captbaritone · captbaritone · Dec 16, 2025
diff --git a/packages/webamp/js/playlistHtml.test.ts b/packages/webamp/js/playlistHtml.test.ts
@@ -0,0 +1,91 @@
+import { createPlaylistURL, getAsDataURI } from "./playlistHtml";
+
+function base64ToUtf8(str: string): string {
+  return decodeURIComponent(
+    Array.prototype.map
+      .call(
+        atob(str),
+        (c: string) => `%${`00${c.charCodeAt(0).toString(16)}`.slice(-2)}`
+      )
+      .join("")
+  );
+}
+
+describe("playlistHtml", () => {
+  describe("createPlaylistURL", () => {
+    it("handles track names with characters outside Latin-1 range", () => {
+      const props = {
+        averageTrackLength: "3:45",
+        numberOfTracks: 3,
+        playlistLengthSeconds: 15,
+        playlistLengthMinutes: 11,
+        tracks: [
+          "Song with emoji 🎵🎶",
+          "中文歌曲名称.mp3",
+          "Песня на русском.mp3",
+        ],
+      };
+
+      const result = createPlaylistURL(props);
+
+      // Should be a valid data URI
+      expect(result).toMatch(/^data:text\/html;base64,/);
+
+      // Decode the base64 to check the content
+      const base64Content = result.replace("data:text/html;base64,", "");
+      const decodedHTML = base64ToUtf8(base64Content);
+
+      // Check that all track names are present in the decoded HTML
+      expect(decodedHTML).toContain("Song with emoji 🎵🎶");
+      expect(decodedHTML).toContain("中文歌曲名称.mp3");
+      expect(decodedHTML).toContain("Песня на русском.mp3");
+
+      // Verify playlist metadata is included
+      expect(decodedHTML).toContain("3");
+      expect(decodedHTML).toContain("3:45");
+      expect(decodedHTML).toContain("11");
+      expect(decodedHTML).toContain("15");
+    });
+
+    it("creates valid HTML with basic track names", () => {
+      const props = {
+        averageTrackLength: "4:20",
+        numberOfTracks: 1,
+        playlistLengthSeconds: 20,
+        playlistLengthMinutes: 4,
+        tracks: ["test-track.mp3"],
+      };
+
+      const result = createPlaylistURL(props);
+
+      expect(result).toMatch(/^data:text\/html;base64,/);
+
+      const base64Content = result.replace("data:text/html;base64,", "");
+      const decodedHTML = atob(base64Content);
+
+      expect(decodedHTML).toContain("<html>");
+      expect(decodedHTML).toContain("test-track.mp3");
+      expect(decodedHTML).toContain("Winamp Generated PlayList");
+    });
+  });
+
+  describe("getAsDataURI", () => {
+    it("converts text to base64 data URI", () => {
+      const text = "Hello, World!";
+      const result = getAsDataURI(text);
+
+      expect(result).toBe("data:text/html;base64,SGVsbG8sIFdvcmxkIQ==");
+    });
+
+    it("handles text with HTML tags", () => {
+      const text = "<html>Test</html>";
+      const result = getAsDataURI(text);
+
+      expect(result).toMatch(/^data:text\/html;base64,/);
+
+      const base64Content = result.replace("data:text/html;base64,", "");
+      const decoded = atob(base64Content);
+      expect(decoded).toBe(text);
+    });
+  });
+});
diff --git a/packages/webamp/js/playlistHtml.tsx b/packages/webamp/js/playlistHtml.tsx
@@ -1,3 +1,4 @@
+import React from "react";
 import { createRoot } from "react-dom/client";
 import { flushSync } from "react-dom";
 
@@ -9,8 +10,15 @@ interface Props {
   tracks: string[];
 }
 
-export const getAsDataURI = (text: string): string =>
-  `data:text/html;base64,${window.btoa(text)}`;
+export const getAsDataURI = (text: string): string => {
+  // Properly encode UTF-8 to base64
+  // btoa() only handles Latin-1 (ISO-8859-1), so we need to encode UTF-8 first
+  const utf8Bytes = encodeURIComponent(text).replace(
+    /%([0-9A-F]{2})/g,
+    (_, p1) => String.fromCharCode(parseInt(p1, 16))
+  );
+  return `data:text/html;base64,${window.btoa(utf8Bytes)}`;
+};
 
 // Replaces deprecated "noshade" attribute
 const noshadeStyle = {