mod load_chunks;
mod unload_chunks;
mod tick;
mod entity;
mod chunks;

use vek::*;
use common::{
    state::State,
    terrain::TerrainChunk,
    rtsim::{RtSimEntity, RtSimId, RtSimController},
    vol::RectRasterableVol,
    comp,
};
use specs::{DispatcherBuilder, WorldExt};
use specs_idvs::IdvStorage;
use slab::Slab;
use rand::prelude::*;
use self::{
    entity::Entity,
    chunks::Chunks,
};

pub struct RtSim {
    tick: u64,
    chunks: Chunks,
    entities: Slab<Entity>,
}

impl RtSim {
    pub fn new(world_chunk_size: Vec2<u32>) -> Self {
        Self {
            tick: 0,
            chunks: Chunks::new(world_chunk_size),
            entities: Slab::new(),
        }
    }

    pub fn hook_load_chunk(&mut self, key: Vec2<i32>) {
        if let Some(chunk) = self.chunks.chunk_mut(key) {
            if !chunk.is_loaded {
                chunk.is_loaded = true;
                self.chunks.chunks_to_load.push(key);
            }
        }
    }

    pub fn hook_unload_chunk(&mut self, key: Vec2<i32>) {
        if let Some(chunk) = self.chunks.chunk_mut(key) {
            if chunk.is_loaded {
                chunk.is_loaded = false;
                self.chunks.chunks_to_unload.push(key);
            }
        }
    }

    pub fn assimilate_entity(&mut self, entity: RtSimId) {
        tracing::info!("Assimilated rtsim entity {}", entity);
        self.entities.get_mut(entity).map(|e| e.is_loaded = false);
    }

    pub fn reify_entity(&mut self, entity: RtSimId) {
        tracing::info!("Reified rtsim entity {}", entity);
        self.entities.get_mut(entity).map(|e| e.is_loaded = true);
    }

    pub fn update_entity(&mut self, entity: RtSimId, pos: Vec3<f32>) {
        self.entities.get_mut(entity).map(|e| e.pos = pos);
    }

    pub fn destroy_entity(&mut self, entity: RtSimId) {
        tracing::info!("Destroyed rtsim entity {}", entity);
        self.entities.remove(entity);
    }
}

const LOAD_CHUNK_SYS: &str = "rtsim_load_chunk_sys";
const UNLOAD_CHUNK_SYS: &str = "rtsim_unload_chunk_sys";
const TICK_SYS: &str = "rtsim_tick_sys";

pub fn add_server_systems(dispatch_builder: &mut DispatcherBuilder) {
    dispatch_builder.add(unload_chunks::Sys, UNLOAD_CHUNK_SYS, &[]);
    dispatch_builder.add(load_chunks::Sys, LOAD_CHUNK_SYS, &[UNLOAD_CHUNK_SYS]);
    dispatch_builder.add(tick::Sys, TICK_SYS, &[LOAD_CHUNK_SYS, UNLOAD_CHUNK_SYS]);
}

pub fn init(state: &mut State, world: &world::World) {
    let mut rtsim = RtSim::new(world.sim().get_size());

    for _ in 0..10000 {
        let pos = rtsim.chunks.size().map2(
            TerrainChunk::RECT_SIZE,
            |sz, chunk_sz| thread_rng().gen_range(0, sz * chunk_sz) as i32,
        );

        let id = rtsim.entities.insert(Entity {
            is_loaded: false,
            pos: Vec3::from(pos.map(|e| e as f32)),
            seed: thread_rng().gen(),
            controller: RtSimController::default(),
            last_tick: 0,
            brain: Default::default(),
        });

        tracing::info!("Spawned rtsim NPC {} at {:?}", id, pos);
    }

    state.ecs_mut().insert(rtsim);
    state.ecs_mut().register::<RtSimEntity>();
    tracing::info!("Initiated real-time world simulation");
}