from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from sqlalchemy.orm import Session
from typing import List

from database.database import get_db
from database.models import User, UserRole
from database import schemas
from services.auth_service import (
    authenticate_user, create_access_token, verify_token,
    get_password_hash, verify_password
)

router = APIRouter(prefix="/api/auth", tags=["auth"])
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/auth/login")

async def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    token_data = verify_token(token, credentials_exception)
    user = db.query(User).filter(User.username == token_data.username).first()
    if user is None:
        raise credentials_exception
    if not user.is_active:
        raise HTTPException(status_code=400, detail="Inactive user")
    return user

async def get_current_admin(current_user: User = Depends(get_current_user)):
    if current_user.role != UserRole.admin:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Not enough permissions"
        )
    return current_user

@router.options("/login")
async def login_options():
    """OPTIONS preflight 요청 처리"""
    return {"message": "OK"}

@router.post("/login", response_model=schemas.Token)
async def login(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
    user = authenticate_user(db, form_data.username, form_data.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    access_token = create_access_token(data={"sub": user.username})
    return {
        "access_token": access_token,
        "token_type": "bearer",
        "user": user
    }

@router.get("/me", response_model=schemas.User)
async def read_users_me(current_user: User = Depends(get_current_user)):
    return current_user

@router.post("/users", response_model=schemas.User)
async def create_user(
    user: schemas.UserCreate,
    current_admin: User = Depends(get_current_admin),
    db: Session = Depends(get_db)
):
    # 중복 확인
    db_user = db.query(User).filter(User.username == user.username).first()
    if db_user:
        raise HTTPException(status_code=400, detail="Username already registered")
    
    # 사용자 생성
    db_user = User(
        username=user.username,
        hashed_password=get_password_hash(user.password),
        full_name=user.full_name,
        role=user.role
    )
    db.add(db_user)
    db.commit()
    db.refresh(db_user)
    return db_user

@router.get("/users", response_model=List[schemas.User])
async def read_users(
    skip: int = 0,
    limit: int = 100,
    current_admin: User = Depends(get_current_admin),
    db: Session = Depends(get_db)
):
    users = db.query(User).offset(skip).limit(limit).all()
    return users

@router.put("/users/{user_id}", response_model=schemas.User)
async def update_user(
    user_id: int,
    user_update: schemas.UserUpdate,
    current_admin: User = Depends(get_current_admin),
    db: Session = Depends(get_db)
):
    db_user = db.query(User).filter(User.id == user_id).first()
    if not db_user:
        raise HTTPException(status_code=404, detail="User not found")
    
    # 업데이트
    update_data = user_update.dict(exclude_unset=True)
    if "password" in update_data:
        update_data["hashed_password"] = get_password_hash(update_data.pop("password"))
    
    for field, value in update_data.items():
        setattr(db_user, field, value)
    
    db.commit()
    db.refresh(db_user)
    return db_user

@router.delete("/users/{username}")
async def delete_user(
    username: str,
    current_admin: User = Depends(get_current_admin),
    db: Session = Depends(get_db)
):
    db_user = db.query(User).filter(User.username == username).first()
    if not db_user:
        raise HTTPException(status_code=404, detail="User not found")
    
    # hyungi 계정은 삭제 불가
    if db_user.username == "hyungi":
        raise HTTPException(status_code=400, detail="Cannot delete primary admin user")
    
    db.delete(db_user)
    db.commit()
    return {"detail": "User deleted successfully"}

@router.post("/change-password")
async def change_password(
    password_change: schemas.PasswordChange,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    # 현재 비밀번호 확인
    if not verify_password(password_change.current_password, current_user.hashed_password):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Incorrect current password"
        )
    
    # 새 비밀번호 설정
    current_user.hashed_password = get_password_hash(password_change.new_password)
    db.commit()
    
    return {"detail": "Password changed successfully"}