from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import delete, select
from sqlalchemy.orm import Session

from app.auth.dependencies import get_current_user, require_roles
from app.models.auth import CognitoUser
from app.models.db import Priority
from app.models.schemas import PriorityCreate, PriorityResponse
from app.utils.database import get_db

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


@router.post("/", response_model=PriorityResponse, status_code=status.HTTP_201_CREATED)
@require_roles("admin")
def create_priority(
    priority: PriorityCreate,
    db: Session = Depends(get_db),
    user: CognitoUser = Depends(get_current_user),
):
    """Create a new priority"""
    # Check if priority with this ID already exists
    existing = db.get(Priority, priority.id)
    if existing:
        raise HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail=f"Priority with ID {priority.id} already exists",
        )

    db_priority = Priority(**priority.model_dump())
    db.add(db_priority)
    db.commit()
    db.refresh(db_priority)
    return db_priority


@router.get("/", response_model=list[PriorityResponse])
@require_roles("admin")
def list_priorities(
    db: Session = Depends(get_db), user: CognitoUser = Depends(get_current_user)
):
    """List all priorities"""
    return db.query(Priority).all()


@router.get("/{priority_id}", response_model=PriorityResponse)
@require_roles("admin")
def get_priority(
    priority_id: int,
    db: Session = Depends(get_db),
    user: CognitoUser = Depends(get_current_user),
):
    """Get a priority by id"""
    priority = db.get(Priority, priority_id)
    if not priority:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, detail="Priority not found"
        )
    return priority


@router.delete("/{priority_id}", status_code=status.HTTP_204_NO_CONTENT)
@require_roles("admin")
def delete_priority(
    priority_id: int,
    db: Session = Depends(get_db),
    user: CognitoUser = Depends(get_current_user),
):
    """Delete a priority (if not in use)"""
    from app.models.db import ChannelURL

    # Check if priority exists
    priority = db.get(Priority, priority_id)
    if not priority:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, detail="Priority not found"
        )

    # Check if priority is in use
    in_use = db.scalar(
        select(ChannelURL).where(ChannelURL.priority_id == priority_id).limit(1)
    )

    if in_use:
        raise HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail="Cannot delete priority that is in use by channel URLs",
        )

    db.execute(delete(Priority).where(Priority.id == priority_id))
    db.commit()
    return None