"""
Logic for accounting intervals.

Provides logic for getting accounting intervals for revenue calculation
"""

from ows_accounting import config
from ows_accounting import response
from ows_accounting.constants import db
from ows_accounting.constants import error
from ows_accounting.models import accounting_period
from ows_accounting.models import ows_contracts


def _format_interval(contract, accounting_period):
    """Get properly formatted interval item for response.

    Args:
        contract (dict): Booked contracts data
        accounting_period (dict): Accounting period data

    Returns:
        dict: Accounting interval data
    """
    if contract['payment_interval'] == db.PAYMENT_INTERVAL_MONTH:
        number = accounting_period['month']
    else:
        number = accounting_period['quarter']
    return {
        'type': contract['payment_interval'],
        'number': number,
        'year': accounting_period['year'],
        'currency_id': contract['currency_id'],
        'periods': [contract['period_id']]
    }


def _find_interval_index_by_quarter(intervals, quarter, year):
    """Get interval index in the list by quarter and year.

    Args:
        intervals (list): Accounting intervals list
        quarter (int): Interval quarter
        year (int): Interval year

    Returns:
        int: List index or None
    """
    for index, interval in enumerate(intervals):
        if (interval['type'] == db.PAYMENT_INTERVAL_QUARTER and
                interval['number'] == quarter and interval['year'] == year):
            return index
    return None


def get_intervals_from_contracts(account_type, account_id, recent_intervals):
    """Get accounting intervals from booked contracts.

    Args:
        account_type (str): account type from GRASS.
        account_id (int): account id.
        recent_intervals: number of intervals to get info

    Returns:
        response.Response: Accounting intervals info or error.
    """
    intervals = []
    contracts_offset = 0

    while True:
        contracts_response = ows_contracts.get_booked_contracts(
            account_type, account_id, contracts_offset)
        if not contracts_response:
            return contracts_response
        pagination_info = contracts_response.message['pagination']
        if pagination_info['limit'] <= 0:
            return response.response.create_error_response(
                code=error.ERROR_CODE_OWS_CONTRACTS,
                message=error.ERROR_MESSAGE_INVALID_PAGINATION)

        for contract in contracts_response.message['items']:
            if contract['period_id'] > int(config.ACTIVE_ACCOUNTING_PERIOD):
                continue
            period_response = accounting_period.get_period_by_id(
                contract['period_id'])
            if not period_response:
                return period_response
            period = period_response.message

            if contract['payment_interval'] == db.PAYMENT_INTERVAL_MONTH:
                if len(intervals) == recent_intervals:
                    return response.Response(intervals)
                intervals.append(_format_interval(contract, period))
            else:
                existing_index = _find_interval_index_by_quarter(
                    intervals, period['quarter'], period['year'])
                if existing_index is not None:
                    intervals[existing_index]['periods'].append(
                        contract['period_id'])
                elif len(intervals) == recent_intervals:
                    return response.Response(intervals)
                else:
                    intervals.append(_format_interval(contract, period))

        contracts_offset += pagination_info['limit']
        if contracts_offset >= pagination_info['total_records']:
            return response.Response(intervals)


def get_period_by_id(period_id):
    """Get accounting period by id.

    Args:
        period_id (int): Period Id.
    Returns:
        response.Response: Accounting period data or error
                           in Response object.
    """
    return accounting_period.get_period_by_id(period_id)