// Migration: copy pre-registrations from babyghosts → ghostguild
//
// Usage (from ghostguild-org root):
//   BG_MONGODB_URI="<babyghosts uri>" node server/migrations/import-babyghosts-preregistrations.js
//
// The ghostguild URI is read from NUXT_MONGODB_URI or MONGODB_URI in your .env.
// Set DRY_RUN=1 to preview without writing anything.

import { MongoClient } from "mongodb";
import { config } from "dotenv";
import { resolve, dirname } from "path";
import { fileURLToPath } from "url";

const __dirname = dirname(fileURLToPath(import.meta.url));
config({ path: resolve(__dirname, "../../.env") });

const BG_URI = process.env.BG_MONGODB_URI;
const GG_URI = process.env.NUXT_MONGODB_URI || process.env.MONGODB_URI;
const DRY_RUN = process.env.DRY_RUN === "1";

if (!BG_URI) {
  console.error("ERROR: BG_MONGODB_URI is not set.");
  process.exit(1);
}
if (!GG_URI) {
  console.error(
    "ERROR: No ghostguild MongoDB URI found (NUXT_MONGODB_URI or MONGODB_URI).",
  );
  process.exit(1);
}

async function run() {
  console.log("=== Importing babyghosts pre-registrations into ghostguild ===");
  if (DRY_RUN) console.log("DRY RUN – nothing will be written.\n");

  const bgClient = new MongoClient(BG_URI);
  const ggClient = new MongoClient(GG_URI);

  await bgClient.connect();
  await ggClient.connect();

  try {
    const source = bgClient.db("babyghosts").collection("guild_waitlist");
    const dest = ggClient.db().collection("preregistrations");

    const records = await source.find({}).toArray();
    console.log(
      `Found ${records.length} record(s) in babyghosts.guild_waitlist.\n`,
    );

    if (records.length === 0) {
      console.log("Nothing to import.");
      return;
    }

    let inserted = 0;
    let skipped = 0;
    let errors = 0;

    for (const doc of records) {
      const email = doc.email?.trim().toLowerCase();

      if (!email) {
        console.warn(`  SKIP – record ${doc._id} has no email.`);
        skipped++;
        continue;
      }

      if (DRY_RUN) {
        console.log(`  [dry-run] ${email}`);
        inserted++;
        continue;
      }

      try {
        const result = await dest.updateOne(
          { email },
          { $setOnInsert: doc },
          { upsert: true },
        );

        if (result.upsertedCount > 0) {
          console.log(`  INSERT  ${email}`);
          inserted++;
        } else {
          console.log(`  EXISTS  ${email} (skipped)`);
          skipped++;
        }
      } catch (err) {
        console.error(`  ERROR   ${email}: ${err.message}`);
        errors++;
      }
    }

    console.log("\n=== Summary ===");
    console.log(`  Inserted : ${inserted}`);
    console.log(`  Skipped  : ${skipped}`);
    console.log(`  Errors   : ${errors}`);
  } finally {
    await bgClient.close();
    await ggClient.close();
    console.log("\nDone.");
  }
}

run().catch((err) => {
  console.error("Unexpected error:", err);
  process.exit(1);
});