from fastapi import APIRouter, Depends, HTTPException, status
from sqlmodel import Session, select
from app.core.db import get_session
from app.core.auth import require_any_access, require_write_access, require_admin
from app.schemas.models import Payment, Transaction
from app.schemas.schemas import (
    PaymentCreate, 
    PaymentUpdate, 
    PaymentResponse, 
    UserResponse
)
from typing import List

router = APIRouter(prefix="/payments", tags=["payments"])

# Create Payment
@router.post("/", response_model=PaymentResponse, status_code=status.HTTP_201_CREATED)
def create_payment(
    payment: PaymentCreate, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_write_access)
):
    """Create new payment (requires write access)."""
    # Validate transaction exists
    transaction = session.get(Transaction, payment.transaction_id)
    if not transaction:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Transaction not found"
        )
    
    # Create payment with audit fields
    payment_data = payment.model_dump()
    payment_data["created_by"] = current_user.id
    payment_data["updated_by"] = current_user.id
    
    db_payment = Payment(**payment_data)
    
    session.add(db_payment)
    session.commit()
    session.refresh(db_payment)
    return db_payment

# Read all Payments
@router.get("/", response_model=List[PaymentResponse])
def read_payments(
    skip: int = 0, 
    limit: int = 100, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_any_access)
):
    """Get all payments (requires authentication)."""
    payments = session.exec(
        select(Payment).offset(skip).limit(limit)
    ).all()
    return payments

# Read Payments by transaction
@router.get("/transaction/{transaction_id}", response_model=List[PaymentResponse])
def read_payments_by_transaction(
    transaction_id: int,
    skip: int = 0, 
    limit: int = 100, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_any_access)
):
    """Get payments for a specific transaction (requires authentication)."""
    # Validate transaction exists
    transaction = session.get(Transaction, transaction_id)
    if not transaction:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Transaction not found"
        )
    
    statement = select(Payment).where(
        Payment.transaction_id == transaction_id
    ).offset(skip).limit(limit)
    
    payments = session.exec(statement).all()
    return payments

# Read single Payment by ID
@router.get("/{payment_id}", response_model=PaymentResponse)
def read_payment_by_id(
    payment_id: int, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_any_access)
):
    """Get specific payment by ID (requires authentication)."""
    payment = session.get(Payment, payment_id)
    if not payment:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, 
            detail="Payment not found"
        )
    return payment

# Update Payment
@router.put("/{payment_id}", response_model=PaymentResponse)
def update_payment(
    payment_id: int, 
    payment: PaymentUpdate, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_write_access)
):
    """Update specific payment (requires write access)."""
    db_payment = session.get(Payment, payment_id)
    if not db_payment:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, 
            detail="Payment not found"
        )
    
    update_data = payment.model_dump(exclude_unset=True)
    
    # Validate transaction if being updated
    if "transaction_id" in update_data:
        transaction = session.get(Transaction, update_data["transaction_id"])
        if not transaction:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Transaction not found"
            )
    
    # Track who updated
    update_data["updated_by"] = current_user.id
    
    # Update payment
    for key, value in update_data.items():
        setattr(db_payment, key, value)
    
    session.add(db_payment)
    session.commit()
    session.refresh(db_payment)
    return db_payment

# Delete Payment
@router.delete("/{payment_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_payment(
    payment_id: int, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_admin)
):
    """Delete specific payment (admin only)."""
    payment = session.get(Payment, payment_id)
    if not payment:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, 
            detail="Payment not found"
        )
    
    session.delete(payment)
    session.commit()
    return None