import { execFileSync } from "child_process";
import { writeFileSync } from "fs";
import { fileURLToPath } from "url";
import { dirname, join } from "path";

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

const PROMPT_NAME = process.env.PROMPT_NAME;
if (!PROMPT_NAME) {
  console.error("PROMPT_NAME env var required");
  process.exit(1);
}

// Write prompts.json from env var.
// Future: if PROMPTS_URL is set, fetch from S3 or similar instead.
if (process.env.PROMPTS_JSON) {
  writeFileSync(join(__dirname, "prompts.json"), process.env.PROMPTS_JSON);
  console.log(`[${PROMPT_NAME}] Wrote prompts.json from PROMPTS_JSON env var`);
} else {
  console.error("PROMPTS_JSON env var required");
  process.exit(1);
}

function msUntilNext4pmUTC() {
  const now = new Date();
  const next = new Date(now);
  next.setUTCHours(16, 0, 0, 0);
  if (next <= now) next.setUTCDate(next.getUTCDate() + 1);
  return next - now;
}

function runScheduler() {
  console.log(`[${PROMPT_NAME}] Running scheduler at ${new Date().toISOString()}`);
  try {
    execFileSync("node", [join(__dirname, "scheduler.js"), PROMPT_NAME], { stdio: "inherit" });
  } catch {
    console.error(`[${PROMPT_NAME}] scheduler.js exited with error`);
  }
  scheduleNext();
}

function scheduleNext() {
  const ms = msUntilNext4pmUTC();
  const next = new Date(Date.now() + ms);
  console.log(`[${PROMPT_NAME}] Next run at ${next.toISOString()}`);
  setTimeout(runScheduler, ms);
}

scheduleNext();