import { resolve } from "node:path";
import { Resend } from "resend";
import { config } from "./config.ts";
import { renderNewsletter } from "./render.tsx";

// ─────────────────────────────────────────────────────────────────────────────
// TEST SENDS ONLY. The recipient is the single RESEND_TEST_TO address — there is
// no CLI flag or code path that can send to any other address. This script
// exists so you can preview a newsletter in a real inbox (yours) before the
// actual campaign, which is sent manually from Resend's web editor.
// ─────────────────────────────────────────────────────────────────────────────
const LOCKED_TO = process.env.RESEND_TEST_TO;

// Sandbox sender: Resend only delivers onboarding@resend.dev mail to the email
// on your own Resend account, so this is doubly locked. Override the display
// name only via RESEND_FROM if you later verify your own domain.
const FROM = process.env.RESEND_FROM ?? `${config.brandName} (test) <onboarding@resend.dev>`;

function usage(): never {
  console.error(
    "Usage: bun run send-test <input.md> [subject] [--dry] [--upload-assets]\n" +
      "  Sends a TEST email of <input.md> to the RESEND_TEST_TO address only.\n" +
      "  --dry            render + report without contacting Resend.\n" +
      "  --upload-assets  upload local images to R2 and rewrite their URLs.\n" +
      "  Requires RESEND_API_KEY and RESEND_TEST_TO (e.g. in a .env file).",
  );
  process.exit(1);
}

async function main() {
  const args = process.argv.slice(2);
  const dry = args.includes("--dry");
  const positional = args.filter((a) => !a.startsWith("--"));
  const [inputArg, subjectArg] = positional;
  if (!inputArg) usage();
  if (!LOCKED_TO) {
    console.error(
      "RESEND_TEST_TO is not set. Set it to the recipient of test sends (e.g. in a .env file).",
    );
    process.exit(1);
  }

  const { html, subject: defaultSubject, issue, title } = await renderNewsletter(
    resolve(inputArg),
    { upload: args.includes("--upload-assets") },
  );
  const subject = subjectArg ?? defaultSubject;

  console.log(`Newsletter ${issue}: ${title}`);
  console.log(`  from:    ${FROM}`);
  console.log(`  to:      ${LOCKED_TO}`);
  console.log(`  subject: ${subject}`);
  console.log(`  html:    ${html.length} bytes`);

  if (dry) {
    console.log("\n--dry: not sending.");
    return;
  }

  const apiKey = process.env.RESEND_API_KEY;
  if (!apiKey) {
    console.error(
      "\nRESEND_API_KEY is not set. Add it to a .env file (bun loads it automatically).",
    );
    process.exit(1);
  }

  const resend = new Resend(apiKey);
  const { data, error } = await resend.emails.send({
    from: FROM,
    to: [LOCKED_TO],
    subject,
    html,
  });

  if (error) {
    console.error("\nResend error:", error);
    process.exit(1);
  }
  console.log(`\nSent test email to ${LOCKED_TO} (id: ${data?.id})`);
}

await main();