import { readFile } from 'node:fs/promises';
import { fileURLToPath } from 'node:url';
import { dirname, resolve } from 'node:path';

type UpdateItem = {
  name: string;
  amount: number;
  displayName?: string | null;
};

const __dirname = dirname(fileURLToPath(import.meta.url));

const TARGET_URL = process.env.UPDATE_URL ?? 'https://localhost:3000/api/me-system/update';
const INTERVAL_MS = Number(process.env.INTERVAL_MS ?? 10_000);
const JSON_PATH = process.env.JSON_PATH ?? resolve(__dirname, 'me_system_update.json');
const MAX_VARIATION = Number(process.env.MAX_VARIATION ?? 0.05);

if (TARGET_URL.startsWith('https://')) {
  process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
}

function mutate(items: UpdateItem[]): UpdateItem[] {
  return items.map((item) => {
    const delta = (Math.random() * 2 - 1) * MAX_VARIATION;
    const next = Math.max(0, Math.round(item.amount * (1 + delta)));
    return { ...item, amount: next };
  });
}

async function sendUpdate(items: UpdateItem[]): Promise<void> {
  const startedAt = Date.now();
  try {
    const res = await fetch(TARGET_URL, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify(items),
    });
    const took = Date.now() - startedAt;
    const text = await res.text();
    console.log(
      `[${new Date().toISOString()}] POST ${res.status} (${took} ms, ${items.length} items) -> ${text}`,
    );
  } catch (err) {
    console.error(`[${new Date().toISOString()}] request failed:`, err);
  }
}

async function main(): Promise<void> {
  const raw = await readFile(JSON_PATH, 'utf8');
  let current: UpdateItem[] = JSON.parse(raw);

  console.log(
    `Loaded ${current.length} items from ${JSON_PATH}\n` +
      `Posting to ${TARGET_URL} every ${INTERVAL_MS} ms (max ±${MAX_VARIATION * 100}% per tick).`,
  );

  await sendUpdate(current);

  setInterval(() => {
    current = mutate(current);
    void sendUpdate(current);
  }, INTERVAL_MS);
}

main().catch((err) => {
  console.error('Fatal:', err);
  process.exit(1);
});