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

from app.core.dependencies import get_current_user
from app.core.security import create_access_token, hash_password, verify_password
from app.database import get_db
from app.models.user import User
from app.schemas.schemas import TokenResponse, UserCreate, UserResponse

router = APIRouter()


@router.post("/register", response_model=TokenResponse, status_code=201)
async def register(body: UserCreate, db: AsyncSession = Depends(get_db)):
    if len(body.password) < 8:
        raise HTTPException(status_code=400, detail="Password must be at least 8 characters")
    if "@" not in body.email:
        raise HTTPException(status_code=400, detail="Invalid email address")

    # Check for duplicate email
    existing = await db.execute(select(User).where(User.email == body.email.lower()))
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=409, detail="Email already registered")

    # First registered user becomes admin
    count_result = await db.execute(select(func.count()).select_from(User))
    is_first_user = count_result.scalar() == 0

    user = User(
        email=body.email.lower(),
        hashed_password=hash_password(body.password),
        is_admin=is_first_user,
    )
    db.add(user)
    await db.commit()
    await db.refresh(user)

    return TokenResponse(access_token=create_access_token(user.id), user=user)


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

    if not user or not verify_password(body.password, user.hashed_password):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect email or password",
        )

    return TokenResponse(access_token=create_access_token(user.id), user=user)


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