From d61f17a0f3952e80d68e1df18a56b960bb9f3827 Mon Sep 17 00:00:00 2001
From: Antonio De Lucreziis <antonio.delucreziis@gmail.com>
Date: Tue, 15 Nov 2022 02:53:16 +0100
Subject: [PATCH] Refactoring to Typescript...

---
 client/{App.jsx => App.tsx}                   |  14 +-
 client/components/Header.jsx                  |  11 +-
 client/components/Problem.jsx                 |   7 +-
 client/components/Solution.jsx                |   6 +-
 client/entry-client.jsx                       |   4 -
 client/entry-client.tsx                       |   4 +
 client/{entry-server.jsx => entry-server.tsx} |  10 +-
 client/{hooks.jsx => hooks.tsx}               |   0
 client/pages/{Admin.jsx => Admin.tsx}         |   3 +-
 client/pages/{Home.jsx => Home.tsx}           |   2 +
 client/pages/{Login.jsx => Login.tsx}         |   2 +-
 client/pages/{Problem.jsx => Problem.tsx}     |   2 +-
 client/pages/{Profile.jsx => Profile.tsx}     |   6 +-
 client/styles/main.scss                       |  25 +-
 index.html                                    |   2 +-
 package.json                                  |  20 +-
 pnpm-lock.yaml                                | 106 ++++++--
 server.js => server.ts                        |   9 +-
 server/db/{database.js => database.ts}        | 137 ++++++----
 server/db/example-data.js                     |   7 -
 server/db/example-data.ts                     |  17 ++
 server/middlewares.js                         |  47 ----
 server/middlewares.ts                         |  61 +++++
 server/routes.js                              | 170 ------------
 server/routes.ts                              | 249 ++++++++++++++++++
 shared/db-refs.ts                             |  25 ++
 shared/model.ts                               |  62 +++++
 shared/ssr.ts                                 |   6 +
 tsconfig.json                                 |  23 ++
 tsconfig.node.json                            |  10 +
 30 files changed, 702 insertions(+), 345 deletions(-)
 rename client/{App.jsx => App.tsx} (63%)
 delete mode 100644 client/entry-client.jsx
 create mode 100644 client/entry-client.tsx
 rename client/{entry-server.jsx => entry-server.tsx} (53%)
 rename client/{hooks.jsx => hooks.tsx} (100%)
 rename client/pages/{Admin.jsx => Admin.tsx} (91%)
 rename client/pages/{Home.jsx => Home.tsx} (97%)
 rename client/pages/{Login.jsx => Login.tsx} (97%)
 rename client/pages/{Problem.jsx => Problem.tsx} (98%)
 rename client/pages/{Profile.jsx => Profile.tsx} (87%)
 rename server.js => server.ts (91%)
 rename server/db/{database.js => database.ts} (50%)
 delete mode 100644 server/db/example-data.js
 create mode 100644 server/db/example-data.ts
 delete mode 100644 server/middlewares.js
 create mode 100644 server/middlewares.ts
 delete mode 100644 server/routes.js
 create mode 100644 server/routes.ts
 create mode 100644 shared/db-refs.ts
 create mode 100644 shared/model.ts
 create mode 100644 shared/ssr.ts
 create mode 100644 tsconfig.json
 create mode 100644 tsconfig.node.json

diff --git a/client/App.jsx b/client/App.tsx
similarity index 63%
rename from client/App.jsx
rename to client/App.tsx
index 77863e2..28dace6 100644
--- a/client/App.jsx
+++ b/client/App.tsx
@@ -1,14 +1,14 @@
 import Router from 'preact-router'
 import { route } from 'preact-router'
 import { useEffect } from 'preact/hooks'
-import { AdminPage } from './pages/Admin.jsx'
+import { AdminPage } from './pages/Admin'
 
-import { HomePage } from './pages/Home.jsx'
-import { LoginPage } from './pages/Login.jsx'
-import { ProblemPage } from './pages/Problem.jsx'
-import { ProfilePage } from './pages/Profile.jsx'
+import { HomePage } from './pages/Home'
+import { LoginPage } from './pages/Login'
+import { ProblemPage } from './pages/Problem'
+import { ProfilePage } from './pages/Profile'
 
-const Redirect = ({ to }) => {
+const Redirect = ({ to }: { default: boolean; to: string }) => {
     useEffect(() => {
         route(to, true)
     }, [])
@@ -20,7 +20,7 @@ const Redirect = ({ to }) => {
     )
 }
 
-export const App = ({ url }) => {
+export const App = ({ url }: { url?: string }) => {
     return (
         <Router url={url}>
             <HomePage path="/" />
diff --git a/client/components/Header.jsx b/client/components/Header.jsx
index 005a09c..bd08868 100644
--- a/client/components/Header.jsx
+++ b/client/components/Header.jsx
@@ -1,8 +1,9 @@
 import { Link } from 'preact-router/match'
+import { isAdministrator, USER_ROLE_ADMIN, USER_ROLE_MODERATOR } from '../../shared/constants.js'
 
 const ROLE_LABEL = {
-    admin: 'Admin',
-    moderator: 'Moderatore',
+    [USER_ROLE_ADMIN]: 'Admin',
+    [USER_ROLE_MODERATOR]: 'Moderatore',
 }
 
 export const Header = ({ user, noLogin }) => (
@@ -13,7 +14,7 @@ export const Header = ({ user, noLogin }) => (
         <nav>
             {user ? (
                 <>
-                    {user.role !== 'student' && (
+                    {isAdministrator(user.role) && (
                         <div class="nav-item">
                             <Link activeClassName="active" href="/admin">
                                 Pannello Admin
@@ -22,8 +23,8 @@ export const Header = ({ user, noLogin }) => (
                     )}
                     <div class="nav-item">
                         <Link activeClassName="active" href="/profile">
-                            @{user.username}
-                            {user.role !== 'student' && <> ({ROLE_LABEL[user.role]})</>}
+                            @{user.id}
+                            {isAdministrator(user.role) && <> ({ROLE_LABEL[user.role]})</>}
                         </Link>
                     </div>
                 </>
diff --git a/client/components/Problem.jsx b/client/components/Problem.jsx
index f6ca9aa..234b352 100644
--- a/client/components/Problem.jsx
+++ b/client/components/Problem.jsx
@@ -1,6 +1,6 @@
 import { Markdown } from './Markdown.jsx'
 
-export const Problem = ({ id, content, createdBy }) => {
+export const Problem = ({ id, content, solutionsCount }) => {
     return (
         <div class="problem">
             <div class="problem-header">
@@ -11,6 +11,11 @@ export const Problem = ({ id, content, createdBy }) => {
             <div class="problem-content">
                 <Markdown source={content} />
             </div>
+            {solutionsCount > 0 && (
+                <div class="problem-footer">
+                    {solutionsCount} soluzion{solutionsCount === 1 ? 'e' : 'i'}
+                </div>
+            )}
         </div>
     )
 }
diff --git a/client/components/Solution.jsx b/client/components/Solution.jsx
index 19c8393..112d7d2 100644
--- a/client/components/Solution.jsx
+++ b/client/components/Solution.jsx
@@ -1,6 +1,10 @@
+import { refToUserId } from '../../shared/db-refs.js'
 import { Markdown } from './Markdown.jsx'
 
-export const Solution = ({ userId, problemId, content }) => {
+export const Solution = ({ sentBy, forProblem, content }) => {
+    const userId = refToUserId(sentBy)
+    const problemId = refToUserId(forProblem)
+
     return (
         <div class="solution">
             <div class="solution-header">
diff --git a/client/entry-client.jsx b/client/entry-client.jsx
deleted file mode 100644
index bcbb351..0000000
--- a/client/entry-client.jsx
+++ /dev/null
@@ -1,4 +0,0 @@
-import { hydrate } from 'preact'
-import { App } from './App.jsx'
-
-hydrate(<App />, document.body)
diff --git a/client/entry-client.tsx b/client/entry-client.tsx
new file mode 100644
index 0000000..fb04c7a
--- /dev/null
+++ b/client/entry-client.tsx
@@ -0,0 +1,4 @@
+import { hydrate } from 'preact'
+import { App } from './App'
+
+// hydrate(<App />, document.body)
diff --git a/client/entry-server.jsx b/client/entry-server.tsx
similarity index 53%
rename from client/entry-server.jsx
rename to client/entry-server.tsx
index 43f9af7..1170d3b 100644
--- a/client/entry-server.jsx
+++ b/client/entry-server.tsx
@@ -1,13 +1,15 @@
 import renderToString from 'preact-render-to-string'
-import { App } from './App.jsx'
-import { MetadataContext } from './hooks.jsx'
+// import { App } from './App'
+import { MetadataContext } from './hooks'
 
-export function render(url) {
+import { RenderedPage } from '../shared/ssr'
+
+export default (url: string): RenderedPage => {
     const metadata = {}
 
     const html = renderToString(
         <MetadataContext.Provider value={metadata}>
-            <App url={url} />
+            {/* <App url={url} /> */}
         </MetadataContext.Provider>
     )
 
diff --git a/client/hooks.jsx b/client/hooks.tsx
similarity index 100%
rename from client/hooks.jsx
rename to client/hooks.tsx
diff --git a/client/pages/Admin.jsx b/client/pages/Admin.tsx
similarity index 91%
rename from client/pages/Admin.jsx
rename to client/pages/Admin.tsx
index 4bf38a9..1c93fbb 100644
--- a/client/pages/Admin.jsx
+++ b/client/pages/Admin.tsx
@@ -1,5 +1,6 @@
 import { route } from 'preact-router'
 import { useEffect, useState } from 'preact/hooks'
+import { isAdministrator, isStudent } from '../../shared/constants.js'
 import { server } from '../api.jsx'
 import { Header } from '../components/Header.jsx'
 import { MarkdownEditor } from '../components/MarkdownEditor.jsx'
@@ -27,7 +28,7 @@ export const AdminPage = ({}) => {
     const [user] = useCurrentUser(user => {
         if (!user) {
             route('/login', true)
-        } else if (user.role !== 'admin' && user.role !== 'moderator') {
+        } else if (isStudent(user.role)) {
             route('/', true)
         }
     })
diff --git a/client/pages/Home.jsx b/client/pages/Home.tsx
similarity index 97%
rename from client/pages/Home.jsx
rename to client/pages/Home.tsx
index ccba210..049f666 100644
--- a/client/pages/Home.jsx
+++ b/client/pages/Home.tsx
@@ -10,6 +10,8 @@ export const HomePage = () => {
     const [user] = useCurrentUser()
     const [problems] = useReadResource('/api/problems', [])
 
+    console.log(problems)
+
     return (
         <main class="page-home">
             <Header {...{ user }} />
diff --git a/client/pages/Login.jsx b/client/pages/Login.tsx
similarity index 97%
rename from client/pages/Login.jsx
rename to client/pages/Login.tsx
index e912850..b1e084b 100644
--- a/client/pages/Login.jsx
+++ b/client/pages/Login.tsx
@@ -13,7 +13,7 @@ export const LoginPage = () => {
                 'Content-Type': 'application/json',
             },
             body: JSON.stringify({
-                username,
+                id: username,
             }),
         })
 
diff --git a/client/pages/Problem.jsx b/client/pages/Problem.tsx
similarity index 98%
rename from client/pages/Problem.jsx
rename to client/pages/Problem.tsx
index fbeb592..43adbd5 100644
--- a/client/pages/Problem.jsx
+++ b/client/pages/Problem.tsx
@@ -20,7 +20,7 @@ export const ProblemPage = ({ id }) => {
 
     const sendSolution = async () => {
         await server.post('/api/solution', {
-            problemId: id,
+            forProblem: id,
             content: source,
         })
 
diff --git a/client/pages/Profile.jsx b/client/pages/Profile.tsx
similarity index 87%
rename from client/pages/Profile.jsx
rename to client/pages/Profile.tsx
index e67731c..46e9f12 100644
--- a/client/pages/Profile.jsx
+++ b/client/pages/Profile.tsx
@@ -13,7 +13,7 @@ export const ProfilePage = ({}) => {
             route('/login', true)
         }
 
-        setSolutions(await server.get(`/api/solutions?user=${user.username}`))
+        setSolutions(await server.get(`/api/solutions?user=${user.id}`))
     })
 
     const handleLogout = () => {
@@ -27,8 +27,8 @@ export const ProfilePage = ({}) => {
                 <Header {...{ user }} />
                 <div class="subtitle">Le tue soluzioni</div>
                 <div class="solution-list">
-                    {solutions.map(({ problemId, content }) => (
-                        <Solution {...{ problemId, content }} />
+                    {solutions.map(({ forProblem, content }) => (
+                        <Solution {...{ forProblem, content }} />
                     ))}
                 </div>
                 <div class="subtitle">Altro</div>
diff --git a/client/styles/main.scss b/client/styles/main.scss
index 3642128..8bb8b1a 100644
--- a/client/styles/main.scss
+++ b/client/styles/main.scss
@@ -22,7 +22,7 @@ body {
 
     font-family: 'Lato', sans-serif;
     font-weight: 300;
-    font-size: 20px;
+    font-size: 18px;
 
     line-height: 1;
 }
@@ -70,7 +70,7 @@ input[type='text'] {
     cursor: pointer;
     font-family: 'Lato';
     font-weight: 600;
-    font-size: 18px;
+    font-size: 16px;
     color: #555;
 
     border: 1px solid #c8c8c8;
@@ -102,7 +102,7 @@ input[type='text'] {
 
         font-family: 'Lato';
         font-weight: 600;
-        font-size: 18px;
+        font-size: 16px;
         color: #555;
     }
 }
@@ -112,7 +112,7 @@ button {
 
     font-family: 'Lato';
     font-weight: 600;
-    font-size: 18px;
+    font-size: 16px;
     color: #555;
 
     border: 1px solid #c8c8c8;
@@ -199,7 +199,7 @@ $heading-scale: 1.25;
 .text-body {
     font-family: 'EB Garamond', serif;
     font-weight: 400;
-    font-size: 21px;
+    font-size: 18px;
 
     line-height: 1.41;
 
@@ -232,7 +232,7 @@ main {
     gap: 2rem;
 
     .subtitle {
-        font-size: 24px;
+        font-size: 22px;
     }
 }
 
@@ -301,6 +301,9 @@ header {
         display: flex;
         gap: 1rem;
 
+        height: 100%;
+        align-items: center;
+
         .nav-item {
             font-size: 24px;
             font-weight: 300;
@@ -327,7 +330,7 @@ header {
     background: #ffffff;
 
     display: grid;
-    grid-template-rows: auto 1fr;
+    grid-template-rows: auto 1fr auto;
     gap: 0.5rem;
 
     .problem-header {
@@ -336,7 +339,7 @@ header {
         gap: 0.25rem;
 
         .problem-title {
-            font-size: 24px;
+            font-size: 22px;
             font-weight: 400;
         }
     }
@@ -344,6 +347,10 @@ header {
     .problem-content {
         @extend .text-body;
     }
+
+    .problem-footer {
+        font-size: 16px;
+    }
 }
 
 .solution {
@@ -420,7 +427,7 @@ header {
 
         textarea {
             font-family: 'DM Mono', monospace;
-            font-size: 18px;
+            font-size: 16px;
 
             resize: none;
             overflow-y: hidden;
diff --git a/index.html b/index.html
index 54cf890..7b53266 100644
--- a/index.html
+++ b/index.html
@@ -30,6 +30,6 @@
     </head>
     <body>
         <!-- SSR OUTLET -->
-        <script type="module" src="/client/entry-client.jsx"></script>
+        <script type="module" src="/client/entry-client.tsx"></script>
     </body>
 </html>
diff --git a/package.json b/package.json
index 77afbf4..b7f1e69 100644
--- a/package.json
+++ b/package.json
@@ -5,11 +5,13 @@
     "main": "index.js",
     "type": "module",
     "scripts": {
-        "dev": "MODE=development node server.js",
-        "build": "run-s build:client build:server",
-        "build:client": "vite build --outDir dist/client",
-        "build:server": "vite build --ssr client/entry-server.jsx --outDir dist/server",
-        "serve": "node server.js"
+        "dev": "run-s build:server serve:dev",
+        "build": "run-s build:client build:ssr build:server",
+        "build:server": "esbuild server.ts --bundle --platform=node --format=esm --external:./node_modules/* --outdir=dist/server",
+        "build:client": "vite build --outDir dist/entry-client",
+        "build:ssr": "vite build --ssr client/entry-server.tsx --outDir dist/entry-server",
+        "serve:dev": "MODE=development node dist/server/server.js",
+        "serve": "node dist/server/server.js"
     },
     "license": "MIT",
     "dependencies": {
@@ -35,7 +37,13 @@
         "vite": "^3.2.2"
     },
     "devDependencies": {
+        "@types/cookie-parser": "^1.4.3",
+        "@types/express": "^4.17.14",
+        "@types/morgan": "^1.9.3",
+        "@types/node": "^18.11.9",
         "concurrently": "^7.5.0",
-        "npm-run-all": "^4.1.5"
+        "esbuild": "^0.15.13",
+        "npm-run-all": "^4.1.5",
+        "typescript": "^4.8.4"
     }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9322971..3625e9a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -3,10 +3,15 @@ lockfileVersion: 5.4
 specifiers:
   '@preact/preset-vite': ^2.4.0
   '@preact/signals': ^1.1.2
+  '@types/cookie-parser': ^1.4.3
+  '@types/express': ^4.17.14
+  '@types/morgan': ^1.9.3
+  '@types/node': ^18.11.9
   body-parser: ^1.20.1
   chalk: ^5.1.2
   concurrently: ^7.5.0
   cookie-parser: ^1.4.6
+  esbuild: ^0.15.13
   express: ^4.18.2
   katex: ^0.16.3
   morgan: ^1.10.0
@@ -20,6 +25,7 @@ specifiers:
   remark-parse: ^10.0.1
   remark-rehype: ^10.1.0
   sass: ^1.55.0
+  typescript: ^4.8.4
   unified: ^10.1.2
   url-pattern: ^1.0.3
   vite: ^3.2.2
@@ -47,8 +53,14 @@ dependencies:
   vite: 3.2.2_sass@1.56.0
 
 devDependencies:
+  '@types/cookie-parser': 1.4.3
+  '@types/express': 4.17.14
+  '@types/morgan': 1.9.3
+  '@types/node': 18.11.9
   concurrently: 7.5.0
+  esbuild: 0.15.13
   npm-run-all: 4.1.5
+  typescript: 4.8.4
 
 packages:
 
@@ -302,7 +314,6 @@ packages:
     cpu: [arm]
     os: [android]
     requiresBuild: true
-    dev: false
     optional: true
 
   /@esbuild/linux-loong64/0.15.13:
@@ -311,7 +322,6 @@ packages:
     cpu: [loong64]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /@jridgewell/gen-mapping/0.1.1:
@@ -426,12 +436,48 @@ packages:
       picomatch: 2.3.1
     dev: false
 
+  /@types/body-parser/1.19.2:
+    resolution: {integrity: sha512-ALYone6pm6QmwZoAgeyNksccT9Q4AWZQ6PvfwR37GT6r6FWUPguq6sUmNGSMV2Wr761oQoBxwGGa6DR5o1DC9g==}
+    dependencies:
+      '@types/connect': 3.4.35
+      '@types/node': 18.11.9
+    dev: true
+
+  /@types/connect/3.4.35:
+    resolution: {integrity: sha512-cdeYyv4KWoEgpBISTxWvqYsVy444DOqehiF3fM3ne10AmJ62RSyNkUnxMJXHQWRQQX2eR94m5y1IZyDwBjV9FQ==}
+    dependencies:
+      '@types/node': 18.11.9
+    dev: true
+
+  /@types/cookie-parser/1.4.3:
+    resolution: {integrity: sha512-CqSKwFwefj4PzZ5n/iwad/bow2hTCh0FlNAeWLtQM3JA/NX/iYagIpWG2cf1bQKQ2c9gU2log5VUCrn7LDOs0w==}
+    dependencies:
+      '@types/express': 4.17.14
+    dev: true
+
   /@types/debug/4.1.7:
     resolution: {integrity: sha512-9AonUzyTjXXhEOa0DnqpzZi6VHlqKMswga9EXjpXnnqxwLtdvPPtlO8evrI5D9S6asFRCQ6v+wpiUKbw+vKqyg==}
     dependencies:
       '@types/ms': 0.7.31
     dev: false
 
+  /@types/express-serve-static-core/4.17.31:
+    resolution: {integrity: sha512-DxMhY+NAsTwMMFHBTtJFNp5qiHKJ7TeqOo23zVEM9alT1Ml27Q3xcTH0xwxn7Q0BbMcVEJOs/7aQtUWupUQN3Q==}
+    dependencies:
+      '@types/node': 18.11.9
+      '@types/qs': 6.9.7
+      '@types/range-parser': 1.2.4
+    dev: true
+
+  /@types/express/4.17.14:
+    resolution: {integrity: sha512-TEbt+vaPFQ+xpxFLFssxUDXj5cWCxZJjIcB7Yg0k0GMHGtgtQgpvx/MUQUeAkNbA9AAGrwkAsoeItdTgS7FMyg==}
+    dependencies:
+      '@types/body-parser': 1.19.2
+      '@types/express-serve-static-core': 4.17.31
+      '@types/qs': 6.9.7
+      '@types/serve-static': 1.15.0
+    dev: true
+
   /@types/hast/2.3.4:
     resolution: {integrity: sha512-wLEm0QvaoawEDoTRwzTXp4b4jpwiJDvR5KMnFnVodm3scufTlBOWRD6N1OBf9TZMhjlNsSfcO5V+7AF4+Vy+9g==}
     dependencies:
@@ -448,14 +494,43 @@ packages:
       '@types/unist': 2.0.6
     dev: false
 
+  /@types/mime/3.0.1:
+    resolution: {integrity: sha512-Y4XFY5VJAuw0FgAqPNd6NNoV44jbq9Bz2L7Rh/J6jLTiHBSBJa9fxqQIvkIld4GsoDOcCbvzOUAbLPsSKKg+uA==}
+    dev: true
+
+  /@types/morgan/1.9.3:
+    resolution: {integrity: sha512-BiLcfVqGBZCyNCnCH3F4o2GmDLrpy0HeBVnNlyZG4fo88ZiE9SoiBe3C+2ezuwbjlEyT+PDZ17//TAlRxAn75Q==}
+    dependencies:
+      '@types/node': 18.11.9
+    dev: true
+
   /@types/ms/0.7.31:
     resolution: {integrity: sha512-iiUgKzV9AuaEkZqkOLDIvlQiL6ltuZd9tGcW3gwpnX8JbuiuhFlEGmmFXEXkN50Cvq7Os88IY2v0dkDqXYWVgA==}
     dev: false
 
+  /@types/node/18.11.9:
+    resolution: {integrity: sha512-CRpX21/kGdzjOpFsZSkcrXMGIBWMGNIHXXBVFSH+ggkftxg+XYP20TESbh+zFvFj3EQOl5byk0HTRn1IL6hbqg==}
+    dev: true
+
   /@types/parse5/6.0.3:
     resolution: {integrity: sha512-SuT16Q1K51EAVPz1K29DJ/sXjhSQ0zjvsypYJ6tlwVsRV9jwW5Adq2ch8Dq8kDBCkYnELS7N7VNCSB5nC56t/g==}
     dev: false
 
+  /@types/qs/6.9.7:
+    resolution: {integrity: sha512-FGa1F62FT09qcrueBA6qYTrJPVDzah9a+493+o2PCXsesWHIn27G98TsSMs3WPNbZIEj4+VJf6saSFpvD+3Zsw==}
+    dev: true
+
+  /@types/range-parser/1.2.4:
+    resolution: {integrity: sha512-EEhsLsD6UsDM1yFhAvy0Cjr6VwmpMWqFBCb9w07wVugF7w9nfajxLuVmngTIpgS6svCnm6Vaw+MZhoDCKnOfsw==}
+    dev: true
+
+  /@types/serve-static/1.15.0:
+    resolution: {integrity: sha512-z5xyF6uh8CbjAu9760KDKsH2FcDxZ2tFCsA4HIMWE6IkiYMXfVoa+4f9KX+FN0ZLsaMw1WNG2ETLA6N+/YA+cg==}
+    dependencies:
+      '@types/mime': 3.0.1
+      '@types/node': 18.11.9
+    dev: true
+
   /@types/unist/2.0.6:
     resolution: {integrity: sha512-PBjIUxZHOuj0R15/xuwJYjFi+KZdNFrehocChv4g5hu6aFroHue8m0lBP0POdK2nKzbw0cgV1mws8+V/JAcEkQ==}
     dev: false
@@ -872,7 +947,6 @@ packages:
     cpu: [x64]
     os: [android]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-android-arm64/0.15.13:
@@ -881,7 +955,6 @@ packages:
     cpu: [arm64]
     os: [android]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-darwin-64/0.15.13:
@@ -890,7 +963,6 @@ packages:
     cpu: [x64]
     os: [darwin]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-darwin-arm64/0.15.13:
@@ -899,7 +971,6 @@ packages:
     cpu: [arm64]
     os: [darwin]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-freebsd-64/0.15.13:
@@ -908,7 +979,6 @@ packages:
     cpu: [x64]
     os: [freebsd]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-freebsd-arm64/0.15.13:
@@ -917,7 +987,6 @@ packages:
     cpu: [arm64]
     os: [freebsd]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-32/0.15.13:
@@ -926,7 +995,6 @@ packages:
     cpu: [ia32]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-64/0.15.13:
@@ -935,7 +1003,6 @@ packages:
     cpu: [x64]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-arm/0.15.13:
@@ -944,7 +1011,6 @@ packages:
     cpu: [arm]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-arm64/0.15.13:
@@ -953,7 +1019,6 @@ packages:
     cpu: [arm64]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-mips64le/0.15.13:
@@ -962,7 +1027,6 @@ packages:
     cpu: [mips64el]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-ppc64le/0.15.13:
@@ -971,7 +1035,6 @@ packages:
     cpu: [ppc64]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-riscv64/0.15.13:
@@ -980,7 +1043,6 @@ packages:
     cpu: [riscv64]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-linux-s390x/0.15.13:
@@ -989,7 +1051,6 @@ packages:
     cpu: [s390x]
     os: [linux]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-netbsd-64/0.15.13:
@@ -998,7 +1059,6 @@ packages:
     cpu: [x64]
     os: [netbsd]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-openbsd-64/0.15.13:
@@ -1007,7 +1067,6 @@ packages:
     cpu: [x64]
     os: [openbsd]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-sunos-64/0.15.13:
@@ -1016,7 +1075,6 @@ packages:
     cpu: [x64]
     os: [sunos]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-windows-32/0.15.13:
@@ -1025,7 +1083,6 @@ packages:
     cpu: [ia32]
     os: [win32]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-windows-64/0.15.13:
@@ -1034,7 +1091,6 @@ packages:
     cpu: [x64]
     os: [win32]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild-windows-arm64/0.15.13:
@@ -1043,7 +1099,6 @@ packages:
     cpu: [arm64]
     os: [win32]
     requiresBuild: true
-    dev: false
     optional: true
 
   /esbuild/0.15.13:
@@ -1074,7 +1129,6 @@ packages:
       esbuild-windows-32: 0.15.13
       esbuild-windows-64: 0.15.13
       esbuild-windows-arm64: 0.15.13
-    dev: false
 
   /escalade/3.1.1:
     resolution: {integrity: sha512-k0er2gUkLf8O0zKJiAhmkTnJlTvINGv7ygDNPbeIsX/TJjGJZHuh9B2UxbsaEkmlEo9MfhrSzmhIlhRlI2GXnw==}
@@ -2489,6 +2543,12 @@ packages:
       mime-types: 2.1.35
     dev: false
 
+  /typescript/4.8.4:
+    resolution: {integrity: sha512-QCh+85mCy+h0IGff8r5XWzOVSbBO+KfeYrMQh7NJ58QujwcE22u+NUSmUxqF+un70P9GXKxa2HCNiTTMJknyjQ==}
+    engines: {node: '>=4.2.0'}
+    hasBin: true
+    dev: true
+
   /unbox-primitive/1.0.2:
     resolution: {integrity: sha512-61pPlCD9h51VoreyJ0BReideM3MDKMKnh6+V9L08331ipq6Q8OFXZYiqP6n/tbHx4s5I9uRhcye6BrbkizkBDw==}
     dependencies:
diff --git a/server.js b/server.ts
similarity index 91%
rename from server.js
rename to server.ts
index 4755444..74823a3 100644
--- a/server.js
+++ b/server.ts
@@ -7,6 +7,7 @@ import morgan from 'morgan'
 import { createServer as createViteServer } from 'vite'
 
 import { createApiRouter } from './server/routes.js'
+import { RenderFunction } from './shared/ssr.js'
 
 const HTML_ROUTES = ['/', '/login', '/problem/:id', '/admin', '/profile']
 
@@ -46,7 +47,8 @@ async function createDevRouter() {
             const transformedTemplate = await vite.transformIndexHtml(req.originalUrl, indexHtml)
 
             // Load (to be bundled) entry point for server side rendering
-            const { render } = await vite.ssrLoadModule('./client/entry-server.jsx')
+            const render: RenderFunction = (await vite.ssrLoadModule('./client/entry-server.tsx'))
+                .default
 
             const { html, metadata } = render(req.originalUrl)
 
@@ -80,9 +82,10 @@ async function createDevRouter() {
 
 async function createProductionRouter() {
     // Load bundled entry point for server side rendering
-    const { render } = await import('./dist/server/entry-server.js')
+    const render: RenderFunction = ((await import('./dist/entry-server/entry-server.js')) as any)
+        .default
 
-    const r = new express.Router()
+    const r = express.Router()
 
     r.use('/', express.static('dist/client'))
 
diff --git a/server/db/database.js b/server/db/database.ts
similarity index 50%
rename from server/db/database.js
rename to server/db/database.ts
index e0d4146..f55be9c 100644
--- a/server/db/database.js
+++ b/server/db/database.ts
@@ -2,21 +2,39 @@ import crypto from 'crypto'
 
 import { readFile, writeFile, access, constants } from 'fs/promises'
 
-function once(fn, message) {
+import {
+    CommonProps as MetaProps,
+    Problem,
+    ProblemId,
+    Solution,
+    SolutionId,
+    User,
+    UserId,
+} from '../../shared/model'
+
+function once<T extends (...args: any) => any>(fn: T, message: string): T {
     let flag = false
 
-    return (...args) => {
+    return ((...args: any) => {
         if (flag) {
             throw new Error(message ?? `cannot run more than once`)
         }
         flag = true
         return fn(...args)
-    }
+    }) as T
+}
+
+interface Lock {
+    (): void
+}
+
+interface Mutex {
+    lock(): Promise<Lock>
 }
 
-function createMutex() {
+function createMutex(): Mutex {
     let locked = false
-    const waiters = []
+    const waiters: ((fn: () => void) => void)[] = []
 
     const unlock = () => {
         if (waiters.length > 0) {
@@ -29,7 +47,7 @@ function createMutex() {
         }
     }
 
-    const lock = () => {
+    const lock = (): Promise<Lock> => {
         if (locked) {
             console.log(`[Mutex] Putting into queue`)
             return new Promise(resolve => {
@@ -38,20 +56,26 @@ function createMutex() {
         } else {
             console.log(`[Mutex] Acquiring the lock`)
             locked = true
-            return once(unlock, `lock already released`)
+            return Promise.resolve(once(unlock, `lock already released`))
         }
     }
 
     return { lock }
 }
 
-// l = createLock()
-// unlock1 = await l.lock() // immediate
-//                                          unlock2 = await l.lock() // hangs...
-// unlock1()                                // l2 restarts...
-//                                          unlock2() // no waiters so noop
+type DatabaseConnection = {
+    path: string
+    initialValue: Database
+    mu: Mutex
+}
+
+export type Database = {
+    users: Record<string, User>
+    problems: Record<string, Problem>
+    solutions: Record<string, Solution>
+}
 
-export function createDatabase(path, initialValue) {
+export function createDatabase(path: string, initialValue: Database) {
     return {
         path,
         initialValue,
@@ -59,8 +83,11 @@ export function createDatabase(path, initialValue) {
     }
 }
 
-async function withDatabase({ path, initialValue, mu }, fn) {
-    const unlock = await mu.lock()
+async function withDatabase<R>(
+    { path, initialValue, mu }: DatabaseConnection,
+    fn: (db: Database) => R | Promise<R>
+): Promise<R> {
+    const unlock: Lock = await mu.lock()
 
     try {
         await access(path, constants.R_OK)
@@ -82,43 +109,30 @@ async function withDatabase({ path, initialValue, mu }, fn) {
     return result
 }
 
-export const getUsers = db =>
+//
+// Users
+//
+
+export const getUsers = (db: DatabaseConnection) =>
     withDatabase(db, state => {
         return Object.values(state.users)
     })
 
-export const getUser = (db, id) =>
-    withDatabase(db, state => {
+export const getUser = (db: DatabaseConnection, id: string) =>
+    withDatabase(db, (state: Database): User | null => {
         return state.users[id] ?? null
     })
 
-// export const createUser = (db, { email, username }) =>
-//     withDatabase(db, state => {
-//         state.users[username] = {
-//             email,
-//             username,
-//         }
-//     })
-
-// export const updateUser = (db, username, { email, password }) =>
-//     withDatabase(db, state => {
-//         state.users[username] = {
-//             email,
-//             password,
-//         }
-//     })
-
 //
 // Problems
 //
 
-export const createProblem = (db, { content, createdBy }) =>
+export const createProblem = (
+    db: DatabaseConnection,
+    { content, createdBy }: Omit<Problem, 'id' | 'createdAt'>
+): Promise<ProblemId> =>
     withDatabase(db, state => {
-        const nextId = (
-            Object.keys(state.problems)
-                .map(k => parseInt(k))
-                .reduce((acc, id) => Math.max(acc, id)) + 1
-        ).toString()
+        const nextId = (Object.keys(state.problems).length + 1).toString() as ProblemId
 
         state.problems[nextId] = {
             id: nextId,
@@ -130,12 +144,12 @@ export const createProblem = (db, { content, createdBy }) =>
         return nextId
     })
 
-export const getProblem = (db, id) =>
+export const getProblem = (db: DatabaseConnection, id: string): Promise<Problem> =>
     withDatabase(db, state => {
         return state.problems[id]
     })
 
-export const getProblems = db =>
+export const getProblems = (db: DatabaseConnection): Promise<Problem[]> =>
     withDatabase(db, state => {
         return Object.values(state.problems)
     })
@@ -144,31 +158,52 @@ export const getProblems = db =>
 // Solutions
 //
 
-export const createSolution = (db, { userId, problemId, content }) =>
+export const createSolution = (
+    db: DatabaseConnection,
+    { sentBy, forProblem, content }: Omit<Solution, MetaProps>
+): Promise<SolutionId> =>
     withDatabase(db, state => {
         const id = crypto.randomBytes(10).toString('hex')
         state.solutions[id] = {
             id,
-            userId,
-            problemId,
+            sentBy,
+            forProblem,
             content,
+            status: 'pending',
         }
+
+        return id
     })
 
-export const getSolution = (db, id) =>
+export const getSolution = (db: DatabaseConnection, id: SolutionId): Promise<Solution> =>
     withDatabase(db, state => {
         return state.solutions[id]
     })
 
-export const getSolutions = (db, { userId, problemId } = {}) =>
+export const updateSolution = (
+    db: DatabaseConnection,
+    id: SolutionId,
+    solution: Omit<Solution, MetaProps>
+): Promise<Solution> =>
+    withDatabase(db, state => {
+        state.solutions[id] = { id, ...solution }
+        return state.solutions[id]
+    })
+
+type SolutionsQuery = Partial<{
+    sentBy: UserId
+    forProblem: ProblemId
+}>
+
+export const getSolutions = (db: DatabaseConnection, { sentBy, forProblem }: SolutionsQuery = {}) =>
     withDatabase(db, state => {
         let solutions = Object.values(state.solutions)
 
-        if (userId) {
-            solutions = solutions.filter(s => s.userId === userId)
+        if (sentBy) {
+            solutions = solutions.filter(s => s.sentBy === sentBy)
         }
-        if (problemId) {
-            solutions = solutions.filter(s => s.problemId === problemId)
+        if (forProblem) {
+            solutions = solutions.filter(s => s.forProblem === forProblem)
         }
 
         return solutions
diff --git a/server/db/example-data.js b/server/db/example-data.js
deleted file mode 100644
index 4302361..0000000
--- a/server/db/example-data.js
+++ /dev/null
@@ -1,7 +0,0 @@
-export const initialDatabaseValue = {
-    users: {
-        ['BachoSeven']: {},
-        ['aziis98']: {},
-    },
-    problems: {},
-}
diff --git a/server/db/example-data.ts b/server/db/example-data.ts
new file mode 100644
index 0000000..a34ce07
--- /dev/null
+++ b/server/db/example-data.ts
@@ -0,0 +1,17 @@
+import { UserId } from '../../shared/model'
+import { Database } from './database'
+
+export const initialDatabaseValue: Database = {
+    users: {
+        ['BachoSeven']: {
+            id: 'BachoSeven' as UserId,
+            role: 'admin',
+        },
+        ['aziis98']: {
+            id: 'aziis98' as UserId,
+            role: 'admin',
+        },
+    },
+    problems: {},
+    solutions: {},
+}
diff --git a/server/middlewares.js b/server/middlewares.js
deleted file mode 100644
index 10c7b7b..0000000
--- a/server/middlewares.js
+++ /dev/null
@@ -1,47 +0,0 @@
-import { Router } from 'express'
-
-const createRouter = setup => options => {
-    const r = new Router()
-    setup(r, options)
-    return r
-}
-
-export const createStatusRouter = createRouter(r => {
-    r.get('/', (req, res) => {
-        res.json({ url: req.originalUrl, status: 'ok' })
-    })
-})
-
-export class PingRouter extends Router {
-    constructor() {
-        super()
-
-        this.post('/', (req, res) => {
-            if (req.body?.message === 'ping') {
-                res.json('pong')
-            } else {
-                res.status(400)
-                res.json('Invalid request')
-            }
-        })
-    }
-}
-
-export const INVALID_SESSION = `invalid session token`
-
-export const authMiddleware = getUserForSession => async (req, res, next) => {
-    if (req.cookies.sid) {
-        const user = await getUserForSession(req.cookies.sid)
-        if (user) {
-            req.user = user
-        } else {
-            res.cookie('sid', '', { expires: new Date() })
-        }
-    }
-
-    next()
-}
-
-export const authenticatedMiddleware = (req, res, next) => {
-    req.user && next()
-}
diff --git a/server/middlewares.ts b/server/middlewares.ts
new file mode 100644
index 0000000..d52a019
--- /dev/null
+++ b/server/middlewares.ts
@@ -0,0 +1,61 @@
+import express, { NextFunction, Request, Response, Router } from 'express'
+import { User } from '../shared/model'
+
+const createRouter =
+    <T>(setup: (r: Router, options?: T) => void) =>
+    (options: T) => {
+        const r = express.Router()
+        setup(r, options)
+        return r
+    }
+
+export const createStatusRouter = createRouter(r => {
+    r.get('/', (req, res) => {
+        res.json({ url: req.originalUrl, status: 'ok' })
+    })
+}) as () => Router
+
+// export class PingRouter extends express.Router {
+//     constructor() {
+//         super()
+
+//         this.post('/', (req, res) => {
+//             if (req.body?.message === 'ping') {
+//                 res.json('pong')
+//             } else {
+//                 res.status(400)
+//                 res.json('Invalid request')
+//             }
+//         })
+//     }
+// }
+
+export const INVALID_SESSION = `invalid session token`
+
+export const authMiddleware =
+    <U>(getUserForSession: (sid: string) => U) =>
+    async (req: Request, res: Response, next: NextFunction) => {
+        if (req.cookies.sid) {
+            const user = await getUserForSession(req.cookies.sid)
+            if (user) {
+                // @ts-ignore
+                req.user = user
+            } else {
+                res.cookie('sid', '', { expires: new Date() })
+            }
+        }
+
+        next()
+    }
+
+interface AuthenticatedRequest extends Request {
+    user: User | null
+}
+
+export const authenticatedMiddleware = (
+    req: AuthenticatedRequest,
+    res: Response,
+    next: NextFunction
+) => {
+    req.user && next()
+}
diff --git a/server/routes.js b/server/routes.js
deleted file mode 100644
index b401c49..0000000
--- a/server/routes.js
+++ /dev/null
@@ -1,170 +0,0 @@
-import crypto from 'crypto'
-
-import bodyParser from 'body-parser'
-import cookieParser from 'cookie-parser'
-
-import express from 'express'
-
-import { createStatusRouter, PingRouter } from './middlewares.js'
-import {
-    createDatabase,
-    createProblem,
-    createSolution,
-    getProblem,
-    getProblems,
-    getSolutions,
-    getUser,
-    getUsers,
-} from './db/database.js'
-import { initialDatabaseValue } from './db/example-data.js'
-
-export async function createApiRouter() {
-    const sessions = {
-        store: {},
-        createSession(username) {
-            const sid = crypto.randomBytes(10).toString('hex')
-            this.store[sid] = username
-            return sid
-        },
-        getUserForSession(sid) {
-            return this.store[sid] ?? null
-        },
-    }
-
-    const db = createDatabase('./db.local.json', initialDatabaseValue)
-
-    async function getRequestUser(req) {
-        const userId = sessions.getUserForSession(req.cookies.sid)
-        if (!userId) {
-            return null
-        }
-
-        const user = await getUser(db, userId)
-
-        return user
-    }
-
-    const r = express.Router()
-
-    r.use(bodyParser.json())
-    r.use(cookieParser())
-
-    r.use('/api/status', createStatusRouter())
-    r.use('/api/ping', new PingRouter())
-
-    r.get('/api/current-user', async (req, res) => {
-        res.json(await getRequestUser(req))
-    })
-
-    r.post('/api/login', async (req, res) => {
-        const { username } = req.body
-
-        const user = await getUser(db, username)
-        if (!user) {
-            res.sendStatus(403)
-            return
-        }
-
-        res.cookie('sid', sessions.createSession(username), { maxAge: 1000 * 60 * 60 * 24 * 7 })
-        res.json({ status: 'ok' })
-    })
-
-    r.post('/api/logout', (req, res) => {
-        res.cookie('sid', '', { expires: new Date() })
-        res.json({ status: 'ok' })
-    })
-
-    r.get('/api/users', async (req, res) => {
-        const requestUser = await getRequestUser(req)
-        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
-            res.sendStatus(401)
-            return
-        }
-
-        const users = await getUsers(db)
-        res.json(users)
-    })
-
-    r.get('/api/problems', async (req, res) => {
-        res.json(await getProblems(db))
-    })
-
-    r.get('/api/problem/:id', async (req, res) => {
-        res.json(await getProblem(db, req.params.id))
-    })
-
-    r.post('/api/problem', async (req, res) => {
-        const user = await getRequestUser(req)
-        if (!user) {
-            res.sendStatus(401)
-            return
-        }
-        if (user.role !== 'admin' && user.role !== 'moderator') {
-            res.sendStatus(401)
-            return
-        }
-
-        const id = await createProblem(db, {
-            content: req.body.content,
-            createBy: user.username,
-        })
-
-        res.json(id)
-    })
-
-    r.get('/api/solutions', async (req, res) => {
-        let queryUserId = req.query.user
-        let queryProblemId = req.query.problem
-
-        const requestUser = await getRequestUser(req)
-        if (!requestUser) {
-            res.sendStatus(401)
-            return
-        }
-
-        // if current user is not an administrator then force the user query to current user
-        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
-            queryUserId = requestUser.username
-        }
-
-        res.json(await getSolutions(db, { userId: queryUserId, problemId: queryProblemId }))
-    })
-
-    r.post('/api/solution', async (req, res) => {
-        const user = await getRequestUser(req)
-        if (!user) {
-            res.sendStatus(401)
-            return
-        }
-
-        await createSolution(db, {
-            userId: user.username,
-            problemId: req.body.problemId,
-            content: req.body.content,
-        })
-
-        res.send({ status: 'ok' })
-    })
-
-    r.get('/api/user/:id', async (req, res) => {
-        const requestUser = await getRequestUser(req)
-        if (!requestUser) {
-            res.sendStatus(401)
-            return
-        }
-        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
-            res.sendStatus(401)
-            return
-        }
-
-        const requestedUser = await getUser(db, req.params.id)
-        if (!requestedUser) {
-            res.sendStatus(404)
-            return
-        }
-
-        res.json(requestedUser)
-    })
-
-    return r
-}
diff --git a/server/routes.ts b/server/routes.ts
new file mode 100644
index 0000000..bdb951a
--- /dev/null
+++ b/server/routes.ts
@@ -0,0 +1,249 @@
+import crypto from 'crypto'
+
+import bodyParser from 'body-parser'
+import cookieParser from 'cookie-parser'
+
+import express, { Request, Response, Router } from 'express'
+
+import { createStatusRouter } from './middlewares'
+
+import {
+    createDatabase,
+    createProblem,
+    createSolution,
+    getProblem,
+    getProblems,
+    getSolution,
+    getSolutions,
+    getUser,
+    getUsers,
+    updateSolution,
+} from './db/database'
+
+import { isAdministrator, isStudent, Problem, ProblemId, UserId } from '../shared/model'
+import { initialDatabaseValue } from './db/example-data'
+
+export async function createApiRouter() {
+    type SessionId = string
+
+    const sessions = {
+        store: {},
+        createSession(userId: UserId) {
+            const sid = crypto.randomBytes(10).toString('hex')
+            this.store[sid] = userId
+            return sid
+        },
+        getUserForSession(sid: SessionId) {
+            return this.store[sid] ?? null
+        },
+    }
+
+    const db = createDatabase('./db.local.json', initialDatabaseValue)
+
+    async function getRequestUser(req: Request) {
+        const userId = sessions.getUserForSession(req.cookies.sid)
+        if (!userId) {
+            return null
+        }
+
+        console.log(userId)
+
+        return await getUser(db, userId)
+    }
+
+    const r: Router = express.Router()
+
+    r.use(bodyParser.json())
+    r.use(cookieParser())
+
+    r.use('/api/status', createStatusRouter())
+    // r.use('/api/ping', new PingRouter())
+
+    r.get('/api/current-user', async (req, res) => {
+        res.json(await getRequestUser(req))
+    })
+
+    r.post('/api/login', async (req, res) => {
+        const { id } = req.body
+
+        const user = await getUser(db, id)
+        if (!user) {
+            res.sendStatus(403)
+            return
+        }
+
+        res.cookie('sid', sessions.createSession(id), { maxAge: 1000 * 60 * 60 * 24 * 7 })
+        res.json({ status: 'ok' })
+    })
+
+    r.post('/api/logout', (req, res) => {
+        res.cookie('sid', '', { expires: new Date() })
+        res.json({ status: 'ok' })
+    })
+
+    r.get('/api/users', async (req, res) => {
+        const requestUser = await getRequestUser(req)
+        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
+            res.sendStatus(401)
+            return
+        }
+
+        const users = await getUsers(db)
+        res.json(users)
+    })
+
+    r.get('/api/problems', async (req, res) => {
+        type ProblemWithSolutionsCount = Problem & { solutionsCount?: number }
+
+        const problems: ProblemWithSolutionsCount[] = await getProblems(db)
+        const solutions = await getSolutions(db)
+
+        const solutionCounts: Record<ProblemId, number> = {}
+
+        for (const s of solutions) {
+            solutionCounts[s.forProblem] ||= 0
+            solutionCounts[s.forProblem]++
+        }
+
+        for (const p of problems) {
+            p.solutionsCount = solutionCounts[p.id] || 0
+        }
+
+        res.json(problems)
+    })
+
+    r.get('/api/problem/:id', async (req, res) => {
+        res.json(await getProblem(db, req.params.id))
+    })
+
+    r.post('/api/problem', async (req, res) => {
+        const user = await getRequestUser(req)
+        if (!user) {
+            res.sendStatus(401)
+            return
+        }
+        if (user.role !== 'admin' && user.role !== 'moderator') {
+            res.sendStatus(401)
+            return
+        }
+
+        const id = await createProblem(db, {
+            content: req.body.content,
+            createdBy: user.id,
+        })
+
+        res.json(id)
+    })
+
+    r.get('/api/solution/:id', async (req, res) => {
+        const user = await getRequestUser(req)
+
+        // l'utente deve essere loggato
+        if (!user) {
+            res.sendStatus(401)
+            return
+        }
+
+        const solution = await getSolution(db, req.params.id)
+
+        // uno studente che prova a ottenere la soluzione di un altro utente
+        if (!isAdministrator(user.role) && solution.sentBy !== user.id) {
+            res.sendStatus(401)
+            return
+        }
+
+        res.json(solution)
+    })
+
+    r.get('/api/solutions', async (req, res) => {
+        let queryUserId = req.query.user as string
+        let queryProblemId = req.query.problem as string
+
+        const requestUser = await getRequestUser(req)
+        if (!requestUser) {
+            res.sendStatus(401)
+            return
+        }
+
+        // if current user is not an administrator then force the user query to current user
+        if (!isAdministrator(requestUser.role)) {
+            queryUserId = requestUser.id
+        }
+
+        res.json(
+            await getSolutions(db, {
+                sentBy: queryUserId as UserId,
+                forProblem: queryProblemId as ProblemId,
+            })
+        )
+    })
+
+    r.post('/api/solution', async (req, res) => {
+        const user = await getRequestUser(req)
+        if (!user) {
+            res.sendStatus(401)
+            return
+        }
+
+        await createSolution(db, {
+            sentBy: user.id,
+            forProblem: req.body.problemId,
+            content: req.body.content,
+            status: 'pending',
+        })
+
+        res.send({ status: 'ok' })
+    })
+
+    r.post('/api/solution/:id', async (req, res) => {
+        const user = await getRequestUser(req)
+
+        // l'utente deve essere loggato
+        if (!user) {
+            res.sendStatus(401)
+            return
+        }
+
+        const solutionId = req.params.id
+        const solution = await getSolution(db, solutionId)
+
+        // uno studente non può modificare una soluzione di un altro utente
+        if (isStudent(user.role) && solution.sentBy !== user.id) {
+            res.sendStatus(401)
+            return
+        }
+
+        // modifico la soluzione con il json mandato dal client nel body della richiesta
+        await updateSolution(db, solutionId, req.body)
+
+        res.json({ status: 'ok' })
+    })
+
+    r.get('/api/user/:id', async (req, res) => {
+        const user = await getRequestUser(req)
+
+        // intanto l'utente deve essere loggato
+        if (!user) {
+            res.sendStatus(401)
+            return
+        }
+
+        // solo gli amministratori possono usare questa route
+        if (!isAdministrator(user.role)) {
+            res.sendStatus(401)
+            return
+        }
+
+        const requestedUser = await getUser(db, req.params.id)
+
+        // l'utente richiesto magari deve esistere
+        if (!requestedUser) {
+            res.sendStatus(404)
+            return
+        }
+
+        res.json(requestedUser)
+    })
+
+    return r
+}
diff --git a/shared/db-refs.ts b/shared/db-refs.ts
new file mode 100644
index 0000000..bf9547c
--- /dev/null
+++ b/shared/db-refs.ts
@@ -0,0 +1,25 @@
+import { ProblemId, SolutionId, UserId } from './model'
+
+// export function refToUserId(ref: string): UserId {
+//     if (!ref.startsWith('user/')) {
+//         throw new Error(`"${ref}" is not a reference to a User`)
+//     }
+
+//     return ref.slice('user/'.length)
+// }
+
+// export function refToProblemId(ref: string): ProblemId {
+//     if (!ref.startsWith('problem/')) {
+//         throw new Error(`"${ref}" is not a reference to a Problem`)
+//     }
+
+//     return ref.slice('problem/'.length)
+// }
+
+// export function refToSolutionId(ref: string): SolutionId {
+//     if (!ref.startsWith('solution/')) {
+//         throw new Error(`"${ref}" is not a reference to a Solution`)
+//     }
+
+//     return ref.slice('solution/'.length)
+// }
diff --git a/shared/model.ts b/shared/model.ts
new file mode 100644
index 0000000..7d3cd04
--- /dev/null
+++ b/shared/model.ts
@@ -0,0 +1,62 @@
+//
+// Common
+//
+
+export type CommonProps = 'id' | 'createdAt'
+
+type Opaque<T, K, L extends string = 'opaque'> = T & { _: K; __: L }
+
+type Id<T> = Opaque<string, T, 'id'>
+
+//
+// Users
+//
+
+export type AdministratorRole = 'admin' | 'moderator'
+export type StudentRole = 'student'
+
+export type UserRole = AdministratorRole | StudentRole
+
+export type UserId = Id<User>
+
+export type User = {
+    id: UserId
+    role: UserRole
+}
+
+export function isAdministrator(role: UserRole): role is AdministratorRole {
+    return role !== 'student'
+}
+
+export function isStudent(role: UserRole): role is StudentRole {
+    return role === 'student'
+}
+
+//
+// Problems
+//
+
+export type ProblemId = Id<Problem>
+
+export type Problem = {
+    id: ProblemId
+    content: string
+    createdBy: UserId
+    createdAt: string
+}
+
+//
+// Solutions
+//
+
+export type SolutionStatus = 'pending' | 'rejected' | 'accepted'
+
+export type SolutionId = string
+
+export type Solution = {
+    id: SolutionId
+    sentBy: UserId
+    forProblem: ProblemId
+    content: string
+    status: SolutionStatus
+}
diff --git a/shared/ssr.ts b/shared/ssr.ts
new file mode 100644
index 0000000..85b1c9b
--- /dev/null
+++ b/shared/ssr.ts
@@ -0,0 +1,6 @@
+export type RenderedPage = {
+    html: string
+    metadata: any
+}
+
+export type RenderFunction = (url: string) => RenderedPage
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..c31d2e1
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,23 @@
+{
+    "compilerOptions": {
+        "target": "ESNext",
+        "useDefineForClassFields": true,
+        "lib": ["DOM", "DOM.Iterable", "ESNext"],
+        "allowJs": false,
+        "skipLibCheck": true,
+        "esModuleInterop": false,
+        "allowSyntheticDefaultImports": true,
+        "strict": true,
+        "noImplicitAny": true,
+        "forceConsistentCasingInFileNames": true,
+        "module": "ESNext",
+        "moduleResolution": "Node",
+        "resolveJsonModule": true,
+        "isolatedModules": true,
+        "noEmit": true,
+        "jsx": "react-jsx",
+        "jsxImportSource": "preact"
+    },
+    "include": ["client", "shared"],
+    "references": [{ "path": "./tsconfig.node.json" }]
+}
diff --git a/tsconfig.node.json b/tsconfig.node.json
new file mode 100644
index 0000000..0d5580b
--- /dev/null
+++ b/tsconfig.node.json
@@ -0,0 +1,10 @@
+{
+    "compilerOptions": {
+        "composite": true,
+        "module": "ESNext",
+        "moduleResolution": "Node",
+        "noImplicitAny": true,
+        "allowSyntheticDefaultImports": true
+    },
+    "include": ["server", "shared"]
+}