"""General purpose helper methods."""


import csv
from io import StringIO
from itertools import islice

from abacus_common_data.country import Country

from lib.constants import ERROR_UNKNOWN_COUNTRY
from lib.utils import ows


def chunk_collection_by_size(collection, size):
    """Split provided collection into required chunks.

    Arguments:
        collection (list | tuple): initial collection
        size (int): required chunk size
    """
    collection_type = type(collection)
    collection = iter(collection)
    return iter(lambda: collection_type(islice(collection, size)), collection_type())


def json_to_csv(json_data, only_headers=()):
    """Convert specified json object into csv format.

    Arguments:
        json_data (List[dict]): keys are headers for the csv
        only_headers (tuple): use only specified headers in output
    """
    if not json_data:
        return ''
    fields = only_headers or list(json_data[0].keys())
    csvfile = StringIO()
    writer = csv.DictWriter(csvfile, fieldnames=fields, extrasaction='ignore')
    writer.writeheader()
    writer.writerows(json_data)
    return csvfile.getvalue()


def get_country_by_code(country_code):
    """Get country by country_code."""
    try:
        country = Country(str(country_code.upper()))
        return country
    except KeyError:
        raise Exception(
            ERROR_UNKNOWN_COUNTRY.format(code=country_code)
        )


def get_accounting_period_state(accounting_period_id: int, action_name: str) -> dict:
    """Get abacus_state records for an accounting period filtered by action_name.

    Args:
        accounting_period_id (int): ID of the parent accounting period
        action_name (str): name of the abacus_state action_name to filter by

    Returns:
        the abacus_state record as a dict
    """
    accounting_period_states = ows.get_accounting_period_state(accounting_period_id)

    if not accounting_period_states:
        raise ValueError('Accounting Period states not found')

    action = [
        state for state in accounting_period_states
        if state['action_name'] == action_name
    ]

    if not action:
        raise ValueError(f'Accounting Period {action_name} state not found')

    return action[0]


def get_sales_file_ids(accounting_period_id: int) -> list:
    """Get sales files in the parent accounting period. Return their IDs in a list.

    Args:
        accounting_period_id (int): ID of the parent accounting period

    Returns:
        a list of sales_files
    """
    sales_files = ows.get_accounting_period_sales_files(accounting_period_id)
    return [sales_file.get('sales_file_id') for sales_file in sales_files]