Fixes saving chat log for 516 byond (#89864)

tgui/global.d.ts

@@ -178,6 +178,11 @@ type ByondType = {
    * Maps icons to their ref
    */
   iconRefMap: Record<string, string>;
+
+  /**
+   * Downloads a blob, platform-agnostic
+   */
+  saveBlob(blob: Blob, filename: string, ext: string): void;
 };
 
 /**

tgui/packages/tgui-panel/chat/renderer.jsx

@@ -624,13 +624,13 @@ class ChatRenderer {
       '</body>\n' +
       '</html>\n';
     // Create and send a nice blob
-    const blob = new Blob([pageHtml]);
+    const blob = new Blob([pageHtml], { type: 'text/plain' });
     const timestamp = new Date()
       .toISOString()
       .substring(0, 19)
       .replace(/[-:]/g, '')
       .replace('T', '-');
-    window.navigator.msSaveBlob(blob, `ss13-chatlog-${timestamp}.html`);
+    Byond.saveBlob(blob, `ss13-chatlog-${timestamp}.html`, '.html');
   }
 }
 

tgui/public/tgui.html

@@ -345,6 +345,37 @@
     loadAsset({ url: url, sync: sync, type: 'css' });
   };
 
+  Byond.saveBlob = function (blob, filename, ext) {
+    if (window.navigator.msSaveBlob) {
+      window.navigator.msSaveBlob(blob, filename);
+    } else if (window.showSaveFilePicker) {
+      var accept = {};
+      accept[blob.type] = [ext];
+
+      var opts = {
+        suggestedName: filename,
+        types: [
+          {
+            description: 'SS13 file',
+            accept: accept,
+          },
+        ],
+      };
+
+      window
+        .showSaveFilePicker(opts)
+        .then(function (file) {
+          return file.createWritable();
+        })
+        .then(function (file) {
+          return file.write(blob).then(function () {
+            return file.close();
+          });
+        })
+        .catch(function () {});
+    }
+  };
+
   // Icon cache
   Byond.iconRefMap = {};
 })();