"""Auth-Endpoints: Login, Logout, Me, Erst-Setup (Initial-Admin)."""
from __future__ import annotations

import logging

from fastapi import APIRouter, Depends, HTTPException, Request, status
from pydantic import BaseModel, Field
from sqlmodel import Session

from app.core import migrate
from app.core.auth import (
    current_user,
    get_user_by_username,
    has_any_user,
    hash_password,
    verify_password,
)
from app.core.db import get_session
from app.models.user import User

router = APIRouter(prefix="/api/auth", tags=["auth"])
log = logging.getLogger("voice-agent.auth")


class LoginIn(BaseModel):
    username: str = Field(min_length=1, max_length=64)
    password: str = Field(min_length=1, max_length=200)


class SetupIn(BaseModel):
    username: str = Field(min_length=3, max_length=64, pattern=r"^[A-Za-z0-9._@-]+$")
    password: str = Field(min_length=8, max_length=200)


def _user_dict(u: User) -> dict:
    return {
        "id": u.id,
        "username": u.username,
        "is_admin": u.is_admin,
        "default_profile": u.default_profile or "meeting",
        # Leerer String = User hat keine Modell-Wahl getroffen → Mac-Worker
        # nimmt seinen .env-Default. UI zeigt das als „Standard (Worker)".
        "default_model": u.default_model or "",
    }


class UpdateMeIn(BaseModel):
    default_profile: str | None = Field(default=None, max_length=64)
    # Leerer String bedeutet bewusst „kein Override" — wird gespeichert.
    default_model: str | None = Field(default=None, max_length=128)


@router.get("/me")
def me(user: User = Depends(current_user)):
    return _user_dict(user)


@router.patch("/me")
def update_me(payload: UpdateMeIn, user: User = Depends(current_user), session: Session = Depends(get_session)):
    changed = False
    if payload.default_profile is not None:
        user.default_profile = payload.default_profile.strip() or "meeting"
        changed = True
    if payload.default_model is not None:
        user.default_model = payload.default_model.strip()
        changed = True
    if changed:
        session.add(user)
        session.commit()
        session.refresh(user)
    return _user_dict(user)


class ChangePasswordIn(BaseModel):
    current_password: str = Field(min_length=1, max_length=200)
    new_password: str = Field(min_length=8, max_length=200)


@router.post("/me/password")
def change_password(
    payload: ChangePasswordIn,
    user: User = Depends(current_user),
    session: Session = Depends(get_session),
):
    """User ändert eigenes Passwort.

    Aktuelles Passwort muss korrekt sein — verhindert Übernahme, wenn jemand
    eine offene Browser-Session findet. Admin-Reset läuft weiter über
    /api/admin/users/<id>/password (ohne current_password).
    """
    if not verify_password(payload.current_password, user.password_hash):
        log.warning("Password-Change abgelehnt für user=%s (aktuelles Passwort falsch)", user.username)
        raise HTTPException(status.HTTP_400_BAD_REQUEST, "Aktuelles Passwort falsch")
    user.password_hash = hash_password(payload.new_password)
    session.add(user)
    session.commit()
    log.info("Password geändert für user=%s (id=%d)", user.username, user.id)
    return {"ok": True}


@router.get("/needs-setup")
def needs_setup(session: Session = Depends(get_session)):
    """Vor Login prüfen ob noch kein User existiert (erstes Deployment)."""
    return {"needs_setup": not has_any_user(session)}


@router.post("/login")
def login(payload: LoginIn, request: Request, session: Session = Depends(get_session)):
    username = payload.username.strip()
    user = get_user_by_username(session, username)
    if not user:
        log.warning("Login fehlgeschlagen: User '%s' nicht gefunden", username)
        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Benutzername oder Passwort falsch")
    if not verify_password(payload.password, user.password_hash):
        log.warning(
            "Login fehlgeschlagen: Passwort falsch für user=%s (hash_len=%d, prefix=%s)",
            user.username, len(user.password_hash), user.password_hash[:7],
        )
        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Benutzername oder Passwort falsch")
    request.session["user_id"] = user.id
    log.info("Login OK: user=%s id=%d admin=%s", user.username, user.id, user.is_admin)
    return _user_dict(user)


@router.post("/logout")
def logout(request: Request):
    request.session.clear()
    return {"ok": True}


@router.post("/setup")
def setup(payload: SetupIn, request: Request, session: Session = Depends(get_session)):
    """Erstellt den ersten Admin und ordnet alle Bestand-Jobs ihm zu.
    Nur möglich, solange kein User existiert."""
    if has_any_user(session):
        raise HTTPException(status.HTTP_409_CONFLICT, "Setup bereits abgeschlossen")
    user = User(
        username=payload.username.strip(),
        password_hash=hash_password(payload.password),
        is_admin=True,
    )
    session.add(user)
    session.commit()
    session.refresh(user)
    log.info("Initial-Admin angelegt: %s (id=%d)", user.username, user.id)
    n = migrate.assign_orphan_jobs_to(user.id)
    request.session["user_id"] = user.id
    return {**_user_dict(user), "migrated_jobs": n}