import { NextRequest, NextResponse } from 'next/server'
import { getLibrary, resolveLibraryRoot, resolveAndJail } from '@/lib/libraries'
import { getComicPageBuffer } from '@/lib/comics'
import { requireLibraryAccess } from '@/lib/auth'
import { getDb } from '@/lib/db'

const EXT_TO_MIME: Record<string, string> = {
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.png': 'image/png',
  '.webp': 'image/webp',
  '.gif': 'image/gif',
}

export async function GET(request: NextRequest) {
  const { searchParams } = request.nextUrl
  const libraryId = searchParams.get('libraryId')
  const issueKey = searchParams.get('issueKey')
  const pageIndexStr = searchParams.get('pageIndex')

  if (!libraryId || !issueKey || pageIndexStr === null) {
    return NextResponse.json({ error: 'Missing libraryId, issueKey, or pageIndex' }, { status: 400 })
  }

  const pageIndex = parseInt(pageIndexStr, 10)
  if (isNaN(pageIndex) || pageIndex < 0) {
    return NextResponse.json({ error: 'Invalid pageIndex' }, { status: 400 })
  }

  const auth = await requireLibraryAccess(request, libraryId)
  if (auth instanceof NextResponse) return auth

  const library = getLibrary(libraryId)
  if (!library) {
    return NextResponse.json({ error: 'Library not found' }, { status: 404 })
  }

  const db = getDb()
  const row = db
    .prepare('SELECT file_path FROM media_items WHERE item_key = ? AND item_type = ?')
    .get(issueKey, 'comic_issue') as { file_path: string | null } | undefined

  if (!row?.file_path) {
    return NextResponse.json({ error: 'Issue not found' }, { status: 404 })
  }

  const root = resolveLibraryRoot(library)

  let absPath: string
  try {
    absPath = resolveAndJail(root, row.file_path)
  } catch {
    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
  }

  const result = getComicPageBuffer(absPath, pageIndex)
  if (!result) {
    return NextResponse.json({ error: 'Page not found' }, { status: 404 })
  }

  const mimeType = EXT_TO_MIME[result.ext] ?? 'image/jpeg'

  return new NextResponse(result.buffer as unknown as BodyInit, {
    status: 200,
    headers: {
      'Content-Type': mimeType,
      'Content-Length': String(result.buffer.length),
      'Cache-Control': 'public, max-age=86400',
    },
  })
}