import os.path
from xml.dom.minidom import *


class MessageMapping:
    TAG_MAPPING_GROUP = "mappings"
    TAG_MAPPING = "mapping"

    ATTR_ID = "id"
    ATTR_LINENO = "line_number"
    ATTR_HAS_PACKET = "mapped"

    ATTR_PACKET_TIME = "packet_time"

    def __init__(self, messages):
        self.messages = messages
        self.id_to_packet = {}

    def map_message(self, message, packet):
        self.id_to_packet[message.msg_id] = packet

    def to_xml(self):
        doc = Document()

        mappings = doc.createElement(self.TAG_MAPPING_GROUP)
        doc.appendChild(mappings)

        for message in self.messages:
            mapping = doc.createElement(self.TAG_MAPPING)
            mapping.setAttribute(self.ATTR_ID, str(message.msg_id))
            mapping.setAttribute(self.ATTR_LINENO, str(message.line_no))

            packet = self.id_to_packet.get(message.msg_id)
            mapping.setAttribute(self.ATTR_HAS_PACKET, "true" if packet is not None else "false")
            if packet:
                mapping.setAttribute(self.ATTR_PACKET_TIME, str(packet.time))

            mappings.appendChild(mapping)

        return doc

    def write_to(self, buffer, close = True):
        buffer.write(self.to_xml().toprettyxml())
        if close: buffer.close()

    def write_to_file(self, filename: str, *args, **kwargs):
        self.write_to(open(filename, "w", *args, **kwargs))

    def write_next_to_pcap_file(self, pcap_filename : str, mapping_ext = "_mapping.xml", *args, **kwargs):
        pcap_base = os.path.splitext(pcap_filename)[0]

        self.write_to_file(pcap_base + mapping_ext, *args, **kwargs)