import 'server-only'
import { cookies } from 'next/headers'
import { createHash, randomBytes } from 'crypto'
import { prisma } from './prisma'

const COOKIE_NAME = 'ops_session'
const SESSION_TTL_MS = 24 * 60 * 60 * 1000

export function generateSessionToken(): string {
  return randomBytes(32).toString('hex')
}

export function hashToken(token: string): string {
  return createHash('sha256').update(token).digest('hex')
}

export async function createSession(userId: string, token: string): Promise<void> {
  const expiresAt = new Date(Date.now() + SESSION_TTL_MS)
  await prisma.session.create({
    data: {
      user_id: userId,
      token_hash: hashToken(token),
      expires_at: expiresAt,
    },
  })
}

export async function getCurrentUser() {
  const cookieStore = await cookies()
  const token = cookieStore.get(COOKIE_NAME)?.value
  if (!token) return null

  const session = await prisma.session.findUnique({
    where: { token_hash: hashToken(token) },
    include: { user: true },
  })

  if (!session) return null

  if (session.expires_at < new Date()) {
    await prisma.session.delete({ where: { id: session.id } })
    return null
  }

  return session.user
}

export async function invalidateSession(token: string): Promise<void> {
  await prisma.session.deleteMany({
    where: { token_hash: hashToken(token) },
  })
}