/**
 * archive.js
 *
 * Provides base functionality for unarchiving.
 *
 * Licensed under the MIT License
 *
 * Copyright(c) 2011 Google Inc.
 */

var bitjs = bitjs || {};
bitjs.archive = bitjs.archive || {};

(function() {

// ===========================================================================
// Stolen from Closure because it's the best way to do Java-like inheritance.
bitjs.base = function(me, opt_methodName, var_args) {
  var caller = arguments.callee.caller;
  if (caller.superClass_) {
    // This is a constructor. Call the superclass constructor.
    return caller.superClass_.constructor.apply(
        me, Array.prototype.slice.call(arguments, 1));
  }

  var args = Array.prototype.slice.call(arguments, 2);
  var foundCaller = false;
  for (var ctor = me.constructor;
       ctor; ctor = ctor.superClass_ && ctor.superClass_.constructor) {
    if (ctor.prototype[opt_methodName] === caller) {
      foundCaller = true;
    } else if (foundCaller) {
      return ctor.prototype[opt_methodName].apply(me, args);
    }
  }

  // If we did not find the caller in the prototype chain,
  // then one of two things happened:
  // 1) The caller is an instance method.
  // 2) This method was not called by the right caller.
  if (me[opt_methodName] === caller) {
    return me.constructor.prototype[opt_methodName].apply(me, args);
  } else {
    throw Error(
        'goog.base called from a method of one name ' +
        'to a method of a different name');
  }
};
bitjs.inherits = function(childCtor, parentCtor) {
  /** @constructor */
  function tempCtor() {};
  tempCtor.prototype = parentCtor.prototype;
  childCtor.superClass_ = parentCtor.prototype;
  childCtor.prototype = new tempCtor();
  childCtor.prototype.constructor = childCtor;
};
// ===========================================================================

/**
 * An unarchive event.
 *
 * @param {string} type The event type.
 * @constructor
 */
bitjs.archive.UnarchiveEvent = function(type) {
  /**
   * The event type.
   * @type {string}
   * @private
   */
  this.type_ = type;
};

/**
 * Returns the event type.
 *
 * @return {string} the event type.
 */
bitjs.archive.UnarchiveEvent.prototype.getType = function() {
  return this.type_;
};

/**
 * The UnarchiveEvent types.
 */
bitjs.archive.UnarchiveEvent.Type = {
  START: 'start',
  PROGRESS: 'progress',
  EXTRACT: 'extract',
  FINISH: 'finish',
  ERROR: 'error'
};

/**
 * All extracted files returned by an Unarchiver will implement
 * the following interface:
 *
 * interface UnarchivedFile {
 *   string filename
 *   TypedArray filedata  
 * }
 *
 */

/**
 * Base class for all Unarchivers.
 *
 * @param {ArrayBuffer} arrayBuffer The Array Buffer.
 * @constructor
 */
bitjs.archive.Unarchiver = function(arrayBuffer) {
  /**
   * The ArrayBuffer object.
   * @type {ArrayBuffer}
   * @protected
   */
  this.ab = arrayBuffer;

  /**
   * A map from event type to an array of listeners.
   * @type {Map.<string, Array>}
   */
  this.listeners_ = {};
  for (var type in bitjs.archive.UnarchiveEvent.Type) {
    this.listeners_[bitjs.archive.UnarchiveEvent.Type[type]] = [];
  }
};

/**
 * Private web worker initialized during start().
 * @type {Worker}
 * @private
 */
bitjs.archive.Unarchiver.prototype.worker_ = null;

/**
 * This method must be overridden by the subclass to return the script filename.
 * @return {string} The script filename.
 * @protected.
 */
bitjs.archive.Unarchiver.prototype.getScriptFileName = function() {
  throw "Subclasses of AbstractUnarchiver must overload getScriptFileName()";
};

/**
 * Adds an event listener for UnarchiveEvents.
 *
 * @param {string} Event type.
 * @param {function} An event handler function.
 */
bitjs.archive.Unarchiver.prototype.addEventListener = function(type, listener) {
  if (type in this.listeners_) {
    if (this.listeners_[type].indexOf(listener) == -1) {
      this.listeners_[type].push(listener);
    }
  }
};

/**
 * Removes an event listener.
 *
 * @param {string} Event type.
 * @param {EventListener|function} An event listener or handler function.
 */
bitjs.archive.Unarchiver.prototype.removeEventListener = function(type, listener) {
  if (type in this.listeners_) {
    var index = this.listeners_[type].indexOf(listener);
    if (index != -1) {
      this.listeners_[type].splice(index, 1);
    }
  }
};

/**
 * Receive an event and pass it to the listener functions.
 *
 * @param {bitjs.archive.UnarchiveEvent} e
 * @private
 */
bitjs.archive.Unarchiver.prototype.handleWorkerEvent_ = function(e) {
  if (e instanceof bitjs.archive.UnarchiveEvent) {
    var listeners = this.listeners_[e.getType()];
    if (listeners instanceof Array) {
      listeners.forEach(function (listener) { listener(e) });
    }
  } else {
    console.log(e);
  }
};

/**
 * Starts the unarchive in a separate Web Worker thread and returns immediately.
 */
 bitjs.archive.Unarchiver.prototype.start = function() {
  var scriptFileName = this.getScriptFileName();
  if (scriptFileName) {
    this.worker_ = new Worker(scriptFileName);

    this.worker_.onerror = function(e) {
      alert("Worker error: " + e.message);
      throw e;
    };

    this.worker_.onmessage = function(e) {
      alert("Worker onmessage: " + e);
    };

    this.worker_.postMessage({file: this.ab});
  }
}

/**
 * Unzipper
 * @extends {bitjs.archive.Unarchiver}
 * @constructor
 */
bitjs.archive.Unzipper = function(arrayBuffer) {
  bitjs.base(this, arrayBuffer);
};
bitjs.inherits(bitjs.archive.Unzipper, bitjs.archive.Unarchiver);
bitjs.archive.Unzipper.prototype.getScriptFileName = function() { return "unzip.js" };


})();