from datetime import timedelta

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session

from app.config import settings
from app.database import get_db
from app.dependencies import (
    generate_reset_token,
    get_current_user,
    reset_token_expiry,
)
from app.models.user import User
from app.schemas.user import (
    ForgotPasswordRequest,
    LoginRequest,
    MessageResponse,
    ResetPasswordRequest,
    TokenResponse,
    UserCreate,
    UserResponse,
    UserUpdate,
)
from app.services.user_service import (
    authenticate_user,
    create_password_reset_token,
    create_user,
    get_user_by_email,
    get_user_by_username,
    get_valid_reset_token,
    update_user,
)
from app.utils.security import create_access_token, create_refresh_token, hash_password

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


@router.post("/register", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
def register(data: UserCreate, db: Session = Depends(get_db)) -> User:
    if get_user_by_email(db, data.email.lower()):
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Email already registered")

    if get_user_by_username(db, data.username.lower()):
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Username already taken")

    return create_user(db, data)


@router.post("/login", response_model=TokenResponse)
def login(data: LoginRequest, db: Session = Depends(get_db)) -> TokenResponse:
    user = authenticate_user(db, data.username_or_email, data.password)
    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid username/email or password",
        )

    if not user.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Account is inactive")

    access_token = create_access_token(
        user.email,
        timedelta(days=7) if data.remember_me else None,
    )

    return TokenResponse(
        access_token=access_token,
        refresh_token=create_refresh_token(user.email),
        user=UserResponse.model_validate(user),
    )


@router.get("/me", response_model=UserResponse)
def get_me(current_user: User = Depends(get_current_user)) -> User:
    return current_user


@router.patch("/me", response_model=UserResponse)
def update_me(
    data: UserUpdate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
) -> User:
    return update_user(db, current_user, data)


@router.post("/forgot-password", response_model=MessageResponse)
def forgot_password(data: ForgotPasswordRequest, db: Session = Depends(get_db)) -> MessageResponse:
    user = get_user_by_email(db, data.email.lower())
    if user is None:
        return MessageResponse(message="If that email exists, a reset link has been sent.")

    token = generate_reset_token()
    create_password_reset_token(db, user, token, reset_token_expiry())

    response = MessageResponse(message="If that email exists, a reset link has been sent.")
    if settings.debug:
        response.reset_token = token
    return response


@router.post("/reset-password", response_model=MessageResponse)
def reset_password(data: ResetPasswordRequest, db: Session = Depends(get_db)) -> MessageResponse:
    reset = get_valid_reset_token(db, data.token)
    if reset is None:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid or expired reset token")

    user = db.query(User).filter(User.id == reset.user_id).first()
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")

    user.hashed_password = hash_password(data.new_password)
    reset.used = True
    db.commit()

    return MessageResponse(message="Password reset successfully. You can now log in.")