"""User management router."""

from typing import Annotated

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

from app.database import get_db
from app.models.user import User

router = APIRouter()


# ── Pydantic schemas ──────────────────────────────────────────────────────

class UserCreate(BaseModel):
    username: str
    email: EmailStr
    password: str


class UserResponse(BaseModel):
    id: int
    username: str
    email: str
    is_active: bool

    model_config = {"from_attributes": True}


class UserUpdate(BaseModel):
    email: EmailStr | None = None
    is_active: bool | None = None


# ── Endpoints ─────────────────────────────────────────────────────────────

@router.post(
    "/",
    response_model=UserResponse,
    status_code=status.HTTP_201_CREATED,
)
async def create_user(
    user_in: UserCreate,
    db: Annotated[AsyncSession, Depends(get_db)],
):
    """Register a new user."""
    # Check uniqueness of username
    existing = await db.execute(select(User).where(User.username == user_in.username))
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="Username already taken")

    # Check uniqueness of email
    existing = await db.execute(select(User).where(User.email == user_in.email))
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="Email already registered")

    from app.routers.auth import hash_password

    hashed = hash_password(user_in.password)

    user = User(
        username=user_in.username,
        email=user_in.email,
        hashed_password=hashed,
    )
    db.add(user)
    await db.commit()
    await db.refresh(user)
    return user


@router.get("/me", response_model=UserResponse)
async def get_current_user(
    db: Annotated[AsyncSession, Depends(get_db)],
    # current_user would come from JWT dependency in real usage
):
    """Get the currently authenticated user (placeholder)."""
    raise HTTPException(status_code=501, detail="Not implemented")


@router.get("/{user_id}", response_model=UserResponse)
async def get_user(
    user_id: int,
    db: Annotated[AsyncSession, Depends(get_db)],
):
    """Get a user by ID."""
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    return user


@router.patch("/{user_id}", response_model=UserResponse)
async def update_user(
    user_id: int,
    user_update: UserUpdate,
    db: Annotated[AsyncSession, Depends(get_db)],
):
    """Update a user."""
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")

    if user_update.email is not None:
        user.email = user_update.email
    if user_update.is_active is not None:
        user.is_active = user_update.is_active

    await db.commit()
    await db.refresh(user)
    return user


@router.delete("/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_user(
    user_id: int,
    db: Annotated[AsyncSession, Depends(get_db)],
):
    """Delete a user."""
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    await db.delete(user)
    await db.commit()