From 0c3a6ebf2fd911e61c89ec8341c2d1db99cfe857 Mon Sep 17 00:00:00 2001
From: Innei <i@innei.in>
Date: Sun, 9 Jul 2023 23:01:26 +0800
Subject: [PATCH] fix: toc

Signed-off-by: Innei <i@innei.in>
---
 global.d.ts                                   |  11 +-
 .../widgets/shared/ArticleRightAside.tsx      |  72 +++++++++--
 src/components/widgets/toc/TocAside.tsx       | 112 ++++++++++--------
 src/components/widgets/toc/TocItem.tsx        |   9 --
 src/styles/theme.css                          |  26 +++-
 5 files changed, 157 insertions(+), 73 deletions(-)

diff --git a/global.d.ts b/global.d.ts
index 5ac91e7b6a..19bb826ae7 100644
--- a/global.d.ts
+++ b/global.d.ts
@@ -11,12 +11,11 @@ declare global {
     } & Props
   >
 
-  export type Component<P = {}> = FC<
-    {
-      className?: string
-    } & P &
-      PropsWithChildren
-  >
+  export type Component<P = {}> = FC<ComponentType & P>
+
+  export type ComponentType = {
+    className?: string
+  } & PropsWithChildren
 
   // TODO should remove in next TypeScript version
   interface Document {
diff --git a/src/components/widgets/shared/ArticleRightAside.tsx b/src/components/widgets/shared/ArticleRightAside.tsx
index a56ae3efd0..c4d3df3bee 100644
--- a/src/components/widgets/shared/ArticleRightAside.tsx
+++ b/src/components/widgets/shared/ArticleRightAside.tsx
@@ -1,19 +1,73 @@
-import React from 'react'
+'use client'
+
+import React, { useEffect, useRef, useState } from 'react'
+import clsx from 'clsx'
+import type { TocAsideRef } from '../toc'
+
+import { useViewport } from '~/atoms'
 
 import { TocAside } from '../toc'
 import { ReadIndicator } from './ReadIndicator'
 
 export const ArticleRightAside: Component = ({ children }) => {
+  const asideRef = useRef<TocAsideRef>(null)
+  const [isScrollToBottom, setIsScrollToBottom] = useState(false)
+  const [isScrollToTop, setIsScrollToTop] = useState(false)
+  const [canScroll, setCanScroll] = useState(false)
+  const h = useViewport((v) => v.h)
+  useEffect(() => {
+    const $ = asideRef.current?.getContainer()
+    if (!$) return
+
+    // if $ can not scroll, return null
+    if ($.scrollHeight <= $.clientHeight + 2) return
+
+    setCanScroll(true)
+
+    const handler = () => {
+      // to bottom
+      if ($.scrollTop + $.clientHeight + 20 > $.scrollHeight) {
+        setIsScrollToBottom(true)
+        setIsScrollToTop(false)
+      }
+
+      // if scroll to top,
+      // set isScrollToTop to true
+      else if ($.scrollTop === 0) {
+        setIsScrollToTop(true)
+        setIsScrollToBottom(false)
+      } else {
+        setIsScrollToBottom(false)
+        setIsScrollToTop(false)
+      }
+    }
+    $.addEventListener('scroll', handler)
+
+    handler()
+
+    return () => {
+      $.removeEventListener('scroll', handler)
+    }
+  }, [h])
+
   return (
-    <aside className="sticky top-2 h-[calc(100vh-6rem-4.5rem-150px)]">
-      <TocAside
-        as="div"
-        className="top-[120px] ml-4"
-        treeClassName="absolute h-full min-h-[120px]"
-        accessory={ReadIndicator}
-      />
+    <aside className="sticky top-[120px] mt-[120px] h-[calc(100vh-6rem-4.5rem-150px-120px)]">
+      <div className="relative h-full">
+        <TocAside
+          as="div"
+          className="static ml-4"
+          treeClassName={clsx(
+            'absolute h-full min-h-[120px] overflow-auto',
+            isScrollToBottom && 'mask-t',
+            isScrollToTop && 'mask-b',
+            canScroll && !isScrollToBottom && !isScrollToTop && 'mask-both',
+          )}
+          accessory={ReadIndicator}
+          ref={asideRef}
+        />
+      </div>
       {React.cloneElement(children as any, {
-        className: 'ml-4 translate-y-full',
+        className: 'ml-4 translate-y-[calc(100%+24px)]',
       })}
     </aside>
   )
diff --git a/src/components/widgets/toc/TocAside.tsx b/src/components/widgets/toc/TocAside.tsx
index 658af2a765..650118e39a 100644
--- a/src/components/widgets/toc/TocAside.tsx
+++ b/src/components/widgets/toc/TocAside.tsx
@@ -1,6 +1,12 @@
 'use client'
 
-import React, { useEffect, useMemo, useRef } from 'react'
+import React, {
+  forwardRef,
+  useEffect,
+  useImperativeHandle,
+  useMemo,
+  useRef,
+} from 'react'
 
 import { throttle } from '~/lib/_'
 import { clsxm } from '~/lib/helper'
@@ -17,56 +23,66 @@ export interface TocSharedProps {
 
   as?: React.ElementType
 }
-export const TocAside: Component<TocAsideProps & TocSharedProps> = ({
-  className,
-  children,
-  treeClassName,
-  accessory,
-  as: As = 'aside',
-}) => {
-  const containerRef = useRef<HTMLUListElement>(null)
-  const $article = useWrappedElement()
+export interface TocAsideRef {
+  getContainer: () => HTMLUListElement | null
+}
+export const TocAside = forwardRef<
+  TocAsideRef,
+  TocAsideProps & TocSharedProps & ComponentType
+>(
+  (
+    { className, children, treeClassName, accessory, as: As = 'aside' },
+    ref,
+  ) => {
+    const containerRef = useRef<HTMLUListElement>(null)
+    const $article = useWrappedElement()
+
+    useImperativeHandle(ref, () => ({
+      getContainer: () => containerRef.current,
+    }))
 
-  if (typeof $article === 'undefined') {
-    throw new Error('<Toc /> must be used in <WrappedElementProvider />')
-  }
-  const $headings = useMemo(() => {
-    if (!$article) {
-      return []
+    if (typeof $article === 'undefined') {
+      throw new Error('<Toc /> must be used in <WrappedElementProvider />')
     }
+    const $headings = useMemo(() => {
+      if (!$article) {
+        return []
+      }
 
-    return [
-      ...$article.querySelectorAll('h1,h2,h3,h4,h5,h6'),
-    ] as HTMLHeadingElement[]
-  }, [$article])
+      return [
+        ...$article.querySelectorAll('h1,h2,h3,h4,h5,h6'),
+      ] as HTMLHeadingElement[]
+    }, [$article])
 
-  useEffect(() => {
-    const setMaxWidth = throttle(() => {
-      if (containerRef.current) {
-        containerRef.current.style.maxWidth = `${
-          window.innerWidth -
-          containerRef.current.getBoundingClientRect().x -
-          30
-        }px`
-      }
-    }, 14)
-    setMaxWidth()
+    useEffect(() => {
+      const setMaxWidth = throttle(() => {
+        if (containerRef.current) {
+          containerRef.current.style.maxWidth = `${
+            window.innerWidth -
+            containerRef.current.getBoundingClientRect().x -
+            30
+          }px`
+        }
+      }, 14)
+      setMaxWidth()
 
-    window.addEventListener('resize', setMaxWidth)
-    return () => {
-      window.removeEventListener('resize', setMaxWidth)
-    }
-  }, [])
+      window.addEventListener('resize', setMaxWidth)
+      return () => {
+        window.removeEventListener('resize', setMaxWidth)
+      }
+    }, [])
 
-  return (
-    <As className={clsxm('st-toc z-[3]', 'relative font-sans', className)}>
-      <TocTree
-        $headings={$headings}
-        containerRef={containerRef}
-        className={clsxm('absolute max-h-[75vh]', treeClassName)}
-        accessory={accessory}
-      />
-      {children}
-    </As>
-  )
-}
+    return (
+      <As className={clsxm('st-toc z-[3]', 'relative font-sans', className)}>
+        <TocTree
+          $headings={$headings}
+          containerRef={containerRef}
+          className={clsxm('absolute max-h-[75vh]', treeClassName)}
+          accessory={accessory}
+        />
+        {children}
+      </As>
+    )
+  },
+)
+TocAside.displayName = 'TocAside'
diff --git a/src/components/widgets/toc/TocItem.tsx b/src/components/widgets/toc/TocItem.tsx
index 59922e2417..0647c7ae07 100644
--- a/src/components/widgets/toc/TocItem.tsx
+++ b/src/components/widgets/toc/TocItem.tsx
@@ -38,15 +38,6 @@ export const TocItem: FC<{
 
   const $ref = useRef<HTMLAnchorElement>(null)
 
-  // useEffect(() => {
-  //   if (!active) {
-  //     return
-  //   }
-  //   if (!getIsInteractive()) return
-  //   const state = history.state
-  //   history.replaceState(state, '', `#${anchorId}`)
-  // }, [active, anchorId])
-
   useEffect(() => {
     if (active) {
       $ref.current?.scrollIntoView({ behavior: 'smooth' })
diff --git a/src/styles/theme.css b/src/styles/theme.css
index 0e52787c9c..f938b36911 100644
--- a/src/styles/theme.css
+++ b/src/styles/theme.css
@@ -9,7 +9,8 @@
     background-size: 0% 1.5px;
     background-repeat: no-repeat;
     /* NOTE: this won't work with background images   */
-    text-shadow: 0.05em 0 theme(colors.base-100),
+    text-shadow:
+      0.05em 0 theme(colors.base-100),
       -0.05em 0 theme(colors.base-100);
     transition: all 500ms ease;
 
@@ -114,3 +115,26 @@
     }
   }
 }
+
+.mask-both {
+  mask-image: linear-gradient(
+    rgba(255, 255, 255, 0) 0%,
+    rgb(255, 255, 255) 10%,
+    rgb(255, 255, 255) 90%,
+    rgba(255, 255, 255, 0) 100%
+  );
+}
+
+.mask-b {
+  mask-image: linear-gradient(
+    rgb(255, 255, 255) 90%,
+    rgba(255, 255, 255, 0) 100%
+  );
+}
+
+.mask-t {
+  mask-image: linear-gradient(
+    rgba(255, 255, 255, 0) 0%,
+    rgb(255, 255, 255) 10%
+  );
+}