"""Authentication routes: register, login, me, admin setup."""
from __future__ import annotations

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from fastapi import APIRouter, Depends, HTTPException, status

from app.core.security import create_access_token, hash_password, verify_password
from app.core.settings_service import get_setting
from app.db import get_db_dep
from app.deps import get_current_user
from app.models import User
from app.schemas import AdminSetupRequest, TokenOut, UserLogin, UserOut, UserRegister

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


@router.post("/register", response_model=TokenOut, status_code=status.HTTP_201_CREATED)
async def register(payload: UserRegister, db: AsyncSession = Depends(get_db_dep)):
    existing = await db.execute(select(User).where((User.email == payload.email) | (User.username == payload.username)))
    if existing.scalars().first():
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="user_already_exists")
    user = User(
        email=payload.email,
        username=payload.username,
        hashed_password=hash_password(payload.password),
        is_admin=False,
    )
    db.add(user)
    await db.commit()
    await db.refresh(user)
    token = create_access_token(subject=str(user.id), extra={"is_admin": user.is_admin})
    return TokenOut(access_token=token, user=UserOut.model_validate(user))


@router.post("/login", response_model=TokenOut)
async def login(payload: UserLogin, db: AsyncSession = Depends(get_db_dep)):
    # Accept either email or username in the `login` field.
    login_value = (payload.login or "").strip()
    if not login_value:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="login_required")
    result = await db.execute(
        select(User).where((User.email == login_value) | (User.username == login_value))
    )
    user = result.scalars().first()
    if not user or not verify_password(payload.password, user.hashed_password):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="invalid_credentials")
    if not user.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="user_disabled")
    token = create_access_token(subject=str(user.id), extra={"is_admin": user.is_admin})
    return TokenOut(access_token=token, user=UserOut.model_validate(user))


@router.get("/me", response_model=UserOut)
async def me(user: User = Depends(get_current_user)):
    return user


@router.post("/admin-setup", response_model=TokenOut)
async def admin_setup(payload: AdminSetupRequest, db: AsyncSession = Depends(get_db_dep)):
    """One-time endpoint to create the first admin user using a setup token."""
    # Check if any admin already exists
    existing_admins = await db.execute(select(User).where(User.is_admin.is_(True)))
    if existing_admins.scalars().first() is not None:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="admin_already_exists")

    # Validate setup token (from DB or env)
    db_token = await get_setting(db, "admin.setup_token", default=None)
    env_token = payload.token  # what the user supplied
    if not db_token or db_token != env_token:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="invalid_setup_token")

    # Check user collision
    existing = await db.execute(select(User).where((User.email == payload.email) | (User.username == payload.username)))
    if existing.scalars().first():
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="user_already_exists")

    user = User(
        email=payload.email,
        username=payload.username,
        hashed_password=hash_password(payload.password),
        is_admin=True,
    )
    db.add(user)
    await db.commit()
    await db.refresh(user)
    token = create_access_token(subject=str(user.id), extra={"is_admin": user.is_admin})
    return TokenOut(access_token=token, user=UserOut.model_validate(user))