import { basename, dirname, extname } from 'node:path/posix';
import { rename, writeFile } from 'node:fs/promises';
import { join } from 'node:path';

export function buildLegacyInventory(paths) {
  const inventory = {};
  for (const fullPath of paths) {
    if (!fullPath.startsWith('icons/')) {
      continue;
    }

    const relative = fullPath.slice('icons/'.length);
    const directory = dirname(relative);
    const file = basename(relative);
    const extension = extname(file);
    const name = extension ? file.slice(0, -extension.length) : file;
    inventory[directory] ??= {};
    inventory[directory][name] = file;
  }
  return inventory;
}

async function atomicJson(path, value) {
  const temporary = `${path}.tmp-${process.pid}`;
  await writeFile(temporary, JSON.stringify(value), { encoding: 'utf8', mode: 0o644 });
  await rename(temporary, path);
}

export async function writeInventories({ repositoryPath, paths, branch, commit, publicBases, generatedAt = new Date() }) {
  const legacy = buildLegacyInventory(paths);
  const versioned = {
    version: 2,
    branch,
    commit,
    generatedAt: generatedAt.toISOString(),
    publicBases,
    assets: paths.filter((path) => path.startsWith('game/') || path.startsWith('icons/')),
    directories: legacy,
  };

  await atomicJson(join(repositoryPath, 'hook', 'list.json'), legacy);
  await atomicJson(join(repositoryPath, 'hook', 'inventory.v2.json'), versioned);
  return versioned;
}