fox/src/.vitepress/plugins/utils/file-processor.ts

import { readFileSync, writeFileSync, existsSync } from 'fs'
import { relative, resolve } from 'path'
import type { SidebarItem } from './types'
import { parseFrontmatter, stringifyFrontmatter } from './frontmatter'
import { mergeSectionLinks, extractTopLevelLinks, extractItemsForPage } from './links'
import { normalizeLink } from './path-utils'
import { SectionLinkListItem } from '../../theme/components/SectionLinkList/SectionLinkList.types'

const removeDuplicates = (links: SectionLinkListItem[]) => {
  const result: SectionLinkListItem[] = []
  const seenLinks = new Set<string>()
  
  for (const link of links) {
    if (link.link) {
      const normalized = normalizeLink(link.link)
      if (!seenLinks.has(normalized)) {
        seenLinks.add(normalized)
        result.push(link)
      }
    }
  }
  
  return result
}

const hasChanges = (
  existingLinks: SectionLinkListItem[],
  mergedLinks: SectionLinkListItem[],
  newLinks: SectionLinkListItem[]
) => {
  const existingLinksSet = new Set(
    existingLinks
      .map(link => link.link)
      .filter((link): link is string => Boolean(link))
      .map(normalizeLink)
  )
  
  const hasNewLinks = newLinks.some(
    link => link.link && !existingLinksSet.has(normalizeLink(link.link))
  )

  if (hasNewLinks) return true

  const sidebarLinksSet = new Set(
    newLinks
      .map(link => link.link)
      .filter((link): link is string => Boolean(link))
      .map(normalizeLink)
  )

  const existingSidebarLinks = existingLinks
    .filter(link => link.link && sidebarLinksSet.has(normalizeLink(link.link)))
    .map(link => normalizeLink(link.link!))
    .join('|')
  
  const mergedSidebarLinks = mergedLinks
    .slice(0, newLinks.length)
    .filter(link => link.link && sidebarLinksSet.has(normalizeLink(link.link)))
    .map(link => normalizeLink(link.link!))
    .join('|')

  return existingSidebarLinks !== mergedSidebarLinks && mergedLinks.length === existingLinks.length
}

export const processIndexFile = (
  filePath: string,
  sidebarItems: SidebarItem[],
  srcDir: string
) => {
  if (!existsSync(filePath)) return false

  try {
    const fileContent = readFileSync(filePath, 'utf-8')
    const { frontmatter, content } = parseFrontmatter(fileContent)

    const relativePath = relative(srcDir, filePath).replace(/\\/g, '/')
    const normalizedPath = relativePath.startsWith('/') ? relativePath : `/${relativePath}`

    const rawExistingLinks: SectionLinkListItem[] = Array.isArray(frontmatter.section_links)
      ? [...frontmatter.section_links]
      : []
    
    const existingLinks = removeDuplicates(rawExistingLinks)
    const newLinks = extractTopLevelLinks(sidebarItems, normalizedPath, srcDir)

    if (!newLinks.length) return false

    const mergedLinks = removeDuplicates(mergeSectionLinks(existingLinks, newLinks))

    if (!hasChanges(existingLinks, mergedLinks, newLinks)) return false

    frontmatter.section_links = mergedLinks
    const updatedContent = stringifyFrontmatter(frontmatter, content)
    writeFileSync(filePath, updatedContent, 'utf-8')
    return true
  } catch {
    return false
  }
}

export const processPageWithItems = (
  filePath: string,
  sidebarItems: SidebarItem[],
  srcDir: string
) => {
  if (!existsSync(filePath)) return false

  try {
    const fileContent = readFileSync(filePath, 'utf-8')
    const { frontmatter, content } = parseFrontmatter(fileContent)

    const relativePath = relative(srcDir, filePath).replace(/\\/g, '/')
    const normalizedPath = relativePath.startsWith('/') ? relativePath : `/${relativePath}`

    const rawExistingLinks: SectionLinkListItem[] = Array.isArray(frontmatter.section_links)
      ? [...frontmatter.section_links]
      : []
    
    const existingLinks = removeDuplicates(rawExistingLinks)
    const newLinks = extractItemsForPage(sidebarItems, normalizedPath, srcDir)

    if (!newLinks.length) return false

    const mergedLinks = removeDuplicates(mergeSectionLinks(existingLinks, newLinks))

    if (!hasChanges(existingLinks, mergedLinks, newLinks)) return false

    frontmatter.section_links = mergedLinks
    const updatedContent = stringifyFrontmatter(frontmatter, content)
    writeFileSync(filePath, updatedContent, 'utf-8')
    return true
  } catch {
    return false
  }
}