package templates

import "sync"

// Bundle versions: a short content hash per static JS bundle, set once
// at server startup. Script tags render /static/<bundle>.js?v=<hash>,
// so any rebuild that changes a bundle's bytes automatically changes
// its cache key — browsers fetch the new bundle with no manual stamp
// bumps (the manual ?v=N stamp is exactly how a fixed search dropdown
// stayed broken for one deploy: the HTML kept pointing at the old,
// cached URL).
//
// An unset bundle renders ?v=0; the /static route also sends
// Cache-Control: no-cache, so worst case browsers revalidate — the
// hash is the fast path, not the correctness mechanism.

var bundleVersionsMu sync.RWMutex
var bundleVersions = map[string]string{}

// SetBundleVersion records the content hash for a bundle ("main.js").
// Called once at startup for each built bundle.
func SetBundleVersion(name, hash string) {
	bundleVersionsMu.Lock()
	defer bundleVersionsMu.Unlock()
	bundleVersions[name] = hash
}

// BundleVersion returns the recorded version for a bundle, or "0".
func BundleVersion(name string) string {
	bundleVersionsMu.RLock()
	defer bundleVersionsMu.RUnlock()
	if v, ok := bundleVersions[name]; ok && v != "" {
		return v
	}
	return "0"
}

// MainJSVersion is the templ-side accessor for the main bundle stamp.
func MainJSVersion() string {
	return BundleVersion("main.js")
}

// ReaderJSVersion is the templ-side accessor for the reader bundle stamp.
func ReaderJSVersion() string {
	return BundleVersion("reader.js")
}