MermsCoreFlask/app/api/services/select_offer.py

from flask import request, jsonify
from marshmallow import ValidationError
from app.api.helpers.response_helper import ResponseHelper
from app.api.services.base_service import BaseService
from app.api.enums import TransactionType
from app.models.transaction_offers import TransactionOffer
from app.utils.logger import logger
from app.api.schemas.select_offer import SelectOfferSchema
from app.extensions import db
from app.models import Offer
from datetime import date
from dateutil.relativedelta import relativedelta

class SelectOfferService(BaseService):
    TRANSACTION_TYPE = TransactionType.SELECT_OFFER

    @staticmethod
    def process_request(data):
        """
        Process the SelectOffer request.

        Args:
            data (dict): The request data.

        Returns:
            dict: A standardized response.
        """
        try:
            with db.session.begin():
                validated_data = SelectOfferService.validate_data(
                    data, SelectOfferSchema()
                )
                account_id = validated_data.get("accountId")
                customer_id = validated_data.get("customerId")
                amount = validated_data.get("requestedAmount")
                product_id = validated_data.get("productId")
                transaction_offer_id = validated_data.get("offerId")
                transaction_id = validated_data.get("transactionId")
                request_id = validated_data.get("requestId")

                offer_id = int(transaction_offer_id[5:])  # The last part is int

                #"offerId": "SAL30001129",

                if SelectOfferService.validate_account_ownership(
                    account_id=account_id, customer_id=customer_id
                ):
                    transaction = SelectOfferService.log_transaction(
                        validated_data=validated_data
                    )

                    if not transaction:
                        logger.error(f"Failed to log transaction")
                        return ResponseHelper.error(result_description="Failed to log transaction.")
                else:  
                    return ResponseHelper.error(result_description="Invalid Customer or Account")

                # Get the offer by product ID
                offer = Offer.get_offer_by_product_id(product_id)

                transaction_offer = TransactionOffer.get_transaction_offer(transaction_offer_id=offer_id)

                if not transaction_offer:
                    logger.error(f"offer {offer_id} not found for customer {customer_id} and transaction {transaction_id}.")
                    return ResponseHelper.error(result_description="Offer not found.")

                db.session.flush()

                if amount < transaction_offer.min_amount:
                    logger.error(f"The amount {amount} is less than the minimum allowed offer amount {transaction_offer.min_amount}.")
                    return ResponseHelper.error(result_description="The amount is less than the minimum allowed offer amount.")
                elif amount > transaction_offer.eligible_amount:
                    logger.error(f"The amount {amount} is greater than the eligible offer amount {transaction_offer.eligible_amount}.")
                    return ResponseHelper.error(result_description="The amount is greater than the eligible offer amount.")

                    

                charges = SelectOfferService.calculate_charges(offer, amount)
                upfront_payment = charges["upfront_payment"]
                total_amount = charges["total_amount"]
                installment_amount = charges["installment_amount"]
                interest = charges["interest"]
                management = charges["management"]
                insurance = charges["insurance"]
                vat = charges["vat"]
                repayment_amount = charges["repayment_amount"]
                interest_amount = charges["interest_amount"]


                # Calculate the repayment dates
                tenor = offer.tenor
                start_date = date.today()

                # Convert tenor to months
                months = offer.schedule # tenor  // 30

                recommended_repayment_dates = [
                    (start_date + relativedelta(months=i + 1)).isoformat()
                    for i in range(months)
                ]

            

                offers = [
                    {
                        "offerId": transaction_offer_id,
                        "productId": product_id,
                        "amount": amount,
                        "upfrontPayment": upfront_payment,
                        "interestRate": offer.interest_rate,
                        "interestFee": interest_amount,
                        "managementRate": offer.management_rate,
                        "managementFee": management["fee"],
                        "insuranceRate": offer.insurance_rate,
                        "insuranceFee": insurance["fee"],
                        "VATRate": offer.vat_rate,
                        "VATAmount": vat["fee"],
                        "recommendedRepaymentDates": recommended_repayment_dates,
                        "repaymentAmount": repayment_amount,
                        "installmentAmount": installment_amount,
                        "totalRepaymentAmount": total_amount,
                    }
                ]

                # "offerId": offer.id,
                # "productId": product_id,
                # "amount": amount,
                # "upfrontPayment": upfront_payment,
                # "interestRate": interest["rate"],
                # "managementRate": management["rate"],
                # "managementFee": management["fee"],
                # "insuranceRate": insurance["rate"],
                # "insuranceFee": insurance["fee"],
                # "VATRate": vat["rate"],
                # "VATAmount": vat["fee"],
                # "recommendedRepaymentDates": recommended_repayment_dates,
                # "installmentAmount": installment_amount,
                # "totalRepaymentAmount": total_amount,
                #
                # Business logic - selecting an offer
                response_data = {
                    "outstandingDebtAmount": 0,
                    "requestId": request_id,
                    "transactionId": transaction_id,
                    "customerId": customer_id,
                    "accountId": account_id,
                    "loan": offers,
                }

                db.session.commit()
                return ResponseHelper.success(data=response_data)

        except ValidationError as err:

            logger.error(f"Validation Error: {getattr(err, 'messages', str(err))}")
            db.session.rollback()
            return ResponseHelper.unprocessable_entity(result_description="Validation exception")
        
        except  ValueError as err:
            logger.error(f"{getattr(err, 'messages', str(err))}")
            db.session.rollback()
            return ResponseHelper.error(result_description=str(err))

        except Exception as e:
            logger.error(f"An error occurred: {str(e)}", exc_info=True)
            db.session.rollback()
            return ResponseHelper.internal_server_error()