import { NextApiRequest, NextApiResponse } from 'next';
import { z } from 'zod';
import ServerError from '@/config/util/ServerError';
import nc, { NextHandler } from 'next-connect';
import createNewUser from '@/services/user/createNewUser';
import CreateUserValidationSchema from '@/services/user/schema/CreateUserValidationSchema';
import NextConnectConfig from '@/config/nextConnect/NextConnectConfig';
import findUserByUsername from '@/services/user/findUserByUsername';
import findUserByEmail from '@/services/user/findUserByEmail';

interface RegisterUserRequest extends NextApiRequest {
  body: z.infer<typeof CreateUserValidationSchema>;
}

const validateRequest =
  ({
    bodySchema,
    querySchema,
  }: {
    bodySchema?: z.ZodSchema<any>;
    querySchema?: z.ZodSchema<any>;
  }) =>
  async (req: NextApiRequest, res: NextApiResponse, next: NextHandler) => {
    if (bodySchema) {
      const parsed = bodySchema.safeParse(req.body);
      if (!parsed.success) {
        throw new ServerError('Invalid request body.', 400);
      }
    }

    if (querySchema) {
      const parsed = querySchema.safeParse(req.query);
      if (!parsed.success) {
        throw new ServerError(parsed.error.message, 400);
      }
      req.query = parsed.data;
    }

    next();
  };

const registerUser = async (req: RegisterUserRequest, res: NextApiResponse) => {
  const [usernameTaken, emailTaken] = await Promise.all([
    findUserByUsername(req.body.username),
    findUserByEmail(req.body.email),
  ]);

  if (usernameTaken) {
    throw new ServerError(
      'Could not register a user with that username as it is already taken.',
      409,
    );
  }

  if (emailTaken) {
    throw new ServerError(
      'Could not register a user with that email as it is already taken.',
      409,
    );
  }

  const user = await createNewUser(req.body);
  res.status(201).json({
    message: 'User created successfully.',
    payload: user,
    statusCode: 201,
    success: true,
  });
};

const handler = nc(NextConnectConfig).post(
  validateRequest({ bodySchema: CreateUserValidationSchema }),
  registerUser,
);

export default handler;