create(
                        grounded_common,
                        LandingType::Normal,
                    )))
                } else {
                    None
                }
            }
        }
    }
}