const crypto = require("crypto");
const pool = require("../db/pool");
const { SESSION_TTL_DAYS } = require("../utils/session-cookie");

function generateSessionId() {
  if (typeof crypto.randomUUID === "function") {
    return crypto.randomUUID().replace(/-/g, "") + crypto.randomBytes(8).toString("hex");
  }
  return crypto.randomBytes(32).toString("hex");
}

exports.createSession = async (userId, userAgent = null) => {
  const id = generateSessionId();
  const result = await pool.query(
    `INSERT INTO sessions (id, user_id, expires_at, user_agent)
     VALUES ($1, $2, NOW() + ($3 || ' days')::interval, $4)
     RETURNING id, user_id, created_at, expires_at`,
    [id, userId, String(SESSION_TTL_DAYS), userAgent]
  );
  return result.rows[0];
};

exports.getActiveSessionWithUser = async (sessionId) => {
  const result = await pool.query(
    `SELECT
      s.id,
      s.user_id,
      s.expires_at,
      u.username,
      u.role
    FROM sessions s
    JOIN users u ON u.id = s.user_id
    WHERE s.id = $1
      AND s.expires_at > NOW()`,
    [sessionId]
  );

  const session = result.rows[0] || null;
  if (!session) return null;

  await pool.query(
    `UPDATE sessions
     SET last_seen_at = NOW()
     WHERE id = $1`,
    [sessionId]
  );

  return session;
};

exports.deleteSession = async (sessionId) => {
  await pool.query(
    `DELETE FROM sessions WHERE id = $1`,
    [sessionId]
  );
};