ui: allow deleting contest/homework via edit page

packages/ui-default/pages/contest_edit.page.js

@@ -1,8 +1,34 @@
 import { NamedPage } from 'vj/misc/Page';
+import { ConfirmDialog } from 'vj/components/dialog';
 import ProblemSelectAutoComplete from 'vj/components/autocomplete/ProblemSelectAutoComplete';
+import tpl from 'vj/utils/tpl';
+import i18n from 'vj/utils/i18n';
+import request from 'vj/utils/request';
 
-const page = new NamedPage(['contest_edit', 'contest_create'], () => {
+const page = new NamedPage(['contest_edit', 'contest_create', 'homework_create', 'homework_edit'], (pagename) => {
   ProblemSelectAutoComplete.getOrConstruct($('[name="pids"]'), { multi: true });
+  if (pagename.endsWith('edit')) {
+    let confirmed = false;
+    $(document).on('click', '[name="operation"]', (ev) => {
+      ev.preventDefault();
+      if (confirmed) {
+        return request.post('.', { operation: 'delete' }).then((res) => {
+          window.location.href = res.url;
+        });
+      }
+      const message = `Confirm deleting this ${pagename.split('_')[0]}? Its status will be deleted as well.`;
+      return new ConfirmDialog({
+        $body: tpl`
+          <div class="typo">
+            <p>${i18n(message)}</p>
+          </div>`,
+      }).open().then((action) => {
+        if (action !== 'yes') return;
+        confirmed = true;
+        ev.target.click();
+      });
+    });
+  }
 });
 
 export default page;