import "./player.css";
import { Engine, type SaveApi } from "./engine";
import { loadTranslator, preferredLanguage } from "./i18n";
import { RUNTIMES } from "./runtimes";
import { cloudActive, makeSaveApi } from "./saves";
import type { GameData, Manifest, SaveData, ScriptModule } from "./types";

async function getJSON<T>(url: string): Promise<T> {
  const r = await fetch(url, { credentials: "same-origin" });
  if (!r.ok) throw new Error(`${r.status} ${url}`);
  return r.json();
}

function blob(manifest: Manifest, path: string) {
  const f = manifest.files[path];
  if (!f) throw new Error(`в версии нет файла ${path}`);
  return `/api/versions/${manifest.versionId}/files/${f.hash}`;
}

function saveApi<T = SaveData>(versionId: number, cloud: boolean): SaveApi<T> {
  return makeSaveApi<T>(versionId, cloud);
}

export interface PlayerHandle { destroy(): void }

export async function launch(root: HTMLElement, versionId: number, onExit: () => void,
                             onProgress: (text: string) => void): Promise<PlayerHandle> {
  onProgress("Загрузка манифеста");
  const manifest = await getJSON<Manifest>(`/api/versions/${versionId}/manifest`);
  const game = await getJSON<GameData>(blob(manifest, "game.json"));
  onProgress(`Загрузка скриптов (${game.scripts.length})`);
  // ?lang= and ?at= come from the translation editor ("play from here")
  const url = new URLSearchParams(location.search);
  const asked = url.get("lang");
  const lang = asked && (asked === game.sourceLang || game.locales?.[asked]) ? asked : preferredLanguage(game);
  const [modules, tr] = await Promise.all([
    Promise.all(game.scripts.map((s) => getJSON<ScriptModule>(blob(manifest, s)))),
    loadTranslator(game, manifest, lang),
  ]);
  // files the game reads while it starts (`renpy.file(...)`) have to be here before its first line runs
  if (game.dataFiles?.length) {
    const texts = await Promise.all(game.dataFiles.map((path) =>
      fetch(blob(manifest, `data/${path}`), { credentials: "same-origin" }).then((r) => (r.ok ? r.text() : ""))));
    game.dataText = Object.fromEntries(game.dataFiles.map((path, i) => [path.toLowerCase(), texts[i]]));
  }
  const cloud = await cloudActive();
  if (game.runtime) {
    const load = RUNTIMES[game.runtime];
    if (!load) throw new Error(`Неизвестная среда исполнения игры: ${game.runtime}`);
    return (await load())({ root, game, manifest, modules, url, tr, onExit, versionId, saveApi: (id) => saveApi(id, cloud) });
  }
  // volume belongs to the game, not to one of its versions (forks and mods share it)
  const gameId = await getJSON<{ game_id: number }>(`/api/versions/${versionId}`).then((v) => v.game_id, () => null);
  const engine = new Engine(root, game, manifest, modules, saveApi(versionId, cloud),
                            `pgvn:persistent:${versionId}`, onExit, tr,
                            (code) => loadTranslator(game, manifest, code),
                            gameId === null ? `pgvn:audio:version:${versionId}` : `pgvn:audio:game:${gameId}`);
  const at = url.get("at");
  if (at) engine.startAt(at);
  else engine.start();
  return engine;
}