/*
  Copyright (C) 2013-2017 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 DEBUG = false;
var protocol_version = 4;
var account_url = null;
var crypto_v2_logins_size=0;

SERVER = {OK : 0, FAILED : 1, RESTART_REQUEST : 2};

// 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++)
    {
	var 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);
}

async function generate_request(domain, login, mkey, iv, old)
{
    if (old)
    {
	var v = "@@" + domain + ";" + login;
	debug("will encrypt " + v);
	enc = encrypt_ecb(mkey, v);
    }
    else
    {
	var v = domain + ";" + login;
	debug("will encrypt " + v);
	while ((v.length % 16))
	    v += "\0";
	hash = await digest(v);
	v += hash.slice(8, 24);
	enc = encrypt_cbc(mkey, iv, v);
    }
    return enc;
}

async function ask_server(form, field, logins, domain, wdomain, mkey, submit)
{
    account_url = await getPref("account_url");

    var salt = parseURI.parseUri(account_url);
    salt = salt["host"] + salt["path"];

    debug("salt " + salt);

    pbkdf2_level = await getPref("pbkdf2_level");

    global_iv = await simple_pbkdf2(salt, mkey, pbkdf2_level);
    global_iv = global_iv.slice(0, 16);
    mkey = crypto_pbkdf2(mkey, salt, pbkdf2_level);

    debug("global_iv " + a2hex(global_iv));
    
    keys = "";
    for(key_index=0, a=0; a<logins.length; a++, key_index++)
    {
	enc = await generate_request(domain, logins[a], mkey, global_iv, 0);
	keys += (keys.length != 0) ? "&" : "";
	keys += "k" + key_index + "=" + a2hex(enc);

	if (wdomain != "")
	{
	    enc = await generate_request(wdomain, logins[a], mkey, global_iv, 0);
	    keys += (keys.length != 0) ? "&" : "";
	    keys += "k" + (++key_index) + "=" + a2hex(enc);
	}
    }

    if (await getPref("crypto_v1_compatible"))
    {
	crypto_v2_logins_size = key_index;
	for(a=0; a<logins.length; a++, key_index++)
	{
	    enc = await generate_request(domain, logins[a], mkey, global_iv, 1);
	    keys += (keys.length != 0) ? "&" : "";
	    keys += "k" + key_index + "=" + a2hex(enc);

	    if (wdomain != "")
	    {
		enc = await generate_request(wdomain, logins[a], mkey, global_iv, 1);
		keys += (keys.length != 0) ? "&" : "";
		keys += "k" + (++key_index) + "=" + a2hex(enc);
	    }
	}
    }
    debug("Keys " + keys);

    var gPassRequest = new XMLHttpRequest();

    var ret = SERVER.OK;

    // gPassRequest.addEventListener("progress", function(evt) { ; }, false);
    gPassRequest.addEventListener("load", async function(evt) { 
	var ciphered_password = "";
	var server_pbkdf2_level = 0;
	var server_version = 0;
	var matched_key = 0;

	var r = this.responseText.split("\n");
	debug("resp " + r);

	for(var a=0; a<r.length; a++)
	{
	    debug("Analyse " + r[a]);

	    params = r[a].split("=");
	    if (params.length != 2 && params[0] != "<end>")
	    {
		notify("Error : It seems that it's not a gPass server",
		       this.responseText);
		ret = SERVER.FAILED;
		break;
	    }

	    switch(params[0])
	    {
	    case "protocol":
		debug("protocol : " + params[1]);

		if (params[1].indexOf("gpass-") != 0)
		{
		    notify("Error : It seems that it's not a gPass server",
			   this.responseText);
		    ret = SERVER.FAILED;
		    break;
		}

		server_protocol_version = params[1].match(/\d+/)[0];
		
		if (server_protocol_version > protocol_version)
		{
		    notify("Protocol version not supported, please upgrade your addon",
			   "Protocol version not supported, please upgrade your addon");
		    ret = SERVER.FAILED;
		}
		else
		{
		    switch (server_protocol_version)
		    {
		    case 2:
			server_pbkdf2_level = 1000;
			break;
		    case 3:
			// Version 3 : nothing special to do
		    case 4:
			// Version 4 : nothing special to do
			break;
		    }
		}
		break;
	   case "matched_key":
		matched_key = params[1];
	    case "pass":
		ciphered_password = params[1];
		break;
	    case "pkdbf2_level":
	    case "pbkdf2_level": 
		server_pbkdf2_level = parseInt(params[1].match(/\d+/)[0], 10);
		if (server_pbkdf2_level != NaN &&
		    server_pbkdf2_level != pbkdf2_level &&
		    server_pbkdf2_level >= 1000) // Minimum level for PBKDF2 !
		{
		    debug("New pbkdf2 level " + server_pbkdf2_level);
		    pbkdf2_level = server_pbkdf2_level;
		    setPref("pbkdf2_level", pbkdf2_level);
		    ret = SERVER.RESTART_REQUEST;
		}
		break;
	    case "<end>":
		break;
	    default:
		debug("Unknown command " + params[0]);

		notify("Error : It seems that it's not a gPass server",
		       this.responseText);
		ret = SERVER.FAILED;
		break;
	    }
	}

	if (ret != SERVER.OK)
	{
	    return;
	}

	if (ciphered_password != "")
	{
	    debug("Ciphered password : " + ciphered_password);
	    if (matched_key >= crypto_v2_logins_size || server_protocol_version < 4)
		// Crypto v1
	    {
		clear_password = await decrypt_ecb(mkey, hex2a(ciphered_password));
		// Remove trailing \0 and salt
		clear_password = clear_password.replace(/\0*$/, "");
		clear_password = clear_password.substr(0, clear_password.length-3);
	    }
	    else
	    {
		clear_password = await decrypt_cbc(mkey, global_iv, hex2a(ciphered_password));
		clear_password = clear_password.replace(/\0*$/, "");
		clear_password = clear_password.substr(3, clear_password.length);
	    }
	    debug("Clear password " + clear_password);
	    field.value = clear_password;
	    // Remove gPass event listener and submit again with clear password
	    if (submit)
	    {
		form.removeEventListener("submit", on_sumbit, true);
		// Propagate change
		change_cb = field.onchange;
		if (change_cb)
		    change_cb();
		// Try to type "enter"
		var evt = new KeyboardEvent("keydown");
		delete evt.which;
		evt.which = 13;
		field.dispatchEvent(evt);
		// Submit form
		form.submit();
	    }
	    else
	    {
		notify("Password successfully replaced",
		       "Password successfully replaced");
	    }
	}
	else
	{
	    debug("No password found");

	    ret = SERVER.FAILED;

	    notify("No password found in database",
		   "No password found in database");
	}
    }, false);
    gPassRequest.addEventListener("error", function(evt) { 
	debug("error"); 
	ret = false;
	notify("Error",
	       "Error");
    }, false);
    debug("connect to " + account_url);
    gPassRequest.open("POST", account_url, true);
    gPassRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    gPassRequest.send(keys);

    return ret;
}

function wildcard_domain(domain)
{
    var parts = domain.split(".");

    if (parts.length >= 3)
    {
	// Seems to be a two level root domain (ie zzz.xxx.co.uk ...)
	if (parts[parts.length-2].lenght <= 3)
	{
	    if (parts.length > 3)
		return "*" + "." + parts[parts.length-3] + "." + parts[parts.length-2] + "." + parts[parts.length-1];
	}
	// Standard root domain (zzz.xxx.com)
	else
	    return "*" + "." + parts[parts.length-2] + "." + parts[parts.length-1];
    }
    // Simple xxx.com
    else if (parts.length == 2)
	return "*" + "." + parts[0] + "." + parts[1];

    return "";
}

function _add_name(logins, name)
{
    for(var i=0; i<logins.length; i++)
	if (logins[i] == name) return ;
    logins.push(name);
}

function try_get_name(fields, type_filters, match)
{
    var user = null;
    var all_logins = new Array();

    for (var i=0; i<fields.length; i++)
    {
	var field = fields[i];

	for (var a=0; a<type_filters.length; a++)
	{
	    if ((match && field.getAttribute("type") == type_filters[a]) ||
		(!match && field.getAttribute("type") != type_filters[a]))
	    {
		if (field.hasAttribute("name") && field.value != "")
		{
		    name = field.getAttribute("name");
		    // Subset of common user field
		    if      (name == "user")     user = field.value;
		    else if (name == "usr")      user = field.value;
		    else if (name == "username") user = field.value;
		    else if (name == "login")    user = field.value;

		    _add_name(all_logins, field.value);
		}
	    }
	}
    }

    if (user != null)
	return new Array(user);
    else
	return all_logins;
}

function on_sumbit(e)
{
    var form = this;
    var fields = form.getElementsByTagName("input");

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

    type_filters = new Array();
    // Get all <input type="text"> && <input type="email">
    type_filters.push("text");
    type_filters.push("email");
    logins = try_get_name(fields, type_filters, true);

    // Get all other fields except text, email and password
    if (!logins.length)
    {
	type_filters.push("password");
	logins = try_get_name(fields, type_filters, false);
    }

    // Look for <input type="password" value="@@...">
    for (var 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 && password.indexOf("@_") != 0)
		continue;

	    // Remove current value to limit master key stealing
	    field.value = "";
	    
	    mkey = password.substring(2);

	    e.preventDefault();

	    var ret = ask_server(form, field, logins, domain, wdomain, mkey, (password.indexOf("@@") == 0));

	    ret.then(function(ret){
		switch(ret)
		{
		    case SERVER.OK:
		    break;
		    case SERVER.FAILED:
		    if (logins !== all_logins)
		    {
			ask_server(form, field, all_logins, domain, wdomain, mkey, (password.indexOf("@@") == 0));
		    }
		    break;
		    case SERVER.RESTART_REQUEST:
		    i = -1; // Restart loop
		    break;
		    }
		});
	}
    }

    return false;
}

function document_loaded(doc)
{
    var has_login_form = false;

    // If there is a password in the form, add a "submit" listener
    for(var i=0; i<doc.forms.length; i++)
    {
	var form = doc.forms[i];
	var fields = form.getElementsByTagName("input");
	for (a=0; a<fields.length; a++)
	{
	    var field = fields[a];
	    if (field.getAttribute("type") == "password")
	    {
		block_url(form.action);
		old_cb = form.onsubmit;
		if (old_cb)
		    form.removeEventListener("submit", old_cb);
		form.addEventListener("submit", on_sumbit);
		if (old_cb)
		    form.addEventListener("submit", old_cb);
		has_login_form = true;
		break;
	    }
	}
    }

    /* Request can be sent to another URL... */
    if (has_login_form)
	block_url("<all_urls>");
}

document_loaded(document);

async function self_test()
{
    mkey = crypto_pbkdf2("password", "salt", 4096);
    res = await encrypt_ecb(mkey, "DDDDDDDDDDDDDDDD");
    
    reference = new Uint8Array([0xc4, 0x76, 0x01, 0x07, 0xa1, 0xc0, 0x2f, 0x22, 0xee, 0xbe, 0x60,
				0xff, 0x65, 0x33, 0x5b, 0x9e]);
    if (res != ab2str(reference))
    {
    	console.log("Self test ERROR !");
    }
    else
    	console.log("Self test OK !");
}

//self_test();