import isArrayLike from './internal/isArrayLike.js'
import breakLoop from './internal/breakLoop.js'
import eachOfLimit from './eachOfLimit.js'
import once from './internal/once.js'
import onlyOnce from './internal/onlyOnce.js'
import wrapAsync from './internal/wrapAsync.js'
import awaitify from './internal/awaitify.js'

// eachOf implementation optimized for array-likes
function eachOfArrayLike(coll, iteratee, callback) {
    callback = once(callback);
    var index = 0,
        completed = 0,
        {length} = coll,
        canceled = false;
    if (length === 0) {
        callback(null);
    }

    function iteratorCallback(err, value) {
        if (err === false) {
            canceled = true
        }
        if (canceled === true) return
        if (err) {
            callback(err);
        } else if ((++completed === length) || value === breakLoop) {
            callback(null);
        }
    }

    for (; index < length; index++) {
        iteratee(coll[index], index, onlyOnce(iteratorCallback));
    }
}

// a generic version of eachOf which can handle array, object, and iterator cases.
function eachOfGeneric (coll, iteratee, callback) {
    return eachOfLimit(coll, Infinity, iteratee, callback);
}

/**
 * Like [`each`]{@link module:Collections.each}, except that it passes the key (or index) as the second argument
 * to the iteratee.
 *
 * @name eachOf
 * @static
 * @memberOf module:Collections
 * @method
 * @alias forEachOf
 * @category Collection
 * @see [async.each]{@link module:Collections.each}
 * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 * @param {AsyncFunction} iteratee - A function to apply to each
 * item in `coll`.
 * The `key` is the item's key, or index in the case of an array.
 * Invoked with (item, key, callback).
 * @param {Function} [callback] - A callback which is called when all
 * `iteratee` functions have finished, or an error occurs. Invoked with (err).
 * @returns {Promise} a promise, if a callback is omitted
 * @example
 *
 * // dev.json is a file containing a valid json object config for dev environment
 * // dev.json is a file containing a valid json object config for test environment
 * // prod.json is a file containing a valid json object config for prod environment
 * // invalid.json is a file with a malformed json object
 *
 * let configs = {}; //global variable
 * let validConfigFileMap = {dev: 'dev.json', test: 'test.json', prod: 'prod.json'};
 * let invalidConfigFileMap = {dev: 'dev.json', test: 'test.json', invalid: 'invalid.json'};
 *
 * // asynchronous function that reads a json file and parses the contents as json object
 * function parseFile(file, key, callback) {
 *     fs.readFile(file, "utf8", function(err, data) {
 *         if (err) return calback(err);
 *         try {
 *             configs[key] = JSON.parse(data);
 *         } catch (e) {
 *             return callback(e);
 *         }
 *         callback();
 *     });
 * }
 *
 * // Using callbacks
 * async.forEachOf(validConfigFileMap, parseFile, function (err) {
 *     if (err) {
 *         console.error(err);
 *     } else {
 *         console.log(configs);
 *         // configs is now a map of JSON data, e.g.
 *         // { dev: //parsed dev.json, test: //parsed test.json, prod: //parsed prod.json}
 *     }
 * });
 *
 * //Error handing
 * async.forEachOf(invalidConfigFileMap, parseFile, function (err) {
 *     if (err) {
 *         console.error(err);
 *         // JSON parse error exception
 *     } else {
 *         console.log(configs);
 *     }
 * });
 *
 * // Using Promises
 * async.forEachOf(validConfigFileMap, parseFile)
 * .then( () => {
 *     console.log(configs);
 *     // configs is now a map of JSON data, e.g.
 *     // { dev: //parsed dev.json, test: //parsed test.json, prod: //parsed prod.json}
 * }).catch( err => {
 *     console.error(err);
 * });
 *
 * //Error handing
 * async.forEachOf(invalidConfigFileMap, parseFile)
 * .then( () => {
 *     console.log(configs);
 * }).catch( err => {
 *     console.error(err);
 *     // JSON parse error exception
 * });
 *
 * // Using async/await
 * async () => {
 *     try {
 *         let result = await async.forEachOf(validConfigFileMap, parseFile);
 *         console.log(configs);
 *         // configs is now a map of JSON data, e.g.
 *         // { dev: //parsed dev.json, test: //parsed test.json, prod: //parsed prod.json}
 *     }
 *     catch (err) {
 *         console.log(err);
 *     }
 * }
 *
 * //Error handing
 * async () => {
 *     try {
 *         let result = await async.forEachOf(invalidConfigFileMap, parseFile);
 *         console.log(configs);
 *     }
 *     catch (err) {
 *         console.log(err);
 *         // JSON parse error exception
 *     }
 * }
 *
 */
function eachOf(coll, iteratee, callback) {
    var eachOfImplementation = isArrayLike(coll) ? eachOfArrayLike : eachOfGeneric;
    return eachOfImplementation(coll, wrapAsync(iteratee), callback);
}

export default awaitify(eachOf, 3)