persist language preference; close #42

src/components/markdown/LanguageSection.tsx

@@ -12,11 +12,21 @@ export const LanguageSection = props => {
     if (type === 'JavaSection') sections['java'] = child;
     if (type === 'PySection') sections['py'] = child;
   });
+  const languages = {
+    cpp: 'C++',
+    java: 'Java',
+    py: 'Python',
+  };
   if (!sections.hasOwnProperty(lang)) {
     return (
-      <div>
-        This section isn't yet available in your chosen language: {lang}. Please
-        choose a different default language.
+      <div className="p-4 bg-red-100 text-red-800 rounded">
+        <b>
+          This section isn't yet available in your chosen language:{' '}
+          {languages[lang]}.
+        </b>{' '}
+        Please choose a different default language for now. Feel free to file a
+        request to add support for {languages[lang]} using the "Contact Us"
+        button.
       </div>
     );
   }
@@ -24,13 +34,13 @@ export const LanguageSection = props => {
 };
 
 export const CPPSection = props => {
-  return <div>{props.children}</div>;
+  return <>{props.children}</>;
 };
 
 export const JavaSection = props => {
-  return <div>{props.children}</div>;
+  return <>{props.children}</>;
 };
 
 export const PySection = props => {
-  return <div>{props.children}</div>;
+  return <>{props.children}</>;
 };

src/components/markdown/Resources.tsx

@@ -2,6 +2,8 @@ import * as React from 'react';
 import Dots from '../Dots';
 import Tooltip from '../tooltip/Tooltip';
 import TextTooltip from '../tooltip/TextTooltip';
+import { useContext } from 'react';
+import UserSettingsContext from '../../context/UserSettingsContext';
 
 export function ResourcesListComponent(props) {
   const embedded = props.embedded;
@@ -44,7 +46,6 @@ export function ResourcesListComponent(props) {
 const books = {
   CPH: '/CPH.pdf',
   PAPS: 'https://www.csc.kth.se/~jsannemo/slask/main.pdf',
-  IUSACO: 'https://darrenyao.com/usacobook/java.pdf',
   CP1:
     'https://www.comp.nus.edu.sg/~stevenha/myteaching/competitive_programming/cp1.pdf',
 };
@@ -91,10 +92,18 @@ export const sourceTooltip = {
 };
 
 export function ResourceComponent(props) {
+  const userSettings = useContext(UserSettingsContext);
+
   const source = props.source;
   let url = props.url;
   if (!url) {
-    if (source in books) {
+    if (source === 'IUSACO') {
+      if (userSettings.primaryLang === 'java') {
+        url = 'https://darrenyao.com/usacobook/java.pdf';
+      } else {
+        url = 'https://darrenyao.com/usacobook/cpp.pdf';
+      }
+    } else if (source in books) {
       url = books[source];
     } else
       throw `No URL. Did you make a typo in the source (${source})? Resource title: ${props.title}`;

src/context/UserSettingsContext.tsx

@@ -1,5 +1,6 @@
-import { createContext, useCallback, useState } from 'react';
+import { createContext } from 'react';
 import * as React from 'react';
+import useStickyState from '../hooks/useStickyState';
 
 const UserSettingsContext = createContext({
   primaryLang: 'cpp',
@@ -7,7 +8,10 @@ const UserSettingsContext = createContext({
 });
 
 export const UserSettingsProvider = ({ children }) => {
-  const [primaryLang, setPrimaryLang] = useState('cpp');
+  const [primaryLang, setPrimaryLang] = useStickyState(
+    'cpp',
+    'user-primary-lang'
+  );
   return (
     <UserSettingsContext.Provider
       value={{