from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select

from app.database import get_db
from app.models.user import User
from app.schemas.auth import LoginRequest, TokenResponse
from app.schemas.user import UserCreate, UserOut
from app.services.auth import verify_password, hash_password, create_access_token
from app.deps import get_current_user

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


class ChangePasswordRequest(BaseModel):
    current_password: str
    new_password: str


@router.post("/login", response_model=TokenResponse)
async def login(body: LoginRequest, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(User).where(User.username == body.username))
    user = result.scalar_one_or_none()

    if not user or not verify_password(body.password, user.hashed_password):
        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Invalid username or password")
    if not user.is_active:
        raise HTTPException(status.HTTP_403_FORBIDDEN, "Account is inactive")

    token = create_access_token({"sub": str(user.id), "role": user.role})
    return TokenResponse(access_token=token)


@router.put("/change-password", status_code=200)
async def change_password(
    body: ChangePasswordRequest,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    if not verify_password(body.current_password, current_user.hashed_password):
        raise HTTPException(400, "Current password is incorrect.")
    if len(body.new_password) < 6:
        raise HTTPException(400, "New password must be at least 6 characters.")

    current_user.hashed_password = hash_password(body.new_password)
    try:
        await db.commit()
    except Exception:
        await db.rollback()
        raise
    return {"message": "Password changed successfully."}


@router.post("/register", response_model=UserOut, status_code=201)
async def register(body: UserCreate, db: AsyncSession = Depends(get_db)):
    result = await db.execute(
        select(User).where((User.username == body.username) | (User.email == body.email))
    )
    if result.scalar_one_or_none():
        raise HTTPException(400, "Username or email already exists")

    user = User(
        username=body.username,
        email=body.email,
        hashed_password=hash_password(body.password),
        role=body.role,
    )
    db.add(user)
    try:
        await db.commit()
        await db.refresh(user)
    except Exception:
        await db.rollback()
        raise
    return user