package middleware

import (
	"net/http"
	"strings"
	"time"
	"vctp/version"
)

// CacheMiddleware sets the Cache-Control header based on the version.
func CacheMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if version.Value == "dev" {
			w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
			w.Header().Set("Pragma", "no-cache")
			w.Header().Set("Expires", "0")
		} else {
			cacheControl := "public, max-age=31536000"
			if isVersionedAssetRequest(r) {
				cacheControl += ", immutable"
			}
			w.Header().Set("Cache-Control", cacheControl)
			w.Header().Set("Expires", time.Now().UTC().Add(365*24*time.Hour).Format(http.TimeFormat))
		}
		w.Header().Set("Vary", "Accept-Encoding")
		next.ServeHTTP(w, r)
	})
}

func isVersionedAssetRequest(r *http.Request) bool {
	if r == nil {
		return false
	}
	if r.URL.Query().Get("v") != "" {
		return true
	}
	return strings.Contains(r.URL.Path, "@")
}