/*
 * AMD Helper function module
 * Separated into its own file as this is the part needed for full AMD support in SFX builds
 * NB since implementations have now diverged this can be merged back with amd.js
 */

hook('fetch', function(fetch) {
  return function(load) {
    // script load implies define global leak
    if (load.metadata.scriptLoad && isBrowser)
      __global.define = this.amdDefine;
    return fetch.call(this, load);
  };
});
 
hookConstructor(function(constructor) {
  return function() {
    var loader = this;
    constructor.call(this);

    var commentRegEx = /(\/\*([\s\S]*?)\*\/|([^:]|^)\/\/(.*)$)/mg;
    var cjsRequirePre = "(?:^|[^$_a-zA-Z\\xA0-\\uFFFF.])";
    var cjsRequirePost = "\\s*\\(\\s*(\"([^\"]+)\"|'([^']+)')\\s*\\)";
    var fnBracketRegEx = /\(([^\)]*)\)/;
    var wsRegEx = /^\s+|\s+$/g;
    
    var requireRegExs = {};

    function getCJSDeps(source, requireIndex) {

      // remove comments
      source = source.replace(commentRegEx, '');

      // determine the require alias
      var params = source.match(fnBracketRegEx);
      var requireAlias = (params[1].split(',')[requireIndex] || 'require').replace(wsRegEx, '');

      // find or generate the regex for this requireAlias
      var requireRegEx = requireRegExs[requireAlias] || (requireRegExs[requireAlias] = new RegExp(cjsRequirePre + requireAlias + cjsRequirePost, 'g'));

      requireRegEx.lastIndex = 0;

      var deps = [];

      var match;
      while (match = requireRegEx.exec(source))
        deps.push(match[2] || match[3]);

      return deps;
    }

    /*
      AMD-compatible require
      To copy RequireJS, set window.require = window.requirejs = loader.amdRequire
    */
    function require(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, arguments.length - 1));

      // amd require
      if (typeof names == 'string' && typeof callback == 'function')
        names = [names];
      if (names instanceof Array) {
        var dynamicRequires = [];
        for (var i = 0; i < names.length; i++)
          dynamicRequires.push(loader['import'](names[i], referer));
        Promise.all(dynamicRequires).then(function(modules) {
          if (callback)
            callback.apply(null, modules);
        }, errback);
      }

      // commonjs require
      else if (typeof names == 'string') {
        var defaultJSExtension = loader.defaultJSExtensions && names.substr(names.length - 3, 3) != '.js';
        var normalized = loader.decanonicalize(names, referer);
        if (defaultJSExtension && normalized.substr(normalized.length - 3, 3) == '.js')
          normalized = normalized.substr(0, normalized.length - 3);
        var module = loader.get(normalized);
        if (!module)
          throw new Error('Module not already loaded loading "' + names + '" as ' + normalized + (referer ? ' from "' + referer + '".' : '.'));
        return module.__useDefault ? module['default'] : module;
      }

      else
        throw new TypeError('Invalid require');
    }

    function define(name, deps, factory) {
      if (typeof name != 'string') {
        factory = deps;
        deps = name;
        name = null;
      }
      if (!(deps instanceof Array)) {
        factory = deps;
        deps = ['require', 'exports', 'module'].splice(0, factory.length);
      }

      if (typeof factory != 'function')
        factory = (function(factory) {
          return function() { return factory; }
        })(factory);

      // in IE8, a trailing comma becomes a trailing undefined entry
      if (deps[deps.length - 1] === undefined)
        deps.pop();

      // remove system dependencies
      var requireIndex, exportsIndex, moduleIndex;
      
      if ((requireIndex = indexOf.call(deps, 'require')) != -1) {
        
        deps.splice(requireIndex, 1);

        // only trace cjs requires for non-named
        // named defines assume the trace has already been done
        if (!name)
          deps = deps.concat(getCJSDeps(factory.toString(), requireIndex));
      }

      if ((exportsIndex = indexOf.call(deps, 'exports')) != -1)
        deps.splice(exportsIndex, 1);
      
      if ((moduleIndex = indexOf.call(deps, 'module')) != -1)
        deps.splice(moduleIndex, 1);

      function execute(req, exports, module) {
        var depValues = [];
        for (var i = 0; i < deps.length; i++)
          depValues.push(req(deps[i]));

        module.uri = module.id;

        module.config = function() {};

        // add back in system dependencies
        if (moduleIndex != -1)
          depValues.splice(moduleIndex, 0, module);
        
        if (exportsIndex != -1)
          depValues.splice(exportsIndex, 0, exports);
        
        if (requireIndex != -1) {
          function contextualRequire(names, callback, errback) {
            if (typeof names == 'string' && typeof callback != 'function')
              return req(names);
            return require.call(loader, names, callback, errback, module.id);
          }
          contextualRequire.toUrl = function(name) {
            // normalize without defaultJSExtensions
            var defaultJSExtension = loader.defaultJSExtensions && name.substr(name.length - 3, 3) != '.js';
            var url = loader.decanonicalize(name, module.id);
            if (defaultJSExtension && url.substr(url.length - 3, 3) == '.js')
              url = url.substr(0, url.length - 3);
            return url;
          };
          depValues.splice(requireIndex, 0, contextualRequire);
        }

        // set global require to AMD require
        var curRequire = __global.require;
        __global.require = require;

        var output = factory.apply(exportsIndex == -1 ? __global : exports, depValues);

        __global.require = curRequire;

        if (typeof output == 'undefined' && module)
          output = module.exports;

        if (typeof output != 'undefined')
          return output;
      }

      var entry = createEntry();
      entry.name = name && (loader.decanonicalize || loader.normalize).call(loader, name);
      entry.deps = deps;
      entry.execute = execute;

      loader.pushRegister_({
        amd: true,
        entry: entry
      });
    }
    define.amd = {};

    // reduction function to attach defines to a load record
    hook('reduceRegister_', function(reduceRegister) {
      return function(load, register) {
        // only handle AMD registers here
        if (!register || !register.amd)
          return reduceRegister.call(this, load, register);

        var curMeta = load && load.metadata;
        var entry = register.entry;

        if (curMeta)
          curMeta.format = 'amd';

        // anonymous define
        if (!entry.name) {
          if (!curMeta)
            throw new TypeError('Unexpected anonymous AMD define.');

          if (curMeta.entry && !curMeta.entry.name)
            throw new Error('Multiple anonymous defines in module ' + load.name);
          
          curMeta.entry = entry;
        }
        // named define
        else {
          // if we don't have any other defines, 
          // then let this be an anonymous define
          // this is just to support single modules of the form:
          // define('jquery')
          // still loading anonymously
          // because it is done widely enough to be useful
          // as soon as there is more than one define, this gets removed though
          if (curMeta) {
            if (!curMeta.entry && !curMeta.bundle)
              curMeta.entry = entry;
            else if (curMeta.entry && curMeta.entry.name)
              curMeta.entry = undefined;

            // note this is now a bundle
            curMeta.bundle = true;
          }

          // define the module through the register registry
          if (!(entry.name in this.defined))
            this.defined[entry.name] = entry;
        }
      };
    });

    loader.amdDefine = define;
    loader.amdRequire = require;
  };
});