import type { NextAuthOptions } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { prisma } from "@/lib/prisma";
import { compare } from "bcryptjs";
import { z } from "zod";
import { consumeRateLimit, getClientIpFromHeaders } from "@/lib/rate-limit";

const credentialsSchema = z.object({
  email: z.string().email(),
  password: z.string().min(8)
});

function limitLoginAttempt(
  headers: Headers | Record<string, string | string[] | undefined> | undefined,
  email: string
) {
  const ip = getClientIpFromHeaders(headers ?? {});
  const normalizedEmail = email.trim().toLowerCase();
  return consumeRateLimit(
    `auth-login:${ip}:${normalizedEmail}`,
    8,
    10 * 60_000
  );
}

export const authOptions: NextAuthOptions = {
  session: {
    strategy: "jwt",
    maxAge: 2 * 60 * 60 // 2 Stunden
  },
  pages: {
    signIn: "/anmelden"
  },
  providers: [
    CredentialsProvider({
      name: "Anmeldung",
      credentials: {
        email: { label: "E-Mail", type: "email" },
        password: { label: "Passwort", type: "password" }
      },
      async authorize(credentials, req) {
        const parsed = credentialsSchema.safeParse(credentials);
        const rawEmail =
          typeof credentials?.email === "string" ? credentials.email : "unknown";
        const limit = limitLoginAttempt(req?.headers, rawEmail);
        if (!limit.ok) return null;
        if (!parsed.success) return null;

        const user = await prisma.user.findUnique({
          where: { email: parsed.data.email }
        });

        if (!user || !user.isActive || user.role !== "ADMIN") return null;

        const valid = await compare(parsed.data.password, user.hashedPassword);
        if (!valid) return null;

        return {
          id: user.id,
          email: user.email,
          name: user.name,
          role: user.role,
          slug: user.slug
        };
      }
    })
  ],
  callbacks: {
    async jwt({ token, user }) {
      if (user) {
        token.id = user.id;
        token.role = user.role;
        token.slug = user.slug;
      }
      return token;
    },
    async session({ session, token }) {
      if (session.user) {
        session.user.id = token.id;
        session.user.role = token.role;
        session.user.slug = token.slug;
      }
      return session;
    }
  },
  secret: process.env.NEXTAUTH_SECRET
};