text: /**
   * Copyright 2013 Facebook, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  var inherits = require('util').inherits;
  var zlib = require('zlib');
  
  var docblock = require('../parse/docblock');
  var ResourceLoader = require('./ResourceLoader');
  var extractFBSprites = require('../parse/css').extractFBSprites;
  var CSS = require('../resource/CSS');
  var MessageList = require('../MessageList');
  
  
  /**
   * @class Loads and parses CSS files
   * Extracts options from the docblock, calculates gziped network size. Network
   * size calculation is off by default due to it's perf cost. Use options
   * parameter to switch them on.
   *
   * @extends {ResourceLoader}
   * @param {Object|null} options Object with the following options:
   *                              - extractNetworkSize
   *                              - extractFBSprites
   */
  function CSSLoader(options) {
    ResourceLoader.call(this, options);
    var extractNetworkSize = !!this.options.networkSize;
  
    if (extractNetworkSize) {
      this.extractExtra = this.extractNetworkSize;
    } else {
      this.extractExtra = function(css, sourceCode, messages, callback) {
        // make async to break long stack traces
        process.nextTick(function() {
          callback(messages, css);
        });
      };
    }
  }
  inherits(CSSLoader, ResourceLoader);
  CSSLoader.prototype.path = __filename;
  
  CSSLoader.prototype.getResourceTypes = function() {
    return [CSS];
  };
  
  CSSLoader.prototype.getExtensions = function() {
    return ['.css'];
  };
  
  /**
   * Extracts aproximate network size by gziping the source
   * @todo (voloko) why not minify?
   * Off by default due to perf cost
   *
   * @protected
   * @param  {CSS}   css
   * @param  {String}   sourceCode
   * @param  {Function} callback
   */
  CSSLoader.prototype.extractNetworkSize =
    function(css, sourceCode, messages, callback) {
    zlib.deflate(sourceCode, function(err, buffer) {
      css.networkSize = buffer.length;
      callback(messages, css);
    });
  };
  
  /**
   * Initialize a resource with the source code and configuration
   * Loader can parse, gzip, minify the source code to build the resulting
   * Resource value object
   *
   * @protected
   * @param {String}               path      resource being built
   * @param {ProjectConfiguration} configuration configuration for the path
   * @param {String}               sourceCode
   * @param {Function}             callback
   */
  CSSLoader.prototype.loadFromSource =
    function(path, configuration, sourceCode, messages, callback) {
    var css = new CSS(path);
  
    var props = docblock.parse(docblock.extract(sourceCode));
  
    props.forEach(function(pair) {
      var name = pair[0];
      var value = pair[1];
  
      switch (name) {
        case 'provides':
          css.id = value;
          break;
        case 'providesModule':
          css.isModule = true;
          css.id = 'css:' + value;
          break;
        case 'css':
          value.split(/\s+/).forEach(css.addRequiredCSS, css);
          break;
        case 'requires':
          value.split(/\s+/).forEach(css.addRequiredLegacyComponent, css);
          break;
        case 'nonblocking':
          css.isNonblocking = true;
          break;
        case 'nopackage':
          css.isNopackage = true;
          break;
        case 'permanent':
          css.isPermanent = true;
          break;
        case 'option':
        case 'options':
          value.split(/\s+/).forEach(function(key) {
            css.options[key] = true;
          });
          break;
        case 'author':
        case 'deprecated':
          // Support these so Diviner can pick them up.
          break;
        case 'nolint':
        case 'generated':
        case 'preserve-header':
          // various options
          break;
        case 'layer':
          // This directive is currently used by Connect JS library
          break;
        default:
          messages.addClowntownError(css.path, 'docblock',
            'Unknown directive ' + name);
      }
    });
  
    if (this.options.extractFBSprites) {
      css.fbSprites = extractFBSprites(sourceCode);
    }
  
    css.finalize();
  
    this.extractExtra(css, sourceCode, messages, callback);
  };
  
  
  /**
   * Only match *.css files
   * @param  {String} filePath
   * @return {Bollean}
   */
  CSSLoader.prototype.matchPath = function(filePath) {
    return filePath.lastIndexOf('.css') === filePath.length - 4;
  };
  
  /**
   * Post process is called after the map is updated but before the update
   * task is complete.
   * Used to resolve local required paths and /index.js directory requires
   *
   * @param  {ResourceMap}      map
   * @param  {Array.<Resource>} resources
   * @param  {Function}         callback
   */
  CSSLoader.prototype.postProcess = function(map, resources, callback) {
    var messages = MessageList.create();
  
    resources.forEach(function(r) {
      var resource, i, required;
  
      required = r.requiredCSS;
      for (i = 0; i < required.length; i++) {
        resource = map.getResource('CSS', 'css:' + required[i]);
        if (resource && resource.isModule) {
          required[i] = 'css:' + required[i];
        }
      }
    });
  
    process.nextTick(function() {
      callback(messages);
    });
  };
  
  
  module.exports = CSSLoader;
  