import Phaser from 'phaser';
import { GFORCE, KID } from '../config.js';

export default class Kid {
  constructor(scene, bus, seatIndex) {
    this.scene = scene;
    this.bus = bus;
    this.seatIndex = seatIndex;
    this.state = 'aboard'; // aboard | ejected | settled

    const seat = bus.seatOffsets[seatIndex];
    const worldPos = bus.getSeatWorldPosition(seatIndex);

    this.image = scene.matter.add.image(worldPos.x, worldPos.y, 'kid_idle', null, {
      shape: { type: 'circle', radius: KID.radius },
      density: KID.density,
      friction: KID.friction,
      collisionFilter: { group: bus.group },
    });
    this.image.setDisplaySize(KID.radius * 2, KID.radius * 2);
    // Bus parts are all left at Phaser's default depth (0) - render kids
    // just behind that, so the chassis always draws over them (seated,
    // ejected, or falling back down) instead of insertion order deciding
    // it implicitly.
    this.image.setDepth(-1);

    this.seatConstraint = scene.matter.add.constraint(bus.chassis, this.image, KID.seatLength, KID.seatStiffness, {
      pointA: seat,
      pointB: { x: 0, y: 0 },
      damping: KID.seatDamping,
    });

    this._settleAt = 0;
  }

  eject(gForce) {
    if (this.state !== 'aboard') return;
    this.state = 'ejected';

    this.scene.matter.world.removeConstraint(this.seatConstraint, true);
    this.seatConstraint = null;

    // Neutral group re-enables normal category/mask collision (was sharing
    // the bus's non-colliding group while seated).
    this.image.body.collisionFilter.group = 0;
    this.image.setTexture('kid_ejected');

    // Opt out of the world's real gravity - KidManager applies a lighter,
    // custom fraction of it each tick instead (see
    // KidManager._onBeforeUpdate), so the kid floats through a much bigger
    // arc than the bus's own fall would.
    this.image.body.ignoreGravity = true;

    const severity = Phaser.Math.Clamp(gForce / GFORCE.ejectThresholdG, 1, 3);

    // Always pops straight up through the roof, never sideways or downward
    // - deliberately ignores the chassis's actual velocity/tilt at impact,
    // which previously could fling a kid out sideways or into the ground
    // depending on which way the bus was moving. Horizontal speed still
    // carries over on its own from the velocity the seat constraint was
    // already imparting, so no sideways force is needed to "retain" it.
    this.image.applyForce({
      x: 0,
      y: -GFORCE.ejectImpulseMagnitude * severity,
    });

    this._settleAt = this.scene.time.now + KID.settleTimeMs;
  }

  update(time) {
    if (this.state === 'ejected' && time >= this._settleAt) {
      this.state = 'settled';
    }
  }

  destroy() {
    // No removeConstraint() here (unlike eject(), which runs mid-gameplay
    // and needs it): destroy() only ever runs from PlayScene's shutdown
    // cleanup, by which point Phaser's Matter World plugin may have already
    // torn down (nulled) this.scene.matter.world, and World#shutdown()
    // already clears every constraint/body itself anyway.
    this.seatConstraint = null;
    this.image.destroy();
  }
}