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";

/**
 *  导出一个解构导出一个定制化的NextAuth对象，在其他地方引用，结构出来的函数在具体的功能页面发挥作用，
 *  eg： signIn 函数在登陆页面、signOut 函数在推出页面
 */

//{...authConfig} 在 TypeScript 或 JavaScript 中，{ ...authConfig }
//使用了 对象展开语法（spread syntax），它的作用是将一个对象的属性展开（复制）到另一个对象中
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");
        //返回null的话错误信息会抛出到页面，所以调用登陆的地方需要try catch 处理错误信息
        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.");
  }
}