/**
 * Copyright 2015 CANAL+ Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { CustomLoaderError } from "../../errors";
import type { IManifestLoader, ILoadedManifestFormat } from "../../public_types";
import getMonotonicTimeStamp from "../../utils/monotonic_timestamp";
import type { CancellationError, CancellationSignal } from "../../utils/task_canceller";
import type { IManifestLoaderOptions, IRequestedData } from "../types";

export default function callCustomManifestLoader(
  customManifestLoader: IManifestLoader,
  fallbackManifestLoader: (
    url: string | undefined,
    loaderOptions: IManifestLoaderOptions,
    cancelSignal: CancellationSignal,
  ) => Promise<IRequestedData<ILoadedManifestFormat>>,
): (
  url: string | undefined,
  loaderOptions: IManifestLoaderOptions,
  cancelSignal: CancellationSignal,
) => Promise<IRequestedData<ILoadedManifestFormat>> {
  return (
    url: string | undefined,
    loaderOptions: IManifestLoaderOptions,
    cancelSignal: CancellationSignal,
  ): Promise<IRequestedData<ILoadedManifestFormat>> => {
    return new Promise((res, rej) => {
      const timeAPIsDelta = Date.now() - getMonotonicTimeStamp();
      /** `true` when the custom segmentLoader should not be active anymore. */
      let hasFinished = false;

      /**
       * Callback triggered when the custom manifest loader has a response.
       * @param {Object} _args
       */
      const resolve = (_args: {
        data: ILoadedManifestFormat;
        size?: number | undefined;
        duration?: number | undefined;
        url?: string | undefined;
        receivingTime?: number | undefined;
        sendingTime?: number | undefined;
      }) => {
        if (hasFinished || cancelSignal.isCancelled()) {
          return;
        }
        hasFinished = true;
        cancelSignal.deregister(abortCustomLoader);

        const receivedTime =
          _args.receivingTime !== undefined
            ? _args.receivingTime - timeAPIsDelta
            : undefined;
        const sendingTime =
          _args.sendingTime !== undefined ? _args.sendingTime - timeAPIsDelta : undefined;

        res({
          responseData: _args.data,
          size: _args.size,
          requestDuration: _args.duration,
          url: _args.url,
          receivedTime,
          sendingTime,
        });
      };

      /**
       * Callback triggered when the custom manifest loader fails
       * @param {*} err - The corresponding error encountered
       */
      const reject = (err: unknown): void => {
        if (hasFinished || cancelSignal.isCancelled()) {
          return;
        }
        hasFinished = true;
        cancelSignal.deregister(abortCustomLoader);

        // Format error and send it
        const castedErr = err as
          | null
          | undefined
          | { message?: string; canRetry?: boolean; xhr?: XMLHttpRequest };
        const message =
          castedErr?.message ??
          "Unknown error when fetching the Manifest through a " +
            "custom manifestLoader.";
        const emittedErr = new CustomLoaderError(
          message,
          castedErr?.canRetry ?? false,
          castedErr?.xhr,
        );
        rej(emittedErr);
      };

      /**
       * Callback triggered when the custom manifest loader wants to fallback to
       * the "regular" implementation
       */
      const fallback = () => {
        if (hasFinished || cancelSignal.isCancelled()) {
          return;
        }
        hasFinished = true;
        cancelSignal.deregister(abortCustomLoader);
        fallbackManifestLoader(url, loaderOptions, cancelSignal).then(res, rej);
      };

      const callbacks = { reject, resolve, fallback };
      const abort = customManifestLoader(
        { url, timeout: loaderOptions.timeout, cmcdPayload: loaderOptions.cmcdPayload },
        callbacks,
      );

      cancelSignal.register(abortCustomLoader);

      /**
       * The logic to run when the custom loader is cancelled while pending.
       * @param {Error} err
       */
      function abortCustomLoader(err: CancellationError) {
        if (hasFinished) {
          return;
        }
        hasFinished = true;
        if (typeof abort === "function") {
          abort();
        }
        rej(err);
      }
    });
  };
}