use super::{
    CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext, dash,
    ground, wait,
};
use crate::fighter::animation::AnimKind;
use crate::fighter::state::{self, FighterState};

#[derive(Debug, Clone, Hash)]
pub struct WalkState;

impl FighterStateImpl for WalkState {
    const NAME: &'static str = "Walk";
    fn check_interrupt(&self, state_context: &mut InterruptContext) -> Option<FighterState> {
        if let Some(state) = ground::grounded_movement_common_interrupts(state_context) {
            return Some(state);
        }
        wait::check_input(state_context).or_else(|| dash::check_input(state_context)).or_else(|| state::ground_attack::check_interrupt(state_context))
    }

    fn on_enter(&mut self, state_context: &mut EnterContext) {
        state_context.play_animation(AnimKind::Walk, true);
    }

    fn update(&mut self, state_context: &mut UpdateContext) {
        let last_frame = state_context.input.get_last_frame();
        let (accel, target_vel) = state_context
            .fighter_attributes
            .get_accel_and_target_walk(&last_frame);

        let accel = ground::compute_ground_accel(
            accel,
            target_vel,
            state_context.velocity.x,
            state_context.fighter_attributes,
            &state_context.game_settings,
        );

        state_context.velocity.x += accel;

        ground::apply_grounded_motion(
            state_context.velocity,
            state_context.translation,
            state_context.prev_translation,
        );
    }

    fn check_collision_interrupt(
        &mut self,
        state_context: &mut CollisionContext,
    ) -> Option<FighterState> {
        ground::collision_interrupt(state_context, false)
    }

    fn is_visually_grounded<'a>(&'a self) -> bool {
        true
    }
}

pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {
    let input_frame = state_context.input.get_last_frame();

    if !input_frame.movement.x.is_zero() {
        return Some(FighterState::Walk(WalkState));
    }

    None
}