/*!
 * base-config <https://github.com/jonschlinkert/base-config>
 *
 * Copyright (c) 2015-2016, Jon Schlinkert.
 * Licensed under the MIT License.
 */

'use strict';

var utils = require('./utils');

/**
 * Expose `config`
 */

module.exports = function() {
  return create('config');
};

/**
 * Create a function for mapping `app` properties onto the
 * given `prop` namespace.
 *
 * @param {String} `prop` The namespace to use
 * @param {Object} `argv`
 * @return {Object}
 * @api public
 */

function create(prop) {
  if (typeof prop !== 'string') {
    throw new Error('expected the first argument to be a string.');
  }

  return function(app) {
    if (this.isRegistered('base-' + prop)) return;

    // map config
    var config = utils.mapper(app)
      // store/data
      .map('store', store(app.store))
      .map('data')

      // options
      .map('enable')
      .map('disable')
      .map('option')
      .alias('options', 'option')

      // get/set
      .map('set')
      .map('del')

    // Expose `prop` (config) on the instance
    app.define(prop, proxy(config));

    // Expose `process` on app[prop]
    app[prop].process = config.process;
  };

  function store(app) {
    if (!app) return {};
    var mapper = utils.mapper(app);
    app.define(prop, proxy(mapper));
    return mapper;
  }
}

/**
 * Proxy to support `app.config` as a function or object
 * with methods, allowing the user to do either of
 * the following:
 *
 * ```js
 * base.config({foo: 'bar'});
 *
 * // or
 * base.config.map('foo', 'bar');
 * ```
 */

function proxy(config) {
  function fn(key, val) {
    if (typeof val === 'string') {
      config.alias.apply(config, arguments);
      return config;
    }

    if (typeof key === 'string') {
      config.map.apply(config, arguments);
      return config;
    }

    if (!utils.isObject(key)) {
      throw new TypeError('expected key to be a string or object');
    }

    for (var prop in key) {
      fn(prop, key[prop]);
    }
    return config;
  }
  fn.__proto__ = config;
  return fn;
}

/**
 * Expose `create`
 */

module.exports.create = create;