/*
  Copyright (C) 2013 Grégory Soutadé
  
  This file is part of gPass.
  
  gPass is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  
  gPass 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 General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with gPass.  If not, see <http://www.gnu.org/licenses/>.
*/

var {Cc, Ci} = require("chrome");
var notifications = require("sdk/notifications");

// http://www.timdown.co.uk/jshashtable/
var Hashtable = require("jshashtable-3.0").Hashtable;
// http://code.google.com/p/crypto-js/
var sha256 = require("jssha256").sha256;
var aes = require("jsaes").aes;
var parseURI = require("parseuri").parseURI;
var prefSet = require("simple-prefs");
// Global document
var doc;
var DEBUG = false;


// http://stackoverflow.com/questions/3745666/how-to-convert-from-hex-to-ascii-in-javascript
function hex2a(hex) {
    var str = '';
    for (var i = 0; i < hex.length; i += 2)
        str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
    return str;
}

function a2hex(str) {
    var hex = '';
    for (var i = 0; i < str.length; i++)
    {
	c = str.charCodeAt(i).toString(16);
	if (c.length == 1) c = "0" + c;
        hex += c;
    }
    return hex;
}

function debug(s)
{
    if (DEBUG)
	console.log(s);
}

function on_sumbit()
{
    var form = this;
    var fields = form.getElementsByTagName("input");
    var my_map = new Hashtable();

    domain = parseURI.parseUri(form.ownerDocument.baseURI);
    domain = domain["host"];

    // Get all <input type="text">
    for (i=0; i<fields.length; i++)
    {
	var field = fields[i];
	if (field.getAttribute("type") == "text")
	{
	    if (field.hasAttribute("name"))
		my_map.put(field.getAttribute("name"), field.value);
	}
    }

    // Look for <input type="password" value="@@...">
    for (i=0; i<fields.length; i++)
    {
	var field = fields[i];

	if (field.getAttribute("type") == "password")
	{
	    debug(field.value);
	    password = field.value;
	    if (password.indexOf("@@") != 0)
		continue;

	    mkey = password.substring(2);
	    mkey = sha256.digest(mkey);

	    user = null;
	    // Subset of common user field
	    if      (my_map.containsKey("user"))     user = my_map.get("user");
	    else if (my_map.containsKey("usr"))      user = my_map.get("usr");
	    else if (my_map.containsKey("username")) user = my_map.get("username");
	    else if (my_map.containsKey("login"))    user = my_map.get("login");

	    // If no one found, use all
	    logins = (user != null) ? new Array(user) : my_map.values();

	    keys = "";
	    for(a=0; a<logins.length; a++)
	    {
		v = "@@" + domain + ";" + logins[a];
		debug("will encrypt " + v);
		debug("with " + mkey);
		enc = aes.encryptLongString(v, aes.init(hex2a(mkey)));
		aes.finish();
		debug("res " + enc);

		keys += (keys.length != 0) ? "&" : "";
		keys += "k" + a + "=" + a2hex(enc);
	    }

	    debug(keys);

	    // Need to do a synchronous request
	    var gPassRequest = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].
	    	createInstance(Ci.nsIXMLHttpRequest);

	    var ret = true;
	    // gPassRequest.addEventListener("progress", function(evt) { ; }, false);
	    gPassRequest.addEventListener("load", function(evt) { 
	    	r = this.responseText.split("\n");
		debug("resp " + r);
	    	if (r[0] != "<end>" && r[0].startsWith("pass="))
	    	{
		    ciphered_password = r[0].split("=");
		    ciphered_password = ciphered_password[1];
		    debug("Ciphered password : " + ciphered_password);
		    clear_password = aes.decryptLongString(hex2a(ciphered_password), aes.init(hex2a(mkey)));
		    aes.finish();
		    // Remove salt
		    clear_password = clear_password.replace(/\0*$/, "");
		    clear_password = clear_password.substr(0, clear_password.length-3);
	    	    debug("Clear password " + clear_password);
	    	    field.value = clear_password;
	    	}
		else
		{
		    debug("No password found");

		    ret = false;

		    notifications.notify({
			title: "gPasss",
			text: "No password found in database",
			data: "No password found in database",
		    });
		}
		}, false);
	    gPassRequest.addEventListener("error", function(evt) { 
		debug("error"); 
		ret = false;
		notifications.notify({
		    title: "gPasss",
		    text: "Error",
		    data: "Error",
		});

	    }, false);
	    debug("connect to " + prefSet.prefs["account_url"]);
	    gPassRequest.open("POST", prefSet.prefs["account_url"], false);
	    gPassRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
	    gPassRequest.send(keys);

	    if (!ret) return ret;
	}
    }
}

function document_loaded(event)
{
    // If there is a password in the form, add a "submit" listener
    for(i=0; i<doc.document.forms.length; i++)
    {
	var form = doc.document.forms[i];
	var fields = form.getElementsByTagName("input");
	for (a=0; a<fields.length; a++)
	{
	    var field = fields[a];
	    if (field.getAttribute("type") == "password")
	    {
		form.addEventListener("submit", on_sumbit);
		break;
	    }
	}
    }
}

var httpRequestObserver =
    {
	observe: function(subject, topic, data) 
	{
	    if (topic == "content-document-global-created")
	    {
		doc = subject;
		doc.addEventListener("DOMContentLoaded", document_loaded, false);
	    }
	}
    };

var observerService = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
observerService.addObserver(httpRequestObserver, "content-document-global-created", false);