"""Exchange Rate Logic."""

from typing import Type

from owsresponse import response
from sqlalchemy.exc import IntegrityError

from royalties import models
from royalties.constants.error import (
    ERROR_CSV_EMPTY,
    ERROR_EXCHANGE_RATE_SAVE,
    ERROR_STATEMENT_PERIOD_NOT_ACCEPTING_FILES,
)
from royalties.schemas.exchange_rate import ExchangeRateSchema
from royalties.utils.csv_parser import CSVParser
from royalties.utils.exchange_rate_format import ExchangeRateStandardFXParser
from royalties.utils.format_error import validation_error
from royalties.utils.strings import base64decode

exchange_rates_schema = ExchangeRateSchema(many=True, exclude=['exchange_rate_id'])


def bulk_load_exchange_rates(params: dict) -> Type[response.Response]:
    """Verify user data and import data.

    Args:
        params(dict): POST request body
        Required Parameters:
        statement_period_id: ID of statement period
        exchange_rates: Encoded string of csv data
    Returns:
        A List of newly created exchange rates record.
    """
    statement_period_id = params.get('statement_period_id')
    csv_data = params.get('exchange_rates')

    if not csv_data:
        return validation_error(ERROR_CSV_EMPTY)

    statement_period = models.StatementPeriod.get_by_id_or_error(statement_period_id)

    if not statement_period.is_accepting_file_attachments():
        return validation_error(ERROR_STATEMENT_PERIOD_NOT_ACCEPTING_FILES)

    return bulk_save_exchange_rates(statement_period_id, base64decode(csv_data))


def bulk_save_exchange_rates(
    statement_period_id: int, csv_data: str
) -> Type[response.Response]:
    """Save new exchange rates.

    Args:
        statement_period_id: ID of statement period
        csv_data: Decoded string of csv data
    Returns:
        A List of newly created exchange rates record.
    """
    formatter = ExchangeRateStandardFXParser(statement_period_id)
    parser = CSVParser.init_from_standard_format(csv_data, formatter)
    parser.parse_string(csv_data)
    results = parser.get_results()
    if results.get('errors'):
        return validation_error({'rows': [], 'errors': results.get('errors')})
    new_models = []
    for row in results.get('rows'):
        if row['from_currency_code'] == row['to_currency_code']:
            continue
        new_models.append(
            models.ExchangeRate.build(
                statement_period_id=row['statement_period_id'],
                from_currency_code=row['from_currency_code'],
                to_currency_code=row['to_currency_code'],
                rate=row['rate'],
            )
        )
    try:
        models.ExchangeRate.commit_changes(*new_models)
    except IntegrityError as e:
        row = results.get('rows')[0]
        return validation_error(
            {
                'rows': [],
                'errors': [
                    ERROR_EXCHANGE_RATE_SAVE.format(
                        period=row['statement_period_id'],
                        from_cur=row['from_currency_code'],
                        to_cur=row['to_currency_code'],
                        reason=str(e),
                    )
                ],
            }
        )
    return response.Response(
        status=201,
        message={'rows': exchange_rates_schema.dump(new_models), 'errors': []},
    )