"""Zustandsabgleich: was läuft wirklich? (Vertrag: GET /health → core.version, bundle.source/version/stale)"""
from __future__ import annotations

import time
from concurrent.futures import ThreadPoolExecutor

from sqlalchemy import select

from app.db import session
from app.models import Tenant
from app.services import contract, deploy

_CACHE: dict = {"ts": 0.0, "data": None}
TTL = 30.0


def _http_get(url: str):
    import httpx
    r = httpx.get(url, timeout=6, follow_redirects=True)
    return r.status_code, (r.json() if r.headers.get("content-type", "").startswith("application/json") else {})


def probe(host: str, expect_tag: str, expect_bundle: int | None, get=_http_get) -> dict:
    out = {"host": host, "reachable": False, "core": None, "bundle": None, "drift": [], "error": None}
    try:
        status, body = get(f"https://{host}/health")
    except Exception as exc:  # noqa: BLE001
        out["error"] = f"{type(exc).__name__}: {str(exc)[:120]}"
        out["drift"].append("nicht erreichbar")
        return out
    out["reachable"] = status == 200
    if status != 200:
        out["drift"].append(f"HTTP {status}")
    core, bundle = body.get("core"), body.get("bundle")
    out["core"], out["bundle"] = core, bundle
    if core is None:
        out["drift"].append("Core ohne Vertrag (alte Version)")
    elif expect_tag and deploy._hex_tag(expect_tag) and not contract.same_sha(core.get("version", ""), expect_tag):
        out["drift"].append(f"Core {core.get('version', '')[:10]} statt {expect_tag[:10]}")
    if expect_bundle is not None:
        if not bundle:
            out["drift"].append("meldet keine Bundle-Quelle")
        elif bundle.get("source") != "admin" or bundle.get("version") != expect_bundle or bundle.get("stale"):
            out["drift"].append(f"Bundle {bundle.get('source')} v{bundle.get('version')}{' (veraltet)' if bundle.get('stale') else ''} statt admin v{expect_bundle}")
    elif bundle and bundle.get("source") not in ("git", None):
        out["drift"].append(f"Bundle-Quelle {bundle.get('source')}, erwartet git")
    return out


def probe_all(get=_http_get, refresh: bool = False, workers: int = 6) -> dict:
    if not refresh and _CACHE["data"] is not None and time.time() - _CACHE["ts"] < TTL:
        return _CACHE["data"]
    with session() as db:
        items = []
        for t in db.scalars(select(Tenant).where(Tenant.status == "active").order_by(Tenant.id)):
            items.append((t.id, deploy.host_for(db, t), deploy.effective_tag(db, t), t.current_version if t.source == "admin" else None))
    with ThreadPoolExecutor(max_workers=workers) as ex:
        res = list(ex.map(lambda it: (it[0], probe(it[1], it[2], it[3], get)), items))
    data = {tid: r for tid, r in res}
    _CACHE.update(ts=time.time(), data=data)
    return data