package spa_handler

import (
	"fmt"
	"net/http"

	"github.com/gorilla/websocket"
)

func clientScript(clientVersion string) string {
	return fmt.Sprintf(`
<!-- [spa_handler] Live Reloading Script Start -->
<script type="application/javascript">
	function spaHandlerLiveReloaderConnect() {
		const ws = new WebSocket("/_livereloader_");
		ws.onopen = function() {
			console.info('[spa_handler]: live reloader connected!');
		};
		ws.onmessage = function(event) {
			try {
				const message = JSON.parse(event.data);
				if (message && message.clientVersion && message.clientVersion !== '%s') {
					console.info('[spa_handler]: receive reload');
					location.reload(true);
				}
			} catch (err) {
				console.warning('[spa_handler]: something was wrong! ', err)
			}
		};
		ws.onclose = function() {
			console.info('[spa_handler]: connection closed');
			setTimeout(function() {
				console.info('[spa_handler]: try reconnect');
				spaHandlerLiveReloaderConnect();
			}, 5000);
		};
		ws.onerror = function(err) {
			console.warning('[spa_handler]: something was wrong with websocket connection! ', err)
		};
	}
	document.onload = function() {
		spaHandlerLiveReloaderConnect();
	};
</script>
<!-- [spa_handler] Live Reloading Script End -->
`, clientVersion)
}

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

type reloader struct {
	clientVersion string
}

func (rel reloader) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		fmt.Println("Error upgrading:", err)
		return
	}
	defer conn.Close()
	_ = conn.WriteMessage(websocket.TextMessage, []byte(fmt.Sprintf("{\"clientVersion\":\"%s\"}", rel.clientVersion)))
	for {
		_, _, err := conn.ReadMessage()
		if err != nil {
			fmt.Println("Error reading message:", err)
			break
		}
	}
}