Add loading indicator to group switcher

src/app/agregator/old-schedule.txt

@@ -0,0 +1,64 @@
+import { Day } from '@/shared/model/day'
+import { parsePage } from '@/app/parser/schedule'
+import contentTypeParser from 'content-type'
+import { JSDOM } from 'jsdom'
+// import { content as mockContent } from './mock'
+import { reportParserError } from '@/app/logger'
+// import { groups } from '@/shared/data/groups'
+
+// const fetchingGroups: {
+//   [groupID: number]: boolean
+// } = Object.fromEntries(Object.values(groups).map(([gId]) => [gId, false]))
+
+// const callbacks: {
+//   [groupID: number]: Set<{ resolve: (days: Day[]) => void, reject: (e: unknown) => void }>
+// } = Object.fromEntries(Object.values(groups).map(([gId]) => [gId, new Set()]))
+
+export async function getSchedule(groupID: number, groupName: string): Promise<Day[]> {
+  // if (fetchingGroups[groupID]) {
+  //   return new Promise((resolve, reject) => {
+  //     callbacks[groupID].add({
+  //       resolve: (days: Day[]) => resolve(days),
+  //       reject
+  //     })
+  //   })
+  // } else {
+  //   fetchingGroups[groupID] = true
+  // }
+
+  // try {
+  //   const result = await parseSchedule(groupID, groupName)
+  //   fetchingGroups[groupID] = false
+  //   Array.from(callbacks[groupID].values()).forEach(({ resolve }) => resolve(result))
+  //   callbacks[groupID].clear()
+  //   return result
+  // } catch(e) {
+  //   fetchingGroups[groupID] = false
+  //   console.log(Array.from(callbacks[groupID].values()).length)
+  //   Array.from(callbacks[groupID].values()).forEach(({ reject }) => reject(e))
+  //   callbacks[groupID].clear()
+  //   throw e
+  // }
+}
+
+export async function parseSchedule(groupID: number, groupName: string) {
+  const page = await fetch(`${process.env.PROXY_URL ?? 'https://lk.ks.psuti.ru'}/?mn=2&obj=${groupID}`)
+  // const page = { text: async () => mockContent, status: 200, headers: { get: (s: string) => s && 'text/html' } }
+  const content = await page.text()
+  const contentType = page.headers.get('content-type')
+  if (page.status === 200 && contentType && contentTypeParser.parse(contentType).type === 'text/html') {
+    try {
+      const root = new JSDOM(content).window.document
+      return parsePage(root, groupName)
+    } catch (e) {
+      console.error('Error while parsing lk.ks.psuti.ru')
+      reportParserError(new Date().toISOString(), 'Не удалось сделать парсинг для группы', groupName)
+      throw e
+    }
+  } else {
+    console.error(page.status, contentType)
+    console.error(content.length > 500 ? content.slice(0, 500 - 3) + '...' : content)
+    reportParserError(new Date().toISOString(), 'Не удалось получить страницу для группы', groupName)
+    throw new Error('Error while fetching lk.ks.psuti.ru')
+  }
+}

src/pages/[group].tsx

@@ -18,10 +18,11 @@ type PageProps = {
     name: string
   }
   parsedAt: Date
+  cacheAvailableFor: string[]
 }
 
 export default function HomePage(props: NextSerialized<PageProps>) {
-  const { schedule, group, parsedAt } = nextDeserialized<PageProps>(props)
+  const { schedule, group, cacheAvailableFor, parsedAt } = nextDeserialized<PageProps>(props)
 
   React.useEffect(() => {
     if (typeof window !== 'undefined') {
@@ -51,7 +52,7 @@ export default function HomePage(props: NextSerialized<PageProps>) {
         <meta property="og:title" content={`Группа ${group.name} — Расписание занятий в Колледже Связи`} />
         <meta property="og:description" content={`Расписание занятий группы ${group.name} на неделю в Колледже Связи ПГУТИ. Расписание пар, материалы для подготовки и изменения в расписании.`} />
       </Head>
-      <NavBar />
+      <NavBar cacheAvailableFor={cacheAvailableFor} />
       <LastUpdateAt date={parsedAt} />
       <Schedule days={schedule} />
     </>
@@ -102,6 +103,10 @@ export async function getServerSideProps(context: GetServerSidePropsContext<{ gr
       return { props: {} }
     }
 
+    const cacheAvailableFor = Array.from(cachedSchedules.entries())
+      .filter(([, v]) => v.lastFetched.getTime() + maxCacheDurationInMS > Date.now())
+      .map(([k]) => k)
+
     context.res.setHeader('ETag', `"${etag}"`)
     return {
       props: nextSerialized({
@@ -110,7 +115,8 @@ export async function getServerSideProps(context: GetServerSidePropsContext<{ gr
         group: {
           id: group,
           name: groups[group][1]
-        }
+        },
+        cacheAvailableFor
       })
     }
   } else {

src/shadcn/ui/button.tsx

@@ -3,6 +3,7 @@ import { Slot } from "@radix-ui/react-slot"
 import { cva, type VariantProps } from "class-variance-authority"
 
 import { cn } from "@/shared/utils"
+import { Spinner } from "@/shared/ui/spinner"
 
 const buttonVariants = cva(
   "inline-flex items-center justify-center rounded-md text-sm font-medium ring-offset-background transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50",
@@ -37,17 +38,26 @@ export interface ButtonProps
   extends React.ButtonHTMLAttributes<HTMLButtonElement>,
     VariantProps<typeof buttonVariants> {
   asChild?: boolean
+  loading?: boolean
 }
 
 const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
-  ({ className, variant, size, asChild = false, ...props }, ref) => {
+  ({ className, variant, size, asChild = false, disabled, loading, children, ...props }, ref) => {
     const Comp = asChild ? Slot : "button"
     return (
-      <Comp
+      <>
-        className={cn(buttonVariants({ variant, size, className }))}
+        <Comp
-        ref={ref}
+          className={cn(buttonVariants({ variant, size, className }))}
-        {...props}
+          ref={ref}
-      />
+          disabled={loading || disabled}
+          {...props}
+        >
+          {loading && (
+            <Spinner />
+          )}
+          {children}
+        </Comp>
+      </>
     )
   }
 )

src/shared/context/nav-context.tsx

@@ -0,0 +1,19 @@
+import React from 'react'
+
+type ContextState = { cacheAvailableFor: string[], isLoading: false | string, setIsLoading: (isLoading: false | string) => void }
+
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore
+export const NavContext = React.createContext<ContextState>(null)
+
+export function NavContextProvider({ cacheAvailableFor, children }: React.PropsWithChildren<{
+  cacheAvailableFor: string[]
+}>) {
+  const [isLoading, setIsLoading] = React.useState<ContextState['isLoading']>(false)
+
+  return (
+    <NavContext.Provider value={{ cacheAvailableFor, isLoading, setIsLoading }}>
+      {children}
+    </NavContext.Provider>
+  )
+}

src/shared/ui/spinner.tsx

@@ -0,0 +1,7 @@
+import styles from './styles.module.scss'
+
+export function Spinner() {
+  return (
+    <div className={styles.spinner} />
+  )
+}

src/shared/ui/styles.module.scss

@@ -0,0 +1,15 @@
+.spinner {
+  border: 2px solid rgba(255, 255, 255, 0.3);
+  border-radius: 50%;
+  border-left: 2px solid transparent;
+  border-top: 2px solid transparent;
+  width: 16px;
+  height: 16px;
+  animation: spin 1s linear infinite;
+  margin-right: 8px;
+}
+
+@keyframes spin {
+  0% { transform: rotate(0deg); }
+  100% { transform: rotate(360deg); }
+}

src/widgets/navbar/index.tsx

@@ -7,8 +7,11 @@ import Link from 'next/link'
 import { useRouter } from 'next/router'
 import { FaGithub } from 'react-icons/fa'
 import cx from 'classnames'
+import { NavContext, NavContextProvider } from '@/shared/context/nav-context'
 
-export function NavBar() {
+export function NavBar({ cacheAvailableFor }: {
+  cacheAvailableFor: string[]
+}) {
   const { resolvedTheme } = useTheme()
   const [schemeTheme, setSchemeTheme] = React.useState<string>()
   const navRef = React.useRef<HTMLDivElement>(null)
@@ -37,23 +40,25 @@ export function NavBar() {
   }, [theme])
 
   return (
-    <header className="sticky top-0 w-full p-2 bg-background z-[1] pb-0 mb-2 shadow-header">
+    <NavContextProvider cacheAvailableFor={cacheAvailableFor}>
-      <nav className={cx('rounded-lg p-2 w-full flex justify-between', { 'bg-slate-200': theme === 'light', 'bg-slate-900': theme === 'dark' })} ref={navRef}>
+      <header className="sticky top-0 w-full p-2 bg-background z-[1] pb-0 mb-2 shadow-header">
-        <ul className="flex gap-2">
+        <nav className={cx('rounded-lg p-2 w-full flex justify-between', { 'bg-slate-200': theme === 'light', 'bg-slate-900': theme === 'dark' })} ref={navRef}>
-          <NavBarItem url="/ps7">ПС-7</NavBarItem>
+          <ul className="flex gap-2">
-          <NavBarItem url="/pks35k">ПКС-35к</NavBarItem>
+            <NavBarItem url="/ps7">ПС-7</NavBarItem>
-          <AddGroupButton />
+            <NavBarItem url="/pks35k">ПКС-35к</NavBarItem>
-        </ul>
+            <AddGroupButton />
-        <div className='flex gap-1 min-[500px]:gap-2'>
+          </ul>
-          <Link href='https://github.com/VityaSchel/kspguti-schedule' target='_blank' rel='nofollower noreferrer'>
+          <div className='flex gap-1 min-[500px]:gap-2'>
-            <Button variant='outline' size='icon' tabIndex={-1}>
+            <Link href='https://github.com/VityaSchel/kspguti-schedule' target='_blank' rel='nofollower noreferrer'>
-              <FaGithub />
+              <Button variant='outline' size='icon' tabIndex={-1}>
-            </Button>
+                <FaGithub />
-          </Link>
+              </Button>
-          <ThemeSwitcher />
+            </Link>
-        </div>
+            <ThemeSwitcher />
-      </nav>
+          </div>
-    </header>
+        </nav>
+      </header>
+    </NavContextProvider>
   )
 }
 
@@ -62,12 +67,50 @@ function NavBarItem({ url, children }: React.PropsWithChildren<{
 }>) {
   const router = useRouter()
   const isActive = router.asPath === url
+  const { cacheAvailableFor, isLoading, setIsLoading } = React.useContext(NavContext)
+
+  const handleStartLoading = async () => {
+    let isLoaded = false
+
+    const loadEnd = () => {
+      isLoaded = true
+      setIsLoading(false)
+    }
+
+    router.events.on('routeChangeComplete', loadEnd)
+    router.events.on('routeChangeError', loadEnd)
+
+    if (cacheAvailableFor.includes(url.slice(1))) {
+      await new Promise(resolve => setTimeout(resolve, 500))
+      if(isLoaded) return
+    }
+    setIsLoading(url)
+
+    return () => {
+      router.events.off('routeChangeComplete', loadEnd)
+      router.events.off('routeChangeError', loadEnd)
+    }
+  }
+
+  const button = (
+    <Button 
+      tabIndex={-1} variant={isActive ? 'default' : 'secondary'} 
+      disabled={Boolean(isLoading)}
+      loading={isLoading === url}
+    >
+      {children}
+    </Button>
+  )
 
   return (
     <li>
-      <Link href={url}>
+      {isLoading ? (
-        <Button tabIndex={-1} variant={isActive ? 'default' : 'secondary'}>{children}</Button>
+        button
-      </Link>
+      ) : (
+        <Link href={url} onClick={handleStartLoading}>
+          {button}
+        </Link>
+      )}
     </li>
   )
 }