// SystemJS Loader Class and Extension helpers
function SystemJSLoader() {
  Loader.call(this);

  this.paths = {};
  this._loader.paths = {};

  systemJSConstructor.call(this);
}

// inline Object.create-style class extension
function SystemProto() {};
SystemProto.prototype = Loader.prototype;
SystemJSLoader.prototype = new SystemProto();
SystemJSLoader.prototype.constructor = SystemJSLoader;

var systemJSConstructor;

function hook(name, hook) {
  SystemJSLoader.prototype[name] = hook(SystemJSLoader.prototype[name] || function() {});
}
function hookConstructor(hook) {
  systemJSConstructor = hook(systemJSConstructor || function() {});
}


var absURLRegEx = /^[^\/]+:\/\//;
function isAbsolute(name) {
  return name.match(absURLRegEx);
}
function isRel(name) {
  return (name[0] == '.' && (!name[1] || name[1] == '/' || name[1] == '.')) || name[0] == '/';
}
function isPlain(name) {
  return !isRel(name) && !isAbsolute(name);
}

var baseURIObj = new URL(baseURI);

function urlResolve(name, parent) {
  // url resolution shortpaths
  if (name[0] == '.') {
    // dot-relative url normalization
    if (name[1] == '/' && name[2] != '.')
      return (parent && parent.substr(0, parent.lastIndexOf('/') + 1) || baseURI) + name.substr(2);
  }
  else if (name[0] != '/' && name.indexOf(':') == -1) {
    // plain parent normalization
    return (parent && parent.substr(0, parent.lastIndexOf('/') + 1) || baseURI) + name;
  }

  return new URL(name, parent && parent.replace(/#/g, '%05') || baseURIObj).href.replace(/%05/g, '#');
}

// NB no specification provided for System.paths, used ideas discussed in https://github.com/jorendorff/js-loaders/issues/25
function applyPaths(loader, name) {
  // most specific (most number of slashes in path) match wins
  var pathMatch = '', wildcard, maxWildcardPrefixLen = 0;

  var paths = loader.paths;
  var pathsCache = loader._loader.paths;

  // check to see if we have a paths entry
  for (var p in paths) {
    if (paths.hasOwnProperty && !paths.hasOwnProperty(p))
      continue;

    // paths sanitization
    var path = paths[p];
    if (path !== pathsCache[p])
      path = paths[p] = pathsCache[p] = urlResolve(paths[p], isRel(paths[p]) ? baseURI : loader.baseURL);

    // exact path match
    if (p.indexOf('*') === -1) {
      if (name == p)
        return paths[p];
      
      // support trailing / in paths rules
      else if (name.substr(0, p.length - 1) == p.substr(0, p.length - 1) && (name.length < p.length || name[p.length - 1] == p[p.length - 1]) && (paths[p][paths[p].length - 1] == '/' || paths[p] == '')) {
        return paths[p].substr(0, paths[p].length - 1) + (name.length > p.length ? (paths[p] && '/' || '') + name.substr(p.length) : '');
      }
    }
    // wildcard path match
    else {
      var pathParts = p.split('*');
      if (pathParts.length > 2)
        throw new TypeError('Only one wildcard in a path is permitted');

      var wildcardPrefixLen = pathParts[0].length;
      if (wildcardPrefixLen >= maxWildcardPrefixLen &&
          name.substr(0, pathParts[0].length) == pathParts[0] &&
          name.substr(name.length - pathParts[1].length) == pathParts[1]) {
            maxWildcardPrefixLen = wildcardPrefixLen;
            pathMatch = p;
            wildcard = name.substr(pathParts[0].length, name.length - pathParts[1].length - pathParts[0].length);
          }
    }
  }

  var outPath = paths[pathMatch];
  if (typeof wildcard == 'string')
    outPath = outPath.replace('*', wildcard);

  return outPath;
}

function dedupe(deps) {
  var newDeps = [];
  for (var i = 0, l = deps.length; i < l; i++)
    if (indexOf.call(newDeps, deps[i]) == -1)
      newDeps.push(deps[i])
  return newDeps;
}

function group(deps) {
  var names = [];
  var indices = [];
  for (var i = 0, l = deps.length; i < l; i++) {
    var index = indexOf.call(names, deps[i]);
    if (index === -1) {
      names.push(deps[i]);
      indices.push([i]);
    }
    else {
      indices[index].push(i);
    }
  }
  return { names: names, indices: indices };
}

var getOwnPropertyDescriptor = true;
try {
  Object.getOwnPropertyDescriptor({ a: 0 }, 'a');
}
catch(e) {
  getOwnPropertyDescriptor = false;
}

// converts any module.exports object into an object ready for SystemJS.newModule
function getESModule(exports) {
  var esModule = {};
  // don't trigger getters/setters in environments that support them
  if ((typeof exports == 'object' || typeof exports == 'function') && exports !== __global) {
      if (getOwnPropertyDescriptor) {
        for (var p in exports) {
          // The default property is copied to esModule later on
          if (p === 'default')
            continue;
          defineOrCopyProperty(esModule, exports, p);
        }
      }
      else {
        extend(esModule, exports);
      }
  }
  esModule['default'] = exports;
  defineProperty(esModule, '__useDefault', {
    value: true
  });
  return esModule;
}

function defineOrCopyProperty(targetObj, sourceObj, propName) {
  try {
    var d;
    if (d = Object.getOwnPropertyDescriptor(sourceObj, propName))
      defineProperty(targetObj, propName, d);
  }
  catch (ex) {
    // Object.getOwnPropertyDescriptor threw an exception, fall back to normal set property
    // we dont need hasOwnProperty here because getOwnPropertyDescriptor would have returned undefined above
    targetObj[propName] = sourceObj[propName];
    return false;
  }
}

function extend(a, b, prepend) {
  var hasOwnProperty = b && b.hasOwnProperty;
  for (var p in b) {
    if (hasOwnProperty && !b.hasOwnProperty(p))
      continue;
    if (!prepend || !(p in a))
      a[p] = b[p];
  }
  return a;
}

// meta first-level extends where:
// array + array appends
// object + object extends
// other properties replace
function extendMeta(a, b, prepend) {
  var hasOwnProperty = b && b.hasOwnProperty;
  for (var p in b) {
    if (hasOwnProperty && !b.hasOwnProperty(p))
      continue;
    var val = b[p];
    if (!(p in a))
      a[p] = val;
    else if (val instanceof Array && a[p] instanceof Array)
      a[p] = [].concat(prepend ? val : a[p]).concat(prepend ? a[p] : val);
    else if (typeof val == 'object' && val !== null && typeof a[p] == 'object')
      a[p] = extend(extend({}, a[p]), val, prepend);
    else if (!prepend)
      a[p] = val;
  }
}

function extendPkgConfig(pkgCfgA, pkgCfgB, pkgName, loader, warnInvalidProperties) {
  for (var prop in pkgCfgB) {
    if (indexOf.call(['main', 'format', 'defaultExtension', 'basePath'], prop) != -1) {
      pkgCfgA[prop] = pkgCfgB[prop];
    }
    else if (prop == 'map') {
      extend(pkgCfgA.map = pkgCfgA.map || {}, pkgCfgB.map);
    }
    else if (prop == 'meta') {
      extend(pkgCfgA.meta = pkgCfgA.meta || {}, pkgCfgB.meta);
    }
    else if (prop == 'depCache') {
      for (var d in pkgCfgB.depCache) {
        var dNormalized;

        if (d.substr(0, 2) == './')
          dNormalized = pkgName + '/' + d.substr(2);
        else
          dNormalized = coreResolve.call(loader, d);
        loader.depCache[dNormalized] = (loader.depCache[dNormalized] || []).concat(pkgCfgB.depCache[d]);
      }
    }
    else if (warnInvalidProperties && indexOf.call(['browserConfig', 'nodeConfig', 'devConfig', 'productionConfig'], prop) == -1 && 
        (!pkgCfgB.hasOwnProperty || pkgCfgB.hasOwnProperty(prop))) {
      warn.call(loader, '"' + prop + '" is not a valid package configuration option in package ' + pkgName);
    }
  }
}

// deeply-merge (to first level) config with any existing package config
function setPkgConfig(loader, pkgName, cfg, prependConfig) {
  var pkg;

  // first package is config by reference for fast path, cloned after that
  if (!loader.packages[pkgName]) {
    pkg = loader.packages[pkgName] = cfg;
  }
  else {
    var basePkg = loader.packages[pkgName];
    pkg = loader.packages[pkgName] = {};

    extendPkgConfig(pkg, prependConfig ? cfg : basePkg, pkgName, loader, prependConfig);
    extendPkgConfig(pkg, prependConfig ? basePkg : cfg, pkgName, loader, !prependConfig);
  }
  
  // main object becomes main map
  if (typeof pkg.main == 'object') {
    pkg.map = pkg.map || {};
    pkg.map['./@main'] = pkg.main;
    pkg.main['default'] = pkg.main['default'] || './';
    pkg.main = '@main';
  }

  return pkg;
}

function warn(msg) {
  if (this.warnings && typeof console != 'undefined' && console.warn)
    console.warn(msg);
}