/*
  SystemJS AMD Format
  Provides the AMD module format definition at System.format.amd
  as well as a RequireJS-style require on System.requirejs
*/
(function() {
  System.formats.push('amd');

  // AMD Module Format Detection RegEx
  // define([.., .., ..], ...)
  // define(varName); || define(function(require, exports) {}); || define({})
  var amdRegEx = /(?:^\s*|[}{\(\);,\n\?\&]\s*)define\s*\(\s*("[^"]+"\s*,|'[^']+'\s*,\s*)?(\[(\s*("[^"]+"|'[^']+')\s*,)*(\s*("[^"]+"|'[^']+')\s*)?\]|function\s*|{|[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*\))/;

  /*
    AMD-compatible require
    To copy RequireJS, set window.require = window.requirejs = System.requirejs
  */
  var require = System.requirejs = function(names, callback, errback, referer) {
    // in amd, first arg can be a config object... we just ignore
    if (typeof names == 'object' && !(names instanceof Array))
      return require.apply(null, Array.prototype.splice.call(arguments, 1));

    // amd require
    if (names instanceof Array)
      Promise.all(names.map(function(name) {
        return System.import(name, referer);
      })).then(callback, errback);

    // commonjs require
    else if (typeof names == 'string')
      return System.get(names);

    else
      throw 'Invalid require';
  }
  function makeRequire(parentName, deps, depsNormalized) {
    return function(names, callback, errback) {
      if (typeof names == 'string' && deps.indexOf(names) != -1)
        return System.get(depsNormalized[deps.indexOf(names)]);
      return require(names, callback, errback, { name: parentName });
    }
  }

  System.format.amd = {
    detect: function(load) {
      return !!load.source.match(amdRegEx);
    },
    deps: function(load, global, exec) {

      var deps;
      var meta = load.metadata;

      global.define = function(name, _deps, factory) {

        if (typeof name != 'string') {
          factory = _deps;
          _deps = name;
        }
        else {
          meta.name = name;
        }
        if (!(_deps instanceof Array)) {
          factory = _deps;
          // CommonJS AMD form
          _deps = ['require', 'exports', 'module'].concat(System.format.cjs.deps(load, global, eval));
        }
        deps = _deps;
        
        if (typeof factory != 'function') {
          meta.factory = function() {
            return factory;
          }
        }
        else {
          meta.factory = factory;
        }
      }
      global.define.amd = {};

      // ensure no NodeJS environment detection
      delete global.module;
      delete global.exports;

      exec();

      var index;
      if ((index = deps.indexOf('require')) != -1) {
        meta.requireIndex = index;
        deps.splice(index, 1);
      }
      if ((index = deps.indexOf('exports')) != -1) {
        meta.exportsIndex = index;
        deps.splice(index, 1);
      }
      if ((index = deps.indexOf('module')) != -1) {
        meta.moduleIndex = index;
        deps.splice(index, 1);
      }

      delete global.define;

      meta.deps = deps;

      return deps;

    },
    execute: function(depNames, load, global, exec) {
      var meta = load.metadata;
      var deps = [];
      for (var i = 0; i < depNames.length; i++)
        deps[i] = System.get(depNames[i]);

      var require, exports = {}, module;
      
      // add back in system dependencies
      if (meta.moduleIndex !== undefined)
        deps.splice(meta.moduleIndex, 0, module = { id: load.name, uri: load.address, config: function() { return {}; }, exports: exports });
      if (meta.exportsIndex !== undefined)
        deps.splice(meta.exportsIndex, 0, exports);
      if (meta.requireIndex !== undefined)
        deps.splice(meta.requireIndex, 0, require = makeRequire(load.name, meta.deps, depNames));

      return meta.factory.apply(global, deps) || module && module.exports || undefined;
    }
  };
})();