from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, field_validator
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
from route.auth_utils import get_current_user, require_admin_key, hash_password

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


class UserCreate(BaseModel):
    username: str
    password: str
    first_name: str
    last_name: str

    @field_validator("username")
    @classmethod
    def username_clean(cls, v: str) -> str:
        v = v.strip()
        if len(v) < 3:
            raise ValueError("Username must be at least 3 characters")
        return v

    @field_validator("password")
    @classmethod
    def password_strength(cls, v: str) -> str:
        if len(v) < 8:
            raise ValueError("Password must be at least 8 characters")
        return v


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


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, dependencies=[Depends(require_admin_key)])
def create_user(payload: UserCreate):
    Session = get_session()
    with Session() as session:
        existing = session.query(User).filter(User.username == payload.username).first()
        if existing:
            raise HTTPException(status_code=400, detail="Username already taken")
        user = User(
            first_name=payload.first_name.strip(),
            last_name=payload.last_name.strip(),
            username=payload.username,
            hashed_password=hash_password(payload.password),
        )
        session.add(user)
        session.commit()
        session.refresh(user)
        return {"id": str(user.id), "username": user.username}


@router.put("/{user_id}")
def update_user(user_id: str, payload: UserUpdate, current_user: User = Depends(get_current_user)):
    Session = get_session()
    try:
        uid = uuid.UUID(user_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    if uid != current_user.id:
        raise HTTPException(status_code=403, detail="You can only update your own profile")
    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, current_user: User = Depends(get_current_user)):
    Session = get_session()
    try:
        uid = uuid.UUID(user_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    if uid != current_user.id:
        raise HTTPException(status_code=403, detail="You can only delete your own account")
    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("/me")
def get_me(current_user: User = Depends(get_current_user)):
    return {"id": str(current_user.id), "username": current_user.username, "first_name": current_user.first_name, "last_name": current_user.last_name}


@router.get("/{user_id}")
def get_user(user_id: str, current_user: User = Depends(get_current_user)):
    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}