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 Partner
from app.schemas.schemas import (
    PartnerCreate, 
    PartnerUpdate, 
    PartnerResponse, 
    UserResponse
)
from typing import List

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

# Create Partner
@router.post("/", response_model=PartnerResponse, status_code=status.HTTP_201_CREATED)
def create_partner(
    partner: PartnerCreate, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_write_access)
):
    """Create a new partner (requires write access)."""
    # Check if TIN number already exists
    statement = select(Partner).where(Partner.tin_number == partner.tin_number)
    existing_partner = session.exec(statement).first()
    if existing_partner:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Partner with this TIN number already exists"
        )
    
    # Create new partner
    partner_data = partner.model_dump()
    db_partner = Partner(**partner_data)
    
    session.add(db_partner)
    session.commit()
    session.refresh(db_partner)
    return db_partner

# Read all Partners
@router.get("/", response_model=List[PartnerResponse])
def read_partners(
    skip: int = 0, 
    limit: int = 100, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_any_access)
):
    """Get all partners (requires authentication)."""
    partners = session.exec(select(Partner).offset(skip).limit(limit)).all()
    return partners

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

# Update Partner
@router.put("/{partner_id}", response_model=PartnerResponse)
def update_partner(
    partner_id: int, 
    partner: PartnerUpdate, 
    session: Session = Depends(get_session),
    current_user: UserResponse = Depends(require_write_access)
):
    """Update specific partner (requires write access)."""
    db_partner = session.get(Partner, partner_id)
    if not db_partner:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, 
            detail="Partner not found"
        )
    
    # Check for TIN number conflicts if updating TIN
    update_data = partner.model_dump(exclude_unset=True)
    if "tin_number" in update_data:
        statement = select(Partner).where(
            Partner.tin_number == update_data["tin_number"],
            Partner.id != partner_id
        )
        existing_partner = session.exec(statement).first()
        if existing_partner:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Partner with this TIN number already exists"
            )
    
    # Update partner
    for key, value in update_data.items():
        setattr(db_partner, key, value)
    
    session.add(db_partner)
    session.commit()
    session.refresh(db_partner)
    return db_partner

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