/*
 * Copyright 2007-2013 Charles du Jeu - Abstrium SAS <team (at) pyd.io>
 * This file is part of Pydio.
 *
 * Pydio is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Pydio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Pydio.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The latest code can be found at <http://pyd.io/>.
 */

/**
 * Manage background tasks
 */
class BackgroundTasksManager extends Observable {

	/**
	 * Constructor
	 * @param actionManager ActionManager
	 */
	constructor(actionManager){
        super();
        this.queue = [];
		this.actionManager = actionManager;
		this.working = false;
	}
	/**
	 * Add an action to the queue
	 * @param actionName String Name of the action
	 * @param parameters Object Parameters of the action, NOT HASH
	 * @param messageId String An i18n id of the message to be displayed during the action
	 */
	queueAction(actionName, parameters,messageId){
		var actionDef = {};
		actionDef['name'] = actionName;
		actionDef['messageId'] = messageId;
		actionDef['parameters'] = parameters;
		this.queue.push(actionDef);
	}
	
	/**
	 * Processes the next action in the queue
	 */
	next(){
		if(!this.queue.length){
			 this.finished();
			 return;
		}
		if(this.working) return;
		var actionDef = this.queue[0];
        if(actionDef['name'] == "javascript_instruction" && actionDef['parameters']['callback']){
            var cb = actionDef['parameters']['callback'];
            this.notify("update_message", actionDef['messageId']);
    		this.queue.shift();
            cb();
            this.working = false;
            this.next();
        }else{
            var client = PydioApi.getClient();
            var params = {get_action: actionDef['name']};
            for(var k in actionDef['parameters']){
                if(actionDef['parameters'].hasOwnProperty(k)) params[k] = actionDef['parameters'][k];
            }
            client.request(params, function(transport){
                var xmlResponse = transport.responseXML;
                if(xmlResponse == null || xmlResponse.documentElement == null) {
                    this.working = false;
                    this.next();
                    return;
                }
                this.parseAnswer(transport.responseXML);
                this.working = false;
            }.bind(this), null, {method: 'POST'});
            this.notify("update_message", actionDef['messageId']);
    		this.queue.shift();
    		this.working = true;
        }
	}

	/**
	 * Parses the response. Should probably use the actionBar parser instead.
	 * @param xmlResponse XMLDocument
	 */
	parseAnswer(xmlResponse){
		var childs = xmlResponse.documentElement.childNodes;	
		var delay = 0;
		for(var i=0; i<childs.length;i++)
		{
			if(childs[i].tagName == "message")
			{
				var type = childs[i].getAttribute('type');
				if(type != 'SUCCESS'){
					this.interruptOnError(childs[i].firstChild.nodeValue);
				}
			} else if(childs[i].nodeName == 'nodes_diff') {
                var dm = this.actionManager.getDataModel();
                if(dm.getAjxpNodeProvider().parseAjxpNodesDiffs){
                    dm.getAjxpNodeProvider().parseAjxpNodesDiffs(childs[i], dm, !window.currentLightBox);
                }
            } else if(childs[i].nodeName == "trigger_bg_action"){
				var name = childs[i].getAttribute("name");
				var messageId = childs[i].getAttribute("messageId");
                delay = parseInt(childs[i].getAttribute("delay"));
				var parameters = {};
				for(var j=0;j<childs[i].childNodes.length;j++){
					var paramChild = childs[i].childNodes[j];
					if(paramChild.tagName == 'param'){
						parameters[paramChild.getAttribute("name")] = paramChild.getAttribute("value");
					}else if(paramChild.tagName == 'clientCallback'){
                        var callbackCode = paramChild.firstChild.nodeValue;
                        var callback = new Function(callbackCode);
                    }
				}
				if(name == "reload_node"){
                    if(delay){
                        window.setTimeout(function(){
                            this.actionManager.getDataModel().requireContextChange(this.actionManager.getDataModel().getContextNode(), true);
                            this.next();
                        }.bind(this), delay*1000);
                        return;
                    }
                    this.actionManager.getDataModel().requireContextChange(this.actionManager.getDataModel().getContextNode(), true);
                }else if(name == "info_message"){
                    this.notify("update_message", messageId);
                }else if(name == "javascript_instruction" && callback){
                    parameters["callback"] = callback;
                    this.queueAction('javascript_instruction', parameters, messageId);
				}else{
					this.queueAction(name, parameters, messageId);
				}
			}
		}
		this.working = false;
        if(delay){
            window.setTimeout(this.next.bind(this), delay*1000);
        }else{
            this.next();
        }
	}
	/**
	 * Interrupt the task on error
	 * @param errorMessage String
	 */
	interruptOnError(errorMessage){
		if(this.queue.length) this.queue = [];
		this.notify("update_message_error", errorMessage);
		this.working = false;
	}
	/**
	 * All tasks are processed
	 */
	finished(){
		this.working = false;
        this.notify("tasks_finished");
	}
	
	/**
	 * Create a stub action with not parameter.
	 */
	addStub(){
		this.queueAction('local_to_remote', {}, 'Stubing a 10s bg action');
	}
}