recall/src/lib/link-suggestions.ts

import { prisma } from '@/lib/prisma'

export interface LinkSuggestion {
  term: string
  noteId: string
  noteTitle: string
}

/**
 * Find potential wiki-link suggestions in content.
 * Returns notes whose titles appear in the content and could be converted to [[links]].
 */
export async function findLinkSuggestions(
  content: string,
  currentNoteId?: string
): Promise<LinkSuggestion[]> {
  if (!content.trim() || content.length < 10) {
    return []
  }

  // Get all note titles except current note
  const allNotes = await prisma.note.findMany({
    where: currentNoteId ? { id: { not: currentNoteId } } : undefined,
    select: { id: true, title: true },
  })

  if (allNotes.length === 0) {
    return []
  }

  // Find titles that appear in content (case-insensitive)
  const suggestions: LinkSuggestion[] = []
  const contentLower = content.toLowerCase()

  for (const note of allNotes) {
    const titleLower = note.title.toLowerCase()
    // Check if title appears as a whole word in content
    const regex = new RegExp(`\\b${escapeRegex(titleLower)}\\b`, 'i')
    if (regex.test(content)) {
      suggestions.push({
        term: note.title,
        noteId: note.id,
        noteTitle: note.title,
      })
    }
  }

  // Sort by title length (longer titles first - more specific matches)
  return suggestions.sort((a, b) => b.noteTitle.length - a.noteTitle.length)
}

/**
 * Replace terms in content with wiki-links
 */
export function applyWikiLinks(
  content: string,
  replacements: { term: string; noteId: string }[]
): string {
  let result = content

  for (const { term, noteId } of replacements) {
    // Replace all occurrences of the term (case-insensitive, whole word only)
    const regex = new RegExp(`\\b(${escapeRegex(term)})\\b`, 'gi')
    result = result.replace(regex, `[[${term}]]`)
  }

  return result
}

function escapeRegex(str: string): string {
  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
}