from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordRequestForm
from sqlalchemy.orm import Session
from datetime import timedelta

from app.db.database import get_db
from app.models.user import User
from app.api.schemas.user import (
    User as UserSchema,
    UserCreate,
    UserUpdate,
    Token,
)
from app.auth.auth import (
    get_password_hash,
    authenticate_user,
    create_access_token,
    get_current_active_user,
    get_current_admin_user,
    ACCESS_TOKEN_EXPIRE_MINUTES,
)

router = APIRouter()


@router.post(
    "/register", response_model=UserSchema, status_code=status.HTTP_201_CREATED
)
async def register_user(user: UserCreate, db: Session = Depends(get_db)):
    """
    Register a new user
    """
    # Check if user with the same email already exists
    db_user_email = db.query(User).filter(User.email == user.email).first()
    if db_user_email:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Email already registered",
        )

    # Check if user with the same username already exists
    db_user_username = db.query(User).filter(User.username == user.username).first()
    if db_user_username:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Username already taken",
        )

    # Create new user
    hashed_password = get_password_hash(user.password)
    db_user = User(
        email=user.email,
        username=user.username,
        hashed_password=hashed_password,
        full_name=user.full_name,
        is_active=user.is_active,
    )
    db.add(db_user)
    db.commit()
    db.refresh(db_user)
    return db_user


@router.post("/login", response_model=Token)
async def login_for_access_token(
    form_data: OAuth2PasswordRequestForm = Depends(),
    db: Session = Depends(get_db),
):
    """
    OAuth2 compatible token login, get an access token for future requests
    """
    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_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    access_token = create_access_token(
        data={"sub": user.username}, expires_delta=access_token_expires
    )
    return {"access_token": access_token, "token_type": "bearer"}


@router.get("/me", response_model=UserSchema)
async def read_users_me(current_user: User = Depends(get_current_active_user)):
    """
    Get current user information
    """
    return current_user


@router.put("/me", response_model=UserSchema)
async def update_user_me(
    user: UserUpdate,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db),
):
    """
    Update current user information
    """
    db_user = db.query(User).filter(User.id == current_user.id).first()

    update_data = user.model_dump(exclude_unset=True)

    # If email is being updated, check for uniqueness
    if "email" in update_data and update_data["email"] != db_user.email:
        db_user_email = (
            db.query(User).filter(User.email == update_data["email"]).first()
        )
        if db_user_email:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Email already registered",
            )

    # Hash the password if it's being updated
    if "password" in update_data:
        update_data["hashed_password"] = get_password_hash(update_data.pop("password"))

    for key, value in update_data.items():
        setattr(db_user, key, value)

    db.commit()
    db.refresh(db_user)
    return db_user


@router.get("/{user_id}", response_model=UserSchema)
async def read_user(
    user_id: int,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_admin_user),
):
    """
    Get user by ID (admin only)
    """
    db_user = db.query(User).filter(User.id == user_id).first()
    if db_user is None:
        raise HTTPException(status_code=404, detail="User not found")
    return db_user


@router.put("/{user_id}", response_model=UserSchema)
async def update_user(
    user_id: int,
    user: UserUpdate,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_admin_user),
):
    """
    Update user information (admin only)
    """
    db_user = db.query(User).filter(User.id == user_id).first()
    if db_user is None:
        raise HTTPException(status_code=404, detail="User not found")

    update_data = user.model_dump(exclude_unset=True)

    # If email is being updated, check for uniqueness
    if "email" in update_data and update_data["email"] != db_user.email:
        db_user_email = (
            db.query(User).filter(User.email == update_data["email"]).first()
        )
        if db_user_email:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Email already registered",
            )

    # Hash the password if it's being updated
    if "password" in update_data:
        update_data["hashed_password"] = get_password_hash(update_data.pop("password"))

    for key, value in update_data.items():
        setattr(db_user, key, value)

    db.commit()
    db.refresh(db_user)
    return db_user


@router.delete(
    "/{user_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None
)
async def delete_user(
    user_id: int,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_admin_user),
):
    """
    Delete a user (admin only)
    """
    db_user = db.query(User).filter(User.id == user_id).first()
    if db_user is None:
        raise HTTPException(status_code=404, detail="User not found")

    db.delete(db_user)
    db.commit()
    return None