//go:build js && wasm

package wasmruntime

import (
	"syscall/js"

	"kjol/vdom"
)

// Router holds the current path in a signal, so reading Path() during render
// re-renders on navigation (and browser back/forward).
type Router struct {
	path *vdom.Signal[string]
}

func NewRouter() *Router {
	r := &Router{path: vdom.NewSignal(currentPath())}
	popstate := js.FuncOf(func(this js.Value, args []js.Value) any {
		r.path.Set(currentPath())
		return nil
	})
	js.Global().Call("addEventListener", "popstate", popstate)
	return r
}

func currentPath() string {
	return js.Global().Get("location").Get("pathname").String()
}

// Path returns the current route (reactive when read during render).
func (r *Router) Path() string { return r.path.Get() }

// Navigate pushes a history entry and re-renders (client-side SPA navigation).
func (r *Router) Navigate(path string) {
	js.Global().Get("history").Call("pushState", nil, "", path)
	r.path.Set(path)
}