package middleware

import (
	"net/http"
	"strings"
)

// SecurityHeadersMiddleware adds essential security headers to all responses
// Based on OWASP guidelines
func SecurityHeadersMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Prevent clickjacking (allow framing for Swagger UI)
		if strings.HasPrefix(r.URL.Path, "/docs") {
			w.Header().Set("X-Frame-Options", "SAMEORIGIN")
		} else {
			w.Header().Set("X-Frame-Options", "DENY")
		}

		// Prevent MIME sniffing
		w.Header().Set("X-Content-Type-Options", "nosniff")

		// Enable XSS filter
		w.Header().Set("X-XSS-Protection", "1; mode=block")

		// Only send referrer for same-origin
		w.Header().Set("Referrer-Policy", "strict-origin-when-cross-origin")

		// Permissions policy (disable potentially dangerous features)
		w.Header().Set("Permissions-Policy", "geolocation=(), microphone=(), camera=()")

		// Content Security Policy - relaxed for Swagger UI docs
		if strings.HasPrefix(r.URL.Path, "/docs") {
			// Swagger UI needs unsafe-inline and unsafe-eval for its scripts
			w.Header().Set("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:")
		} else {
			w.Header().Set("Content-Security-Policy", "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self'")
		}

		// HSTS - uncomment in production with HTTPS
		// w.Header().Set("Strict-Transport-Security", "max-age=31536000; includeSubDomains")

		next.ServeHTTP(w, r)
	})
}
