feat: new jumbotron page for dm hall screen

server/db/database.ts

@@ -65,6 +65,9 @@ export function createDatabaseWrapper(db: DatabaseInternal): DatabaseConnection
         getProblem(id: string): Promise<Problem | null> {
             return getProblem(db, id)
         },
+        getJumbotronProblem(): Promise<Problem | null> {
+            return getJumbotronProblem(db)
+        },
     }
 }
 
@@ -145,6 +148,18 @@ export const getProblem = (db: DatabaseInternal, id: string): Promise<Problem |
         return problem && !problem.deleted ? problem : null
     })
 
+export const getJumbotronProblem = (db: DatabaseInternal): Promise<Problem | null> =>
+    withDatabase(db, state => {
+        const mostRecentProblems = Object.values(state.problems)
+            .filter(p => !p.deleted)
+            .sort((p1, p2) => new Date(p2.createdAt).getTime() - new Date(p1.createdAt).getTime())
+            .slice(0, 3)
+
+        if (mostRecentProblems.length === 0) return null
+
+        return mostRecentProblems[Math.floor(Math.random() * mostRecentProblems.length)]
+    })
+
 export const getProblems = (db: DatabaseInternal): Promise<Problem[]> =>
     withDatabase(db, state => {
         return Object.values(state.problems).filter(p => !p.deleted)

server/db/example-data.ts

@@ -1,5 +1,5 @@
 import { UserId } from '../../shared/model'
-import { Database } from './database'
+import { Database } from '../../shared/database'
 
 export const initialDatabaseValue: Database = {
     users: {},

server/routes.ts

@@ -14,6 +14,7 @@ import {
     createSolution,
     deleteProblem,
     deleteSolution,
+    getJumbotronProblem,
     getProblem,
     getProblems,
     getSolution,
@@ -140,6 +141,11 @@ export async function createApiRouter(): Promise<[Router, DatabaseConnection]> {
         res.json(users)
     })
 
+    r.get('/api/jumbotron', async (req, res) => {
+        const problem = await getJumbotronProblem(db)
+        res.json(problem)
+    })
+
     r.get('/api/problems', async (req, res) => {
         type ProblemWithSolutionsCount = ProblemModel & { solutionsCount?: number }