// A scratch tree per test: a copy of this package's src/ under
// <root>/packages/plugins, plus fixture modules. The loader finds modules
// from its own location, so each tree's copy loads only that tree's modules.
import { cpSync, mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath, pathToFileURL } from "node:url";

export const SRC = resolve(dirname(fileURLToPath(import.meta.url)), "..", "src");

export const USAGE = name => `export const interfaceVersion = 1;
export function readTurn() { return ${JSON.stringify(name)}; }
`;
export const LIMIT = name => `export const interfaceVersion = 2;
export function mayLaunch() { return ${JSON.stringify(name)}; }
export function mustStop() { return false; }
export function report() { return []; }
`;
// A version 1 limit check (before row 125): the loader refuses it.
export const LIMIT_V1 = name => `export const interfaceVersion = 1;
export function mayLaunch() { return ${JSON.stringify(name)}; }
export function mustStop() { return false; }
`;

export function tree(t) {
  const root = mkdtempSync(join(tmpdir(), "mosaic-plugins-"));
  t.after(() => rmSync(root, { recursive: true, force: true }));
  const pkg = join(root, "packages", "plugins");
  cpSync(SRC, join(pkg, "src"), { recursive: true });
  const write = (kind, name, body) => {
    const dir = join(pkg, kind, name);
    mkdirSync(dir, { recursive: true });
    writeFileSync(join(dir, "index.mjs"), body);
    return dir;
  };
  const loaderUrl = pathToFileURL(join(pkg, "src", "loader.mjs")).href;
  async function loader(options = {}) {
    const { createLoader } = await import(loaderUrl);
    const logged = [];
    const instance = createLoader({ log: entry => logged.push(entry), ...options });
    return { ...instance, logged };
  }
  return { root, pkg, write, loader, loaderUrl };
}