from flask import jsonify
from app.utils.logger import logger
from app.api.services.base_service import BaseService
from app.models.transaction import Transaction
from app.models.loan import Loan
from sqlalchemy import func, desc
from datetime import datetime, timedelta, timezone
from app.extensions import db
from app.api.enums.transaction_type import TransactionType


class DashboardService(BaseService):
    @staticmethod
    def get_dashboard_data():
        try:
            now = datetime.now()
            start_of_week = now - timedelta(days=now.weekday())
            start_of_week = start_of_week.replace(hour=0, minute=0, second=0, microsecond=0)

            # Calculate 24 hours ago
            last_24_hours = datetime.now(timezone.utc) - timedelta(hours=24)

            # Loans this week
            loans_this_week = db.session.query(
                func.sum(Loan.initial_loan_amount)
            ).filter(
                Loan.created_at >= start_of_week
            ).scalar() or 0

            # Payments this week
            payments_this_week = db.session.query(
                func.count(Transaction.id)
            ).filter(
                Transaction.created_at >= start_of_week,
                Transaction.type == 'PAYMENT'
            ).scalar() or 0


            # Request summary for the last 24 hours
            eligibility_check_count = db.session.query(
                func.count(Transaction.id)
            ).filter(
               Transaction.type == TransactionType.ELIGIBILITY_CHECK.value,
                Transaction.created_at >= last_24_hours
            ).scalar() or 0

            select_offer_count = db.session.query(
                func.count(Transaction.id)
            ).filter(
                Transaction.type == TransactionType.SELECT_OFFER.value,
                Transaction.created_at >= last_24_hours
            ).scalar() or 0

            provide_loan_count = db.session.query(
                func.count(Transaction.id)
            ).filter(
                Transaction.type == TransactionType.PROVIDE_LOAN.value,
                Transaction.created_at >= last_24_hours
            ).scalar() or 0

            repayment_count = db.session.query(
                func.count(Transaction.id)
            ).filter(
                Transaction.type == TransactionType.REPAYMENT.value,
                Transaction.created_at >= last_24_hours
            ).scalar() or 0
            

            # Recent transactions (not limited to 24 hrs, just latest 15)
            recent_transactions = Transaction.query.order_by(
                Transaction.id.desc()
            ).limit(15).all()

            recent_transactions_data = [{
                'id': t.id,
                'transaction_id': t.transaction_id,
                'account_id': t.account_id,
                'type': t.type,
                'channel': t.channel,
                'created_at': t.created_at.isoformat() if t.created_at else None,
                'updated_at': t.updated_at.isoformat() if t.updated_at else None
            } for t in recent_transactions]

            # Final response
            dashboard_data = {
                "loans": {
                    "value": float(loans_this_week),
                    "currency": "Naira",
                    "currency_text": "₦",
                    "text": "this week"
                },
                "payments": {
                    "value": payments_this_week,
                    "currency": "Naira",
                    "currency_text": "₦",
                    "text": "this week"
                },
                "request_summary": {
                    "eligibility_check": {"Eligibility": eligibility_check_count},
                    "select_offer": {"Offers": select_offer_count},
                    "provide_loan": {"Loans": provide_loan_count},
                    "repayment": {"Repayments": repayment_count}
                },
                "recent_transactions": recent_transactions_data
            }

            return dashboard_data

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