import Phaser from 'phaser';
import { GAME_WIDTH, GAME_HEIGHT, DEBUG, WORLD_SCALE } from '../config.js';
import { getLevelById } from '../data/levels/index.js';
import Bus from '../entities/Bus.js';
import Terrain from '../entities/Terrain.js';
import FinishLine from '../entities/FinishLine.js';
import InputController from '../systems/InputController.js';
import GForceMonitor from '../systems/GForceMonitor.js';
import KidManager from '../systems/KidManager.js';
import CameraRig from '../systems/CameraRig.js';
import EngineSound from '../systems/EngineSound.js';
import { stopMenuMusic } from '../util/music.js';
import { playLevelVoiceLine } from '../util/voiceLine.js';

export default class PlayScene extends Phaser.Scene {
  constructor() {
    super('Play');
  }

  init(data) {
    this.levelId = data.levelId;
    this.level = getLevelById(this.levelId);
    this._levelEnded = false;
    this._timerStarted = false;
    this._timeRemaining = this.level.timeLimit;
  }

  create() {
    stopMenuMusic(this);

    this.cameras.main.setBackgroundColor('#8fc7e8');

    this._buildParallax();

    this.terrain = new Terrain(this, this.level);
    this.finishLine = new FinishLine(this, this.level);

    this.bus = new Bus(this, this.level.startPosition.x, this.level.startPosition.y, this.level.startAngle || 0);

    this.kidManager = new KidManager(this, this.bus, this.level.kidsAboard);

    this.inputController = new InputController(this);

    this.engineSound = new EngineSound(this, this.bus);
    this.voiceSound = playLevelVoiceLine(this, this.levelId);

    this.gForceMonitor = new GForceMonitor(this, this.bus.chassis.body);
    this.gForceMonitor.resetBaseline();

    this.cameraRig = new CameraRig(this, this.bus.chassis, this.level.cameraBounds);

    this._buildGoal();
    this._buildHud();

    this.events.on('kid-status-changed', this._onKidStatusChanged, this);
    this.events.on('level-failed', this._onLevelFailed, this);

    this.matter.world.on('collisionstart', this._onCollisionStart, this);

    this.events.once('shutdown', this._cleanup, this);
  }

  update(time, delta) {
    if (this._levelEnded) return;

    const intent = this.inputController.getIntent();
    if (!this._timerStarted && intent.throttle > 0) this._timerStarted = true;

    this.bus.applyIntent(intent);
    this.engineSound.update();
    this.finishLine.update(time);
    this.cameraRig.update();
    this._updateParallax();
    this._updateTimer(delta);
    this._checkBusFell();
    this._checkAllKidsLost();

    if (DEBUG && this.debugText) {
      const g = this.gForceMonitor.lastGForce || 0;
      this.debugText.setText(`g-force: ${g.toFixed(2)}`);
    }
  }

  _buildParallax() {
    const bounds = this.level.cameraBounds;
    const width = bounds.width + 1000 * WORLD_SCALE;

    // Far layer fills the full viewport height at ONE uniform scale (same
    // factor on both axes, so its native aspect ratio is preserved - no
    // stretch), fixed to the screen (scroll factor 0). _updateParallax()
    // manually scrubs its tilePositionX each frame based on progress from
    // start to goal, so the single image pans start-to-end exactly once
    // over the course of the level.
    const farNative = this._nativeTextureSize('bg_far');
    const farScale = GAME_HEIGHT / farNative.height;
    this.bgFar = this.add.tileSprite(0, 0, GAME_WIDTH, GAME_HEIGHT, 'bg_far').setOrigin(0, 0);
    this.bgFar.setScrollFactor(0, 0);
    this.bgFar.tileScaleX = farScale;
    this.bgFar.tileScaleY = farScale;
    this._bgFarPanRange = Math.max(0, farNative.width - GAME_WIDTH / farScale);

    // Mid/near are ground-level layers stacked from the bottom of the
    // screen upward, each at its own uniform (non-stretching) scale, tiled
    // across the level via the normal scrollFactor-driven parallax. Repeat
    // count isn't pinned to an exact number - it falls out of each layer's
    // target height, and near's is shorter than mid's, so it naturally
    // repeats more often across the same span.
    this._addGroundLayer('bg_mid', bounds.x, width, GAME_HEIGHT * 0.6, 0.45);
    this._addGroundLayer('bg_near', bounds.x, width, GAME_HEIGHT * 0.35, 0.75);
  }

  _nativeTextureSize(key) {
    const src = this.textures.get(key).getSourceImage();
    return { width: src.width, height: src.height };
  }

  // Adds a bottom-anchored parallax layer scaled uniformly (same factor on
  // both axes, so its native aspect ratio is preserved - no stretch),
  // tiled horizontally across `displayWidth` however many times that scale
  // naturally allows.
  _addGroundLayer(key, x, displayWidth, targetHeight, scrollFactorX) {
    const native = this._nativeTextureSize(key);
    const scale = targetHeight / native.height;
    const y = GAME_HEIGHT - targetHeight;
    const layer = this.add.tileSprite(x, y, displayWidth, targetHeight, key).setOrigin(0, 0);
    layer.tileScaleX = scale;
    layer.tileScaleY = scale;
    layer.setScrollFactor(scrollFactorX, 0);
    return layer;
  }

  // Drives bg_far's pan independent of camera scroll: 0 at the bus's start
  // position, 1 at the goal, clamped so overshoot/backing up doesn't run
  // the image past its own ends.
  _updateParallax() {
    if (!this.bgFar) return;
    const startX = this.level.startPosition.x;
    const endX = this.level.goal.x;
    const progress = Phaser.Math.Clamp((this.bus.chassis.x - startX) / Math.max(1, endX - startX), 0, 1);
    this.bgFar.tilePositionX = progress * this._bgFarPanRange;
  }

  // A bus that's fallen past the bottom of the level's own camera bounds
  // is somewhere the camera can never scroll down far enough to show again
  // (that's the literal definition of "off screen" here) - treated the
  // same as losing every kid, since there's no way to recover either.
  _checkBusFell() {
    if (this._isBelowCameraBounds(this.bus.chassis.y)) {
      this.events.emit('level-failed', { reason: 'bus-fell' });
    }
  }

  _isBelowCameraBounds(y) {
    const bounds = this.level.cameraBounds;
    return y > bounds.y + bounds.height;
  }

  // 0 kids aboard isn't itself a fail condition - KidManager just tracks
  // who's still seated. A kid popped loose by a jump is still catchable
  // (falls down through the compartment's open top and re-boards - see
  // KidManager) right up until it's either settled outside the bus or lost
  // down a gap, so the level only fails once EVERY kid has reached one of
  // those two unrecoverable states, not the instant the last one leaves.
  _checkAllKidsLost() {
    if (this.kidManager.kidsAboardCount > 0) return;

    const allUnrecoverable = this.kidManager.kids.every((kid) => {
      return this._isBelowCameraBounds(kid.image.y) || kid.isSettled(this.time.now);
    });

    if (allUnrecoverable) {
      this.events.emit('level-failed', { reason: 'all-kids-lost' });
    }
  }

  // Counts down only once the player has actually hit the gas (throttle >
  // 0) for the first time - sitting idle at the start line costs nothing,
  // matching "the clock is your speedrun, not your reaction time" framing.
  _updateTimer(delta) {
    if (!this._timerStarted || this._timeRemaining <= 0) return;

    this._timeRemaining = Math.max(0, this._timeRemaining - delta / 1000);
    this.timerText.setText(this._formatTime(this._timeRemaining));
    this.timerText.setColor(this._timeRemaining <= 10 ? '#c0392b' : '#1a1f29');

    if (this._timeRemaining <= 0) {
      this.events.emit('level-failed', { reason: 'time-up' });
    }
  }

  _formatTime(seconds) {
    const whole = Math.max(0, Math.ceil(seconds));
    const m = Math.floor(whole / 60);
    const s = whole % 60;
    return `${m}:${String(s).padStart(2, '0')}`;
  }

  _buildGoal() {
    const goal = this.level.goal;
    this.goalBody = this.matter.add.rectangle(goal.x, goal.y, goal.width, goal.height, {
      isStatic: true,
      isSensor: true,
      label: 'goal',
    });
  }

  _buildHud() {
    this.hudIcons = [];
    const startX = 24 * WORLD_SCALE;
    const y = 24 * WORLD_SCALE;
    const spacing = 30 * WORLD_SCALE;
    const iconSize = 24 * WORLD_SCALE;

    for (let i = 0; i < this.level.kidsAboard; i++) {
      const icon = this.add.image(startX + i * spacing, y, 'icon_kid').setDisplaySize(iconSize, iconSize).setScrollFactor(0).setDepth(10);
      this.hudIcons.push(icon);
    }

    this.hudText = this.add.text(startX, y + 24 * WORLD_SCALE, `Kids aboard: ${this.level.kidsAboard}/${this.level.kidsAboard}`, {
      fontFamily: 'monospace',
      fontSize: `${14 * WORLD_SCALE}px`,
      color: '#1a1f29',
      backgroundColor: '#ffffffaa',
    }).setScrollFactor(0).setDepth(10);

    this.timerText = this.add.text(GAME_WIDTH - startX, y, this._formatTime(this._timeRemaining), {
      fontFamily: 'monospace',
      fontSize: `${32 * WORLD_SCALE}px`,
      fontStyle: 'bold',
      color: '#1a1f29',
      backgroundColor: '#ffffffaa',
    }).setOrigin(1, 0).setScrollFactor(0).setDepth(10);

    if (DEBUG) {
      this.debugText = this.add.text(startX, y + 52 * WORLD_SCALE, 'g-force: 0.00', {
        fontFamily: 'monospace',
        fontSize: `${14 * WORLD_SCALE}px`,
        color: '#1a1f29',
        backgroundColor: '#ffffffaa',
      }).setScrollFactor(0).setDepth(10);
    }
  }

  _onKidStatusChanged({ kidsAboard, total }) {
    const ejectedCount = total - kidsAboard;
    for (let i = 0; i < this.hudIcons.length; i++) {
      this.hudIcons[i].setAlpha(i < ejectedCount ? 0.2 : 1);
    }
    this.hudText.setText(`Kids aboard: ${kidsAboard}/${total}`);
  }

  _onLevelFailed({ reason }) {
    if (this._levelEnded) return;
    this._levelEnded = true;
    this.scene.start('LevelFailed', { levelId: this.levelId, reason });
  }

  _onCollisionStart(event, bodyA, bodyB) {
    if (this._levelEnded) return;
    if (this._isGoalHit(bodyA, bodyB)) {
      this._onWin();
    }
  }

  _isGoalHit(bodyA, bodyB) {
    const busBodies = [this.bus.chassis.body, this.bus.wheelRear.body, this.bus.wheelFront.body];
    const isGoal = (b) => b.label === 'goal';
    const isBus = (b) => busBodies.includes(b);
    return (isGoal(bodyA) && isBus(bodyB)) || (isGoal(bodyB) && isBus(bodyA));
  }

  _onWin() {
    this._levelEnded = true;
    const kidsSaved = this.kidManager.kidsAboardCount;
    const total = this.kidManager.total;
    this.scene.start('LevelComplete', { levelId: this.levelId, kidsSaved, total });
  }

  _cleanup() {
    this.events.off('kid-status-changed', this._onKidStatusChanged, this);
    this.events.off('level-failed', this._onLevelFailed, this);
    // No matter.world.off() here: Phaser's Matter World plugin registers its
    // own 'shutdown' listener before this scene's create() ever runs, so it
    // tears down (and nulls out) this.matter.world before this handler
    // fires - calling .off() on it threw "Cannot read properties of null".
    // Matter.World#shutdown() already calls removeAllListeners() on itself
    // internally (verified against the vendored source), so this was always
    // redundant, not just now-unsafe.
    if (this.gForceMonitor) this.gForceMonitor.destroy();
    if (this.kidManager) this.kidManager.destroy();
    if (this.engineSound) this.engineSound.destroy();
    if (this.voiceSound) this.voiceSound.stop();
    if (this.bus) this.bus.destroy();
  }
}