phase-7: code restructure

server/clients/YahooFinanceClient.ts

@@ -0,0 +1,38 @@
+import YahooFinance from 'yahoo-finance2';
+import type { YahooNewsItem, YahooSearchOptions, YahooFinanceLib } from '../types';
+import { YAHOO_MODULES } from '../config/constants';
+
+export class YahooFinanceClient {
+  private lib: YahooFinanceLib;
+
+  constructor() {
+    this.lib = new (YahooFinance as unknown as new (_opts: object) => YahooFinanceLib)({
+      suppressNotices: ['yahooSurvey'],
+    });
+  }
+
+  async fetchSummary(ticker: string, retries = 3, backoff = 1000): Promise<any> {
+    for (let attempt = 0; attempt < retries; attempt++) {
+      try {
+        return await this.lib.quoteSummary(ticker, { modules: YAHOO_MODULES });
+      } catch (error) {
+        if (attempt === retries - 1) throw error;
+        await new Promise<void>((resolve) => setTimeout(resolve, backoff * (attempt + 1)));
+      }
+    }
+  }
+
+  async fetchCalendarEvents(ticker: string): Promise<any | null> {
+    try {
+      const result = await this.lib.quoteSummary(ticker, { modules: ['calendarEvents'] });
+      return result.calendarEvents ?? null;
+    } catch {
+      return null;
+    }
+  }
+
+  async search(query: string, opts: YahooSearchOptions = {}): Promise<YahooNewsItem[]> {
+    const { news = [] } = await this.lib.search(query, opts);
+    return news;
+  }
+}