// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

import {Loader} from '@loaders.gl/loader-utils';
import {normalizeLoader} from '../loader-utils/normalize-loader';
import {getGlobalLoaderState} from '../loader-utils/option-utils';

/**
 * Store global registered loaders on the global object to increase chances of cross loaders-version interoperability
 * This use case is not reliable but can help when testing new versions of loaders.gl with existing frameworks
 */
const getGlobalLoaderRegistry = () => {
  const state = getGlobalLoaderState();
  state.loaderRegistry = state.loaderRegistry || [];
  return state.loaderRegistry;
};

/**
 * Register a list of global loaders
 * @note Registration erases loader type information.
 * @deprecated It is recommended that applications manage loader registration. This function will likely be remove in loaders.gl v5
 */
export function registerLoaders(loaders: Loader[] | Loader) {
  const loaderRegistry = getGlobalLoaderRegistry();

  loaders = Array.isArray(loaders) ? loaders : [loaders];

  for (const loader of loaders) {
    const normalizedLoader = normalizeLoader(loader);
    if (!loaderRegistry.find((registeredLoader) => normalizedLoader === registeredLoader)) {
      // add to the beginning of the loaderRegistry, so the last registeredLoader get picked
      loaderRegistry.unshift(normalizedLoader);
    }
  }
}

/**
 * @deprecated It is recommended that applications manage loader registration. This function will likely be remove in loaders.gl v5
 */
export function getRegisteredLoaders(): Loader[] {
  return getGlobalLoaderRegistry();
}

/** @deprecated For testing only  */
export function _unregisterLoaders() {
  const state = getGlobalLoaderState();
  state.loaderRegistry = [];
}