"""Contract Reserve logic."""

from decimal import Decimal
import logging
from typing import List, Type

from owsresponse import response

from abacus_contract import models
from abacus_contract.config import Config
from abacus_contract.constants.error import ERROR_INVALID_RELEASE_SCHEDULE
from abacus_contract.constants.error import ERROR_RESERVE_ALREADY_EXISTS
from abacus_contract.constants.error import ERROR_RESERVE_MUST_BE_ACTIVE_TO_UPDATE
from abacus_contract.schemas.contract_reserve import ContractReserveSchema
from abacus_contract.schemas.contract_reserve import ContractReserveWithAccountIdSchema
from abacus_contract.utils.format_error import validation_error


logger = logging.getLogger(Config.LOGGER_NAME)


def create_contract_reserve(
    contract_id: int,
    reserve_rate: float,
    reserve_release_offset_in_months: int,
    installments_in_months: int,
    release_schedule: list = None,
) -> Type[response.Response]:
    """Create a contract reserve.

    Args:
        contract_id(int): Id of the contract
        reserve_rate(float): The percentage of reserves to be held
        reserve_release_offset_in_months(int):
            The number of months from when reserves are taken that they begin to be released; 1 - 24
        installments_in_months(int):
            The number of months that reserves taken will be divided across; 1 - 24
        release_schedule(list):
            List of splitted rates
    Returns:
        A dict of contract reserve.
    """  # noqa: E501
    contract = models.Contract.get_by_id_or_error(contract_id)

    if contract.contract_reserve:
        return validation_error(ERROR_RESERVE_ALREADY_EXISTS)

    return _create_contract_reserve(
        contract_id,
        reserve_rate,
        reserve_release_offset_in_months,
        installments_in_months,
        release_schedule
    )


def update_contract_reserve_by_contract_id(
    contract_id: int,
    reserve_rate: float,
    reserve_release_offset_in_months: int,
    installments_in_months: int,
    release_schedule: list = None,
) -> Type[response.Response]:
    """Update a contract reserve by contract_id.

    Args:
        contract(int): Id of the contract
        reserve_rate(float): The percentage of reserves to be held
        reserve_release_offset_in_months(int):
            The number of months from when reserves are taken that they begin to be released; 1 - 24
        installments_in_months(int):
            The number of months that reserves taken will be divided across; 1 - 24
        release_schedule(list):
            List of splitted rates
    Returns:
        A dict of contract reserve.
    """  # noqa: E501
    contract = models.Contract.get_by_id_or_error(contract_id)

    # Validate the action is on an active contract reserve
    if not contract.contract_reserve:
        logger.error(f'Reserve for contract {contract_id} must be active to update')
        return validation_error(ERROR_RESERVE_MUST_BE_ACTIVE_TO_UPDATE)

    # Soft delete the active contract reserve
    models.ContractReserve.delete_by_id_or_error(
        contract.contract_reserve.contract_reserve_id,
        soft_delete=True
    )

    return _create_contract_reserve(
        contract.contract_id,
        reserve_rate,
        reserve_release_offset_in_months,
        installments_in_months,
        release_schedule
    )


def _create_contract_reserve(
    contract_id: int,
    reserve_rate: float,
    reserve_release_offset_in_months: int,
    installments_in_months: int,
    release_schedule: list = None,
) -> Type[response.Response]:
    try:
        if (release_schedule is None):
            release_schedule = _calculate_release_schedule(installments_in_months)
        else:
            release_schedule = _validate_release_schedule(release_schedule)

        contract_reserve = models.ContractReserve.create(
            contract_id=contract_id,
            reserve_rate=reserve_rate,
            reserve_release_offset_in_months=reserve_release_offset_in_months,
            installments_in_months=installments_in_months,
            release_schedule=release_schedule
        )
    except Exception as e:
        return validation_error(str(e))

    return response.Response(
        message=ContractReserveSchema().dump(contract_reserve),
        status=201
    )


def get_reserve_by_contract_id(contract_id: int) -> Type[response.Response]:
    """GET reserve for a specified contract.

    Args:
        contract_id(int): ID of the contract
    Returns:
        A dict of contract reserve
    """
    contract = models.Contract.get_by_id_or_error(contract_id)
    message = ContractReserveSchema().dump(contract.contract_reserve)
    return response.Response(message=message, status=200)


def _calculate_release_schedule(installments_in_months: int) -> List[str]:
    """Calculate release_schedule.

    Args:
        installments_in_months(int):
            The number of months that reserves taken will be divided across; 1 - 24
    Returns:
        List of splitted rates
    """  # noqa: E501
    one_month_installment = format((1 / installments_in_months), '.12f')
    release_schedule = [str(one_month_installment)] * (installments_in_months - 1)

    last_month_installment = \
        1 - Decimal(one_month_installment) * (installments_in_months - 1)
    release_schedule.append(str(last_month_installment))

    return release_schedule


def _validate_release_schedule(release_schedule):
    """Validate if the sum of all release_schedule values equals 1 or not."""
    total = sum(map(Decimal, release_schedule))

    if (total != 1):
        raise Exception(ERROR_INVALID_RELEASE_SCHEDULE)

    return list(map(str, release_schedule))


def get_contract_reserves_by_ids(
    contract_reserve_ids: list
) -> Type[response.Response]:
    """Get reserves by contract_reserve_ids.

    Args:
        contract_reserve_ids(list): List of contract reserve ids.
    Response:
        List of contract reserves
    """
    contract_reserves = models.ContractReserve.get_by_ids(contract_reserve_ids)
    return response.Response(
        message=ContractReserveWithAccountIdSchema(many=True).dump(contract_reserves),
        status=200
    )


def get_contract_reserves_by_contract_ids(
    contract_ids: list
) -> Type[response.Response]:
    """Get reserves associated with specified contract_ids.

    Args:
        contract_ids(list): List of contract ids.
    Response:
        List of contract reserves
    """
    contract_reserves = models.ContractReserve.get_by_contract_ids(
        contract_ids
    )
    return response.Response(
        message=ContractReserveSchema(many=True).dump(contract_reserves),
        status=200
    )