auth.ts

import NextAuth from 'next-auth';
import { authConfig } from './auth.config';
import Credentials from 'next-auth/providers/credentials';
import { z } from 'zod';
import { sql } from '@vercel/postgres';
import type { User } from '@/app/lib/definitions';
import bcrypt from 'bcrypt';

// Credentials provider allows users to log in with a username and password.

// providers is an array where you list different login options such as Google or Github. 

// use zod to validate the email and password before checking if the user exists in the database

// use bcrypt to compare the password from the database with the password provided by the user.

// return the user if the passwords match, otherwise return null.


async function getUser(email: string): Promise<User | undefined> {
    try {
        const user = await sql<User>`SELECT * FROM users WHERE email = ${email}`;
        return user.rows[0];
    } catch (error) {
        console.error('Failed to fetch user', error);
        throw new Error('Failed to fetch user');
    }
}



export const { auth, signIn, signOut } = NextAuth({...authConfig, providers: [
    Credentials({
        async authorize(credentials) {
            const parsedCredentials = z
              .object({ email: z.string().email(), password: z.string().min(6) })
              .safeParse(credentials);

              if (parsedCredentials.success) {
                const { email, password } = parsedCredentials.data;
                const user = await getUser(email);
                if (!user) return null;
                const passwordsMatch = await bcrypt.compare(password, user.password);

                if (passwordsMatch) return user;
              }

              console.log('invalid credentials');
              return null;


          },
        })
    ],
});