from datetime import datetime
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy.orm import Session

from ..auth_utils import get_current_user
from ..database import get_db
from ..models import SystemConfig, User

router = APIRouter()


def _require_admin(current_user: User = Depends(get_current_user)) -> User:
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin only")
    return current_user


class UserOut(BaseModel):
    id: int
    username: str
    email: str
    is_admin: bool
    created_at: Optional[datetime]

    model_config = {"from_attributes": True}


class ConfigOut(BaseModel):
    allow_registration: bool


class ConfigPatch(BaseModel):
    allow_registration: Optional[bool] = None


@router.get("/users", response_model=list[UserOut])
def list_users(
    db: Session = Depends(get_db),
    _: User = Depends(_require_admin),
):
    return db.query(User).order_by(User.id).all()


@router.delete("/users/{user_id}", status_code=204)
def delete_user(
    user_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(_require_admin),
):
    if user_id == current_user.id:
        raise HTTPException(status_code=400, detail="Cannot delete your own account")
    user = db.query(User).filter_by(id=user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    db.delete(user)
    db.commit()


@router.get("/config", response_model=ConfigOut)
def get_config(
    db: Session = Depends(get_db),
    _: User = Depends(_require_admin),
):
    row = db.query(SystemConfig).filter_by(key="allow_registration").first()
    return ConfigOut(allow_registration=row.value == "true" if row else True)


@router.patch("/config", response_model=ConfigOut)
def update_config(
    body: ConfigPatch,
    db: Session = Depends(get_db),
    _: User = Depends(_require_admin),
):
    if body.allow_registration is not None:
        row = db.query(SystemConfig).filter_by(key="allow_registration").first()
        if row:
            row.value = "true" if body.allow_registration else "false"
        else:
            db.add(SystemConfig(key="allow_registration",
                                value="true" if body.allow_registration else "false"))
        db.commit()
    row = db.query(SystemConfig).filter_by(key="allow_registration").first()
    return ConfigOut(allow_registration=row.value == "true" if row else True)