This will cover more aspects of the setup and include additional features. Let's create a new, more comprehensive artifact with this information.
Detailed NextAuth.js Setup with Next.js App Router and PrismaClick to open code
Now, let's go through this detailed setup:

Environment Variables (.env.local):

NEXTAUTH_URL: The canonical URL of your site.
NEXTAUTH_SECRET: A random string used to hash tokens, sign cookies and generate cryptographic keys.
DATABASE_URL: Your database connection string.
Provider-specific variables (e.g., GITHUB_ID, GITHUB_SECRET for GitHub OAuth).
Email provider configuration.


Prisma Schema (prisma/schema.prisma):

Defines the data models for User, Account, Session, and VerificationToken.
These models are required for NextAuth.js to work with Prisma.


Auth Configuration (lib/auth.ts):

Uses PrismaAdapter for database integration.
Configures multiple providers: GitHub, Email, and Credentials.
Sets up session handling with JWT strategy.
Defines custom pages for authentication flows.
Implements callbacks for session and JWT handling.
Sets up event handlers for sign-in and sign-out.


NextAuth API Route (app/api/auth/[...nextauth]/route.ts):

Creates the necessary API routes for NextAuth.js.


Sign-In Page (app/auth/signin/page.tsx):

A custom sign-in page that allows users to choose between different authentication methods.


Middleware (middleware.ts):

Protects specific routes (in this case, /dashboard and its subpaths).
Can be extended to include more complex authorization logic.


Root Layout (app/layout.tsx):

Wraps the application with SessionProvider for global auth state management.
Uses the auth() function to get the session server-side.


Utility Functions (lib/utils.ts):

Includes helper functions like cn for merging Tailwind CSS classes.


Example Component (components/Button.tsx):

Demonstrates how to use utility functions in components.



This setup provides a comprehensive authentication solution with:

Multiple authentication providers (OAuth, Email, Credentials)
Database integration with Prisma
Custom pages for authentication flows
Protected routes with middleware
Server-side session handling
Utility functions for styling and component development

To use this setup:

Install dependencies: next-auth, @prisma/client, @next-auth/prisma-adapter, bcrypt, clsx, tailwind-merge.
Set up your Prisma schema and generate the Prisma client.
Configure your environment variables.
Implement additional custom logic as needed (e.g., user registration, profile management).

This setup gives you a solid foundation for authentication in a Next.js application with the App Router, using Prisma as the ORM. You can extend it further by adding more providers, implementing additional security features, or customizing the authentication flow to fit your specific needs.
Would you like me to elaborate on any specific part of this implementation or explain how to implement any additional features?

// File: .env.local
NEXTAUTH_URL=http://localhost:3000
NEXTAUTH_SECRET= # Linux: `openssl rand -hex 32` or go to https://generate-secret.now.sh/32

DATABASE_URL="postgresql://johndoe:randompassword@localhost:5432/mydb?schema=public"

# Example for GitHub OAuth
GITHUB_ID=
GITHUB_SECRET=

# Example for Email provider
EMAIL_SERVER=smtp://username:<PRESIDIO_ANONYMIZED_EMAIL_ADDRESS>:587
EMAIL_FROM=noreply@example.com

// File: prisma/schema.prisma
generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model Account {
  id                 String  @id @default(cuid())
  userId             String
  type               String
  provider           String
  providerAccountId  String
  refresh_token      String?  @db.Text
  access_token       String?  @db.Text
  expires_at         Int?
  token_type         String?
  scope              String?
  id_token           String?  @db.Text
  session_state      String?

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@unique([provider, providerAccountId])
}

model Session {
  id           String   @id @default(cuid())
  sessionToken String   @unique
  userId       String
  expires      DateTime
  user         User     @relation(fields: [userId], references: [id], onDelete: Cascade)
}

model User {
  id            String    @id @default(cuid())
  name          String?
  email         String?   @unique
  emailVerified DateTime?
  image         String?
  password      String?
  accounts      Account[]
  sessions      Session[]
}

model VerificationToken {
  identifier String
  token      String   @unique
  expires    DateTime

  @@unique([identifier, token])
}

// File: lib/auth.ts
import { NextAuthOptions } from "next-auth"
import { PrismaAdapter } from "@next-auth/prisma-adapter"
import GitHubProvider from "next-auth/providers/github"
import EmailProvider from "next-auth/providers/email"
import CredentialsProvider from "next-auth/providers/credentials"
import bcrypt from "bcrypt"
import { prisma } from "./prisma"

export const authOptions: NextAuthOptions = {
  adapter: PrismaAdapter(prisma),
  providers: [
    GitHubProvider({
      clientId: process.env.GITHUB_ID!,
      clientSecret: process.env.GITHUB_SECRET!,
    }),
    EmailProvider({
      server: process.env.EMAIL_SERVER,
      from: process.env.EMAIL_FROM,
    }),
    CredentialsProvider({
      name: "Credentials",
      credentials: {
        email: { label: "Email", type: "text" },
        password: { label: "Password", type: "password" }
      },
      async authorize(credentials) {
        if (!credentials?.email || !credentials?.password) {
          return null
        }
        const user = await prisma.user.findUnique({
          where: {
            email: credentials.email
          }
        })
        if (!user || !user.password) {
          return null
        }
        const isPasswordValid = await bcrypt.compare(
          credentials.password,
          user.password
        )
        if (!isPasswordValid) {
          return null
        }
        return {
          id: user.id,
          email: user.email,
          name: user.name,
        }
      }
    })
  ],
  session: {
    strategy: "jwt"
  },
  pages: {
    signIn: '/auth/signin',
    signOut: '/auth/signout',
    error: '/auth/error',
    verifyRequest: '/auth/verify-request',
    newUser: '/auth/new-user'
  },
  callbacks: {
    async session({ session, token }) {
      if (session.user) {
        session.user.id = token.sub!
      }
      return session
    },
    async jwt({ token, user, account }) {
      if (user) {
        token.sub = user.id
      }
      if (account) {
        token.accessToken = account.access_token
      }
      return token
    },
  },
  events: {
    async signIn({ user, account, profile, isNewUser }) {
      // Your custom sign-in logic here
    },
    async signOut({ session, token }) {
      // Your custom sign-out logic here
    },
  },
  debug: process.env.NODE_ENV === 'development',
}

// File: app/api/auth/[...nextauth]/route.ts
import NextAuth from "next-auth"
import { authOptions } from "@/lib/auth"

const handler = NextAuth(authOptions)

export { handler as GET, handler as POST }

// File: app/auth/signin/page.tsx
'use client'

import { signIn } from "next-auth/react"
import { useSearchParams } from "next/navigation"

export default function SignIn() {
  const searchParams = useSearchParams()
  const callbackUrl = searchParams.get("callbackUrl") || "/dashboard"

  return (
    <div>
      <button onClick={() => signIn("github", { callbackUrl })}>
        Sign in with GitHub
      </button>
      <button onClick={() => signIn("email", { callbackUrl })}>
        Sign in with Email
      </button>
      {/* Add your custom sign-in form for credentials here */}
    </div>
  )
}

// File: middleware.ts
import { withAuth } from "next-auth/middleware"

export default withAuth(
  function middleware(req) {
    // Your custom middleware logic here
  },
  {
    callbacks: {
      authorized: ({ token }) => !!token,
    },
  }
)

export const config = { matcher: ["/dashboard/:path*"] }

// File: app/layout.tsx
import { SessionProvider } from "next-auth/react"
import { auth } from "@/lib/auth"

export default async function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  const session = await auth()
  return (
    <html lang="en">
      <body>
        <SessionProvider session={session}>{children}</SessionProvider>
      </body>
    </html>
  )
}

// File: lib/utils.ts
import { type ClassValue, clsx } from "clsx"
import { twMerge } from "tailwind-merge"

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}

// Example usage of utils in a component
// File: components/Button.tsx
import { cn } from "@/lib/utils"

export function Button({ className, ...props }) {
  return (
    <button
      className={cn(
        "px-4 py-2 bg-blue-500 text-white rounded hover:bg-blue-600",
        className
      )}
      {...props}
    />
  )
}

To implement Auth.js (NextAuth) with Credentials provider, Next.js App Router, and Prisma, you'll need to set up several files and configurations. Here's an overview of the implementation:

Install necessary packages:
First, you need to install the required packages, including next-auth, @prisma/client, and @auth/prisma-adapter.

Set up Prisma:
Create a schema.prisma file to define your database schema, including user and session models. Run Prisma migrations to set up your database.

Create auth configuration:
Create an auth.ts file in the root of your project:

typescript
import NextAuth from "next-auth"
import Credentials from "next-auth/providers/credentials"
import { PrismaAdapter } from "@auth/prisma-adapter"
import { PrismaClient } from "@prisma/client"

const prisma = new PrismaClient()

export const { handlers, auth, signIn, signOut } = NextAuth({
  adapter: PrismaAdapter(prisma),
  providers: [
    Credentials({
      credentials: {
        username: { label: "Username" },
        password: { label: "Password", type: "password" },
      },
      async authorize({ request }) {
        const response = await fetch(request)
        if (!response.ok) return null
        return (await response.json()) ?? null
      },
    }),
  ],
})
12

Set up API route:
Create a file app/api/auth/[...nextauth]/route.ts:

typescript
import { handlers } from "@/auth"
export const { GET, POST } = handlers
3

Protect routes:
To protect routes, you can use the auth() function in your server components:

typescript
import { auth } from "@/auth"

export default async function ProtectedPage() {
  const session = await auth()
  if (!session) {
    return <div>Not authenticated</div>
  }
  return <div>Protected content</div>
}
32

Client-side authentication:
For client-side authentication, you can use the useSession hook from next-auth/react.

Custom sign-in page:
Create a custom sign-in page if needed, using the signIn function from next-auth/react.

Remember to set up your environment variables, including NEXTAUTH_SECRET and database connection strings.

This is a basic implementation. You may need to adjust it based on your specific requirements, such as custom user models or additional authentication logic.

For the most up-to-date and detailed information, please refer to the official Auth.js documentation.

Certainly! I'll provide the full code for all the relevant files, including the complete implementation of the Interaction model, ensuring everything is integrated and functional. This includes:

The Prisma schema.
Database migrations.
Utility functions for logging interactions and updating quest progress.
Modified pages and components where interactions are logged.
The updated recommendation logic that utilizes interactions.
Any additional files necessary for the application to run smoothly.
Let's proceed step by step.

1. Prisma Schema Updates
First, ensure your prisma/schema.prisma file includes the Interaction model:


// prisma/schema.prisma

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

generator client {
  provider = "prisma-client-js"
}

model User {
  id          Int          @id @default(autoincrement())
  name        String?
  email       String       @unique
  password    String
  tokens      Int          @default(0)
  preferences Preferences?
  quests      QuestProgress[]
  investments Investment[]
  interactions Interaction[]
}

model Preferences {
  id                   Int      @id @default(autoincrement())
  preferredStyles      String[]
  sustainabilityValues String[]
  user                 User     @relation(fields: [userId], references: [id])
  userId               Int      @unique
}

model Product {
  id                   Int      @id @default(autoincrement())
  name                 String
  description          String
  price                Float
  styles               String[]
  sustainabilityRating Int
  interactions         Interaction[]
}

model Quest {
  id          Int             @id @default(autoincrement())
  name        String
  description String
  reward      Int
  action      String
  goal        Int
  questProgress QuestProgress[]
}

model QuestProgress {
  id          Int      @id @default(autoincrement())
  progress    Int      @default(0)
  isCompleted Boolean  @default(false)
  quest       Quest    @relation(fields: [questId], references: [id])
  questId     Int
  user        User     @relation(fields: [userId], references: [id])
  userId      Int
}

model Investment {
  id              Int       @id @default(autoincrement())
  projectName     String
  amount          Int
  expectedReturn  Int
  investedAt      DateTime  @default(now())
  maturityDate    DateTime
  isMatured       Boolean   @default(false)
  user            User      @relation(fields: [userId], references: [id])
  userId          Int
}

model Interaction {
  id         Int        @id @default(autoincrement())
  action     String
  createdAt  DateTime   @default(now())
  product    Product    @relation(fields: [productId], references: [id])
  productId  Int
  user       User       @relation(fields: [userId], references: [id])
  userId     Int

  @@index([userId])
  @@index([productId])
}
Run Database Migration
After updating the schema, run the migration:


npx prisma migrate dev --name add_interactions_model
2. Seed Data with Quests
Update prisma/seed.ts to include quests that will be connected to interactions.


// prisma/seed.ts

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function main() {
  // Seed products
  const products = [
    {
      name: 'Eco-Friendly T-Shirt',
      description: 'Organic cotton t-shirt',
      price: 25.99,
      styles: ['Casual'],
      sustainabilityRating: 5,
    },
    {
      name: 'Recycled Jeans',
      description: 'Jeans made from recycled materials',
      price: 49.99,
      styles: ['Casual', 'Vintage'],
      sustainabilityRating: 4,
    },
    // Add more products as needed
  ];

  for (const product of products) {
    await prisma.product.create({ data: product });
  }

  // Seed quests
  const quests = [
    {
      name: 'First View',
      description: 'View a product for the first time',
      reward: 10,
      action: 'view',
      goal: 1,
    },
    {
      name: 'Shopping Spree',
      description: 'Add 5 products to your cart',
      reward: 20,
      action: 'add_to_cart',
      goal: 5,
    },
    {
      name: 'First Purchase',
      description: 'Make your first purchase',
      reward: 50,
      action: 'purchase',
      goal: 1,
    },
    // Add more quests as needed
  ];

  for (const quest of quests) {
    await prisma.quest.create({ data: quest });
  }
}

main()
  .catch((e) => console.error(e))
  .finally(() => prisma.$disconnect());
Run the seed script:


npx prisma db seed
3. Interaction Service
Create a directory lib at the root of your project if it doesn't exist, and add the file lib/interactionService.ts.


// lib/interactionService.ts

import { prisma } from '@/lib/prisma';

export enum InteractionAction {
  VIEW = 'view',
  ADD_TO_CART = 'add_to_cart',
  PURCHASE = 'purchase',
  RATE = 'rate',
}

export async function logInteraction(
  userId: number,
  productId: number,
  action: InteractionAction
) {
  await prisma.interaction.create({
    data: {
      action,
      user: { connect: { id: userId } },
      product: { connect: { id: productId } },
    },
  });
}
4. Quest Manager
Create lib/questManager.ts to update quest progress based on interactions.


// lib/questManager.ts

import { prisma } from '@/lib/prisma';
import { InteractionAction } from '@/lib/interactionService';

export async function updateQuestProgress(
  userId: number,
  action: InteractionAction
) {
  const activeQuests = await prisma.questProgress.findMany({
    where: {
      userId,
      isCompleted: false,
      quest: { action },
    },
    include: { quest: true },
  });

  for (const questProgress of activeQuests) {
    const newProgress = questProgress.progress + 1;
    const isCompleted = newProgress >= questProgress.quest.goal;

    await prisma.questProgress.update({
      where: { id: questProgress.id },
      data: {
        progress: newProgress,
        isCompleted,
      },
    });

    if (isCompleted) {
      // Reward tokens
      await prisma.user.update({
        where: { id: userId },
        data: { tokens: { increment: questProgress.quest.reward } },
      });

      // Optionally, send a notification to the user
      console.log(
        `User ${userId} completed quest '${questProgress.quest.name}' and earned ${questProgress.quest.reward} tokens!`
      );
    }
  }
}
5. Updated API Routes
5.1 Sign-Up Route
Modify app/api/auth/signup/route.ts to start all quests for a new user.


// app/api/auth/signup/route.ts

import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';

export async function POST(request: Request) {
  const { email, password } = await request.json();

  const existingUser = await prisma.user.findUnique({
    where: { email },
  });

  if (existingUser) {
    return NextResponse.json({ error: 'User already exists' }, { status: 400 });
  }

  const user = await prisma.user.create({
    data: {
      email,
      password,
    },
  });

  // Start all quests for the new user
  const quests = await prisma.quest.findMany();

  for (const quest of quests) {
    await prisma.questProgress.create({
      data: {
        userId: user.id,
        questId: quest.id,
      },
    });
  }

  return NextResponse.json({ userId: user.id }, { status: 201 });
}
5.2 User Preferences Routes
Create Preferences
Create app/api/user/preferences/route.ts:


// app/api/user/preferences/route.ts

import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';

export async function POST(request: Request) {
  const { userId, preferredStyles } = await request.json();

  await prisma.preferences.create({
    data: {
      userId: parseInt(userId),
      preferredStyles,
      sustainabilityValues: [],
    },
  });

  return NextResponse.json({ success: true });
}
Update Preferences
Create app/api/user/preferences/[id]/route.ts:


// app/api/user/preferences/[id]/route.ts

import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';

interface Params {
  params: {
    id: string;
  };
}

export async function PUT(request: Request, { params }: Params) {
  const { sustainabilityValues } = await request.json();

  await prisma.preferences.update({
    where: { userId: parseInt(params.id) },
    data: { sustainabilityValues },
  });

  return NextResponse.json({ success: true });
}
5.3 Tokens API Route
Create app/api/user/tokens/route.ts:


// app/api/user/tokens/route.ts

import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';

export async function POST(request: Request) {
  const { userId, amount } = await request.json();

  await prisma.user.update({
    where: { id: parseInt(userId) },
    data: { tokens: { increment: amount } },
  });

  return NextResponse.json({ success: true });
}
5.4 Get Tokens API Route
Create app/api/user/[id]/tokens/route.ts:


// app/api/user/[id]/tokens/route.ts

import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';

interface Params {
  params: {
    id: string;
  };
}

export async function GET(request: Request, { params }: Params) {
  const user = await prisma.user.findUnique({
    where: { id: parseInt(params.id) },
    select: { tokens: true },
  });

  return NextResponse.json({ tokens: user?.tokens || 0 });
}
6. Modify Components and Pages to Log Interactions
6.1 Product Details Page
Modify app/products/[id]/page.tsx:


// app/products/[id]/page.tsx

import { prisma } from '@/lib/prisma';
import { notFound } from 'next/navigation';
import { Product } from '@prisma/client';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { logInteraction, InteractionAction } from '@/lib/interactionService';
import { updateQuestProgress } from '@/lib/questManager';

interface Params {
  params: {
    id: string;
  };
}

export default async function ProductDetailsPage({ params }: Params) {
  const product: Product | null = await prisma.product.findUnique({
    where: { id: parseInt(params.id) },
  });

  if (!product) {
    return notFound();
  }

  // Get the session to identify the user
  const session = await getServerSession(authOptions);

  if (session) {
    const userId = parseInt(session.user.id);

    // Log the interaction
    await logInteraction(userId, product.id, InteractionAction.VIEW);

    // Update quest progress
    await updateQuestProgress(userId, InteractionAction.VIEW);
  }

  return (
    <div className="max-w-3xl mx-auto mt-8">
      <h1 className="text-3xl font-bold">{product.name}</h1>
      <p className="mt-4">{product.description}</p>
      <p className="mt-2 font-bold text-xl">Price: ${product.price.toFixed(2)}</p>
    </div>
  );
}
6.2 Product Card Component
Modify components/ProductCard.tsx:


// components/ProductCard.tsx

'use client';

import { Product } from '@prisma/client';
import { useCartStore } from '@/store/useCartStore';
import Link from 'next/link';
import { useSession } from 'next-auth/react';
import { logInteraction, InteractionAction } from '@/lib/interactionService';
import { updateQuestProgress } from '@/lib/questManager';

interface ProductCardProps {
  product: Product;
}

export default function ProductCard({ product }: ProductCardProps) {
  const addToCart = useCartStore((state) => state.addItem);
  const { data: session } = useSession();

  const handleAddToCart = async () => {
    addToCart(product);

    if (session) {
      const userId = parseInt(session.user.id);
      // Log interaction
      await logInteraction(userId, product.id, InteractionAction.ADD_TO_CART);

      // Update quest progress
      await updateQuestProgress(userId, InteractionAction.ADD_TO_CART);
    } else {
      alert('Please sign in to add items to your cart.');
    }
  };

  return (
    <div className="border p-4">
      <h2 className="text-xl font-semibold">{product.name}</h2>
      <p className="mt-2">{product.description}</p>
      <p className="mt-1 font-bold">Price: ${product.price.toFixed(2)}</p>
      <div className="mt-4">
        <button
          onClick={handleAddToCart}
          className="bg-blue-500 text-white px-4 py-2 mr-2"
        >
          Add to Cart
        </button>
        <Link href={`/products/${product.id}`} className="text-blue-500">
          View Details
        </Link>
      </div>
    </div>
  );
}
6.3 Cart Page
Modify app/cart/page.tsx:


// app/cart/page.tsx

'use client';

import { useCartStore } from '@/store/useCartStore';
import { useRouter } from 'next/navigation';
import { useSession } from 'next-auth/react';
import { logInteraction, InteractionAction } from '@/lib/interactionService';
import { updateQuestProgress } from '@/lib/questManager';

export default function CartPage() {
  const { items, removeItem, clearCart } = useCartStore();
  const router = useRouter();
  const { data: session } = useSession();

  const totalPrice = items.reduce(
    (total, item) => total + item.product.price * item.quantity,
    0
  );

  const handleCheckout = async () => {
    if (session) {
      const userId = parseInt(session.user.id);

      // Log purchase interactions for each product
      for (const item of items) {
        await logInteraction(userId, item.product.id, InteractionAction.PURCHASE);

        // Update quest progress
        await updateQuestProgress(userId, InteractionAction.PURCHASE);
      }

      alert('Payment Successful! Thank you for your purchase.');

      clearCart();
      router.push('/products');
    } else {
      alert('Please sign in to complete your purchase.');
      router.push('/auth/signin');
    }
  };

  return (
    <div className="max-w-3xl mx-auto mt-8">
      <h1 className="text-3xl font-bold">Your Cart</h1>
      {items.length === 0 ? (
        <p className="mt-4">Your cart is empty.</p>
      ) : (
        <>
          <table className="w-full mt-4">
            <thead>
              <tr>
                <th className="text-left">Product</th>
                <th className="text-left">Price</th>
                <th className="text-left">Quantity</th>
                <th className="text-left">Total</th>
                <th></th>
              </tr>
            </thead>
            <tbody>
              {items.map(({ product, quantity }) => (
                <tr key={product.id}>
                  <td>{product.name}</td>
                  <td>${product.price.toFixed(2)}</td>
                  <td>{quantity}</td>
                  <td>${(product.price * quantity).toFixed(2)}</td>
                  <td>
                    <button
                      onClick={() => removeItem(product.id)}
                      className="text-red-500"
                    >
                      Remove
                    </button>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
          <p className="mt-4 text-xl font-bold">Total: ${totalPrice.toFixed(2)}</p>
          <button
            onClick={handleCheckout}
            className="mt-4 bg-green-500 text-white px-4 py-2"
          >
            Proceed to Payment
          </button>
        </>
      )}
    </div>
  );
}
7. Update Recommendation Logic
Modify app/products/page.tsx to utilize interaction data:


// app/products/page.tsx

import { prisma } from '@/lib/prisma';
import { getServerSession } from 'next-auth';
import { authOptions } from '../api/auth/[...nextauth]/route';
import ProductCard from '@/components/ProductCard';
import { Product } from '@prisma/client';

export default async function ProductsPage() {
  const session = await getServerSession(authOptions);
  let products: Product[];

  if (session) {
    const userId = parseInt(session.user.id);

    const preferences = await prisma.preferences.findUnique({
      where: { userId },
    });

    // Fetch products that match user preferences
    const preferredProducts = await prisma.product.findMany({
      where: {
        AND: [
          {
            styles: {
              hasSome: preferences?.preferredStyles || [],
            },
          },
          {
            sustainabilityRating: {
              gte: 3, // Example threshold
            },
          },
        ],
      },
    });

    // Exclude products the user has already interacted with
    const interactedProductIds = await prisma.interaction.findMany({
      where: { userId },
      select: { productId: true },
    });

    const excludedIds = interactedProductIds.map((interaction) => interaction.productId);

    products = preferredProducts.filter((product) => !excludedIds.includes(product.id));

    // If no products remain after filtering, show default products
    if (products.length === 0) {
      products = await prisma.product.findMany();
    }
  } else {
    products = await prisma.product.findMany();
  }

  return (
    <div className="max-w-5xl mx-auto">
      <h1 className="text-3xl font-bold mt-8">Recommended Products</h1>
      <div className="grid grid-cols-1 md:grid-cols-3 gap-4 mt-4">
        {products.map((product) => (
          <ProductCard key={product.id} product={product} />
        ))}
      </div>
    </div>
  );
}
8. Other Necessary Files
8.1 Navbar Component
To display the user's token balance, create components/Navbar.tsx:


// components/Navbar.tsx

'use client';

import Link from 'next/link';
import { useSession, signOut } from 'next-auth/react';
import { useEffect, useState } from 'react';
import axios from 'axios';

export default function Navbar() {
  const { data: session } = useSession();
  const [tokens, setTokens] = useState<number>(0);

  useEffect(() => {
    const fetchTokens = async () => {
      if (session) {
        const response = await axios.get(`/api/user/${session.user.id}/tokens`);
        setTokens(response.data.tokens);
      }
    };
    fetchTokens();
  }, [session]);

  return (
    <nav className="flex items-center justify-between p-4 bg-gray-100">
      <Link href="/">
        <span className="text-xl font-bold cursor-pointer">Sustainable Fashion</span>
      </Link>
      <div>
        {session ? (
          <div className="flex items-center">
            <span className="mr-4">Tokens: {tokens}</span>
            <Link href="/profile" className="mr-4">
              Profile
            </Link>
            <Link href="/cart" className="mr-4">
              Cart
            </Link>
            <button
              onClick={() => signOut({ callbackUrl: '/auth/signin' })}
              className="text-red-500"
            >
              Sign Out
            </button>
          </div>
        ) : (
          <Link href="/auth/signin">Sign In</Link>
        )}
      </div>
    </nav>
  );
}
8.2 Cart Store
Create store/useCartStore.ts:


// store/useCartStore.ts

import create from 'zustand';
import { Product } from '@prisma/client';

interface CartItem {
  product: Product;
  quantity: number;
}

interface CartState {
  items: CartItem[];
  addItem: (product: Product) => void;
  removeItem: (productId: number) => void;
  clearCart: () => void;
}

export const useCartStore = create<CartState>((set) => ({
  items: [],
  addItem: (product) =>
    set((state) => {
      const existingItem = state.items.find((item) => item.product.id === product.id);
      if (existingItem) {
        // Increase quantity
        return {
          items: state.items.map((item) =>
            item.product.id === product.id
              ? { ...item, quantity: item.quantity + 1 }
              : item
          ),
        };
      } else {
        // Add new item
        return { items: [...state.items, { product, quantity: 1 }] };
      }
    }),
  removeItem: (productId) =>
    set((state) => ({
      items: state.items.filter((item) => item.product.id !== productId),
    })),
  clearCart: () => set({ items: [] }),
}));
9. Onboarding Pages
Ensure that the onboarding process is complete.

9.1 Personal Information Page
app/onboarding/personal-info/page.tsx:


// app/onboarding/personal-info/page.tsx

'use client';

import { useState, FormEvent } from 'react';
import { useSession } from 'next-auth/react';
import { useRouter } from 'next/navigation';
import axios from 'axios';

export default function PersonalInfoPage() {
  const { data: session } = useSession();
  const router = useRouter();
  const [name, setName] = useState('');

  const handleSubmit = async (e: FormEvent) => {
    e.preventDefault();

    await axios.put(`/api/user/${session?.user.id}`, {
      name,
    });

    router.push('/onboarding/style-preferences');
  };

  return (
    <div className="max-w-md mx-auto mt-8">
      <h1 className="text-2xl font-bold">Tell us about yourself</h1>
      <form onSubmit={handleSubmit} className="mt-4">
        <label className="block">
          Name:
          <input
            type="text"
            value={name}
            onChange={(e) => setName(e.target.value)}
            required
            className="w-full border p-2 mt-1"
          />
        </label>
        <button type="submit" className="mt-4 bg-green-500 text-white px-4 py-2">
          Next
        </button>
      </form>
    </div>
  );
}
9.2 Style Preferences Page
app/onboarding/style-preferences/page.tsx:


// app/onboarding/style-preferences/page.tsx

'use client';

import { useState, FormEvent } from 'react';
import { useSession } from 'next-auth/react';
import { useRouter } from 'next/navigation';
import axios from 'axios';

const availableStyles = ['Casual', 'Formal', 'Sporty', 'Vintage', 'Bohemian'];

export default function StylePreferencesPage() {
  const { data: session } = useSession();
  const router = useRouter();
  const [preferredStyles, setPreferredStyles] = useState<string[]>([]);

  const toggleStyle = (style: string) => {
    setPreferredStyles((prev) =>
      prev.includes(style) ? prev.filter((s) => s !== style) : [...prev, style]
    );
  };

  const handleSubmit = async (e: FormEvent) => {
    e.preventDefault();

    await axios.post('/api/user/preferences', {
      userId: session?.user.id,
      preferredStyles,
    });

    router.push('/onboarding/sustainability-values');
  };

  return (
    <div className="max-w-md mx-auto mt-8">
      <h1 className="text-2xl font-bold">Select Your Preferred Styles</h1>
      <form onSubmit={handleSubmit} className="mt-4">
        <div className="grid grid-cols-2 gap-2">
          {availableStyles.map((style) => (
            <label key={style} className="flex items-center">
              <input
                type="checkbox"
                checked={preferredStyles.includes(style)}
                onChange={() => toggleStyle(style)}
                className="mr-2"
              />
              {style}
            </label>
          ))}
        </div>
        <button type="submit" className="mt-4 bg-green-500 text-white px-4 py-2">
          Next
        </button>
      </form>
    </div>
  );
}
9.3 Sustainability Values Page
app/onboarding/sustainability-values/page.tsx:


// app/onboarding/sustainability-values/page.tsx

'use client';

import { useState, FormEvent } from 'react';
import { useSession } from 'next-auth/react';
import { useRouter } from 'next/navigation';
import axios from 'axios';

const sustainabilityOptions = [
  'Organic Materials',
  'Fair Trade',
  'Eco-Friendly Manufacturing',
  'Recycled Materials',
];

export default function SustainabilityValuesPage() {
  const { data: session } = useSession();
  const router = useRouter();
  const [sustainabilityValues, setSustainabilityValues] = useState<string[]>([]);

  const toggleValue = (value: string) => {
    setSustainabilityValues((prev) =>
      prev.includes(value) ? prev.filter((v) => v !== value) : [...prev, value]
    );
  };

  const handleSubmit = async (e: FormEvent) => {
    e.preventDefault();

    await axios.put(`/api/user/preferences/${session?.user.id}`, {
      sustainabilityValues,
    });

    // Reward tokens for completing onboarding
    await axios.post('/api/user/tokens', {
      userId: session?.user.id,
      amount: 100,
    });

    router.push('/products');
  };

  return (
    <div className="max-w-md mx-auto mt-8">
      <h1 className="text-2xl font-bold">Select Your Sustainability Values</h1>
      <form onSubmit={handleSubmit} className="mt-4">
        <div className="grid grid-cols-2 gap-2">
          {sustainabilityOptions.map((value) => (
            <label key={value} className="flex items-center">
              <input
                type="checkbox"
                checked={sustainabilityValues.includes(value)}
                onChange={() => toggleValue(value)}
                className="mr-2"
              />
              {value}
            </label>
          ))}
        </div>
        <button type="submit" className="mt-4 bg-green-500 text-white px-4 py-2">
          Finish
        </button>
      </form>
    </div>
  );
}
10. Authentication Pages
10.1 Sign-In Page
app/auth/signin/page.tsx:


// app/auth/signin/page.tsx

'use client';

import { useState, FormEvent } from 'react';
import { signIn } from 'next-auth/react';
import { useRouter } from 'next/navigation';
import Link from 'next/link';

export default function SignInPage() {
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const router = useRouter();

  const handleSignIn = async (e: FormEvent) => {
    e.preventDefault();

    const res = await signIn('credentials', {
      redirect: false,
      email,
      password,
    });

    if (res && !res.error) {
      router.push('/products');
    } else {
      alert(res?.error || 'An error occurred');
    }
  };

  return (
    <div className="max-w-md mx-auto mt-8">
      <h1 className="text-2xl font-bold">Sign In</h1>
      <form onSubmit={handleSignIn} className="mt-4">
        <label className="block">
          Email:
          <input
            type="email"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
            required
            className="w-full border p-2 mt-1"
          />
        </label>
        <label className="block mt-2">
          Password:
          <input
            type="password"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            required
            className="w-full border p-2 mt-1"
          />
        </label>
        <button type="submit" className="mt-4 bg-blue-500 text-white px-4 py-2">
          Sign In
        </button>
      </form>
      <p className="mt-4">
        Don't have an account?{' '}
        <Link href="/auth/signup" className="text-blue-500">
          Sign Up
        </Link>
      </p>
    </div>
  );
}
10.2 Sign-Up Page
app/auth/signup/page.tsx:


// app/auth/signup/page.tsx

'use client';

import { useState, FormEvent } from 'react';
import { useRouter } from 'next/navigation';
import { signIn } from 'next-auth/react';
import axios from 'axios';
import Link from 'next/link';

export default function SignUpPage() {
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const router = useRouter();

  const handleSignUp = async (e: FormEvent) => {
    e.preventDefault();

    try {
      await axios.post('/api/auth/signup', {
        email,
        password,
      });

      const res = await signIn('credentials', {
        redirect: false,
        email,
        password,
      });

      if (res && !res.error) {
        router.push('/onboarding/personal-info');
      } else {
        alert(res?.error || 'An error occurred');
      }
    } catch (error: any) {
      alert(error.response?.data?.error || 'An error occurred');
    }
  };

  return (
    <div className="max-w-md mx-auto mt-8">
      <h1 className="text-2xl font-bold">Sign Up</h1>
      <form onSubmit={handleSignUp} className="mt-4">
        <label className="block">
          Email:
          <input
            type="email"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
            required
            className="w-full border p-2 mt-1"
          />
        </label>
        <label className="block mt-2">
          Password:
          <input
            type="password"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            required
            className="w-full border p-2 mt-1"
          />
        </label>
        <button type="submit" className="mt-4 bg-blue-500 text-white px-4 py-2">
          Sign Up
        </button>
      </form>
      <p className="mt-4">
        Already have an account?{' '}
        <Link href="/auth/signin" className="text-blue-500">
          Sign In
        </Link>
      </p>
    </div>
  );
}
11. Prisma Client Setup
Create lib/prisma.ts to initialize the Prisma client.


// lib/prisma.ts

import { PrismaClient } from '@prisma/client';

export const prisma = new PrismaClient();
12. NextAuth Configuration
Ensure you have the NextAuth configuration file app/api/auth/[...nextauth]/route.ts:


// app/api/auth/[...nextauth]/route.ts

import NextAuth from 'next-auth';
import { NextAuthOptions } from 'next-auth';
import CredentialsProvider from 'next-auth/providers/credentials';
import { PrismaAdapter } from '@next-auth/prisma-adapter';
import { prisma } from '@/lib/prisma';

export const authOptions: NextAuthOptions = {
  adapter: PrismaAdapter(prisma),
  providers: [
    CredentialsProvider({
      name: 'Credentials',
      credentials: {
        email: { label: 'Email', type: 'email', placeholder: 'email@example.com' },
        password: { label: 'Password', type: 'password' },
      },
      async authorize(credentials) {
        if (!credentials) return null;

        const user = await prisma.user.findUnique({
          where: { email: credentials.email },
        });

        if (user && user.password === credentials.password) {
          return user;
        }
        throw new Error('Invalid email or password');
      },
    }),
  ],
  pages: {
    signIn: '/auth/signin',
    signUp: '/auth/signup',
  },
  session: {
    strategy: 'jwt',
  },
  callbacks: {
    async session({ session, token, user }) {
      if (token) {
        session.user.id = token.sub || '';
      }
      return session;
    },
  },
  secret: process.env.NEXTAUTH_SECRET,
};

const handler = NextAuth(authOptions);

export { handler as GET, handler as POST };
13. Global CSS
In app/globals.css, include Tailwind CSS:


/* app/globals.css */

@tailwind base;
@tailwind components;
@tailwind utilities;
14. App Layout
Create app/layout.tsx to include the Navbar in your application:


// app/layout.tsx

import './globals.css';
import Navbar from '@/components/Navbar';
import { SessionProvider } from 'next-auth/react';

export default function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  return (
    <html lang="en">
      <body>
        <SessionProvider>
          <Navbar />
          {children}
        </SessionProvider>
      </body>
    </html>
  );
}
15. Next.js Configurations
Ensure your tsconfig.json includes the necessary paths:


// tsconfig.json

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/components/*": ["components/*"],
      "@/lib/*": ["lib/*"],
      "@/store/*": ["store/*"],
      "@/app/*": ["app/*"]
    },
    // ... other configurations
  },
  // ... other configurations
}
16. Environmental Variables
Ensure your .env file includes:


DATABASE_URL="postgresql://postgres:yourpassword@localhost:5432/postgres?schema=public"
NEXTAUTH_SECRET=your_nextauth_secret
Replace yourpassword and your_nextauth_secret with your actual values.

Conclusion
This comprehensive implementation includes:

Full code for all files involved in incorporating the Interaction model.
Detailed logic implementation for logging interactions and updating quest progress.
Modified components and pages to capture and utilize user interactions.
An enhanced recommendation engine that leverages interaction data.
Complete onboarding and authentication flows.
With all these pieces in place, you should have a fully functioning Sustainable Fashion Recommendation System with Gamification, incorporating the Interaction model as per your requirements.

If you encounter any issues or have further questions, feel free to ask!


Fix the auth system - modify full code and logic. Make a cli to make all required files. Remove old made files.