From d41eff9eccf66644c4c60f53cb516bf079937a28 Mon Sep 17 00:00:00 2001
From: aman333nolawz <amananudhiu@gmail.com>
Date: Mon, 2 Mar 2026 21:49:13 +0530
Subject: Using astro-erudite for static site generation

---
 src/components/TOCSidebar.astro | 365 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 365 insertions(+)
 create mode 100644 src/components/TOCSidebar.astro

(limited to 'src/components/TOCSidebar.astro')

diff --git a/src/components/TOCSidebar.astro b/src/components/TOCSidebar.astro
new file mode 100644
index 0000000..77be7c6
--- /dev/null
+++ b/src/components/TOCSidebar.astro
@@ -0,0 +1,365 @@
+---
+import { ScrollArea } from '@/components/ui/scroll-area'
+import type { TOCSection } from '@/lib/data-utils'
+import { getParentId, isSubpost } from '@/lib/data-utils'
+import { cn, getHeadingMargin } from '@/lib/utils'
+
+type Props = {
+  sections: TOCSection[]
+  currentPostId: string
+}
+
+const { sections, currentPostId } = Astro.props
+const isCurrentSubpost = isSubpost(currentPostId)
+const parentId = isCurrentSubpost ? getParentId(currentPostId) : currentPostId
+---
+
+{
+  sections.length > 0 && (
+    <div
+      id="toc-sidebar-container"
+      class="sticky top-20 col-start-1 row-span-1 mr-8 ml-auto hidden h-[calc(100vh-5rem)] max-w-md xl:block"
+    >
+      <ScrollArea
+        client:load
+        className="flex max-h-[calc(100vh-8rem)] flex-col overflow-y-auto"
+        type="hover"
+        data-toc-scroll-area
+      >
+        <div class="flex flex-col gap-2 px-4">
+          <span class="text-lg font-medium">Table of Contents</span>
+          {sections.map((section, index) => {
+            const isFirstSubpost =
+              section.type === 'subpost' &&
+              (index === 0 || sections[index - 1].type === 'parent')
+
+            return (
+              <>
+                {isFirstSubpost && (
+                  <div class="mt-2 flex items-center gap-2">
+                    <div class="bg-border h-px flex-1" />
+                    <span class="text-muted-foreground text-xs font-medium">
+                      Subposts
+                    </span>
+                    <div class="bg-border h-px flex-1" />
+                  </div>
+                )}
+
+                {section.type === 'parent' ? (
+                  <ul class="flex list-none flex-col gap-y-2">
+                    {section.headings.map((heading) => (
+                      <li
+                        class={cn(
+                          'text-sm',
+                          getHeadingMargin(heading.depth),
+                          isCurrentSubpost
+                            ? 'text-foreground/40'
+                            : 'text-foreground/60',
+                        )}
+                      >
+                        <a
+                          href={
+                            isCurrentSubpost
+                              ? `/blog/${parentId}#${heading.slug}`
+                              : `#${heading.slug}`
+                          }
+                          class="marker:text-foreground/30 list-none underline decoration-transparent underline-offset-[3px] transition-colors duration-200 hover:decoration-inherit"
+                          data-heading-link={heading.slug}
+                        >
+                          {heading.text}
+                        </a>
+                      </li>
+                    ))}
+                  </ul>
+                ) : (
+                  <div
+                    class={cn(
+                      'rounded-md border p-2',
+                      section.subpostId === currentPostId ? 'bg-muted/50' : '',
+                    )}
+                  >
+                    <ul class="flex list-none flex-col gap-y-2">
+                      <li
+                        class={cn(
+                          'text-xs font-medium',
+                          section.subpostId === currentPostId
+                            ? 'text-foreground'
+                            : 'text-foreground/60',
+                        )}
+                      >
+                        <a
+                          href={
+                            section.subpostId === currentPostId
+                              ? '#'
+                              : `/blog/${section.subpostId}`
+                          }
+                          class="marker:text-foreground/30 list-none underline decoration-transparent underline-offset-[3px] transition-colors duration-200 hover:decoration-inherit"
+                          data-heading-link={
+                            section.subpostId === currentPostId
+                              ? 'top'
+                              : `${section.subpostId}-top`
+                          }
+                        >
+                          {section.title}
+                        </a>
+                      </li>
+                      {section.headings.map((heading) => (
+                        <li
+                          class={cn(
+                            'text-xs',
+                            getHeadingMargin(heading.depth),
+                            section.subpostId === currentPostId
+                              ? 'text-foreground/60'
+                              : 'text-foreground/30',
+                          )}
+                        >
+                          <a
+                            href={
+                              section.subpostId === currentPostId
+                                ? `#${heading.slug}`
+                                : `/blog/${section.subpostId}#${heading.slug}`
+                            }
+                            class="marker:text-foreground/30 hover:text-foreground/60 list-none underline decoration-transparent underline-offset-[3px] transition-colors duration-200 hover:decoration-inherit"
+                            data-heading-link={
+                              section.subpostId === currentPostId
+                                ? heading.slug
+                                : `${section.subpostId}-${heading.slug}`
+                            }
+                          >
+                            {heading.text}
+                          </a>
+                        </li>
+                      ))}
+                    </ul>
+                  </div>
+                )}
+              </>
+            )
+          })}
+        </div>
+      </ScrollArea>
+    </div>
+  )
+}
+
+<script>
+  const HEADER_OFFSET = 150
+
+  class TOCState {
+    links: NodeListOf<Element> = document.querySelectorAll(
+      '[data-heading-link]',
+    )
+    activeIds: string[] = []
+    headings: HTMLElement[] = []
+    regions: { id: string; start: number; end: number }[] = []
+    scrollArea: HTMLElement | null = null
+    tocScrollArea: HTMLElement | null = null
+
+    reset() {
+      this.links = document.querySelectorAll(
+        '#toc-sidebar-container [data-heading-link]',
+      )
+      this.activeIds = []
+      this.headings = []
+      this.regions = []
+      const tocContainer = document.getElementById('toc-sidebar-container')
+      this.scrollArea =
+        tocContainer?.querySelector('[data-radix-scroll-area-viewport]') || null
+      this.tocScrollArea =
+        tocContainer?.querySelector('[data-toc-scroll-area]') || null
+    }
+  }
+
+  const state = new TOCState()
+
+  class HeadingRegions {
+    static build() {
+      state.headings = Array.from(
+        document.querySelectorAll<HTMLElement>(
+          '.prose h2, .prose h3, .prose h4, .prose h5, .prose h6',
+        ),
+      )
+
+      if (state.headings.length === 0) {
+        state.regions = []
+        return
+      }
+
+      state.regions = state.headings.map((heading, index) => {
+        const nextHeading = state.headings[index + 1]
+        return {
+          id: heading.id,
+          start: heading.offsetTop,
+          end: nextHeading ? nextHeading.offsetTop : document.body.scrollHeight,
+        }
+      })
+    }
+
+    static getVisibleIds(): string[] {
+      if (state.headings.length === 0) return []
+
+      const viewportTop = window.scrollY + HEADER_OFFSET
+      const viewportBottom = window.scrollY + window.innerHeight
+      const visibleIds = new Set<string>()
+
+      const isInViewport = (top: number, bottom: number) =>
+        (top >= viewportTop && top <= viewportBottom) ||
+        (bottom >= viewportTop && bottom <= viewportBottom) ||
+        (top <= viewportTop && bottom >= viewportBottom)
+
+      state.headings.forEach((heading) => {
+        const headingBottom = heading.offsetTop + heading.offsetHeight
+        if (isInViewport(heading.offsetTop, headingBottom)) {
+          visibleIds.add(heading.id)
+        }
+      })
+
+      state.regions.forEach((region) => {
+        if (region.start <= viewportBottom && region.end >= viewportTop) {
+          const heading = document.getElementById(region.id)
+          if (heading) {
+            const headingBottom = heading.offsetTop + heading.offsetHeight
+            if (
+              region.end > headingBottom &&
+              (headingBottom < viewportBottom || viewportTop < region.end)
+            ) {
+              visibleIds.add(region.id)
+            }
+          }
+        }
+      })
+
+      return Array.from(visibleIds)
+    }
+  }
+
+  class TOCScrollMask {
+    static update() {
+      if (!state.scrollArea || !state.tocScrollArea) return
+
+      const { scrollTop, scrollHeight, clientHeight } = state.scrollArea
+      const threshold = 5
+      const isAtTop = scrollTop <= threshold
+      const isAtBottom = scrollTop >= scrollHeight - clientHeight - threshold
+
+      state.tocScrollArea.classList.toggle('mask-t-from-90%', !isAtTop)
+      state.tocScrollArea.classList.toggle('mask-b-from-90%', !isAtBottom)
+    }
+  }
+
+  class TOCLinks {
+    static update(headingIds: string[]) {
+      state.links.forEach((link) => {
+        link.classList.remove('text-foreground')
+      })
+
+      headingIds.forEach((id) => {
+        if (id) {
+          const activeLink = document.querySelector(
+            `#toc-sidebar-container [data-heading-link="${id}"]`,
+          )
+          if (activeLink) {
+            activeLink.classList.add('text-foreground')
+          }
+        }
+      })
+
+      this.scrollToActive(headingIds)
+    }
+
+    static scrollToActive(headingIds: string[]) {
+      if (!state.scrollArea || !headingIds.length) return
+
+      const activeLink = document.querySelector(
+        `#toc-sidebar-container [data-heading-link="${headingIds[0]}"]`,
+      )
+      if (!activeLink) return
+
+      const { top: areaTop, height: areaHeight } =
+        state.scrollArea.getBoundingClientRect()
+      const { top: linkTop, height: linkHeight } =
+        activeLink.getBoundingClientRect()
+
+      const currentLinkTop = linkTop - areaTop + state.scrollArea.scrollTop
+      const targetScroll = Math.max(
+        0,
+        Math.min(
+          currentLinkTop - (areaHeight - linkHeight) / 2,
+          state.scrollArea.scrollHeight - state.scrollArea.clientHeight,
+        ),
+      )
+
+      if (Math.abs(targetScroll - state.scrollArea.scrollTop) > 5) {
+        state.scrollArea.scrollTop = targetScroll
+      }
+    }
+  }
+
+  class TOCController {
+    static handleScroll() {
+      const newActiveIds = HeadingRegions.getVisibleIds()
+
+      if (JSON.stringify(newActiveIds) !== JSON.stringify(state.activeIds)) {
+        state.activeIds = newActiveIds
+        TOCLinks.update(state.activeIds)
+      }
+    }
+
+    static handleTOCScroll = () => TOCScrollMask.update()
+
+    static handleResize() {
+      HeadingRegions.build()
+      const newActiveIds = HeadingRegions.getVisibleIds()
+
+      if (JSON.stringify(newActiveIds) !== JSON.stringify(state.activeIds)) {
+        state.activeIds = newActiveIds
+        TOCLinks.update(state.activeIds)
+      }
+
+      TOCScrollMask.update()
+    }
+
+    static init() {
+      state.reset()
+      HeadingRegions.build()
+
+      if (state.headings.length === 0) {
+        TOCLinks.update([])
+        return
+      }
+
+      this.handleScroll()
+      setTimeout(TOCScrollMask.update, 100)
+
+      const options = { passive: true }
+      window.addEventListener('scroll', this.handleScroll, options)
+      window.addEventListener('resize', this.handleResize, options)
+      state.scrollArea?.addEventListener(
+        'scroll',
+        this.handleTOCScroll,
+        options,
+      )
+    }
+
+    static cleanup() {
+      window.removeEventListener('scroll', this.handleScroll)
+      window.removeEventListener('resize', this.handleResize)
+      state.scrollArea?.removeEventListener('scroll', this.handleTOCScroll)
+
+      Object.assign(state, {
+        activeIds: [],
+        headings: [],
+        regions: [],
+        scrollArea: null,
+        tocScrollArea: null,
+      })
+    }
+  }
+
+  document.addEventListener('astro:page-load', () => TOCController.init())
+  document.addEventListener('astro:after-swap', () => {
+    TOCController.cleanup()
+    TOCController.init()
+  })
+  document.addEventListener('astro:before-swap', () => TOCController.cleanup())
+</script>
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