import { isReactive, isReadonly, isRef, toRaw, unref } from "vue";

export const CIRCULAR_REFERENCE_TEXT = "[Circular]";

export interface CircularReferenceMarker {
  __jsonViewCircular: true;
  path?: string;
}

export function createCircularReferenceMarker(path?: string): CircularReferenceMarker {
  return {
    __jsonViewCircular: true,
    path,
  };
}

export function isCircularReferenceMarker(value: unknown): value is CircularReferenceMarker {
  return Boolean(
    value &&
      typeof value === "object" &&
      "__jsonViewCircular" in value &&
      (value as { __jsonViewCircular?: boolean }).__jsonViewCircular
  );
}

export function formatCircularReference(path?: string) {
  return path ? `[Circular: ${path}]` : CIRCULAR_REFERENCE_TEXT;
}

export function normalizeVueValue(
  value: unknown,
  currentPath?: string,
  seenRefs = new WeakMap<object, string | undefined>()
): unknown {
  let current = value;

  while (isRef(current)) {
    const reference = current as object;
    const existingPath = seenRefs.get(reference);
    if (existingPath !== undefined || seenRefs.has(reference)) {
      return createCircularReferenceMarker(existingPath ?? currentPath);
    }
    seenRefs.set(reference, currentPath);
    current = unref(current);
  }

  if (current !== null && typeof current === "object" && (isReactive(current) || isReadonly(current))) {
    return toRaw(current);
  }

  return current;
}