Add bulk import

Also make pressing return submit the manual number

templates/party.html

@@ -25,14 +25,19 @@
         <div class="columns">
             <div class="column col-md-12 col-6">
                 <h2>Handmatig Toevoegen</h2>
+                <form id="student_number_wrapper">
                     <p><label for="student_number">Leerlingnummer:</label></p>
                     <input type="text" id="student_number" name="student_number" placeholder="Leerlingnummer">
                     <button class="btn btn-primary" id="add_student">"Scan"</button>
+                </form>
             </div>
             <div class="column col-md-12 col-6">
                 <h2>Extra opties</h2>
                 <p><a href="/party/{{id}}/lijst">Bekijk een tabel in je browser</a></p>
                 <p><a href="/party/{{id}}/export">Exporteer als CSV</a></p>
+                <p><label for="file-selector">Importeer CSV:</label><input type="file" id="file-selector"
+                        accept=".csv" /></p>
+                <p><button id="file-selector-button">Importeer</button> <span id="import-result"></span></p>
             </div>
         </div>
     </div>
@@ -120,11 +125,19 @@
             return data;
         }).then(set_state);
     }
+    function return_handler(e) {
+        e.preventDefault();
+        let code = document.getElementById("student_number").value;
+        console.log(code);
+        scan_ticket(code);
+    }
+
     function button_click_handler() {
         let code = document.getElementById("student_number").value;
         scan_ticket(code);
     }
     document.getElementById("add_student").addEventListener("click", button_click_handler);
+    document.getElementById("student_number_wrapper").addEventListener("submit", return_handler);
     document.getElementById("start_scan_btn").addEventListener('click', start_scanning);
 
     const videoElement = document.querySelector("video");
@@ -216,5 +229,29 @@
             })
     }
 
+    function upload_csv() {
+        let file = document.getElementById("file-selector").files[0];
+        if (file) {
+            const reader = new FileReader();
+            let num = 0;
+            reader.onload = (evt) => {
+                let result = evt.target.result;
+                for (let line of result.split("\n")) {
+                    for (let llnr of line.split(",")) {
+                        if (llnr.length === 6 && !isNaN(llnr)) {
+                            scan_ticket(llnr);
+                            num += 1;
+                        }
+                    }
+                }
+                document.getElementById("import-result").innerHTML = `${num} leerlingen geïmporteerd!`
+            }
+            reader.readAsText(file);
+        }
+
+    }
+
+    document.getElementById("file-selector-button").addEventListener("click", upload_csv);
+
 </script>
 {% endblock %}