from fastapi import APIRouter, Depends, HTTPException, status, Request
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.templating import Jinja2Templates
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from pydantic import BaseModel

from ..database import get_db
from ..models import User
from ..auth import verify_password, create_token, hash_password, require_admin

router = APIRouter()
templates = Jinja2Templates(directory="app/templates")


class LoginForm(BaseModel):
    username: str
    password: str


class CreateUserForm(BaseModel):
    username: str
    password: str
    role: str = "user"


@router.get("/login", response_class=HTMLResponse)
async def login_page(request: Request):
    return templates.TemplateResponse("login.html", {"request": request})


@router.post("/api/login")
async def login(data: LoginForm, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(User).where(User.username == data.username))
    user = result.scalar_one_or_none()
    if not user or not verify_password(data.password, user.password_hash):
        raise HTTPException(status_code=401, detail="Forkert brugernavn eller adgangskode")

    token = create_token(user.username, user.role)
    resp = RedirectResponse(url="/", status_code=302)
    resp.set_cookie(
        key="token", value=token, httponly=True, max_age=30 * 24 * 3600,
        samesite="lax"
    )
    return resp


@router.post("/api/logout")
async def logout():
    resp = RedirectResponse(url="/login", status_code=302)
    resp.delete_cookie("token")
    return resp


# --- Admin-only: user management ---

@router.post("/api/admin/users")
async def create_user(
    data: CreateUserForm,
    db: AsyncSession = Depends(get_db),
    _: User = Depends(require_admin),
):
    exists = await db.execute(select(User).where(User.username == data.username))
    if exists.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="Bruger findes allerede")

    user = User(
        username=data.username,
        password_hash=hash_password(data.password),
        role=data.role,
    )
    db.add(user)
    await db.commit()
    return {"ok": True, "username": user.username, "role": user.role}


@router.get("/api/admin/users")
async def list_users(
    db: AsyncSession = Depends(get_db),
    _: User = Depends(require_admin),
):
    result = await db.execute(select(User).order_by(User.username))
    users = result.scalars().all()
    return [
        {"id": u.id, "username": u.username, "role": u.role, "created_at": str(u.created_at)}
        for u in users
    ]