import logging
from datetime import datetime
from flask import jsonify
from app.models.repayment import Repayment

# Configure logging
logger = logging.getLogger(__name__)

class RepaymentService:
    """
    Service class for handling repayment-related operations.
    """

    @staticmethod
    def get_all_repayments(filters=None):
        """
        Get all repayments with optional filtering.

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

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

            # Extract filters
            loan_id = filters.get('loan_id')
            customer_id = filters.get('customer_id')
            product_id = filters.get('product_id')
            start_date = filters.get('start_date')
            end_date = filters.get('end_date')

            # 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'))

            # Get repayments with optional filters and pagination
            repayments, total_count = Repayment.get_all_repayments(
                loan_id=loan_id,
                customer_id=customer_id,
                product_id=product_id,
                start_date=start_date,
                end_date=end_date,
                page=page,
                limit=limit
            )

            # Convert repayments to dictionary format
            repayments_data = []
            for repayment in repayments:
                repayments_data.append({
                    'loan_id': repayment.loan_id,
                    'customer_id': repayment.customer_id,
                    'product_id': repayment.product_id,
                    'transaction_id': repayment.transaction_id,
                    'created_at': repayment.created_at.isoformat() if repayment.created_at else None,
                    'updated_at': repayment.updated_at.isoformat() if repayment.updated_at else None
                })

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

            response_data = {
                'repayments': repayments_data,
                'count': len(repayments_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"
            }), 500