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

const BACKLINK_REGEX = /\[\[([^\]]+)\]\]/g

export function parseBacklinks(content: string): string[] {
  const matches = content.matchAll(BACKLINK_REGEX)
  const titles = new Set<string>()

  for (const match of matches) {
    const title = match[1].trim()
    if (title) {
      titles.add(title)
    }
  }

  return Array.from(titles)
}

export async function syncBacklinks(noteId: string, content: string): Promise<void> {
  const linkedTitles = parseBacklinks(content)

  await prisma.backlink.deleteMany({
    where: { sourceNoteId: noteId },
  })

  if (linkedTitles.length === 0) return

  const targetNotes = await prisma.note.findMany({
    where: {
      title: { in: linkedTitles },
    },
    select: { id: true, title: true },
  })

  const titleToId = new Map(targetNotes.map((n) => [n.title.toLowerCase(), n.id]))

  const backlinksToCreate: { sourceNoteId: string; targetNoteId: string }[] = []

  for (const title of linkedTitles) {
    const targetNoteId = titleToId.get(title.toLowerCase())
    if (targetNoteId && targetNoteId !== noteId) {
      backlinksToCreate.push({
        sourceNoteId: noteId,
        targetNoteId,
      })
    }
  }

  if (backlinksToCreate.length > 0) {
    await prisma.backlink.createMany({
      data: backlinksToCreate,
    })
  }
}

export interface BacklinkWithNote {
  id: string
  sourceNoteId: string
  targetNoteId: string
  createdAt: string
  sourceNote: {
    id: string
    title: string
    type: string
  }
}

export async function getBacklinksForNote(noteId: string): Promise<BacklinkWithNote[]> {
  const backlinks = await prisma.backlink.findMany({
    where: { targetNoteId: noteId },
    include: {
      sourceNote: {
        select: {
          id: true,
          title: true,
          type: true,
        },
      },
    },
    orderBy: { createdAt: 'desc' },
  })

  return backlinks.map((bl) => ({
    id: bl.id,
    sourceNoteId: bl.sourceNoteId,
    targetNoteId: bl.targetNoteId,
    createdAt: bl.createdAt.toISOString(),
    sourceNote: {
      id: bl.sourceNote.id,
      title: bl.sourceNote.title,
      type: bl.sourceNote.type,
    },
  }))
}

export async function getOutgoingLinksForNote(noteId: string): Promise<BacklinkWithNote[]> {
  const backlinks = await prisma.backlink.findMany({
    where: { sourceNoteId: noteId },
    include: {
      targetNote: {
        select: {
          id: true,
          title: true,
          type: true,
        },
      },
    },
    orderBy: { createdAt: 'desc' },
  })

  return backlinks.map((bl) => ({
    id: bl.id,
    sourceNoteId: bl.sourceNoteId,
    targetNoteId: bl.targetNoteId,
    createdAt: bl.createdAt.toISOString(),
    sourceNote: {
      id: bl.targetNote.id,
      title: bl.targetNote.title,
      type: bl.targetNote.type,
    },
  }))
}