"""validation handler."""
import logging as logger
from typing import ByteString, Callable, Dict, List, Union

from ddex_ingester_common.constants.xmltodict import DDEX_LIST_FIELDS
from ddex_ingester_common.helpers.xml_document_helper import (
    get_root_element,
)
from ddex_ingester_common.schemas.ddex_schema import DDEXSchema
from ddex_ingester_common.schemas.s3_schema import S3Schema
from rules import (
    RuleResult,
    RULES_PER_INGESTION_SOURCE
)
import xmltodict


def handler(
        xml_data: Union[ByteString, str],
        extended_xml_data: Union[ByteString, str] = '') -> List[RuleResult]:
    """Script entry point."""
    if not xml_data:
        return []

    if isinstance(xml_data, bytes):
        xml_data = xml_data.decode('utf-8')

    doc = xmltodict.parse(
        xml_data,
        force_list=DDEX_LIST_FIELDS)

    if extended_xml_data:
        if isinstance(extended_xml_data, bytes):
            extended_xml_data = extended_xml_data.decode('utf-8')

        extended_doc = xmltodict.parse(
            extended_xml_data,
            force_list=DDEX_LIST_FIELDS
        )
        doc = combine_ddex_documents(doc, extended_doc)

    data = DDEXSchema().load(doc)
    ddex_json = S3Schema().dump(data)

    rules = RULES_PER_INGESTION_SOURCE.get('AWAL')

    # Execute validation against received DDEX
    validation_results = validate(ddex_json, rules)

    return validation_results


def combine_ddex_documents(doc, ext):
    """Combine extended metadata with DDEX document."""
    root = get_root_element(doc)
    root['Project'] = ext['OrchardMessage']['Project']

    """
        We want to retain Tracks as a top level object in the DDEX,
        so remove it from the Product dict after using it to avoid duplication.
    """
    root['Tracks'] = ext['OrchardMessage']['Product']['Tracks']
    del ext['OrchardMessage']['Product']['Tracks']

    root['Product'] = ext['OrchardMessage']['Product']

    if ext['OrchardMessage'].get('OrchardLabelId'):
        root['Product']['VendorId'] = ext['OrchardMessage']['OrchardLabelId']

    if ext['OrchardMessage'].get('OrchardSubaccountId'):
        root['Product']['SubaccountId'] = ext['OrchardMessage']['OrchardSubaccountId']  # noqa

    return doc


def validate(
    data: Dict,
    rules: List[Callable[[Dict], RuleResult]]
) -> List[RuleResult]:
    """Validate incoming data against a set of rules."""
    validation_results = []
    for rule in rules:
        try:
            logger.info(f'Executing validation rule: {rule.__name__}')
            validation_results.append(rule(data))
        except Exception:
            msg = f'Exception while executing rule: {rule.__name__}'
            logger.error(msg)
            raise
    return validation_results