export const INVALIDATION_TYPES = [
  "directory.updated",
  "page.updated",
  "admin.updated",
] as const;

export type InvalidationType = (typeof INVALIDATION_TYPES)[number];

export interface InvalidationEvent {
  type: InvalidationType;
  id: string;
  version: number;
}

export interface OutboxEventLike {
  aggregateId: string;
  eventType: string;
  payload: Record<string, unknown>;
  topic: string;
}

function isInvalidationType(value: string): value is InvalidationType {
  return INVALIDATION_TYPES.some((type) => type === value);
}

export function expectedTopic(event: InvalidationEvent): string {
  switch (event.type) {
    case "directory.updated":
      return "directory";
    case "page.updated":
      return `page:${event.id}`;
    case "admin.updated":
      return "admin";
  }
}

export function toInvalidationEvent(
  record: OutboxEventLike,
): InvalidationEvent | null {
  if (!isInvalidationType(record.eventType)) return null;
  const id = record.payload.id;
  const version = record.payload.version;
  if (
    typeof id !== "string" ||
    id !== record.aggregateId ||
    typeof version !== "number" ||
    !Number.isSafeInteger(version) ||
    version < 0
  ) {
    return null;
  }
  const event: InvalidationEvent = {
    type: record.eventType,
    id,
    version,
  };
  return expectedTopic(event) === record.topic ? event : null;
}

export function parseInvalidationEvent(value: string): InvalidationEvent | null {
  try {
    const parsed = JSON.parse(value) as Record<string, unknown>;
    const type = parsed.type;
    const id = parsed.id;
    const version = parsed.version;
    if (
      typeof type !== "string" ||
      !isInvalidationType(type) ||
      typeof id !== "string" ||
      typeof version !== "number" ||
      !Number.isSafeInteger(version) ||
      version < 0
    ) {
      return null;
    }
    return { type, id, version };
  } catch {
    return null;
  }
}