AfiS-Aktensystem/web/lib/cases/links.ts

import { db } from '@/lib/db'
import { writeAudit } from '@/lib/audit/write'
import { visibleCaseWhere } from '@/lib/access/caseFilter'
import { canEditCase } from '@/lib/access/caseWrite'
import { AccessError, must } from '@/lib/errors'
import { loadVisibleCase } from '@/lib/cases/service'
import type { LinkKindName } from '@/lib/cases/terms'
import type { EffectivePermissions } from '@/lib/auth/permissions'

/**
 * Verknüpfungen zwischen Akten.
 *
 * Die Richtung trägt Bedeutung: `SUCCESSOR` und `MERGED_INTO` sagen etwas
 * anderes, je nachdem, von welcher Seite man liest. `RELATED` ist symmetrisch.
 *
 * Beide Seiten laufen durch die Sichtbarkeitsprüfung. Eine Akte, die der Leser
 * nicht sehen darf, taucht auch als Verknüpfung nicht auf — sonst verriete die
 * Gegenseite ihre Existenz. Das gilt in **beide** Richtungen, deshalb wird der
 * Filter zweimal angewandt.
 */

const AKTE = {
  id: true,
  caseNumber: true,
  title: true,
  status: true,
  classification: true,
  updatedAt: true,
} as const

/** Alle Verknüpfungen einer Akte, aus beiden Richtungen, gefiltert. */
export async function listLinks(p: EffectivePermissions, caseId: string) {
  const sichtbar = visibleCaseWhere(p)

  const [hinaus, herein] = await Promise.all([
    db.caseLink.findMany({
      where: { AND: [{ fromId: caseId }, { to: { is: sichtbar } }] },
      select: { kind: true, createdAt: true, to: { select: AKTE } },
      orderBy: { createdAt: 'desc' },
    }),
    db.caseLink.findMany({
      where: { AND: [{ toId: caseId }, { from: { is: sichtbar } }] },
      select: { kind: true, createdAt: true, from: { select: AKTE } },
      orderBy: { createdAt: 'desc' },
    }),
  ])

  return [
    ...hinaus.map((link) => ({
      kind: link.kind,
      direction: 'out' as const,
      other: link.to,
      createdAt: link.createdAt,
    })),
    ...herein.map((link) => ({
      kind: link.kind,
      direction: 'in' as const,
      other: link.from,
      createdAt: link.createdAt,
    })),
  ]
}

export async function linkCases(
  p: EffectivePermissions,
  input: { fromCaseNumber: string; toCaseNumber: string; kind: LinkKindName },
): Promise<void> {
  const from = await loadVisibleCase(p, input.fromCaseNumber)
  if (!from) throw new AccessError('not-found')
  must(canEditCase(p, from))

  const to = await loadVisibleCase(p, input.toCaseNumber.trim())
  if (!to) throw new AccessError('not-found')
  if (to.id === from.id) throw new AccessError('link-self')

  await db.$transaction(async (tx) => {
    await tx.caseLink.upsert({
      where: { fromId_toId_kind: { fromId: from.id, toId: to.id, kind: input.kind } },
      create: { fromId: from.id, toId: to.id, kind: input.kind, createdById: p.userId },
      update: {},
    })

    await writeAudit(tx, {
      actorId: p.userId,
      action: 'case.link',
      targetType: 'Case',
      targetId: from.id,
      clearanceAtTime: p.clearanceLevel,
      meta: { from: from.caseNumber, to: to.caseNumber, kind: input.kind },
    })
  })
}

/**
 * Verknüpfung lösen. Umkehrbar und deshalb ohne Bestätigungsdialog, siehe
 * docs/09-performance-und-ux.md. Das Protokoll behält sie.
 */
export async function unlinkCases(
  p: EffectivePermissions,
  input: { fromCaseNumber: string; toCaseNumber: string; kind: LinkKindName },
): Promise<void> {
  const from = await loadVisibleCase(p, input.fromCaseNumber)
  if (!from) throw new AccessError('not-found')
  must(canEditCase(p, from))

  const to = await loadVisibleCase(p, input.toCaseNumber)
  if (!to) throw new AccessError('not-found')

  await db.$transaction(async (tx) => {
    await tx.caseLink.deleteMany({
      where: {
        OR: [
          { fromId: from.id, toId: to.id, kind: input.kind },
          { fromId: to.id, toId: from.id, kind: input.kind },
        ],
      },
    })

    await writeAudit(tx, {
      actorId: p.userId,
      action: 'case.unlink',
      targetType: 'Case',
      targetId: from.id,
      clearanceAtTime: p.clearanceLevel,
      meta: { from: from.caseNumber, to: to.caseNumber, kind: input.kind },
    })
  })
}