import express, { Request, Response, NextFunction } from 'express';

const app = express();

// Core Built-in JSON body parser with byte payload limits
app.use(express.json({ limit: '1mb' }));
app.use(express.urlencoded({ extended: true }));

// Express 5 Native Async Route Handler (Errors propagate automatically to error middleware!)
app.get('/api/v1/health', async (req: Request, res: Response) => {
    res.status(200).json({
        status: 'UP',
        uptime: process.uptime(),
        timestamp: new Date().toISOString()
    });
});

// Centralized 4-Argument Error Handling Middleware (Must have 4 parameters!)
app.use((err: Error, req: Request, res: Response, next: NextFunction) => {
    const statusCode = (err as any).statusCode || 500;
    
    console.error(`[${req.method} ${req.url}] Error: ${err.message}`, {
        stack: process.env.NODE_ENV === 'production' ? undefined : err.stack
    });

    res.status(statusCode).json({
        type: 'https://helloaihub.com/errors/internal',
        title: err.name || 'InternalServerError',
        status: statusCode,
        detail: err.message,
        instance: req.originalUrl,
        timestamp: new Date().toISOString()
    });
});

import { z } from 'zod';

export const CreateUserSchema = z.object({
    body: z.object({
        email: z.string().email(),
        password: z.string().min(12, "Password must be at least 12 characters"),
        role: z.enum(['USER', 'ADMIN', 'AUDITOR']).default('USER')
    })
});

// Generic Reusable Zod Validation Middleware
export const validate = (schema: z.AnyZodObject) => 
    async (req: Request, res: Response, next: NextFunction) => {
        try {
            await schema.parseAsync({
                body: req.body,
                query: req.query,
                params: req.params
            });
            next();
        } catch (error) {
            return res.status(400).json({
                type: 'https://helloaihub.com/errors/validation',
                title: 'Validation Failed',
                status: 400,
                errors: (error as z.ZodError).errors
            });
        }
    };