defmodule ExWechat.Message do
    @moduledoc false

    def parse!(xmldoc) do
        node = xmldoc |> Quinn.parse
        msgType = node |> xml_value(:MsgType) |> String.to_atom

        %{
            toUserName:     node |> xml_value(:ToUserName),
            fromUserName:   node |> xml_value(:FromUserName),
            createTime:     node |> xml_value(:CreateTime),
            msgType:        node |> xml_value(:MsgType)
        }
        |> Map.merge(do_parse(msgType, node))
    end

    defp do_parse(:text, node) do
        %{
            content:        node |> xml_value(:Content),
            msgId:          node |> xml_value(:MsgId)
        }
    end

    defp do_parse(:event, node) do
        event = node |> xml_value(:Event)
        %{
            event: event
        }
        |> Map.merge(do_parse(:event, String.to_atom(event), node))
    end

    defp do_parse(:event, :CLICK, node),    do: %{eventKey: (node |> xml_value(:EventKey))}
    defp do_parse(:event, :subscribe, _),   do: %{}
    defp do_parse(:event, :unsubscribe, _),   do: %{}









    def encode!(:text, msg) do
        createTime = Timex.Duration.now |> Timex.Duration.to_seconds |> round
        ~s("""
            <xml>
                <ToUserName><![CDATA[#{msg.toUserName}]]></ToUserName>
                <FromUserName><![CDATA[#{msg.fromUserName}]]></FromUserName>
                <CreateTime>#{createTime}</CreateTime>
                <MsgType><![CDATA[text]]></MsgType>
                <Content><![CDATA[#{msg.content}]]></Content>
            </xml>
            """)
    end

    def encode!(:transfer_customer_service, msg) do
        createTime = Timex.Duration.now |> Timex.Duration.to_seconds |> round
        ~s("""
            <xml>
                <ToUserName><![CDATA[#{msg.toUserName}]]></ToUserName>
                <FromUserName><![CDATA[#{msg.fromUserName}]]></FromUserName>
                <CreateTime>#{createTime}</CreateTime>
                <MsgType><![CDATA[transfer_customer_service]]></MsgType>
            </xml>
            """)
    end



    defp xml_value(xml, tag), do: xml |> Quinn.find(tag) |> do_xml_value
    defp do_xml_value([]), do: nil
    defp do_xml_value([h|_]), do: h |> Map.get(:value) |> List.first
end