feat(db): add lobbies and lobby_players tables + model

packages/db/src/db/schema.ts

@@ -9,6 +9,7 @@ import {
   primaryKey,
   index,
   boolean,
+  integer,
 } from "drizzle-orm/pg-core";
 
 import { sql, relations } from "drizzle-orm";
@@ -19,6 +20,7 @@ import {
   CEFR_LEVELS,
   SUPPORTED_DECK_TYPES,
   DIFFICULTY_LEVELS,
+  LOBBY_STATUSES,
 } from "@lila/shared";
 
 export const terms = pgTable(
@@ -252,12 +254,53 @@ export const accountRelations = relations(account, ({ one }) => ({
   user: one(user, { fields: [account.userId], references: [user.id] }),
 }));
 
-/*
- * INTENTIONAL DESIGN DECISIONS — see decisions.md for full reasoning
- *
- * source + source_id (terms): idempotency key per import pipeline
- * display_name UNIQUE (users): multiplayer requires distinguishable names
- * UNIQUE(term_id, language_code, text): allows synonyms, prevents exact duplicates
- * updated_at omitted: misleading without a trigger to maintain it
- * FK indexes: all FK columns covered, no sequential scans on joins
- */
+export const lobbies = pgTable(
+  "lobbies",
+  {
+    id: uuid().primaryKey().defaultRandom(),
+    code: varchar({ length: 10 }).notNull().unique(),
+    hostUserId: text("host_user_id")
+      .notNull()
+      .references(() => user.id, { onDelete: "cascade" }),
+    status: varchar({ length: 20 }).notNull().default("waiting"),
+    createdAt: timestamp("created_at", { withTimezone: true })
+      .defaultNow()
+      .notNull(),
+  },
+  (table) => [
+    check(
+      "lobby_status_check",
+      sql`${table.status} IN (${sql.raw(LOBBY_STATUSES.map((s) => `'${s}'`).join(", "))})`,
+    ),
+  ],
+);
+
+export const lobby_players = pgTable(
+  "lobby_players",
+  {
+    lobbyId: uuid("lobby_id")
+      .notNull()
+      .references(() => lobbies.id, { onDelete: "cascade" }),
+    userId: text("user_id")
+      .notNull()
+      .references(() => user.id, { onDelete: "cascade" }),
+    score: integer().notNull().default(0),
+    joinedAt: timestamp("joined_at", { withTimezone: true })
+      .defaultNow()
+      .notNull(),
+  },
+  (table) => [primaryKey({ columns: [table.lobbyId, table.userId] })],
+);
+
+export const lobbyRelations = relations(lobbies, ({ one, many }) => ({
+  host: one(user, { fields: [lobbies.hostUserId], references: [user.id] }),
+  players: many(lobby_players),
+}));
+
+export const lobbyPlayersRelations = relations(lobby_players, ({ one }) => ({
+  lobby: one(lobbies, {
+    fields: [lobby_players.lobbyId],
+    references: [lobbies.id],
+  }),
+  user: one(user, { fields: [lobby_players.userId], references: [user.id] }),
+}));