require("dotenv/config");

const fs = require("node:fs");
const crypto = require("node:crypto");
const path = require("node:path");
const mysql = require("mysql2/promise");

const JOURNAL = {
  "0000_aberrant_cobalt_man": 1766460456274,
  "0001_flawless_texas_twister": 1767004087964,
  "0002_equal_wolfpack": 1767145757594,
};

function sha256Hex(input) {
  return crypto.createHash("sha256").update(input).digest("hex");
}

async function main() {
  const url = process.env.DATABASE_URL;
  if (!url) {
    throw new Error("DATABASE_URL is not set");
  }

  const conn = await mysql.createConnection(url);

  await conn.query(
    "CREATE TABLE IF NOT EXISTS `__drizzle_migrations` (id serial primary key, hash text not null, created_at bigint)"
  );

  const [existing] = await conn.query(
    "SELECT id, hash, created_at FROM `__drizzle_migrations` ORDER BY created_at DESC LIMIT 1"
  );
  if (Array.isArray(existing) && existing.length > 0) {
    console.log("✅ __drizzle_migrations already has entries. Skip baselining.");
    await conn.end();
    return;
  }

  const [[accountsRow]] = await conn.query(
    "SELECT COUNT(*) AS cnt FROM information_schema.tables WHERE table_schema=DATABASE() AND table_name='accounts'"
  );
  const accountsExists = Number(accountsRow?.cnt ?? 0) > 0;
  if (!accountsExists) {
    console.log("ℹ️ No existing tables detected (accounts missing). Skip baselining.");
    await conn.end();
    return;
  }

  const [[structureRow]] = await conn.query(
    "SELECT COUNT(*) AS cnt FROM information_schema.columns WHERE table_schema=DATABASE() AND table_name='exams' AND column_name='structure'"
  );
  const examsStructureExists = Number(structureRow?.cnt ?? 0) > 0;

  const [[homeworkRow]] = await conn.query(
    "SELECT COUNT(*) AS cnt FROM information_schema.tables WHERE table_schema=DATABASE() AND table_name='homework_assignments'"
  );
  const homeworkExists = Number(homeworkRow?.cnt ?? 0) > 0;

  const baselineTags = [];
  baselineTags.push("0000_aberrant_cobalt_man");
  if (examsStructureExists) baselineTags.push("0001_flawless_texas_twister");
  if (homeworkExists) baselineTags.push("0002_equal_wolfpack");

  const drizzleDir = path.resolve(__dirname, "..", "..", "drizzle");
  for (const tag of baselineTags) {
    const sqlPath = path.join(drizzleDir, `${tag}.sql`);
    if (!fs.existsSync(sqlPath)) {
      throw new Error(`Missing migration file: ${sqlPath}`);
    }
    const sqlText = fs.readFileSync(sqlPath).toString();
    const hash = sha256Hex(sqlText);
    const createdAt = JOURNAL[tag];
    if (typeof createdAt !== "number") {
      throw new Error(`Missing journal timestamp for: ${tag}`);
    }
    await conn.query(
      "INSERT INTO `__drizzle_migrations` (`hash`, `created_at`) VALUES (?, ?)",
      [hash, createdAt]
    );
  }

  console.log(`✅ Baselined __drizzle_migrations: ${baselineTags.join(", ")}`);
  await conn.end();
}

main().catch((err) => {
  console.error("❌ Baseline failed:", err);
  process.exit(1);
});