---
-- This module was written by Patrik Karlsson and facilitates communication
-- with the Citrix XML Service. It is not feature complete and is missing several
-- functions and parameters.
--
-- The library makes little or no effort to verify that the parameters submitted
-- to each function are compliant with the DTD
--
-- As all functions handling requests take their parameters in the form of tables,
-- additional functionality can be added while not breaking existing scripts
--
-- Details regarding the requests/responses and their parameters can be found in
-- the NFuse.DTD included with Citrix MetaFrame/Xenapp
--
-- This code is based on the information available in:
-- NFuse.DTD - Version 5.0 (draft 1)   24 January 2008
--



local http = require "http"
local stdnse = require "stdnse"
local string = require "string"
local table = require "table"
_ENV = stdnse.module("citrixxml", stdnse.seeall)

--- Decodes html-entities to chars eg. &#32; => <space>
-- Note that only decimal references of ASCII characters are supported.
-- Named and hexadecimal references are left untouched, and so are codepoints
-- greater than 255.
--
-- @param xmldata string to convert
-- @return string with XML character references replaced with the corresponding characters
function decode_xml_document(xmldata)
  if not xmldata then
    return ""
  end
  return (xmldata:gsub("&#%d+;",
                       function (e)
                         local cp = tonumber(e:sub(3, -2))
                         return cp <= 0xFF and string.char(cp) or nil
                       end))
end

--- Sends the request to the server using the http lib
--
-- @param host string or host table of the remote server
-- @param port number or port table of the remote server
-- @param xmldata string, the HTTP data part of the request as XML
--
-- @return string with the response body
--
function send_citrix_xml_request(host, port, xmldata)

  local response = http.post( host, port, "/scripts/WPnBr.dll", { header={["Content-Type"]="text/xml"}}, nil, xmldata)

  -- this is *probably* not the right way to do stuff
  -- decoding should *probably* only be done on XML-values
  -- this is *probably* defined in the standard, for anyone interested
  return decode_xml_document(response.body)

end

--- Request information about the Citrix Server Farm
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function implements all the supported parameters described in:
-- Version 5.0 (draft 1)   24 January 2008
--
-- @param host string or host table of the remote server
-- @param port number or port table of the remote server
-- @return string HTTP response data
--
function request_server_farm_data( host, port )

  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n\z
  <!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n\z
  <NFuseProtocol version=\"1.1\">\z
  <RequestServerFarmData></RequestServerFarmData>\z
  </NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, xmldata)
end

--- Parses the response from the request_server_farm_data request
-- @param response string with the XML response
-- @return table containing server farm names
--
function parse_server_farm_data_response( response )

  local farms = {}

  response = response:gsub("\r?\n","")
  for farm in response:gmatch("<ServerFarmName.->([^<]+)</ServerFarmName>") do
    table.insert(farms, farm)
  end

  return farms

end

--- Sends a request for application data to the Citrix XML service
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function does NOT implement all the supported parameters
--
-- Supported parameters are Scope, ServerType, ClientType, DesiredDetails
--
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @param params table with parameters
-- @return string HTTP response data
--
function request_appdata(host, port, params)

  -- setup the mandatory parameters if they're missing
  local scope = params['Scope'] or "onelevel"
  local server_type = params['ServerType'] or "all"
  local client_type = params['ClientType'] or "ica30"
  local desired_details = params['DesiredDetails'] or nil

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="5.0"><RequestAppData><Scope traverse="',
    scope,
    '" /><ServerType>',
    server_type,
    "</ServerType><ClientType>",
    client_type,
    "</ClientType>"
  }

  if desired_details then
    if type(desired_details) == "string" then
      xmldata[#xmldata+1] = "<DesiredDetails>" .. desired_details .. "</DesiredDetails>"
    elseif type(desired_details) == "table" then
      for _, v in ipairs(desired_details) do
        xmldata[#xmldata+1] = "<DesiredDetails>" .. v .. "</DesiredDetails>"
      end
    else
      assert(desired_details)
    end

  end

  xmldata[#xmldata+1] = "</RequestAppData></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))
end


--- Extracts the Accesslist section of the XML response
--
-- @param xmldata string containing results from the request app data request
-- @return table containing settings extracted from the accesslist section of the response
local function extract_appdata_acls(xmldata)

  local acls = {}
  local users = {}
  local groups = {}

  for acl in xmldata:gmatch("<AccessList>(.-)</AccessList>") do

    if acl:match("AnonymousUser") then
      table.insert(users, "Anonymous")
    else

      for user in acl:gmatch("<User>(.-)</User>") do
        local user_name = user:match("<UserName.->(.-)</UserName>") or ""
        local domain_name = user:match("<Domain.->(.-)</Domain>") or ""

        if user_name:len() > 0 then
          if domain_name:len() > 0 then
            domain_name = domain_name .. "\\"
          end
          table.insert(users, domain_name .. user_name)
        end

      end

      for group in acl:gmatch("<Group>(.-)</Group>") do


        local group_name = group:match("<GroupName.->(.-)</GroupName>") or ""
        local domain_name = group:match("<Domain.->(.-)</Domain>") or ""

        if group_name:len() > 0 then
          if domain_name:len() > 0 then
            domain_name = domain_name .. "\\"
          end
          table.insert(groups, domain_name .. group_name)
        end

      end

    end

    if #users> 0 then
      acls['User'] = users
    end
    if #groups>0 then
      acls['Group'] = groups
    end

  end

  return acls

end


--- Extracts the settings section of the XML response
--
-- @param xmldata string containing results from the request app data request
-- @return table containing settings extracted from the settings section of the response
local function extract_appdata_settings(xmldata)

  local settings = {}

  settings['appisdisabled'] = xmldata:match("<Settings.-appisdisabled=\"(.-)\".->")
  settings['appisdesktop'] = xmldata:match("<Settings.-appisdesktop=\"(.-)\".->")

  for s in xmldata:gmatch("<Settings.->(.-)</Settings>") do
    settings['Encryption'] = s:match("<Encryption.->(.-)</Encryption>")
    settings['EncryptionEnforced'] = s:match("<Encryption minimum=\"(.-)\">")
    settings['AppOnDesktop'] = s:match("<AppOnDesktop.-value=\"(.-)\"/>")
    settings['AppInStartmenu'] = s:match("<AppInStartmenu.-value=\"(.-)\"/>")
    settings['PublisherName'] = s:match("<PublisherName.->(.-)</PublisherName>")
    settings['SSLEnabled'] = s:match("<SSLEnabled.->(.-)</SSLEnabled>")
    settings['RemoteAccessEnabled'] = s:match("<RemoteAccessEnabled.->(.-)</RemoteAccessEnabled>")
  end

  return settings

end

--- Parses the appdata XML response
--
-- @param xmldata string response from request_appdata
-- @return table containing nestled tables closely resembling the DOM model of the XML response
function parse_appdata_response(xmldata)

  local apps = {}
  xmldata = xmldata:gsub("\r?\n",""):gsub(">%s+<", "><")

  for AppData in xmldata:gmatch("<AppData>(.-)</AppData>") do

    local app_name = AppData:match("<FName.->(.-)</FName>") or ""
    local app = {}

    app['FName'] = app_name
    app['AccessList'] = extract_appdata_acls(AppData)
    app['Settings'] = extract_appdata_settings(AppData)

    table.insert(apps, app)

  end

  return apps
end

--
--
-- @param flags string, should be any of following: alt-addr, no-load-bias
--
function request_address(host, port, flags, appname)

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="4.1"><RequestAddress>'
  }

  if flags then
    xmldata[#xmldata+1] = "<Flags>" .. flags .. "</Flags>"
  end

  if appname then
    xmldata[#xmldata+1] = "<Name><AppName>" .. appname .. "</AppName></Name>"
  end

  xmldata[#xmldata+1] = "</RequestAddress></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))
end

--- Request information about the Citrix protocol
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function implements all the supported parameters described in:
-- Version 5.0 (draft 1)   24 January 2008
--
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @param params table with parameters
-- @return string HTTP response data
--
function request_server_data(host, port, params)

  local params = params or {}
  local server_type = params.ServerType or {"all"}
  local client_type = params.ClientType or {"all"}

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="1.1"><RequestServerData>'
  }

  for _, srvtype in pairs(server_type) do
    xmldata[#xmldata+1] = "<ServerType>" .. srvtype .. "</ServerType>"
  end

  for _, clitype in pairs(client_type) do
    xmldata[#xmldata+1] = "<ClientType>" .. clitype .. "</ClientType>"
  end

  xmldata[#xmldata+1] = "</RequestServerData></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))
end

--- Parses the response from the request_server_data request
-- @param response string with the XML response
-- @return table containing the server names
--
function parse_server_data_response(response)

  local servers = {}

  response = response:gsub("\r?\n","")
  for s in response:gmatch("<ServerName>([^<]+)</ServerName>") do
    table.insert(servers, s)
  end

  return servers

end

--- Request information about the Citrix protocol
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function implements all the supported parameters described in:
-- Version 5.0 (draft 1)   24 January 2008
--
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @param params table with parameters
-- @return string HTTP response data
--
function request_protocol_info( host, port, params )

  local params = params or {}

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="1.1"><RequestProtocolInfo>'
  }

  if params['ServerAddress'] then
    xmldata[#xmldata+1] = ('<ServerAddress addresstype="' ..
      params['ServerAddress']['attr']['addresstype'] .. '">' ..
      params['ServerAddress'] .. "</ServerAddress>")
  end

  xmldata[#xmldata+1] = "</RequestProtocolInfo></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))
end

--- Request capability information
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function implements all the supported parameters described in:
-- Version 5.0 (draft 1)   24 January 2008
--
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @return string HTTP response data
--
function request_capabilities( host, port )

  local xmldata = '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
  <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
  <NFuseProtocol version="1.1"><RequestCapabilities>\z
  </RequestCapabilities></NFuseProtocol>\r\n'

  return send_citrix_xml_request(host, port, xmldata)
end

--- Parses the response from the request_capabilities request
-- @param response string with the XML response
-- @return table containing the server capabilities
--
function parse_capabilities_response(response)

  local servers = {}

  response = response:gsub("\r?\n","")
  for s in response:gmatch("<CapabilityId.->([^<]+)</CapabilityId>") do
    table.insert(servers, s)
  end

  return servers

end

--- Tries to validate user credentials against the XML service
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function implements all the supported parameters described in:
-- Version 5.0 (draft 1)   24 January 2008
--
--
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @param params table with parameters
-- @return string HTTP response data
--
function request_validate_credentials(host, port, params )

  local params = params or {}
  local credentials = params['Credentials'] or {}

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="5.0"><RequestValidateCredentials><Credentials>'
  }

  if credentials['UserName'] then
    xmldata[#xmldata+1] = "<UserName>" .. credentials['UserName'] .. "</UserName>"
  end

  if credentials['Password'] then
    xmldata[#xmldata+1] = '<Password encoding="cleartext">' .. credentials['Password'] .. "</Password>"
  end

  if credentials['Domain'] then
    xmldata[#xmldata+1] = '<Domain type="NT">' .. credentials['Domain'] .. "</Domain>"
  end

  xmldata[#xmldata+1] = "</Credentials></RequestValidateCredentials></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))

end


--- Parses the response from request_validate_credentials
-- @param response string with the XML response
-- @return table containing the results
--
function parse_validate_credentials_response(response)
  local tblResult = {}

  response = response:gsub("\r?\n","")
  tblResult['DaysUntilPasswordExpiry'] = response:match("<DaysUntilPasswordExpiry>(.+)</DaysUntilPasswordExpiry>")
  tblResult['ShowPasswordExpiryWarning'] = response:match("<ShowPasswordExpiryWarning>(.+)</ShowPasswordExpiryWarning>")
  tblResult['ErrorId'] = response:match("<ErrorId>(.+)</ErrorId>")

  return tblResult

end

--- Sends a request to reconnect session data
--
-- Consult the NFuse.DTD for a complete list of supported parameters
-- This function does NOT implement all the supported parameters
----
-- @param host string or host table which is to be queried
-- @param port number or port table of the XML service
-- @param params table with parameters
--
function request_reconnect_session_data(host, port, params)

  local params = params or {}
  local Credentials = params.Credentials or {}

  params.ServerType = params.ServerType or {}
  params.ClientType = params.ClientType or {}

  local xmldata = {
    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
    <NFuseProtocol version="5.0"><RequestReconnectSessionData><Credentials>'
  }

  if Credentials.UserName then
    xmldata[#xmldata+1] = "<UserName>" .. Credentials.UserName .. "</UserName>"
  end

  if Credentials.Password then
    xmldata[#xmldata+1] = '<Password encoding="cleartext">' .. Credentials.Password .. "</Password>"
  end

  if Credentials.Domain then
    xmldata[#xmldata+1] = '<Domain type="NT">' .. Credentials.Domain .. "</Domain>"
  end

  xmldata[#xmldata+1] = "</Credentials>"

  if params.ClientName then
    xmldata[#xmldata+1] = "<ClientName>" .. params.ClientName .. "</ClientName>"
  end

  if params.DeviceId then
    xmldata[#xmldata+1] = "<DeviceId>" .. params.DeviceId .. "</DeviceId>"
  end

  for _, srvtype in pairs(params.ServerType) do
    xmldata[#xmldata+1] = "<ServerType>" .. srvtype .. "</ServerType>"
  end

  for _, clitype in pairs(params.ClientType) do
    xmldata[#xmldata+1] = "<ClientType>" .. clitype .. "</ClientType>"
  end

  xmldata[#xmldata+1] = "</RequestReconnectSessionData></NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, table.concat(xmldata))


end

return _ENV;