import logging
from datetime import datetime
from flask import jsonify
from app.models.loan import Loan
from app.utils.logger import logger

# Configure logging
logger = logging.getLogger(__name__)

class LoanService:
    """
    Service class for handling loan-related operations.
    """

    @staticmethod
    def process_request(filters=None):
        """
        Process the get loans request.

        Args:
            filters (dict, optional): Filters for the loans query.

        Returns:
            dict: A standardized response with loans data.
        """
        try:
            if filters is None:
                filters = {}

            # Extract filters
            id = filters.get('id')
            customer_id = filters.get('customer_id')
            account_id = filters.get('account_id')
            status = filters.get('status')
            tenor = filters.get('tenor')
            offer_id = filters.get('offer_id')
            product_id = filters.get('product_id')
            transaction_id = filters.get('transaction_id')
            original_transaction = filters.get('original_transaction')
            start_date = filters.get('start_date')
            end_date = filters.get('end_date')
            due_before = filters.get('due_before')
            due_after = filters.get('due_after')

            # Extract pagination parameters
            page = int(filters.get('page', 1))
            limit = int(filters.get('limit', 20))

            # Ensure page and limit are valid
            if page < 1:
                page = 1
            if limit < 1 or limit > 100:
                limit = 20

            # Convert string dates to datetime objects if provided
            if start_date and isinstance(start_date, str):
                start_date = datetime.fromisoformat(start_date.replace('Z', '+00:00'))
            if end_date and isinstance(end_date, str):
                end_date = datetime.fromisoformat(end_date.replace('Z', '+00:00'))
            if due_before and isinstance(due_before, str):
                due_before = datetime.fromisoformat(due_before.replace('Z', '+00:00'))
            if due_after and isinstance(due_after, str):
                due_after = datetime.fromisoformat(due_after.replace('Z', '+00:00'))

            # Get loans with optional filters and pagination
            loans, total_count = Loan.get_all_loans(
                id=id,
                customer_id=customer_id,
                account_id=account_id,
                status=status,
                tenor=tenor,
                offer_id=offer_id,
                product_id=product_id,
                transaction_id=transaction_id,
                original_transaction=original_transaction,
                start_date=start_date,
                end_date=end_date,
                due_before=due_before,
                due_after=due_after,
                page=page,
                limit=limit
            )

            logger.info(f"Result from loans model cme back")

            # Convert loans to dictionary format
            loans_data = []
            for loan in loans:
                loans_data.append({
                    'id': loan.id,
                    'customer_id': loan.customer_id,
                    'account_id': loan.account_id,
                    'transaction_id': loan.transaction_id,
                    'original_transaction': loan.original_transaction,
                    'offer_id': loan.offer_id,
                    'eligible_amount': loan.eligible_amount,
                    'initial_loan_amount': loan.initial_loan_amount,
                    'current_loan_amount': loan.current_loan_amount,
                    'status': loan.status,
                    'tenor': loan.tenor,
                    'product_id': loan.product_id,
                    'default_penalty_fee': loan.default_penalty_fee,
                    'continuous_fee': loan.continuous_fee,
                    'upfront_fee': loan.upfront_fee,
                    'repayment_amount': loan.repayment_amount,
                    'installment_amount': loan.installment_amount,
                    'due_date': loan.due_date.isoformat() if loan.due_date else None,
                    'created_at': loan.created_at.isoformat() if loan.created_at else None,
                    'updated_at': loan.updated_at.isoformat() if loan.updated_at else None
                })

            # Calculate total pages
            total_pages = (total_count + limit - 1) // limit

            response_data = {
                'loans': loans_data,
                'count': len(loans_data),
                'pagination': {
                    'total_count': total_count,
                    'total_pages': total_pages,
                    'current_page': page,
                    'limit': limit,
                    'has_next': page < total_pages,
                    'has_prev': page > 1
                }
            }

            return response_data

        except Exception as e:
            logger.error(f"An error occurred: {str(e)}", exc_info=True)
            return jsonify({
                "message": "Internal Server Error"
                # "message": f"Internal Server Error: {str(e)}"
            }), 500