import Database from 'better-sqlite3';
import fs from 'node:fs';
import path from 'node:path';

const dataDir = path.resolve(process.cwd(), '.data');
fs.mkdirSync(dataDir, { recursive: true });

const dbPath = path.join(dataDir, 'scriptflow.db');
export const db = new Database(dbPath);

db.pragma('journal_mode = WAL');

db.exec(`
  CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    username TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    password_salt TEXT NOT NULL,
    created_at TEXT NOT NULL DEFAULT (datetime('now'))
  );

  CREATE TABLE IF NOT EXISTS sessions (
    token TEXT PRIMARY KEY,
    user_id INTEGER NOT NULL,
    created_at TEXT NOT NULL DEFAULT (datetime('now')),
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
  );

  CREATE TABLE IF NOT EXISTS drafts (
    user_id INTEGER PRIMARY KEY,
    payload TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
  );
`);

export type UserRow = {
  id: number;
  username: string;
  password_hash: string;
  password_salt: string;
};

export function findUserByUsername(username: string) {
  return db.prepare('SELECT * FROM users WHERE username = ?').get(username) as UserRow | undefined;
}

export function findUserById(id: number) {
  return db.prepare('SELECT * FROM users WHERE id = ?').get(id) as UserRow | undefined;
}

export function createUser(username: string, passwordHash: string, passwordSalt: string) {
  const result = db
    .prepare('INSERT INTO users (username, password_hash, password_salt) VALUES (?, ?, ?)')
    .run(username, passwordHash, passwordSalt);
  return findUserById(Number(result.lastInsertRowid));
}

export function createSession(token: string, userId: number) {
  db.prepare('INSERT INTO sessions (token, user_id) VALUES (?, ?)').run(token, userId);
}

export function findUserBySessionToken(token: string) {
  return db
    .prepare(`
      SELECT users.*
      FROM sessions
      INNER JOIN users ON users.id = sessions.user_id
      WHERE sessions.token = ?
    `)
    .get(token) as UserRow | undefined;
}

export function deleteSession(token: string) {
  db.prepare('DELETE FROM sessions WHERE token = ?').run(token);
}

export function getDraftForUser(userId: number) {
  const row = db.prepare('SELECT payload, updated_at FROM drafts WHERE user_id = ?').get(userId) as { payload: string; updated_at: string } | undefined;
  if (!row) return null;
  return {
    payload: JSON.parse(row.payload),
    updatedAt: row.updated_at,
  };
}

export function saveDraftForUser(userId: number, payload: unknown) {
  const serialized = JSON.stringify(payload);
  const updatedAt = new Date().toISOString();
  db
    .prepare(`
      INSERT INTO drafts (user_id, payload, updated_at)
      VALUES (?, ?, ?)
      ON CONFLICT(user_id) DO UPDATE SET payload = excluded.payload, updated_at = excluded.updated_at
    `)
    .run(userId, serialized, updatedAt);

  return {
    payload,
    updatedAt,
  };
}