import type { CollectionAfterDeleteHook } from "payload";
import type { IAuditLog } from "../audit-log.interface";
import { PayloadAuditLog } from "../payload-audit-log";

export type AuditErasureHookOpts = {
  /** The audit log impl that will perform the erasure. */
  auditLog: IAuditLog;
  /**
   * Erasure mode. Defaults to "pseudonymize" — the softer option that
   * retains the audit trail shape while removing PII linkage. Use
   * "delete" only when the data-subject specifically requests hard removal.
   */
  mode?: "pseudonymize" | "delete";
};

/**
 * Payload `afterDelete` hook factory for GDPR erasure.
 *
 * Wire this on any collection whose `id` doubles as an audit subject
 * (e.g., the users collection). When Payload deletes a document, the
 * hook calls `auditLog.eraseSubject(String(doc.id), mode)`, removing
 * or pseudonymizing all audit entries recorded for that actor.
 *
 * The hook has no schema-specific knowledge — it works on any collection
 * that stores the subject identifier as its document `id`.
 *
 * Non-string, non-numeric ids are silently skipped (safe guard against
 * undefined/null that Payload may produce in edge cases).
 */
export function createAuditErasureHook(
  opts: AuditErasureHookOpts,
): CollectionAfterDeleteHook {
  const mode = opts.mode ?? "pseudonymize";
  return async ({ doc }) => {
    if (typeof doc.id === "string" || typeof doc.id === "number") {
      await opts.auditLog.eraseSubject(String(doc.id), mode);
    }
  };
}

export type ReqScopedAuditErasureHookOpts = {
  /** Erasure mode — see AuditErasureHookOpts. Defaults to "pseudonymize". */
  mode?: "pseudonymize" | "delete";
};

/**
 * Variant of `createAuditErasureHook` for config-composition time (audit
 * finding A6): a Payload collection config is built before any `IAuditLog`
 * can exist (binding the audit log needs the built config), so this hook
 * constructs a `PayloadAuditLog` lazily from the running instance on
 * `req.payload` when the delete fires. No-ops when the `audit-logs`
 * collection is not registered.
 */
export function createReqScopedAuditErasureHook(
  opts: ReqScopedAuditErasureHookOpts = {},
): CollectionAfterDeleteHook {
  const mode = opts.mode ?? "pseudonymize";
  return async ({ doc, req }) => {
    if (typeof doc.id !== "string" && typeof doc.id !== "number") return;
    const payload = req.payload;
    const hasAuditCollection = payload.config.collections?.some(
      (c) => c.slug === "audit-logs",
    );
    if (!hasAuditCollection) return;
    const auditLog = new PayloadAuditLog(
      payload.config,
      async () => payload as never,
    );
    await auditLog.eraseSubject(String(doc.id), mode);
  };
}