import { startCase } from 'es-toolkit';
import { get, set } from 'es-toolkit/compat';

type HasMetadata = {
  metadata?: Record<string, any>;
};

type MetadataKey<T> = {
  key: string;
  type: T;
  title: string;
  description?: string;
};

interface CreateMetadataKeyOptions {
  key: string;
  title?: string;
  description?: string;
}

export function createMetadataKey<T = never>(key: string, opts?: Omit<CreateMetadataKeyOptions, 'key'>): MetadataKey<T>;
export function createMetadataKey<T = never>(opts: CreateMetadataKeyOptions): MetadataKey<T>;
export function createMetadataKey<T = never>(a: any, b?: any): MetadataKey<T> {
  const opts: CreateMetadataKeyOptions =
    typeof a === 'string'
      ? {
          key: a,
          ...b,
        }
      : a;

  const { key } = opts;
  opts.title ||= startCase(key);

  const k: MetadataKey<T> = {
    ...opts,
    type: null as any,
  } as MetadataKey<T>;

  if ('toStringTag' in Symbol && typeof Symbol.toStringTag === 'symbol') {
    Object.defineProperty(k, Symbol.toStringTag, {
      value: key,
    });
  }

  return k;
}

export function defineMetadata<T>(res: HasMetadata, key: MetadataKey<T>, opts: T) {
  res.metadata = res.metadata || {};
  set(res.metadata, key.key, opts);
}

export function getMetadata<T>(res: HasMetadata | undefined | null, key: MetadataKey<T>): T | undefined {
  if (!res?.metadata) return undefined;
  return get(res.metadata, key.key);
}