import Phaser from '../vendor/phaser.js';
import { config } from '../config/Config.js';
import { toColor } from '../utils/Color.js';
import { Rng } from '../utils/Rng.js';
import { Galaxy } from '../galaxy/Galaxy.js';
import { formatSystemReport } from '../galaxy/SystemReport.js';
import { Ship } from '../entities/Ship.js';
import { Planet } from '../entities/Planet.js';
import { Starfield } from '../visuals/Starfield.js';

const FONT_FALLBACK = "'Segoe UI', 'Helvetica Neue', Arial, sans-serif";

/**
 * The game world (v0.3: the home planet — the player's Terran world —
 * in the current system's open space).
 * Click anywhere to fly there.
 */
export class GameScene extends Phaser.Scene {
  constructor() {
    super({ key: 'GameScene' });
  }

  preload() {
    // The planet spritesheet: frameWidth×frameHeight frames; the first
    // frames are Terran worlds (see data/planets.json → frames).
    this.load.spritesheet(
      Planet.TEXTURE_KEY,
      config.get('planets.texture', 'assets/images/planets.png'),
      {
        frameWidth: config.get('planets.frameWidth', 1024),
        frameHeight: config.get('planets.frameHeight', 1024),
      },
    );
  }

  create() {
    // Camera: smoothly follows the ship (updateCamera below). This motion
    // is what drives the parallax starfield — ship flies, view trails.
    this.cameraFollowShip = config.get('game.camera.followShip', true);
    this.cameraFollowRate = config.get('game.camera.followRate', 3.0); // 1/s

    // We are, after all, in a system. Show the player which one. (This
    // also establishes the galaxy — and its seed — for what follows.)
    this.createSystemHud();

    // The home planet — the player's Terran world, always present in the
    // system they start in. It sits at the world origin. Which Terran face
    // it shows is a seed-deterministic pick from the terran pool, so the
    // same galaxy always yields the same home world.
    const homeName = config.get('planets.homePlanet', 'terran');
    const homeRng = Rng.derive(this.galaxy.seed, 'planet', 'home');
    this.planet = new Planet(this, 0, 0, Planet.frameFor(homeName, homeRng), homeName);
    this.planet.setDepth(5); // above the starfield (depths 0–2), below the ship (10)

    // The ship — a short hop (~150 px, edge-to-edge) from the home world's
    // rim, in a seed-derived direction: same galaxy ⇒ same start.
    this.ship = new Ship(this, 0, 0);
    this.ship.setDepth(10);
    const spawn = this.planet.edgePoint(
      Rng.derive(this.galaxy.seed, 'spawn', 'ship').range(0, Math.PI * 2),
      config.get('planets.spawnDistanceFromEdge', 150),
      this.ship.radius,
    );
    this.ship.setPosition(spawn.x, spawn.y);

    // Center the camera on the ship from the very first frame.
    this.cameras.main.setScroll(
      this.ship.x - this.scale.width / 2,
      this.ship.y - this.scale.height / 2,
    );

    // Background (stars are placed around the current camera view).
    this.starfield = new Starfield(this);
    this.starfield.create();

    // Hint
    this.hint = this.add
      .text(this.scale.width / 2, this.scale.height - 26, config.get('game.hintText', ''), {
        fontFamily: FONT_FALLBACK,
        fontSize: '14px',
        color: '#54608a',
      })
      .setOrigin(0.5)
      .setScrollFactor(0); // UI: pinned to the screen, not the world

    // Input: click = fly there. A click inside the planet clamps to the
    // keep-out rim — the ship can stop at the clearance, never inside.
    this.input.on('pointerdown', (pointer) => {
      const aim = this.planet.aimPoint(pointer.worldX, pointer.worldY, this.ship.radius);
      this.showTargetMarker(aim.x, aim.y);
      this.ship.setTarget(aim.x, aim.y);
      this.hideHint();
    });
  }

  /**
   * Top-left HUD: the current system's dossier — name, identity, and what
   *'s ALREADY THERE: colonies, mining stations, cloud bases, stations adrift
   * in open space (or "charted · unclaimed" when nobody's settled here).
   * Formatted by the pure SystemReport helper; this method only renders.
   *
   * The galaxy comes from the shared registry (built by the menu from the
   * chosen seed). Dev boots that skip the menu (dev/test-game.html) get a
   * fresh dev galaxy so the scene always works standalone.
   *
   * The system's CONTENTS are generated here, on arrival — the first touch
   * of the lazy level-2 generation. (Roster/positions were fixed at the
   * menu's New Game click; this is just the "build the room" part.)
   */
  createSystemHud() {
    this.galaxy = this.registry.get('galaxy') ?? null;
    if (!this.galaxy) {
      const seed = Rng.randomSeedString(8);
      this.galaxy = Galaxy.create(seed);
      this.registry.set('galaxy', this.galaxy);
      this.registry.set('seed', seed);
      console.warn(`[orbit] no galaxy in the registry — generated a dev galaxy (seed "${seed}")`);
    }

    const current = this.galaxy.currentSystem();
    const content = this.galaxy.ensureContent(current.id);
    const report = formatSystemReport(content);
    const fam = FONT_FALLBACK;

    let y = 14;
    const line = (text, style) => {
      this.add
        .text(16, y, text, style)
        .setOrigin(0, 0)
        .setScrollFactor(0) // UI: pinned to the screen, not the world
        .setDepth(30);
      y += 20 + (style.fontSize === '17px' ? 6 : 0);
    };

    line(report.title, {
      fontFamily: fam,
      fontSize: '17px',
      fontStyle: 'bold',
      color: toColor(this.galaxy.typeDefs?.[current.type]?.theme?.color ?? '#9fb4e8'),
    });
    line(report.subtitle, { fontFamily: fam, fontSize: '12px', color: '#8fa0c9' });
    y += 2;
    for (const s of report.settlements) {
      line(s.text, { fontFamily: fam, fontSize: '13px', color: toColor(s.color, 0x8fa0c9) });
    }
    line(report.summary, { fontFamily: fam, fontSize: '12px', color: '#54608a' });
    line(`seed ${this.galaxy.seed}`, { fontFamily: fam, fontSize: '11px', color: '#3d476b' });
  }

  update(_time, delta) {
    this.ship.update(_time, delta);
    // The home world is solid: the ship may come within the clearance in
    // data/planets.json of its rim, but never closer (or through it).
    this.planet.constrainShip(this.ship, this.ship.radius);
    this.updateCamera(delta);
    this.starfield.update(); // after the camera, so it sees this frame's motion
  }

  /**
   * The camera chases the ship with a frame-rate-independent ease:
   *   scroll += (shipCenter - scroll) * (1 - e^(-rate·dt))
   * While the ship flies, the camera trails it and the starfield streams
   * past in the opposite direction (real parallax). When the ship stops,
   * the camera keeps easing until it is centered on the ship again — a
   * slow recenter (≈1.5 s at followRate 3) with the stars parallaxing
   * along for the ride.
   */
  updateCamera(delta) {
    if (!this.cameraFollowShip || !this.ship) return;
    const rate = this.cameraFollowRate;
    if (!(rate > 0)) return;

    const cam = this.cameras.main;
    const k = 1 - Math.exp(-rate * (Math.min(delta, 64) / 1000));
    cam.setScroll(
      Phaser.Math.Linear(cam.scrollX, this.ship.x - this.scale.width / 2, k),
      Phaser.Math.Linear(cam.scrollY, this.ship.y - this.scale.height / 2, k),
    );
  }

  showTargetMarker(x, y) {
    const color = toColor(config.get('game.markerColor', '#41c7ff'));
    const marker = this.add.circle(x, y, 10, color, 0.8).setDepth(5);
    this.tweens.add({
      targets: marker,
      scale: 2.4,
      alpha: 0,
      duration: 450,
      ease: 'Sine.easeOut',
      onComplete: () => marker.destroy(),
    });
  }

  hideHint() {
    if (!this.hint || !this.hint.active) return;
    this.tweens.add({
      targets: this.hint,
      alpha: 0,
      duration: 400,
      onComplete: () => {
        this.hint.destroy();
        this.hint = null;
      },
    });
  }

  shutdown() {
    this.starfield?.destroy();
  }
}