from __future__ import annotations

from dataclasses import dataclass

import httpx
from fastapi import HTTPException, status

from app.core.config import Settings


@dataclass
class AuthentikSyncResult:
    user_id: int
    action: str
    authentik_sub: str | None = None


class AuthentikAdminService:
    def __init__(self, settings: Settings) -> None:
        self.base_url = settings.authentik_base_url.rstrip("/")
        self.admin_token = settings.authentik_admin_token
        self.verify_tls = settings.authentik_verify_tls

        if not self.base_url or not self.admin_token:
            raise HTTPException(
                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                detail="authentik_admin_not_configured",
            )

    def _client(self) -> httpx.Client:
        return httpx.Client(
            base_url=self.base_url,
            headers={
                "Authorization": f"Bearer {self.admin_token}",
                "Accept": "application/json",
                "Content-Type": "application/json",
            },
            timeout=10,
            verify=self.verify_tls,
        )

    @staticmethod
    def _safe_username(sub: str, email: str) -> str:
        if email and "@" in email:
            return email.split("@", 1)[0]
        return sub.replace("|", "_")[:150]

    def ensure_user(self, sub: str, email: str, display_name: str | None, is_active: bool = True) -> AuthentikSyncResult:
        payload = {
            "username": self._safe_username(sub=sub, email=email),
            "name": display_name or email,
            "email": email,
            "is_active": is_active,
        }

        with self._client() as client:
            resp = client.get("/api/v3/core/users/", params={"email": email})
            if resp.status_code >= 400:
                raise HTTPException(status_code=502, detail="authentik_lookup_failed")

            data = resp.json()
            results = data.get("results") if isinstance(data, dict) else None
            existing = results[0] if isinstance(results, list) and results else None

            if existing and existing.get("pk") is not None:
                user_pk = int(existing["pk"])
                patch_resp = client.patch(f"/api/v3/core/users/{user_pk}/", json=payload)
                if patch_resp.status_code >= 400:
                    raise HTTPException(status_code=502, detail="authentik_update_failed")
                return AuthentikSyncResult(user_id=user_pk, action="updated", authentik_sub=existing.get("uid"))

            create_resp = client.post("/api/v3/core/users/", json=payload)
            if create_resp.status_code >= 400:
                raise HTTPException(status_code=502, detail="authentik_create_failed")
            created = create_resp.json()
            return AuthentikSyncResult(
                user_id=int(created["pk"]),
                action="created",
                authentik_sub=created.get("uid"),
            )