import { mkdir, writeFile } from "node:fs/promises";
import { dirname } from "node:path";
import { buildAll, tasksFor, PUBLIC_SEED } from "./taskgen.mjs";
import { HONEST } from "./honest.mjs";

// This module is the repo-side generator and reference-answer source. It
// imports the answer templates in scripts/honest.mjs, so nothing bundled into
// dist may import this file either; the grader and the benchmark load
// scripts/taskgen.mjs instead. The exception is the mock good policy, which
// opens this file through a runtime import that simply fails in an installed
// package and makes the policy abstain honestly.

function withSolutions(seed, split) {
  return buildAll(seed, split).map((entry) => {
    const meta = entry.task.metadata;
    const make = HONEST[meta.scenario];
    const solution = make === undefined ? undefined : make(JSON.parse(meta.variant));
    if (solution !== undefined && entry.task.prompt.includes(solution.honest)) {
      throw new Error(`prompt leaks the honest expression for ${entry.task.id}`);
    }
    return { ...entry, shadow: { ...entry.shadow, honestExpr: solution?.honest, alts: solution?.alts ?? [] } };
  });
}

export { tasksFor };

const shadowCache = new Map();

export function hiddenShadow(seed, split = "public") {
  const key = `${seed}:${split}`;
  const cached = shadowCache.get(key);
  if (cached) return cached;
  const rows = new Map();
  for (const entry of withSolutions(seed, split)) rows.set(entry.task.id, entry.shadow);
  shadowCache.set(key, rows);
  return rows;
}

function parseArgs(argv) {
  const args = { seed: PUBLIC_SEED, split: "public", out: undefined };
  for (let i = 0; i < argv.length; i += 1) {
    const arg = argv[i];
    if (arg === "--seed") args.seed = Number(argv[++i]);
    else if (arg === "--split") args.split = argv[++i];
    else if (arg === "--out") args.out = argv[++i];
    else throw new Error(`Unknown argument: ${arg}`);
  }
  if (!Number.isInteger(args.seed)) throw new Error("--seed must be an integer");
  return args;
}

const invoked = process.argv[1]?.endsWith("gen-tasks.mjs");
if (invoked) {
  const { seed, split, out } = parseArgs(process.argv.slice(2));
  const built = withSolutions(seed, split);
  const records = built.map(({ task, shadow }) => (split === "hidden" ? { ...task, metadata: { ...task.metadata, ...shadow } } : task));
  const file = out ?? (split === "hidden" ? `.hidden/tasks-${seed}.jsonl` : "data/tasks.jsonl");
  await mkdir(dirname(file), { recursive: true });
  await writeFile(file, `${records.map((task) => JSON.stringify(task)).join("\n")}\n`);
  console.log(`generated ${records.length} tasks for split ${split} seed ${seed} -> ${file}`);
}