FILTER_ANY = "xap_filter_any"
FILTER_ABSENT = "xap_filter_absent"

Filter = {}
function Filter:new()
   local o={
      filterChain = {},
      callback = nil
   }
   return setmetatable(o, {__index=self})
end

function Filter:add(section, key, value)
   table.insert(self.filterChain, {section=section,key=key,value=value:lower()})
end

function Filter:callback(func, userdata)
   self.callback = func
   self.userdata = userdata
end

function Filter:ismatch(frame)
   local value, match = nil, true -- No filter chain is match

   function filterAddrSubaddress(filterAddr, addr)
      if filterAddr == nil then
         -- empty filterAddr matches all
         match = true
      elseif filterAddr:find('*') == nil and filterAddr:find('>') == nil then
         -- no wildcards - simple compare
         match = filterAddr == addr
      else
         -- Match using wildcard logic
         filterAddr = filterAddr:gsub('%.','%%.') -- escape the .
         filterAddr = filterAddr:gsub('\*','[%%w%%-_]+')
         filterAddr = filterAddr:gsub('>','.*')
         local start,finish = addr:find(filterAddr)
         match = start == 1 and finish == #addr
      end
   end

   for _,fk in pairs(self.filterChain) do
      value = frame:getValue( fk.section, fk.key )
      if fk.value == FILTER_ABSENT then
         match = value == nil
      elseif fk.value == FILTER_ANY then
         match = value ~= nil
      elseif value == nil then
         match = false
      else
         value = value:lower()
         if fk.section == "xap-header" and (fk.key == "target" or
                                            fk.key == "source" or
                                            fk.key == "class") then
            if fk.key == "target" then
               filterAddrSubaddress(value, fk.value)
            else -- source /class
               filterAddrSubaddress(fk.value, value)
            end
         else
            match = value == fk.value
         end
      end
      if not match then break end
   end

   return match
end

function Filter:dispatch(frame)
   if self.callback and self:ismatch(frame) then
      pcall(self.callback, frame, self.userdata)
   end
end

function Filter:getFilterType()
        for _,fk in pairs(self.filterChain) do
                if fk.section == "xap-header" then
                        if fk.key == "source" then
                                return "flt", fk.value
                        end
						if fk.key == "class" then
                                return "cflt", fk.value
                        end
                end
        end
        return nil
end