Upload several Melee exports at once; let admins delete leagues

- The session import takes many files (every round's matches export plus
  the standings export) in one transaction; a bad file, a round repeated
  across files, or two standings exports rejects the whole batch.
- Delete league (with its sessions and results; players are kept).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/server.ts

@@ -176,6 +176,15 @@ app.post("/admin/league/:id/session", admin, async (req, res) => {
   res.redirect(303, BASE + `/session/${s.id}`);
 });
 
+app.post("/admin/league/:id/delete", admin, async (req, res) => {
+  const id = idOf(req);
+  await tx(async (c) => {
+    await c.query("DELETE FROM sessions WHERE league_id=$1", [id]); // matches/results cascade; players are shared, so kept
+    if (!(await c.query("DELETE FROM leagues WHERE id=$1", [id])).rowCount) throw new HttpError(404, "Not found");
+  });
+  res.redirect(303, BASE + "/");
+});
+
 app.post("/admin/session/:id/delete", admin, async (req, res) => {
   const [s] = await q("DELETE FROM sessions WHERE id=$1 RETURNING league_id", [idOf(req)]); // matches/results cascade
   if (!s) throw new HttpError(404, "Not found");
@@ -211,20 +220,36 @@ app.post("/admin/session/:id/import", admin, async (req, res) => {
 
 // Import a Melee matches export (replaces only the rounds in the file) or standings export (replaces the
 // session's imported standings). Uploaded or pasted; decks already entered are kept.
-app.post("/admin/session/:id/import-melee", admin, upload.single("file"), async (req, res) => {
+// Several files at once (any mix of matches exports and at most one standings export) go in one transaction,
+// so a bad file imports nothing.
+app.post("/admin/session/:id/import-melee", admin, upload.array("files", 50), async (req, res) => {
   const sid = idOf(req);
   await find("sessions", sid);
-  const text = req.file ? req.file.buffer.toString("utf8") : String(req.body.data ?? "");
-  let parsed: { matches: Match[] } | { rows: Row[] };
-  try {
-    const table = parseTable(text);
-    parsed = isMatchExport(table) ? { matches: extractMatches(table) } : { rows: extract(table) };
-  } catch (e) { throw new HttpError(400, (e as Error).message); }
-  await ("matches" in parsed ? importMatches(sid, parsed.matches) : importStandings(sid, parsed.rows));
+  const inputs = ((req.files ?? []) as Express.Multer.File[]).map((f) => ({ name: f.originalname, text: f.buffer.toString("utf8") }));
+  if (String(req.body.data ?? "").trim()) inputs.push({ name: "pasted text", text: String(req.body.data) });
+  if (!inputs.length) throw new HttpError(400, "Choose at least one file or paste an export");
+  const matches: Match[] = [], standings: { name: string; rows: Row[] }[] = [], roundFrom = new Map<number, string>();
+  for (const { name, text } of inputs) {
+    try {
+      const table = parseTable(text);
+      if (!isMatchExport(table)) { standings.push({ name, rows: extract(table) }); continue; }
+      const ms = extractMatches(table);
+      for (const r of new Set(ms.map((m) => m.round))) {
+        if (roundFrom.has(r)) throw new Error(`round ${r} is also in ${roundFrom.get(r)}`);
+        roundFrom.set(r, name);
+      }
+      matches.push(...ms);
+    } catch (e) { throw new HttpError(400, `${name}: ${(e as Error).message}`); }
+  }
+  if (standings.length > 1) throw new HttpError(400, `Only one standings export per session: ${standings.map((s) => s.name).join(", ")}`);
+  await tx(async (c) => {
+    if (matches.length) await importMatches(c, sid, matches);
+    if (standings.length) await importStandings(c, sid, standings[0].rows);
+  });
   res.redirect(303, BASE + `/session/${sid}`);
 });
 
-const importMatches = (sid: number, matches: Match[]) => tx(async (c) => {
+async function importMatches(c: Q, sid: number, matches: Match[]) {
   const old = new Map<number, string>((await c.query(
     `SELECT p1_id AS pid, p1_deck AS deck FROM matches WHERE session_id=$1 AND p1_deck IS NOT NULL
      UNION SELECT p2_id, p2_deck FROM matches WHERE session_id=$1 AND p2_deck IS NOT NULL`, [sid])).rows.map((r) => [r.pid, r.deck]));
@@ -237,9 +262,9 @@ const importMatches = (sid: number, matches: Match[]) => tx(async (c) => {
        VALUES($1,$2,$3,$4,$5,$6,$7,$8,$9)`,
       [sid, m.round, a, b, old.get(a) ?? null, b == null ? null : old.get(b) ?? null, m.w1, m.w2, m.draws]);
   }
-});
+}
 
-const importStandings = (sid: number, rows: Row[]) => tx(async (c) => {
+async function importStandings(c: Q, sid: number, rows: Row[]) {
   const old = new Map<number, string | null>((await c.query("SELECT player_id, deck FROM session_results WHERE session_id=$1", [sid])).rows.map((r) => [r.player_id, r.deck]));
   const pid = await resolver(c);
   await c.query("DELETE FROM session_results WHERE session_id=$1", [sid]);
@@ -250,7 +275,7 @@ const importStandings = (sid: number, rows: Row[]) => tx(async (c) => {
        VALUES($1,$2,$3,$4,$5,$6,$7) ON CONFLICT (session_id, player_id) DO NOTHING`,
       [sid, p, r.points, r.deck || old.get(p) || null, ...(r.wdl ?? [null, null, null])]);
   }
-});
+}
 
 app.post("/admin/session/:id/match-decks", admin, async (req, res) => {
   const sid = idOf(req);