import debug from 'debug';
import { sleep } from './util.mjs';

const log = debug('youtube-maze:retry');

/**
 * An error that is expected to be temporary such that the initial action
 * may be retried.
 */
export class TemporaryError extends Error
{
    constructor(message)
    {
        super(message);
        this.name = this.constructor.name;
        Error.captureStackTrace(this, this.constructor);
    }
}

/**
 * Make an async function retry-able.
 *
 * When the underlying function throws a TemporaryError, the initial
 * call will be repeated, under the limits set below.
 *
 * @param function func Async function to call.
 * @param number retries Allowed number of retries before failing.
 * @param number cooldown Time to wait before retrying (ms).
 * @return function New function that is retryable.
 */
export const retryable = (func, retries = 3, cooldown = 1000) =>
{
    return async (...args) =>
    {
        while (true)
        {
            let remRetries = retries;
            let curCooldown = cooldown;

            try
            {
                const result = await func(...args);
                return result;
            }
            catch (err)
            {
                if (err instanceof TemporaryError && remRetries > 0)
                {
                    log(`\
${func.name}(${args}) failed with error "${err.message}"
Retrying in ${curCooldown} ms (${remRetries} retries remaining)`);

                    await sleep(curCooldown);
                    remRetries -= 1;
                    curCooldown *= 2;
                }
                else
                {
                    throw err;
                }
            }
        }
    };
};