import xml.etree.ElementTree as ET
from reqs.messages import Messages


class RequestXmlService:
    REQUEST_NODE_NAME: str = 'request'
    HEADER_NODE_NAME: str = 'header'
    RESULT_NODE_NAME: str = 'result'
    REQUEST_ID_ATTRIBUTE_NAME: str = 'parcel_id'
    RESPONSE_ID_ATTRIBUTE_NAME: str = 'reply_parcel_id'
    SOURCE_REQUEST_ID_ATTRIBUTE_NAME: str = 'source_parcel_id'
    RESULT_CODE_ATTRIBUTE_NAME: str = 'result_code'
    RESULT_MESSAGE_ATTRIBUTE_NAME: str = 'result_message'
    HEADER_XPATH: str = HEADER_NODE_NAME

    def get_request_uuid(self, document: ET.Element) -> str:
        return self.get_header_attribute(document, self.REQUEST_ID_ATTRIBUTE_NAME)

    def get_response_uuid(self, document: ET.Element) -> str:
        return self.get_header_attribute(document, self.RESPONSE_ID_ATTRIBUTE_NAME)

    def get_source_request_uuid(self, document: ET.Element) -> str:
        return self.get_header_attribute(document, self.SOURCE_REQUEST_ID_ATTRIBUTE_NAME)

    def get_header_node(self, document: ET.Element) -> ET.Element:
        return document.find(self.HEADER_XPATH)

    def get_header_attribute(self, document: ET.Element, attribute_name: str) -> str:
        header = self.get_header_node(document)
        if header is None:
            raise Exception(Messages.MISSING_TAG.value)
        result = header.get(attribute_name)
        return result.strip() if result else ''

    def get_request_document(self, request_uuid: str, response_uuid) -> ET.Element:
        document = ET.Element(self.REQUEST_NODE_NAME)
        header = ET.SubElement(document, self.HEADER_NODE_NAME)
        header.set(self.REQUEST_ID_ATTRIBUTE_NAME, request_uuid.strip())
        if response_uuid:
            header.set(self.RESPONSE_ID_ATTRIBUTE_NAME, response_uuid.strip())
        return document

    def get_common_response_xml(self, request_uuid: str, response_uuid: str, result_code: int, result_message: str) -> ET.Element:
        document = self.get_request_document(response_uuid, request_uuid)

        result = ET.SubElement(document, self.RESULT_NODE_NAME)
        result.set(self.RESULT_CODE_ATTRIBUTE_NAME, str(result_code))
        result.set(self.RESULT_MESSAGE_ATTRIBUTE_NAME, result_message)

        return document

    def set_result(self, document: ET.Element, result_code: int, result_message: str):
        result = document.find(self.RESULT_NODE_NAME)
        if result is None:
            result = ET.SubElement(document, self.RESULT_NODE_NAME)
        result.set(self.RESULT_CODE_ATTRIBUTE_NAME, str(result_code))
        result.set(self.RESULT_MESSAGE_ATTRIBUTE_NAME, result_message)

    def set_request_uuid(self, document: ET.Element, request_uuid: str):
        header = self.get_header_node(document)
        header.set(self.REQUEST_ID_ATTRIBUTE_NAME, request_uuid.strip())

    def set_source_request_uuid(self, document: ET.Element, source_request_uuid: str):
        header = self.get_header_node(document)
        header.set(self.SOURCE_REQUEST_ID_ATTRIBUTE_NAME, source_request_uuid.strip())

    def get_common_request_xml(self, request_uuid: str) -> ET.Element:
        return self.get_request_document(request_uuid, None)

    def get_response_xml(self, document: ET.Element, request_uuid, response_uuid: str, result_code: int, result_message: str) -> ET.Element:
        header = document.find(self.HEADER_NODE_NAME)
        header.set(self.REQUEST_ID_ATTRIBUTE_NAME, response_uuid.strip())
        header.set(self.RESPONSE_ID_ATTRIBUTE_NAME, request_uuid.strip() if request_uuid else None)
        result = document.find(self.RESULT_NODE_NAME)
        result.set(self.RESULT_CODE_ATTRIBUTE_NAME, str(result_code))
        result.set(self.RESULT_MESSAGE_ATTRIBUTE_NAME, result_message)

    def get_element(self, document: ET.Element, node: ET.Element, name: str) -> ET.Element:
        for child in node:
            if child.tag.casefold() == name.casefold():
                return child
        return ET.SubElement(document, name)

    def validate_common_request_xml(self, xml: str):
        if not xml:
            raise Exception(Messages.NO_REQUEST_DATA_PROVIDED.name)
        try:
            document = ET.parse(xml)
        except:
            raise Exception(Messages.INVALID_REQUEST_DATA)
        self.validate_common_request_xml(document)

    def validate_common_request_xml(self, document):
        if not document:
            raise Exception(Messages.NO_REQUEST_DATA_PROVIDED.name)
        if document.tag != self.REQUEST_NODE_NAME:
            raise Exception(Messages.MISSING_TAG.name, self.REQUEST_NODE_NAME)
        try:
            request_uuid = self.get_header_attribute(document, self.REQUEST_ID_ATTRIBUTE_NAME)
        except:
            raise Exception(Messages.INVALID_REQUEST_DATA)
        if not request_uuid:
            raise Exception(Messages.MISSING_ATTRIBUTE, self.REQUEST_ID_ATTRIBUTE_NAME, self.HEADER_NODE_NAME)

    def get_result_code(self, document: ET.Element):
        result = self.get_element(document, document, self.RESULT_NODE_NAME)
        if not result:
            return None
        return result.get(self.RESULT_CODE_ATTRIBUTE_NAME)