HORIZON PROJECT

'use strict';

Object.defineProperty(exports, "__esModule", {

    value: true

});

exports.default = autoInject;

var _auto = require('./auto');

var _auto2 = _interopRequireDefault(_auto);

var _baseForOwn = require('lodash/_baseForOwn');

var _baseForOwn2 = _interopRequireDefault(_baseForOwn);

var _arrayMap = require('lodash/_arrayMap');

var _arrayMap2 = _interopRequireDefault(_arrayMap);

var _isArray = require('lodash/isArray');

var _isArray2 = _interopRequireDefault(_isArray);

var _trim = require('lodash/trim');

var _trim2 = _interopRequireDefault(_trim);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var FN_ARGS = /^(function)?\s*[^\(]*\(\s*([^\)]*)\)/m;

var FN_ARG_SPLIT = /,/;

var FN_ARG = /(=.+)?(\s*)$/;

var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;

function parseParams(func) {

    func = func.toString().replace(STRIP_COMMENTS, '');

    func = func.match(FN_ARGS)[2].replace(' ', '');

    func = func ? func.split(FN_ARG_SPLIT) : [];

    func = func.map(function (arg) {

        return (0, _trim2.default)(arg.replace(FN_ARG, ''));

    });

    return func;

}

/**

 * A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent

 * tasks are specified as parameters to the function, after the usual callback

 * parameter, with the parameter names matching the names of the tasks it

 * depends on. This can provide even more readable task graphs which can be

 * easier to maintain.

 *

 * If a final callback is specified, the task results are similarly injected,

 * specified as named parameters after the initial error parameter.

 *

 * The autoInject function is purely syntactic sugar and its semantics are

 * otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}.

 *

 * @name autoInject

 * @static

 * @memberOf module:ControlFlow

 * @method

 * @see [async.auto]{@link module:ControlFlow.auto}

 * @category Control Flow

 * @param {Object} tasks - An object, each of whose properties is a function of

 * the form 'func([dependencies...], callback). The object's key of a property

 * serves as the name of the task defined by that property, i.e. can be used

 * when specifying requirements for other tasks.

 * * The `callback` parameter is a `callback(err, result)` which must be called

 *   when finished, passing an `error` (which can be `null`) and the result of

 *   the function's execution. The remaining parameters name other tasks on

 *   which the task is dependent, and the results from those tasks are the

 *   arguments of those parameters.

 * @param {Function} [callback] - An optional callback which is called when all

 * the tasks have been completed. It receives the `err` argument if any `tasks`

 * pass an error to their callback, and a `results` object with any completed

 * task results, similar to `auto`.

 * @example

 *

 * //  The example from `auto` can be rewritten as follows:

 * async.autoInject({

 *     get_data: function(callback) {

 *         // async code to get some data

 *         callback(null, 'data', 'converted to array');

 *     },

 *     make_folder: function(callback) {

 *         // async code to create a directory to store a file in

 *         // this is run at the same time as getting the data

 *         callback(null, 'folder');

 *     },

 *     write_file: function(get_data, make_folder, callback) {

 *         // once there is some data and the directory exists,

 *         // write the data to a file in the directory

 *         callback(null, 'filename');

 *     },

 *     email_link: function(write_file, callback) {

 *         // once the file is written let's email a link to it...

 *         // write_file contains the filename returned by write_file.

 *         callback(null, {'file':write_file, 'email':'user@example.com'});

 *     }

 * }, function(err, results) {

 *     console.log('err = ', err);

 *     console.log('email_link = ', results.email_link);

 * });

 *

 * // If you are using a JS minifier that mangles parameter names, `autoInject`

 * // will not work with plain functions, since the parameter names will be

 * // collapsed to a single letter identifier.  To work around this, you can

 * // explicitly specify the names of the parameters your task function needs

 * // in an array, similar to Angular.js dependency injection.

 *

 * // This still has an advantage over plain `auto`, since the results a task

 * // depends on are still spread into arguments.

 * async.autoInject({

 *     //...

 *     write_file: ['get_data', 'make_folder', function(get_data, make_folder, callback) {

 *         callback(null, 'filename');

 *     }],

 *     email_link: ['write_file', function(write_file, callback) {

 *         callback(null, {'file':write_file, 'email':'user@example.com'});

 *     }]

 *     //...

 * }, function(err, results) {

 *     console.log('err = ', err);

 *     console.log('email_link = ', results.email_link);

 * });

 */

function autoInject(tasks, callback) {

    var newTasks = {};

    (0, _baseForOwn2.default)(tasks, function (taskFn, key) {

        var params;

        if ((0, _isArray2.default)(taskFn)) {

            params = taskFn.slice(0, -1);

            taskFn = taskFn[taskFn.length - 1];

            newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn);

        } else if (taskFn.length === 1) {

            // no dependencies, use the function as-is

            newTasks[key] = taskFn;

        } else {

            params = parseParams(taskFn);

            if (taskFn.length === 0 && params.length === 0) {

                throw new Error("autoInject task functions require explicit parameters.");

            }

            params.pop();

            newTasks[key] = params.concat(newTask);

        }

        function newTask(results, taskCb) {

            var newArgs = (0, _arrayMap2.default)(params, function (name) {

                return results[name];

            });

            newArgs.push(taskCb);

            taskFn.apply(null, newArgs);

        }

    });

    (0, _auto2.default)(newTasks, callback);

}

module.exports = exports['default'];