Add betting functionality with user management and betting tables

- Implemented user creation and retrieval functions in the database.
- Added betting tables for users and bets, including necessary fields.

Author: matteomekhail

db.ts

@@ -41,3 +41,128 @@ export function clearAllRounds() {
   db.exec("DELETE FROM rounds;");
   db.exec("DELETE FROM sqlite_sequence WHERE name = 'rounds';");
 }
+
+// ── Betting tables ──────────────────────────────────────────────────────────
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS users (
+    id TEXT PRIMARY KEY,
+    nickname TEXT UNIQUE NOT NULL,
+    balance INTEGER DEFAULT 1000,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+  );
+`);
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS bets (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id TEXT NOT NULL,
+    round_num INTEGER NOT NULL,
+    contestant TEXT NOT NULL,
+    amount INTEGER NOT NULL,
+    won INTEGER,
+    payout INTEGER DEFAULT 0,
+    timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE(user_id, round_num)
+  );
+`);
+
+// ── Betting functions ───────────────────────────────────────────────────────
+
+export function createUser(id: string, nickname: string) {
+  const stmt = db.prepare("INSERT INTO users (id, nickname) VALUES ($id, $nickname)");
+  stmt.run({ $id: id, $nickname: nickname });
+  return { id, nickname, balance: 1000 };
+}
+
+export function getUser(id: string) {
+  return db.query("SELECT id, nickname, balance FROM users WHERE id = $id").get({ $id: id }) as { id: string; nickname: string; balance: number } | null;
+}
+
+export function placeBet(userId: string, roundNum: number, contestant: string, amount: number) {
+  const user = getUser(userId);
+  if (!user) throw new Error("User not found");
+  if (amount <= 0) throw new Error("Amount must be positive");
+  if (amount > user.balance) throw new Error("Insufficient balance");
+
+  const existing = db.query("SELECT id FROM bets WHERE user_id = $userId AND round_num = $roundNum").get({ $userId: userId, $roundNum: roundNum });
+  if (existing) throw new Error("Already bet this round");
+
+  db.exec("BEGIN");
+  try {
+    db.prepare("INSERT INTO bets (user_id, round_num, contestant, amount) VALUES ($userId, $roundNum, $contestant, $amount)")
+      .run({ $userId: userId, $roundNum: roundNum, $contestant: contestant, $amount: amount });
+    db.prepare("UPDATE users SET balance = balance - $amount WHERE id = $userId")
+      .run({ $amount: amount, $userId: userId });
+    db.exec("COMMIT");
+  } catch (e) {
+    db.exec("ROLLBACK");
+    throw e;
+  }
+
+  return {
+    bet: { userId, roundNum, contestant, amount },
+    balance: user.balance - amount,
+  };
+}
+
+export function resolveBets(roundNum: number, winnerName: string | null) {
+  const bets = db.query("SELECT id, user_id, contestant, amount FROM bets WHERE round_num = $roundNum AND won IS NULL")
+    .all({ $roundNum: roundNum }) as { id: number; user_id: string; contestant: string; amount: number }[];
+
+  if (bets.length === 0) return;
+
+  db.exec("BEGIN");
+  try {
+    for (const bet of bets) {
+      if (winnerName === null) {
+        // Tie — refund
+        db.prepare("UPDATE bets SET won = 0, payout = $amount WHERE id = $id")
+          .run({ $amount: bet.amount, $id: bet.id });
+        db.prepare("UPDATE users SET balance = balance + $amount WHERE id = $userId")
+          .run({ $amount: bet.amount, $userId: bet.user_id });
+      } else if (bet.contestant === winnerName) {
+        const payout = bet.amount * 2;
+        db.prepare("UPDATE bets SET won = 1, payout = $payout WHERE id = $id")
+          .run({ $payout: payout, $id: bet.id });
+        db.prepare("UPDATE users SET balance = balance + $payout WHERE id = $userId")
+          .run({ $payout: payout, $userId: bet.user_id });
+      } else {
+        db.prepare("UPDATE bets SET won = 0, payout = 0 WHERE id = $id")
+          .run({ $id: bet.id });
+      }
+    }
+    db.exec("COMMIT");
+  } catch (e) {
+    db.exec("ROLLBACK");
+    throw e;
+  }
+}
+
+export function getLeaderboard(limit = 10) {
+  return db.query("SELECT id, nickname, balance FROM users ORDER BY balance DESC LIMIT $limit")
+    .all({ $limit: limit }) as { id: string; nickname: string; balance: number }[];
+}
+
+export function getBetsForRound(roundNum: number) {
+  const rows = db.query(
+    "SELECT contestant, COUNT(*) as count, SUM(amount) as total FROM bets WHERE round_num = $roundNum GROUP BY contestant"
+  ).all({ $roundNum: roundNum }) as { contestant: string; count: number; total: number }[];
+
+  const result: Record<string, { count: number; total: number }> = {};
+  for (const row of rows) {
+    result[row.contestant] = { count: row.count, total: row.total };
+  }
+  return result;
+}
+
+export function getUserBetForRound(userId: string, roundNum: number) {
+  return db.query("SELECT contestant, amount, won, payout FROM bets WHERE user_id = $userId AND round_num = $roundNum")
+    .get({ $userId: userId, $roundNum: roundNum }) as { contestant: string; amount: number; won: number | null; payout: number } | null;
+}
+
+export function clearAllBets() {
+  db.exec("DELETE FROM bets;");
+  db.exec("DELETE FROM users;");
+  db.exec("DELETE FROM sqlite_sequence WHERE name = 'bets';");
+}