Implement fiscal-style research MVP flows

lib/server/repos/filings.ts

@@ -1,4 +1,4 @@
-import { desc, eq } from 'drizzle-orm';
+import { desc, eq, inArray, max } from 'drizzle-orm';
 import type { Filing } from '@/lib/types';
 import { db } from '@/lib/server/db';
 import { filing, filingLink } from '@/lib/server/db/schema';
@@ -87,6 +87,35 @@ export async function getFilingByAccession(accessionNumber: string) {
   return row ? toFiling(row) : null;
 }
 
+export async function listLatestFilingDatesByTickers(tickers: string[]) {
+  const normalizedTickers = [...new Set(
+    tickers
+      .map((ticker) => ticker.trim().toUpperCase())
+      .filter((ticker) => ticker.length > 0)
+  )];
+
+  if (normalizedTickers.length === 0) {
+    return new Map<string, string>();
+  }
+
+  const rows = await db
+    .select({
+      ticker: filing.ticker,
+      latest_filing_date: max(filing.filing_date)
+    })
+    .from(filing)
+    .where(inArray(filing.ticker, normalizedTickers))
+    .groupBy(filing.ticker);
+
+  return new Map(
+    rows
+      .filter((row): row is { ticker: string; latest_filing_date: string } => {
+        return typeof row.ticker === 'string' && typeof row.latest_filing_date === 'string';
+      })
+      .map((row) => [row.ticker, row.latest_filing_date])
+  );
+}
+
 export async function upsertFilingsRecords(items: UpsertFilingInput[]) {
   let inserted = 0;
   let updated = 0;