import Phaser from 'phaser';
import { CAMERA } from '../config.js';

export default class CameraRig {
  constructor(scene, target, bounds) {
    this.scene = scene;
    this.target = target;
    this.cam = scene.cameras.main;

    if (bounds) {
      this.cam.setBounds(bounds.x, bounds.y, bounds.width, bounds.height);
    }

    this.cam.setDeadzone(CAMERA.deadzoneWidth, CAMERA.deadzoneHeight);
    this.cam.startFollow(target, true, CAMERA.lerpX, CAMERA.lerpY);
  }

  // Leans the bus toward the left edge of the screen at rest and out to
  // CAMERA.maxSpeedScreenFraction of the way across at speed, so there's
  // more visible road ahead the faster the bus is moving. Driven through
  // Phaser's followOffset (rather than setting scroll ourselves) so it
  // still rides Phaser's own per-frame lerp smoothing and bounds clamping.
  update() {
    const speed = Math.abs(this.target.body.velocity.x);
    const t = Phaser.Math.Clamp(speed / CAMERA.lookaheadMaxSpeed, 0, 1);
    const screenFraction = Phaser.Math.Linear(CAMERA.restScreenFraction, CAMERA.maxSpeedScreenFraction, t);
    this.cam.followOffset.x = (screenFraction - 0.5) * this.cam.width;
  }
}