import fs from "node:fs";
import path from "node:path";
import Database from "better-sqlite3";
import { ulid } from "ulid";
import { config } from "./config.js";

export type Db = Database.Database;

/**
 * Open (or create) the SQLite database and bring it up to the latest
 * migration. Migrations are plain `.sql` files in `src/migrations/`, applied
 * in filename order and recorded in `schema_migrations` so each runs once.
 */
export function openDb(dbPath: string = config.dbPath): Db {
  fs.mkdirSync(path.dirname(dbPath), { recursive: true });
  const db = new Database(dbPath);
  db.pragma("journal_mode = WAL");
  db.pragma("foreign_keys = ON");
  migrate(db);
  return db;
}

function migrate(db: Db): void {
  db.exec(`
    CREATE TABLE IF NOT EXISTS schema_migrations (
      name       TEXT PRIMARY KEY,
      applied_at TEXT NOT NULL
    )
  `);

  const applied = new Set(
    (db.prepare("SELECT name FROM schema_migrations").all() as Array<{ name: string }>).map((r) => r.name),
  );

  const dir = path.resolve(import.meta.dirname, "migrations");
  const files = fs
    .readdirSync(dir)
    .filter((f) => f.endsWith(".sql"))
    .sort();

  for (const file of files) {
    if (applied.has(file)) continue;
    const sql = fs.readFileSync(path.join(dir, file), "utf8");
    const apply = db.transaction(() => {
      db.exec(sql);
      db.prepare("INSERT INTO schema_migrations (name, applied_at) VALUES (?, ?)").run(
        file,
        new Date().toISOString(),
      );
    });
    apply();
  }
}

/** Bootstrap the first admin from env on first boot (idempotent). */
export function ensureAdmin(db: Db, hashPassword: (pw: string) => Promise<string>): Promise<void> {
  const email = process.env.PUBSCRIPT_ADMIN_EMAIL;
  const password = process.env.PUBSCRIPT_ADMIN_PASSWORD;
  if (!email || !password) return Promise.resolve();

  const existing = db.prepare("SELECT id FROM users WHERE email = ?").get(email) as { id: string } | undefined;
  if (existing) return Promise.resolve();

  return hashPassword(password).then((passHash) => {
    const id = ulid();
    const now = new Date().toISOString();
    db.prepare(
      "INSERT INTO users (id, email, pass_hash, display_name, role, disabled, created_at) VALUES (?, ?, ?, ?, 'admin', 0, ?)",
    ).run(id, email, passHash, email.split("@")[0] ?? "admin", now);
    db.prepare("INSERT INTO audit (id, at, user_id, action, detail) VALUES (?, ?, ?, 'admin.bootstrap', ?)").run(
      ulid(),
      now,
      id,
      JSON.stringify({ email }),
    );
  });
}