local _M = { version = 0.2 }

local function get_client_ip(stream)
    local ip = stream:downstreamLocalAddress()
    if ip then
        return ip
    end

    ip = stream:downstreamDirectRemoteAddress()
    if ip then
        return ip
    end
end

function _M.set_vars_meta(handle)
    local stream = handle:streamInfo()
    local meta = stream:dynamicMetadata()

    local var = {}
    var._cache = meta:get("envoy.filters.http.lua") or {}
    var.remote_addr = get_client_ip(stream)

    setmetatable(var, {
        __index = function(self, key)
            local cached = self._cache[key]
            if cached ~= nil then
                return cached
            end

            return nil
        end,

        __newindex = function(self, key, val)
            meta:set("envoy.filters.http.lua", key, val)
            self._cache[key] = val
        end,

        __pairs = function (self)
            return next, self._cache, nil
        end,
    })

    return var
end

return _M