package security

import (
	"fmt"
	"net/http"
)

// headers is the internal middleware that sets security response headers.
func headers(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		nonce := NonceFrom(r.Context())

		w.Header().Set("X-Content-Type-Options", "nosniff")
		w.Header().Set("X-Frame-Options", "DENY")
		w.Header().Set("Referrer-Policy", "strict-origin-when-cross-origin")
		w.Header().Set("Permissions-Policy", "camera=(), microphone=(), geolocation=()")

		if nonce != "" {
			csp := fmt.Sprintf(
				"default-src 'self'; "+
					"script-src 'nonce-%s' 'strict-dynamic' 'unsafe-inline' https:; "+
					"style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net https://fonts.googleapis.com https://fonts.gstatic.com; "+
					"img-src 'self' data: https:; "+
					"font-src 'self' https://fonts.gstatic.com; "+
					"connect-src 'self'; "+
					"frame-ancestors 'none'; object-src 'none'; base-uri 'self'",
				nonce,
			)
			w.Header().Set("Content-Security-Policy", csp)
		}

		next.ServeHTTP(w, r)
	})
}