import Phaser from 'phaser';

export type LazySceneKey = 'StoryScene' | 'BattleScene' | 'CampScene' | 'EndingScene';

type LazySceneConstructor = new () => Phaser.Scene;

const lazySceneLoaders: Record<LazySceneKey, () => Promise<LazySceneConstructor>> = {
  StoryScene: () => import('./StoryScene').then((module) => module.StoryScene),
  BattleScene: () => import('./BattleScene').then((module) => module.BattleScene),
  CampScene: () => import('./CampScene').then((module) => module.CampScene),
  EndingScene: () => import('./EndingScene').then((module) => module.EndingScene)
};

const pendingSceneLoads = new Map<LazySceneKey, Promise<void>>();

export function isLazySceneKey(key: string): key is LazySceneKey {
  return key === 'StoryScene' || key === 'BattleScene' || key === 'CampScene' || key === 'EndingScene';
}

export async function ensureLazyScene(game: Phaser.Game, key: LazySceneKey) {
  if (game.scene.getScene(key)) {
    return;
  }

  const pendingLoad = pendingSceneLoads.get(key);
  if (pendingLoad) {
    await pendingLoad;
    return;
  }

  const load = lazySceneLoaders[key]().then((SceneClass) => {
    if (!game.scene.getScene(key)) {
      game.scene.add(key, SceneClass, false);
    }
  });
  pendingSceneLoads.set(key, load);
  await load;
}

export async function startLazyScene(scene: Phaser.Scene, key: LazySceneKey, data?: Record<string, unknown>) {
  await ensureLazyScene(scene.game, key);
  scene.scene.start(key, data);
}

export async function startGameScene(scene: Phaser.Scene, key: string, data?: Record<string, unknown>) {
  if (isLazySceneKey(key)) {
    await startLazyScene(scene, key, data);
    return;
  }

  scene.scene.start(key, data);
}

export async function startLazySceneFromGame(game: Phaser.Game, key: LazySceneKey, data?: Record<string, unknown>) {
  await ensureLazyScene(game, key);
  game.scene.start(key, data);
}