blackout/src/pathfinding.rs

use avian2d::prelude::*;
use bevy::{prelude::*, utils::HashMap};
use leafwing_input_manager::{plugin::InputManagerSystem, prelude::*};
use pathfinding::prelude::*;

use crate::{
    core::{PointLike, TransformExt},
    map::Map,
    navigation::{NavigationAction, RotationSpeed, Speed},
};

#[derive(PartialEq, Eq, Clone, Copy, Hash, Debug, Reflect)]
pub struct NegotiatePathAction;

impl Actionlike for NegotiatePathAction {
    fn input_control_kind(&self) -> InputControlKind {
        InputControlKind::DualAxis
    }
}

#[derive(Component, Clone, Copy, Debug, Default, Deref, DerefMut, Eq, Hash, PartialEq, Reflect)]
#[reflect(Component)]
pub struct Destination(pub (i32, i32));

impl_pointlike_for_tuple_component!(Destination);
impl_pointlike_for_tuple_component!(&Destination);

#[derive(Component, Clone, Debug, Default, Reflect)]
#[reflect(Component)]
pub struct NoPath;

#[derive(Component, Clone, Debug, Default, Deref, DerefMut, Reflect)]
#[reflect(Component)]
pub struct Path(pub Vec<(i32, i32)>);

#[derive(Component, Clone, Debug, Default, Reflect, Deref, DerefMut)]
#[reflect(Component)]
pub struct CostMap(pub HashMap<(i32, i32), f32>);

#[derive(Bundle, Deref, DerefMut)]
pub struct PathfindingControlsBundle(pub ActionState<NegotiatePathAction>);

impl Default for PathfindingControlsBundle {
    fn default() -> Self {
        let mut input: ActionState<NegotiatePathAction> = Default::default();
        input.disable();
        Self(input)
    }
}

pub fn find_path<D: 'static + Clone + Default + Send + Sync>(
    start: &dyn PointLike,
    destination: &dyn PointLike,
    map: &Map<D>,
    cost_map: &Option<CostMap>,
) -> Option<(Vec<(i32, i32)>, u32)> {
    astar(
        &start.into(),
        |p| {
            let mut successors: Vec<((i32, i32), u32)> = vec![];
            if p.0 >= 0 && p.1 >= 0 {
                if let Some(tile) = map.at(p.0 as usize, p.1 as usize) {
                    if tile.is_walkable() {
                        for tile in map.get_available_exits(p.0 as usize, p.1 as usize) {
                            let mut cost = tile.2 * 100.;
                            if let Some(cost_map) = cost_map {
                                if let Some(modifier) =
                                    cost_map.get(&(tile.0 as i32, tile.1 as i32))
                                {
                                    cost *= modifier;
                                }
                            }
                            successors.push(((tile.0 as i32, tile.1 as i32), cost as u32));
                        }
                    }
                }
            }
            successors
        },
        |p| (p.distance_squared(destination) * 100.) as u32,
        |p| *p == destination.into(),
    )
}

fn calculate_path(
    mut commands: Commands,
    spatial_query: SpatialQuery,
    mut query: Query<
        (
            Entity,
            &Destination,
            &Transform,
            &Collider,
            Option<&CostMap>,
            Option<&mut ActionState<NegotiatePathAction>>,
        ),
        Changed<Destination>,
    >,
) {
    for (entity, destination, start, collider, cost_map, actions) in &mut query {
        trace!("{entity}: destination: {destination:?}");
        if start.i32() == **destination {
            trace!("{entity}: remove1");
            commands
                .entity(entity)
                .remove::<Path>()
                .remove::<NoPath>()
                .remove::<Destination>();
            continue;
        }
        trace!(
            "{entity:?}: Calculating path from {:?} to {destination:?}",
            start.translation.truncate().i32()
        );
        trace!(
            "{entity:?}: path: calculating from {:?} to {destination:?}",
            start.i32(),
        );
        commands.entity(entity).remove::<Path>().remove::<NoPath>();
        let path = astar(
            &start.i32(),
            |p| {
                let mut successors: Vec<((i32, i32), u32)> = vec![];
                let x = p.0;
                let y = p.1;
                let exits = vec![
                    ((x - 1, y), 1.),
                    ((x + 1, y), 1.),
                    ((x, y - 1), 1.),
                    ((x, y + 1), 1.),
                    ((x - 1, y - 1), 1.5),
                    ((x + 1, y - 1), 1.5),
                    ((x - 1, y + 1), 1.5),
                    ((x + 1, y + 1), 1.5),
                ];
                for exit in &exits {
                    let mut should_push = true;
                    if !spatial_query
                        .shape_intersections(
                            collider,
                            start.translation.truncate(),
                            start.yaw().radians(),
                            SpatialQueryFilter::default(),
                        )
                        .is_empty()
                    {
                        should_push = false;
                    }
                    if should_push {
                        let mut cost = exit.1 * 100.;
                        if let Some(cost_map) = cost_map {
                            if let Some(modifier) = cost_map.get(&(exit.0 .0, exit.0 .1)) {
                                cost *= modifier;
                            }
                        }
                        successors.push((exit.0, cost as u32));
                    }
                }
                successors
            },
            |p| (p.distance_squared(&destination) * 100.) as u32,
            |p| *p == destination.i32(),
        );
        if let Some(path) = path {
            commands.entity(entity).insert(Path(path.0));
        } else {
            commands.entity(entity).insert(NoPath);
            if let Some(mut actions) = actions {
                trace!("{entity:?}: Disabling and resetting because no path");
                actions.disable();
                actions.reset_all();
            }
        }
    }
}

fn remove_destination(mut commands: Commands, mut removed: RemovedComponents<Destination>) {
    for entity in removed.read() {
        if let Some(mut commands) = commands.get_entity(entity) {
            commands.remove::<Path>().remove::<NoPath>();
        }
    }
}

fn negotiate_path(
    mut commands: Commands,
    time: Res<Time>,
    spatial_query: SpatialQuery,
    mut query: Query<(
        Entity,
        Option<&mut ActionState<NegotiatePathAction>>,
        &mut ActionState<NavigationAction>,
        &mut Path,
        &mut Transform,
        &Collider,
        &Speed,
        Option<&RotationSpeed>,
    )>,
) {
    for (
        entity,
        actions,
        mut navigation_actions,
        mut path,
        mut transform,
        collider,
        speed,
        rotation_speed,
    ) in &mut query
    {
        trace!("{entity:?}: negotiating path");
        let start_i32 = transform.translation.truncate().i32();
        trace!(
            "{entity:?}: start pathfinding from {start_i32:?} to {:?}: at {:?}",
            path.last(),
            transform.translation.truncate().i32()
        );
        if path.len() > 0 && path[0] == start_i32 {
            trace!("At start, removing");
            path.remove(0);
        }
        if let Some(next) = path.first() {
            let start = transform.translation.truncate();
            let mut next = Vec2::new(next.0 as f32, next.1 as f32);
            if next.x >= 0. {
                next.x += 0.5;
            } else {
                next.x -= 0.5;
            }
            if next.y >= 0. {
                next.y += 0.5;
            } else {
                next.y -= 0.5;
            }
            let mut direction = next - start;
            direction = direction.normalize();
            direction *= **speed;
            direction *= time.delta_seconds();
            trace!(
                "{entity:?}: Direction: {direction:?}, Distance: {}",
                (next - start).length()
            );
            if spatial_query
                .cast_shape(
                    collider,
                    start,
                    transform.yaw().radians(),
                    Dir2::new_unchecked(direction.normalize()),
                    direction.length(),
                    true,
                    SpatialQueryFilter::default(),
                )
                .is_some()
            {
                trace!("{entity:?} is stuck");
                // TODO: Remove when we have an actual character controller.
                next.x = next.x.trunc();
                next.y = next.y.trunc();
                transform.translation = next.extend(0.);
            } else {
                navigation_actions.set_axis_pair(&NavigationAction::Translate, direction);
            }
            if rotation_speed.is_some() {
                let angle = direction.y.atan2(direction.x);
                transform.rotation = Quat::from_rotation_z(angle);
            }
        } else {
            trace!("{entity:?}: empty path, cleaning");
            if let Some(mut actions) = actions {
                trace!("{entity:?}: Disabling pathfind because at destination");
                actions.reset_all();
                actions.disable();
            }
            commands
                .entity(entity)
                .remove::<Path>()
                .remove::<NoPath>()
                .remove::<Destination>();
            trace!("{entity:?}: pathfinding: cleaned up");
        }
    }
}

fn actions(
    mut commands: Commands,
    mut query: Query<(
        Entity,
        &ActionState<NegotiatePathAction>,
        &mut ActionState<NavigationAction>,
        Option<&mut Destination>,
    )>,
) {
    for (entity, actions, mut navigation_action, destination) in &mut query {
        if actions.action_disabled(&NegotiatePathAction) {
            if destination.is_some() {
                commands.entity(entity).remove::<Destination>();
            }
        } else {
            let pair = actions.axis_pair(&NegotiatePathAction);
            trace!("{entity:?}: Negotiating path to {pair:?}");
            let dest = Destination(pair.xy().i32());
            if let Some(mut current_dest) = destination {
                trace!("Got a destination");
                if *current_dest != dest {
                    trace
!("{entity:?}: New destination {dest:?} differs from {current_dest:?}, zeroing velocity");
                    navigation_action
                        .set_axis_pair(&NavigationAction::SetLinearVelocity, Vec2::ZERO);
                    *current_dest = dest;
                }
            } else {
                trace!("{entity:?}: Adding destination, zeroing velocity");
                navigation_action.set_axis_pair(&NavigationAction::SetLinearVelocity, Vec2::ZERO);
                commands.entity(entity).insert(dest);
            }
        }
    }
}

pub struct PathfindingPlugin;

impl Plugin for PathfindingPlugin {
    fn build(&self, app: &mut App) {
        app.add_plugins(InputManagerPlugin::<NegotiatePathAction>::default())
            .register_type::<Destination>()
            .register_type::<NoPath>()
            .register_type::<Path>()
            .register_type::<CostMap>()
            .add_systems(PreUpdate, negotiate_path)
            .add_systems(
                PreUpdate,
                (actions, calculate_path)
                    .chain()
                    .after(InputManagerSystem::Tick),
            )
            .add_systems(PostUpdate, remove_destination);
    }
}