feat: implement user tracking

src/tracking.ts

@@ -0,0 +1,57 @@
+import { getPlayer } from "./wov";
+
+const TRACKED_PLAYER_FILE = "./.cache/tracked.json";
+
+type TrackedPlayers = Record<string, string[]>;
+
+export async function initTracking(): Promise<void> {
+  if (!(await Bun.file(TRACKED_PLAYER_FILE).exists())) {
+    Bun.file(TRACKED_PLAYER_FILE).write("{}");
+  }
+}
+
+export async function listTrackedPlayers(): Promise<string[]> {
+  const trackedPlayers: TrackedPlayers =
+    await Bun.file(TRACKED_PLAYER_FILE).json();
+
+  return Object.keys(trackedPlayers);
+}
+
+export async function trackWovPlayer(playerId: string): Promise<
+  | { event: "notFound" }
+  | {
+      event: "registered";
+    }
+  | { event: "changed"; oldUsernames: string[]; newUsername: string }
+  | { event: "none" }
+> {
+  const trackedPlayers: TrackedPlayers =
+    await Bun.file(TRACKED_PLAYER_FILE).json();
+
+  const player = await getPlayer(playerId);
+  if (!player) return { event: "notFound" };
+
+  const currentUsernames = trackedPlayers[playerId];
+  if (currentUsernames) {
+    const oldUsernames = [...currentUsernames];
+    if (!currentUsernames.includes(player.username)) {
+      currentUsernames.push(player.username);
+
+      await Bun.file(TRACKED_PLAYER_FILE).write(JSON.stringify(trackedPlayers));
+
+      return {
+        event: "changed",
+        oldUsernames,
+        newUsername: player.username,
+      };
+    } else {
+      return {
+        event: "none",
+      };
+    }
+  } else {
+    trackedPlayers[playerId] = [player.username];
+    await Bun.file(TRACKED_PLAYER_FILE).write(JSON.stringify(trackedPlayers));
+    return { event: "registered" };
+  }
+}