// Engine-independent, reproducible game-directory packaging; no downloads.
import * as fs from 'node:fs/promises';
import { constants } from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { generateAssets } from './assets.mjs';
import { absolute, atomicDirectory, copyTree, disjoint, exists, json, relativeName, safePath, verifyManifest, writeManifest } from './files.mjs';

export const SOURCE = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const WORLDGEN_REPO = path.resolve(SOURCE, '..', 'luanti-mapgenerator-epic');
const WORLDGEN_SOURCE = path.join(WORLDGEN_REPO, 'mods', 'epic_terrain');
const BUNDLED_WORLDGEN = path.basename(SOURCE) === 'last_hearth' && path.dirname(WORLDGEN_REPO) === path.dirname(SOURCE);
export async function readRelease(source = SOURCE) {
  await safePath(path.join(absolute(source), 'release.json'));
  const release = JSON.parse(await fs.readFile(path.join(source, 'release.json'), 'utf8'));
  if (release.format !== 1 || release.gameId !== 'last_hearth' || !/^\d+\.\d+\.\d+(?:-[a-z0-9.-]+)?$/.test(release.version) ||
      release.engine?.name !== 'Luanti' || release.engine?.version !== '5.18.0' || release.node !== '>=22' ||
      release.packageFormat !== 1 || release.backupFormat !== 1) throw new Error('Unsupported release contract.');
  return release;
}

export async function packageGame(destination, { source = SOURCE } = {}) {
  source = absolute(source); destination = absolute(destination);
  // dist/ within the repository is supported; no payload source may overlap it.
  for (const entry of ['mods', 'fixtures', 'tests', 'scripts']) disjoint(path.join(source, entry), destination);
  const release = await readRelease(source);
  if (source === SOURCE && BUNDLED_WORLDGEN) {
    disjoint(WORLDGEN_SOURCE, destination);
    const config = await safePath(path.join(WORLDGEN_SOURCE, 'mod.conf'));
    if (!(await fs.lstat(config)).isFile()) throw new Error('Epic-scale mapgen mod is missing from the workspace.');
  }
  return atomicDirectory(destination, async stage => {
    for (const name of ['game.conf', 'minetest.conf', 'settingtypes.txt', 'LICENSE.txt']) {
      const filename = await safePath(path.join(source, name));
      if (!(await fs.lstat(filename)).isFile()) throw new Error('Package input must be a regular file.');
      await fs.copyFile(filename, path.join(stage, name), constants.COPYFILE_EXCL);
    }
    await copyTree(path.join(source, 'mods'), path.join(stage, 'mods'), {
      exclude: new Set(['hearth/textures', 'hearth/models']),
    });
    if (source === SOURCE && BUNDLED_WORLDGEN) {
      await copyTree(WORLDGEN_SOURCE, path.join(stage, 'mods/epic_terrain'));
    }
    for (const name of ['init', 'model', 'runtime', 'content', 'encounters']) {
      if (!await exists(path.join(stage, 'mods/hearth', name + '.lua'))) throw new Error('Game payload is incomplete.');
    }
    // Generate from the copied inputs, not a changing worktree. Refuse links first.
    await generateAssets(stage, stage);
    await fs.mkdir(path.join(stage, 'fixtures'));
    await safePath(path.join(source, 'tests/fixtures/scenarios.json'));
    const scenarios = JSON.parse(await fs.readFile(path.join(source, 'tests/fixtures/scenarios.json'), 'utf8'));
    await fs.writeFile(path.join(stage, 'fixtures/scenarios.json'), json(scenarios), { flag: 'wx' });
    // Runtime fixture schemas are owned by the game agent; copy JSON contracts
    // verbatim, including config.json and first-session/summer/winter fixtures.
    for (const name of (await fs.readdir(path.join(source, 'tests/fixtures'))).sort()) {
      if (name === 'scenarios.json' || !name.endsWith('.json')) continue;
      relativeName(name);
      const fixture = await safePath(path.join(source, 'tests/fixtures', name));
      if (!(await fs.lstat(fixture)).isFile()) throw new Error('Fixture must be a regular JSON file.');
      JSON.parse(await fs.readFile(fixture, 'utf8'));
      await fs.copyFile(fixture, path.join(stage, 'fixtures', name), constants.COPYFILE_EXCL);
    }
    await fs.writeFile(path.join(stage, 'release.json'), json(release), { flag: 'wx' });
    await writeManifest(stage, 'game');
    await verifyPackage(stage, {requireBundled: source === SOURCE && BUNDLED_WORLDGEN});
  });
}

export async function verifyPackage(directory, {requireBundled} = {}) {
  const manifest = await verifyManifest(directory, 'game');
  await readRelease(directory);
  if (requireBundled === undefined) {
    const configPath = await safePath(path.join(absolute(directory), 'mods/hearth/mod.conf'));
    const config = await fs.readFile(configPath, 'utf8');
    requireBundled = /^\s*depends\s*=.*(?:^|[,\s])creatura(?:$|[,\s])/m.test(config);
  }
  if (requireBundled && BUNDLED_WORLDGEN && !manifest.entries.some(entry => entry.path === 'mods/epic_terrain/init.lua')) {
    throw new Error('Packaged Last Hearth is missing its bundled epic_terrain generator.');
  }
  if (requireBundled && !manifest.entries.some(entry => entry.path === 'mods/creatura/LICENSE')) {
    throw new Error('Packaged Last Hearth is missing Creatura license attribution.');
  }
  return manifest;
}