from datetime import datetime, timedelta

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from passlib.context import CryptContext
from sqlalchemy.orm import Session

from app.config import settings
from app.database import get_db
from app.models.user import User

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/auth/login")


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)


def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES))
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)


def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_db),
) -> User:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        email: str = payload.get("sub")
        if email is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception

    user = db.query(User).filter(User.email == email).first()
    if user is None:
        raise credentials_exception

    # Block unverified users from all protected endpoints
    from app.models.email_verification import EmailVerification
    verification = db.query(EmailVerification).filter(EmailVerification.user_id == user.id).first()
    if verification and verification.verified_at is None:
        raise HTTPException(
            status_code=403,
            detail="Email not verified. Please verify your email before using the app.",
            headers={"X-Unverified": "true"},
        )

    return user


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


def require_moderator(current_user: User = Depends(get_current_user)) -> User:
    if not current_user.is_moderator:
        raise HTTPException(status_code=403, detail="Moderator access required")
    return current_user