not really working

index.html

@@ -2,13 +2,13 @@
     <h1>Kill me please</h1>
 </header>
 <nav>
-    <a href="form">New</a>
+    <a href="order">New</a>
 </nav>
 <main>
     <ul>
         {{range .}}
         <li id="order[{{.ID}}]">
-            {{.Name}} {{.Surname}}
+            <a href="/order/{{.ID}}">{{.Name}} {{.Surname}}</a>
         </li>
         {{end}}
     </ul>

main.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	_ "github.com/mattn/go-sqlite3"
@@ -36,13 +37,23 @@ type handler struct {
 }
 
 func (h *handler) form(w http.ResponseWriter, r *http.Request) {
-	data := order{
+	url := strings.Split(r.URL.String(), "/")
+	o := order{
 		ID:   -1,
 		Date: time.Now(),
-		Cakes: h.cakes,
 	}
+	id, err := strconv.Atoi(url[2])
+	if err == nil {
+		o = h.orders[id]
+	}
+	type formData struct {
+		Order     order
+		Catalogue []cake
+	}
+	data := formData{o, h.cakes}
+
 	w.Header().Set("content-type", "text/html")
-	err := h.tmpl.ExecuteTemplate(w, "form.html", data)
+	err = h.tmpl.ExecuteTemplate(w, "order.html", data)
 	if err != nil {
 		fmt.Println("error executing the template: ", err)
 	}
@@ -111,7 +122,7 @@ func logger(in http.HandlerFunc) http.HandlerFunc {
 
 func main() {
 	var h handler
-	templates, err := template.ParseFiles("index.html", "form.html")
+	templates, err := template.ParseFiles("index.html", "order.html")
 	if err != nil {
 		log.Fatal("can't parse templates: ", err)
 	}
@@ -129,7 +140,7 @@ func main() {
 	cakes = append(cakes, cake{"Malinowa chmurka", 1, 120, 0})
 	h.cakes = cakes
 
-	http.HandleFunc("GET /form", logger(h.form))
+	http.HandleFunc("GET /order/", logger(h.form))
 	http.HandleFunc("GET /", logger(h.index))
 	http.HandleFunc("POST /", logger(h.addOrder))
 	http.ListenAndServe(":8080", nil)

order.html

@@ -6,6 +6,7 @@
 </nav>
 <main>
     <form method="post">
+        {{with .Order}}
         <div>
             <h2>Info</h2>
             <input hidden="true" name="id" value="{{.ID}}">
@@ -27,11 +28,38 @@
         </div>
         <div>
             <h2>Basket</h2>
+            <ul>
                 {{range .Cakes}}
+                <li>
                     <label>{{.Name}} {{.Price}}</label>
-                <input type="number" min="0" name="cake[{{.ID}}]" value="{{.Amount}}">
+                    <input id="cake[{{.ID}}]" type="number" min="0" name="cake[{{.ID}}]" value="{{.Amount}}">
+                </li>
                 {{end}}
+            </ul>
         </div>
+        {{end}}
+        {{with .Catalogue}}
+        <div>
+            <h2>Catalogue</h2>
+            <ul>
+                {{range .}}
+                <li>
+                    {{.Name}} {{.Price}} <button type=button onClick="addCake({{.ID}})">add</button>
+                </li>
+                {{end}}
+            </ul>
+        </div>
+        {{end}}
         <button type="submit">submit</button>
     </form> 
 </main>
+
+<script>
+    function addCake(id){
+        var cake = document.getElementById("cake["+id+"]")
+        if (cake != null){
+            return;
+        }
+        console.log(cake)
+    }
+</script>