use super::{
    CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext, ground, run,
    wait, walk,
};
use crate::fighter::FighterFacingDirection;
use crate::fighter::animation::AnimKind;
use crate::fighter::state::FighterState;
use crate::input::FighterCommands::{SmashMoveLeft, SmashMoveRight};

#[derive(Debug, Clone, Hash)]
pub struct DashState {
    direction: FighterFacingDirection,
}

impl DashState {
    pub fn new(direction: FighterFacingDirection) -> Self {
        Self { direction }
    }
}

impl FighterStateImpl for DashState {
    const NAME: &'static str = "Dash";
    fn check_interrupt(&self, ctx: &mut InterruptContext) -> Option<FighterState> {
        let attributes = ctx.fighter_attributes;

        // A reverse dash can interrupt before IASA
        if let Some(direction) =
            check_smash_input_with_dir(ctx).filter(|direction| *direction != self.direction)
        {
            return Some(FighterState::Dash(DashState::new(direction)));
        }

        if let Some(state) = ground::grounded_movement_common_interrupts(ctx) {
            return Some(state);
        }

        if ctx.is_current_animation_finished() {
            return run::check_input(ctx)
                .or_else(|| walk::check_input(ctx))
                .or_else(|| wait::check_input(ctx));
        }

        if ctx.get_current_animation_frame() > attributes.dash_acceleration_duration {
            return run::check_input(ctx);
        }

        None
    }

    fn on_enter(&mut self, state_context: &mut EnterContext) {
        *state_context.facing_direction = self.direction;
        state_context.velocity.x =
            state_context.fighter_attributes.dash_initial_velocity * self.direction.to_sign();

        state_context.play_animation(AnimKind::Dash, false);

        match state_context.facing_direction {
            FighterFacingDirection::Left => {
                state_context
                    .input
                    .clear_command(crate::input::FighterCommands::SmashMoveLeft);
            }
            FighterFacingDirection::Right => {
                state_context
                    .input
                    .clear_command(crate::input::FighterCommands::SmashMoveRight);
            }
        }
    }

    fn update(&mut self, state_context: &mut UpdateContext) {
        if state_context.get_current_animation_frame()
            < state_context.fighter_attributes.dash_acceleration_duration
        {}

        let last_frame = state_context.input.get_last_frame();
        let (accel, target_vel) = state_context
            .fighter_attributes
            .get_accel_and_target_dashrun(&last_frame, self.direction.to_sign());
        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, true)
    }

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

fn check_smash_input_with_dir(state_context: &InterruptContext) -> Option<FighterFacingDirection> {
    if state_context.input.has_command(SmashMoveLeft) {
        return Some(FighterFacingDirection::Left);
    } else if state_context.input.has_command(SmashMoveRight) {
        return Some(FighterFacingDirection::Right);
    } else {
        None
    }
}

pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {
    check_smash_input_with_dir(state_context).map(|dir| FighterState::Dash(DashState::new(dir)))
}