import { auth } from "@/auth"
import { NextResponse } from "next/server"
import type { NextRequest } from "next/server"

/**
 * Middleware for session validation and route protection
 * 
 * This middleware:
 * - Validates session tokens on protected routes
 * - Redirects unauthenticated users to login
 * - Handles session expiration
 * - Allows access to auth pages for unauthenticated users
 */
export default auth((req) => {
  const { nextUrl } = req
  const isLoggedIn = !!req.auth?.user
  
  // Define protected routes
  const isProtectedRoute = 
    nextUrl.pathname === "/" ||
    nextUrl.pathname.startsWith("/list") ||
    nextUrl.pathname.startsWith("/profile") ||
    nextUrl.pathname.startsWith("/invitations")
  
  // Define auth pages (login, register, etc.)
  const isAuthPage = nextUrl.pathname.startsWith("/auth")
  
  // Allow access to auth pages regardless of authentication status
  if (isAuthPage) {
    // If already logged in and trying to access login/register, redirect to home
    if (isLoggedIn && (nextUrl.pathname === "/auth/login" || nextUrl.pathname === "/auth/register")) {
      return NextResponse.redirect(new URL("/", req.url))
    }
    return NextResponse.next()
  }
  
  // Redirect to login if accessing protected route without authentication
  if (isProtectedRoute && !isLoggedIn) {
    const loginUrl = new URL("/auth/login", req.url)
    // Add callback URL to redirect back after login
    loginUrl.searchParams.set("callbackUrl", nextUrl.pathname)
    return NextResponse.redirect(loginUrl)
  }
  
  // Allow access to public routes
  return NextResponse.next()
})

/**
 * Matcher configuration for middleware
 * Applies middleware to all routes except:
 * - API routes (handled separately)
 * - Static files (_next/static)
 * - Image optimization (_next/image)
 * - Favicon and other public assets
 */
export const config = {
  matcher: [
    /*
     * Match all request paths except for the ones starting with:
     * - api (API routes)
     * - _next/static (static files)
     * - _next/image (image optimization files)
     * - favicon.ico (favicon file)
     * - public assets (images, icons, manifest, sw.js)
     */
    "/((?!api|_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|ico|json|js)$).*)",
  ],
}