from datetime import datetime, timedelta

import bcrypt
from fastapi import APIRouter, Depends, HTTPException
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from sqlalchemy.orm import Session

from .config import settings
from .database import get_db
from .models import User
from .schemas import LoginRequest, Token

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


def hash_password(password: str) -> str:
    return bcrypt.hashpw(password.encode("utf-8"), bcrypt.gensalt()).decode("utf-8")


def verify_password(plain: str, hashed: str) -> bool:
    return bcrypt.checkpw(plain.encode("utf-8"), hashed.encode("utf-8"))


def create_access_token(data: dict) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + timedelta(minutes=settings.access_token_expire_minutes)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, settings.secret_key, algorithm="HS256")


def get_current_user(
    token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)
) -> User:
    try:
        payload = jwt.decode(token, settings.secret_key, algorithms=["HS256"])
        username: str = payload.get("sub")
        if username is None:
            raise HTTPException(status_code=401, detail="Invalid token")
    except JWTError:
        raise HTTPException(status_code=401, detail="Invalid token")
    user = db.query(User).filter(User.username == username).first()
    if user is None:
        raise HTTPException(status_code=401, detail="User not found")
    return user


@router.post("/login", response_model=Token)
def login(request: LoginRequest, db: Session = Depends(get_db)):
    user = db.query(User).filter(User.username == request.username).first()
    if not user or not verify_password(request.password, user.hashed_password):
        raise HTTPException(status_code=401, detail="Invalid credentials")
    token = create_access_token({"sub": user.username})
    return Token(access_token=token)


@router.get("/me")
def me(user: User = Depends(get_current_user)):
    return {"username": user.username}