import fastify from 'fastify';
import { Type, Static } from '@sinclair/typebox';
import { TypeBoxValidatorCompiler } from '@fastify/type-provider-typebox';

// Create Fastify instance
const app = fastify({ logger: true });

// Set up TypeBox validator
app.setValidatorCompiler(TypeBoxValidatorCompiler);

// Define TypeBox schema as the single source of truth
const UserSchema = Type.Object({
    id: Type.Number(),
    name: Type.String(),
    email: Type.String(),
    age: Type.Number({ minimum: 0 })
});

// Derive TypeScript type from the TypeBox schema
type User = Static<typeof UserSchema>;

// Response schema for better documentation
const ResponseSchema = Type.Object({
    user: UserSchema,
    canDrink: Type.Boolean(),
    greeting: Type.String()
});

// Main function to set up the server
async function startServer() {
    // Register Swagger plugin using dynamic import
    await app.register(import('@fastify/swagger'), {
        swagger: {
            info: {
                title: 'User API',
                description: 'API for user operations with TypeBox validation',
                version: '1.0.0'
            },
            tags: [
                { name: 'users', description: 'User related endpoints' }
            ]
        }
    });

    // Register Swagger UI plugin using dynamic import
    await app.register(import('@fastify/swagger-ui'), {
        routePrefix: '/swagger',
        uiConfig: {
            docExpansion: 'list',
            deepLinking: false
        },
        staticCSP: true
    });

    // Register our route
    app.post('/api/users', {
        schema: {
            description: 'Create a new user',
            tags: ['users'],
            body: UserSchema,
            response: {
                200: ResponseSchema
            }
        }
    }, async (request, reply) => {
        const user = request.body as User;

        const canDrink = user.age >= 21;
        const greeting = `Hello ${user.name.toUpperCase()}, your email ${user.email.toLowerCase()} has been recorded`;

        return { user, canDrink, greeting };
    });

    // Wait until all plugins are ready
    await app.ready();

    // Start the server
    try {
        await app.listen({ port: 3000 });
        console.log('Server running at http://localhost:3000');
        console.log('Swagger UI available at: http://localhost:3000/swagger');
    } catch (err) {
        app.log.error(err);
        process.exit(1);
    }
}

// Start the server
startServer();