"""Generate payment summary report task."""

from math import ceil

import pandas

from lib.constants import PAYMENT_GROUP_PAYMENT_ACTIONS, PAYMENT_SCHEDULE_MAP
from lib.constants import PAYMENT_SUMMARY_HEADERS_MAP
from lib.constants import PAYMENT_SUMMARY_HEADERS_MAP_CALCULATE_PAYMENTS
from lib.utils import ows
from tasks.payments_generate_export import helpers


def generate_payment_summary_export_task(dag_run: dict, **kwargs):
    """Task to generate a report of payment_group_payment_accounts to save on S3.

    Args:
        dag_run (dict): a dag's config
    """
    event = helpers.get_event_from_params(dag_run, **kwargs)
    payment_group_payment = ows.get_payment_group_payment_details(event.target_id)

    headers_map = PAYMENT_SUMMARY_HEADERS_MAP
    try:
        # feature flag check using states
        helpers.get_abacus_state(
            PAYMENT_GROUP_PAYMENT_ACTIONS.CALCULATE_PAYMENTS, event.target_id
        )
        headers_map = PAYMENT_SUMMARY_HEADERS_MAP_CALCULATE_PAYMENTS
    except ValueError:
        pass

    report_s3_path = helpers.build_report_summary_location(
        payment_group_payment.get('payment_group_payment_id'),
        payment_group_payment.get('payment_name')
    )

    raw_report_data = _get_report_data(event.target_id)

    payment_group_data = pandas.DataFrame(
        pandas.Series(
            _get_payment_group_payment_details(payment_group_payment)
        )
    )

    filtered_report_data = pandas.DataFrame(
        raw_report_data,
        columns=headers_map.keys()
    )

    filtered_report_data['percent_difference'] = \
        filtered_report_data['percent_difference'].map(
            lambda a: f'{a}%' if pandas.notnull(a) else a)

    filtered_report_data.fillna(value='-', inplace=True)

    formatted_report = filtered_report_data.rename(columns=headers_map)

    blank_line = pandas.DataFrame()
    payment_group_data.to_csv(report_s3_path.url, mode='w', index=False, header=False)
    blank_line.to_csv(report_s3_path.url, mode='a', index=False, lineterminator='\n')
    formatted_report.to_csv(report_s3_path.url, mode='a', index=False, sep='\t')


def _get_report_data(payment_group_payment_id: int) -> list:
    """Request payment_group_payment_accounts from ows-payment in batches.

    Args:
        payment_group_payment_id (int): ID of the parent payment_group_payment

    Returns:
        list of dicts containing payment_group_payment_account data.
    """
    limit = 5000
    offset = 0
    sort_by = 'balance_after_tax'
    sort_order = 'desc'
    report_data = []

    response = ows.get_payment_group_payment_accounts(
        payment_group_payment_id,
        limit,
        offset,
        sort_by,
        sort_order
    )

    report_data.extend(response.get('items', []))

    num_of_batches = ceil(response.get('total_count', 1) / limit)

    for batch_num in range(1, num_of_batches):
        offset = batch_num * limit
        response = ows.get_payment_group_payment_accounts(
            payment_group_payment_id,
            limit,
            offset,
            sort_by,
            sort_order
        )
        report_data.extend(response.get('items', []))

    return report_data


def _get_payment_group_payment_details(payment_group_payment: dict) -> list:
    """Request payment-group from ows-payment and statement-period from ows-royalties.

    Args:
        payment_group_payment (dict): payment group payment details

    Returns:
        list containing payment group payment details.
    """
    created_at = payment_group_payment.get('created_at')
    payment_group_id = payment_group_payment.get('payment_group_id')
    payment_name = payment_group_payment.get('payment_name')
    statement_period_id = payment_group_payment.get('statement_period_id')

    payment_group = ows.get_payment_group_details(payment_group_id)
    group_criteria = payment_group.get('group_criteria')
    group_name = payment_group.get('group_name')
    payment_schedules = group_criteria.get('payment_schedules')

    payment_entities_map = ows.get_reference_payment_entities()
    payment_entities = group_criteria.get('reference_payment_entities', [])
    account_id = group_criteria.get('account_id', None)

    if account_id:
        account_payment_term = ows.get_account_payment_term_by_account_id(account_id)
        payment_schedule = account_payment_term.get('payment_schedule')

        payment_entity_id = account_payment_term.get('payment_entity_id')
        payment_entities = [payment_entities_map[payment_entity_id]]

        payment_schedules = \
            [PAYMENT_SCHEDULE_MAP[payment_schedule]] if payment_schedule else '-'
    else:
        if not payment_schedules:
            payment_schedules = ['All']
        else:
            payment_schedules = [
                PAYMENT_SCHEDULE_MAP[payment_schedule]
                for payment_schedule in payment_schedules
            ]

        payment_entities = [
            payment_entities_map[payment_entity]
            for payment_entity in payment_entities
        ]

    statement_period = ows.get_statement_period_details(statement_period_id)
    statement_period_name = statement_period.get('statement_period_name', None)

    return [
        payment_name,
        f'Statement Period {statement_period_name} ({statement_period_id})',
        created_at,
        group_name,
        ', '.join(payment_entities),
        ', '.join(payment_schedules)
    ]