from fastapi import APIRouter, HTTPException
from pydantic import BaseModel
from typing import Optional
import uuid

from bd import Settings
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

from bd.tables.users import User

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


class UserCreate(BaseModel):
    first_name: Optional[str] = None
    last_name: Optional[str] = None
    name: Optional[str] = None


class UserUpdate(BaseModel):
    first_name: Optional[str]
    last_name: Optional[str]


def get_session():
    settings = Settings()
    engine = create_engine(settings.DATABASE_URL_syncpg, future=True)
    return sessionmaker(bind=engine, future=True)


@router.post("", status_code=201)
def create_user(payload: UserCreate):
    Session = get_session()
    with Session() as session:
        # Support payload with 'name' (single field) or first_name+last_name
        first = payload.first_name
        last = payload.last_name
        if not (first or last) and payload.name:
            parts = payload.name.strip().split()
            if parts:
                first = parts[0]
                last = " ".join(parts[1:]) if len(parts) > 1 else ""
        if not first and not last:
            raise HTTPException(status_code=422, detail="Missing name or first_name/last_name")
        user = User(first_name=first or "", last_name=last or "")
        session.add(user)
        session.commit()
        session.refresh(user)
        return {"id": str(user.id), "first_name": user.first_name, "last_name": user.last_name}


@router.put("/{user_id}")
def update_user(user_id: str, payload: UserUpdate):
    Session = get_session()
    try:
        uid = uuid.UUID(user_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    with Session() as session:
        user = session.get(User, uid)
        if not user:
            raise HTTPException(status_code=404, detail="User not found")
        if payload.first_name is not None:
            user.first_name = payload.first_name
        if payload.last_name is not None:
            user.last_name = payload.last_name
        session.add(user)
        session.commit()
        session.refresh(user)
        return {"id": str(user.id), "first_name": user.first_name, "last_name": user.last_name}


@router.delete("/{user_id}", status_code=204)
def delete_user(user_id: str):
    Session = get_session()
    try:
        uid = uuid.UUID(user_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    with Session() as session:
        user = session.get(User, uid)
        if not user:
            raise HTTPException(status_code=404, detail="User not found")
        session.delete(user)
        session.commit()
        return {}


@router.get("")
def list_users():
    Session = get_session()
    with Session() as session:
        rows = session.query(User).all()
        return [{"id": str(u.id), "first_name": u.first_name, "last_name": u.last_name} for u in rows]


@router.get("/{user_id}")
def get_user(user_id: str):
    Session = get_session()
    try:
        uid = uuid.UUID(user_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    with Session() as session:
        user = session.get(User, uid)
        if not user:
            raise HTTPException(status_code=404, detail="User not found")
        return {"id": str(user.id), "first_name": user.first_name, "last_name": user.last_name}