import NextAuth, { NextAuthOptions, getServerSession } from "next-auth";
import type { Adapter } from "next-auth/adapters";
import AuthentikProvider from "next-auth/providers/authentik";
import serverConfig from "@hoarder/shared/config";
import { db } from "@hoarder/db";
import { DefaultSession } from "next-auth";
import * as bcrypt from "bcrypt";
import CredentialsProvider from "next-auth/providers/credentials";
import { DrizzleAdapter } from "@auth/drizzle-adapter";

import { randomBytes } from "crypto";
import { Provider } from "next-auth/providers/index";
import { apiKeys } from "@hoarder/db/schema";

declare module "next-auth/jwt" {
  export interface JWT {
    user: {
      id: string;
    } & DefaultSession["user"];
  }
}

declare module "next-auth" {
  /**
   * Returned by `useSession`, `getSession` and received as a prop on the `SessionProvider` React Context
   */
  export interface Session {
    user: {
      id: string;
    } & DefaultSession["user"];
  }
}

const providers: Provider[] = [
  CredentialsProvider({
    // The name to display on the sign in form (e.g. "Sign in with...")
    name: "Credentials",
    credentials: {
      email: { label: "Email", type: "email", placeholder: "Email" },
      password: { label: "Password", type: "password" },
    },
    async authorize(credentials) {
      if (!credentials) {
        return null;
      }

      try {
        return await validatePassword(
          credentials?.email,
          credentials?.password,
        );
      } catch (e) {
        return null;
      }
    },
  }),
];

if (serverConfig.auth.authentik) {
  providers.push(AuthentikProvider(serverConfig.auth.authentik));
}

export const authOptions: NextAuthOptions = {
  // https://github.com/nextauthjs/next-auth/issues/9493
  adapter: DrizzleAdapter(db) as Adapter,
  providers: providers,
  session: {
    strategy: "jwt",
  },
  callbacks: {
    async jwt({ token, user }) {
      if (user) {
        token.user = {
          id: user.id,
          name: user.name,
          email: user.email,
          image: user.image,
        };
      }
      return token;
    },
    async session({ session, token }) {
      session.user = { ...token.user };
      return session;
    },
  },
};

export const authHandler = NextAuth(authOptions);

export const getServerAuthSession = () => getServerSession(authOptions);

// API Keys

const BCRYPT_SALT_ROUNDS = 10;
const API_KEY_PREFIX = "ak1";

export async function generateApiKey(name: string, userId: string) {
  const id = randomBytes(10).toString("hex");
  const secret = randomBytes(10).toString("hex");
  const secretHash = await bcrypt.hash(secret, BCRYPT_SALT_ROUNDS);

  const plain = `${API_KEY_PREFIX}_${id}_${secret}`;

  const key = (
    await db
      .insert(apiKeys)
      .values({
        name: name,
        userId: userId,
        keyId: id,
        keyHash: secretHash,
      })
      .returning()
  )[0];

  return {
    id: key.id,
    name: key.name,
    createdAt: key.createdAt,
    key: plain,
  };
}

function parseApiKey(plain: string) {
  const parts = plain.split("_");
  if (parts.length != 3) {
    throw new Error(
      `Malformd API key. API keys should have 3 segments, found ${parts.length} instead.`,
    );
  }
  if (parts[0] !== API_KEY_PREFIX) {
    throw new Error(`Malformd API key. Got unexpected key prefix.`);
  }
  return {
    keyId: parts[1],
    keySecret: parts[2],
  };
}

export async function authenticateApiKey(key: string) {
  const { keyId, keySecret } = parseApiKey(key);
  const apiKey = await db.query.apiKeys.findFirst({
    where: (k, { eq }) => eq(k.keyId, keyId),
    with: {
      user: true,
    },
  });

  if (!apiKey) {
    throw new Error("API key not found");
  }

  const hash = apiKey.keyHash;

  const validation = await bcrypt.compare(keySecret, hash);
  if (!validation) {
    throw new Error("Invalid API Key");
  }

  return apiKey.user;
}

export async function hashPassword(password: string) {
  return bcrypt.hash(password, BCRYPT_SALT_ROUNDS);
}

export async function validatePassword(email: string, password: string) {
  const user = await db.query.users.findFirst({
    where: (u, { eq }) => eq(u.email, email),
  });

  if (!user) {
    throw new Error("User not found");
  }

  if (!user.password) {
    throw new Error("This user doesn't have a password defined");
  }

  const validation = await bcrypt.compare(password, user.password);
  if (!validation) {
    throw new Error("Wrong password");
  }

  return user;
}