import {
  MOVE_MAP,
  RESOLUTION,
  TPS,
} from '@/constants.js';
import ControlMovement from '@/ecs-systems/control-movement.js';
import ApplyMomentum from '@/ecs-systems/apply-momentum.js';
import CalculateAabbs from '@/ecs-systems/calculate-aabbs.js';
import FollowCamera from '@/ecs-systems/follow-camera.js';
import UpdateSpatialHash from '@/ecs-systems/update-spatial-hash.js';
import Ecs from '@/engine/ecs.js';
import {decode, encode} from '@/packets/index.js';

const players = {
  0: {
    Camera: {},
    Controlled: {up: 0, right: 0, down: 0, left: 0},
    Momentum: {},
    Position: {x: 50, y: 50},
    VisibleAabb: {},
    World: {world: 1},
    Sprite: {image: '/assets/bunny.png'},
  },
};

export default class Engine {

  static Ecs = Ecs;

  constructor(Server) {
    const ecs = new this.constructor.Ecs();
    ecs.create({
      AreaSize: {x: RESOLUTION[0] * 4, y: RESOLUTION[1] * 4},
    });
    ecs.addSystem(ControlMovement);
    ecs.addSystem(ApplyMomentum);
    ecs.addSystem(FollowCamera);
    ecs.addSystem(CalculateAabbs);
    ecs.addSystem(UpdateSpatialHash);
    this.ecses = {
      1: ecs,
    };
    this.connections = [];
    this.connectedPlayers = new Map();
    this.frame = 0;
    this.last = Date.now();
    class SilphiusServer extends Server {
      accept(connection, packed) {
        super.accept(connection, decode(packed));
      }
      transmit(connection, packet) {
        super.transmit(connection, encode(packet));
      }
    }
    this.server = new SilphiusServer();
    this.server.addPacketListener((connection, packet) => {
      this.accept(connection, packet);
    });
  }

  accept(connection, {payload, type}) {
    switch (type) {
      case 'Action': {
        const {entity} = this.connectedPlayers.get(connection);
        if (payload.type in MOVE_MAP) {
          entity.Controlled[MOVE_MAP[payload.type]] = payload.value;
        }
        break;
      }
      default:
    }
  }

  async connectPlayer(connection) {
    this.connections.push(connection);
    const entityJson = await this.loadPlayer(connection);
    const ecs = this.ecses[entityJson.World.world];
    const entity = ecs.create(entityJson);
    this.connectedPlayers.set(
      connection,
      {
        entity: ecs.get(entity),
        memory: new Set(),
      },
    );
  }

  disconnectPlayer(connection) {
    const {entity} = this.connectedPlayers.get(connection);
    const ecs = this.ecses[entity.World.world];
    players[0] = JSON.parse(JSON.stringify(entity.toJSON()));
    ecs.destroy(entity.id);
    this.connectedPlayers.delete(connection);
    this.connections.splice(this.connections.indexOf(connection), 1);
  }

  async load() {
  }

  async loadPlayer() {
    return players[0];
  }

  start() {
    return setInterval(() => {
      const elapsed = (Date.now() - this.last) / 1000;
      this.last = Date.now();
      this.tick(elapsed);
      this.update(elapsed);
      this.frame += 1;
    }, 1000 / TPS);
  }

  tick(elapsed) {
    for (const i in this.ecses) {
      this.ecses[i].setClean();
      this.ecses[i].tick(elapsed);
    }
  }

  update(elapsed) {
    for (const connection of this.connections) {
      this.server.send(
        connection,
        {
          type: 'Tick',
          payload: {
            ecs: this.updateFor(connection),
            elapsed,
            frame: this.frame,
          },
        },
      );
    }
  }

  updateFor(connection) {
    const update = {};
    const {entity, memory} = this.connectedPlayers.get(connection);
    const mainEntityId = entity.id;
    const ecs = this.ecses[entity.World.world];
    const {hash} = ecs.system(UpdateSpatialHash);
    const nearby = new Set();
    for (const [cx, cy] of hash.data[entity.id]) {
      hash.chunks[cx][cy].forEach((id) => {
        nearby.add(ecs.get(id));
      });
    }
    const lastMemory = new Set(memory.values());
    for (const entity of nearby) {
      const {id} = entity;
      lastMemory.delete(id);
      if (!memory.has(id)) {
        update[id] = entity.toJSON();
        if (mainEntityId === id) {
          update[id].MainEntity = {};
        }
      }
      else if (ecs.diff[id]) {
        update[id] = ecs.diff[id];
      }
      memory.add(id);
    }
    for (const id of lastMemory) {
      memory.delete(id);
      update[id] = false;
    }
    return update;
  }

}