extends Node
class_name Stanza

const disco_info_queury := "<query xmlns='http://jabber.org/protocol/disco#info'/>"
const disco_items_queury := "<query xmlns='http://jabber.org/protocol/disco#items'/>"

static func yield_as_is():
    return yield()

static func unwrap_query_result(iq: Xml.XmlElement) -> Sums.Result:
    if iq == null or iq.name != "iq" or not "type" in iq.attributes:
        return Sums.Result.make_error(ERR_INVALID_DATA)

    # todo: Delegate strctured XMPP error.
    if iq.attributes["type"] != "result":
        return Sums.Result.make_error(ERR_INVALID_DATA)

    for child in iq.children:
        if child.is_element() and child.name == "query":
            return Sums.Result.make_value(child)

    return Sums.Result.make_error(ERR_INVALID_DATA)

static func form_presence(id: String, from: String, to: String, type, payload: String) -> String:
    if type != null:
        return """<presence from='{from}' id='{id}' to='{to}' type='{type}'>{payload}</presence>""".format({
            "from": from.xml_escape(),
            "id": id.xml_escape(),
            "to": to.xml_escape(),
            "type": type,
            "payload": payload
            })
    else:
        return """<presence from='{from}' id='{id}' to='{to}'>{payload}</presence>""".format({
            "from": from.xml_escape(),
            "id": id.xml_escape(),
            "to": to.xml_escape(),
            "payload": payload
            })

static func presence_result(stanza: Xml.XmlElement) -> Sums.Result:
    if "type" in stanza.attributes and stanza.attributes["type"] == "error":
        return Sums.Result.make_error(stanza)
    else:
        return Sums.Result.make_value(stanza)