import type { FastifyBaseLogger } from "fastify";

export interface CapabilityDescriptor {
  id: string;
  status?: string;
  version?: string;
  owner?: string;
  surfaces?: string[];
}

export type Cl0udStatus = "disabled" | "connected" | "unavailable" | "denied";

export interface Cl0udProbe {
  status: Cl0udStatus;
  capabilities: Record<string, string | undefined>;
  checkedAt: string | null;
  detail?: string;
}

export interface Cl0udClientDeps {
  baseUrl?: string;
  apiToken?: string;
  capabilityIds?: string[];
  logger?: FastifyBaseLogger;
  fetchImpl?: typeof fetch;
  probeIntervalMs?: number;
}

const EXPECTED_IDS = ["c0py.capture.run.v1", "c0py.registry.manage.v1"];

// CL0UD wiring, contract-first: probes the documented capability discovery API
// (GET /capabilities/:id) and surfaces the result in /health as evidence.
// Full policy-decision calls remain gated on CL0UD B-4 / ADR-0031 (estate-level)
// and are deliberately NOT simulated here. With CL0UD_REQUIRED=true the API
// fails closed (503) while the probe cannot confirm ACTIVE capabilities.
export function createCl0udClient(deps: Cl0udClientDeps) {
  const fetchImpl = deps.fetchImpl ?? fetch;
  const ids = deps.capabilityIds ?? EXPECTED_IDS;
  let last: Cl0udProbe = {
    status: deps.baseUrl ? "unavailable" : "disabled",
    capabilities: {},
    checkedAt: null,
    detail: deps.baseUrl ? undefined : "CL0UD_BASE_URL not configured",
  };

  async function probe(): Promise<Cl0udProbe> {
    if (!deps.baseUrl) {
      last = { status: "disabled", capabilities: {}, checkedAt: new Date().toISOString(), detail: "CL0UD_BASE_URL not configured" };
      return last;
    }
    const capabilities: Record<string, string | undefined> = {};
    let unreachable = 0;
    let notActive = 0;
    for (const id of ids) {
      try {
        const res = await fetchImpl(`${deps.baseUrl.replace(/\/$/, "")}/capabilities/${encodeURIComponent(id)}`, {
          headers: deps.apiToken ? { Authorization: `Bearer ${deps.apiToken}` } : {},
          signal: AbortSignal.timeout(5000),
        });
        if (res.ok) {
          const body = (await res.json()) as CapabilityDescriptor & { capability?: CapabilityDescriptor };
          const cap = body.capability ?? body;
          capabilities[id] = cap.status ?? "unknown";
          if (capabilities[id] !== "ACTIVE") notActive += 1;
        } else {
          capabilities[id] = `http_${res.status}`;
          unreachable += 1;
        }
      } catch {
        capabilities[id] = "unreachable";
        unreachable += 1;
      }
    }
    const status: Cl0udStatus =
      unreachable === ids.length
        ? "unavailable"
        : unreachable === 0 && notActive === 0
          ? "connected"
          : "denied";
    last = { status, capabilities, checkedAt: new Date().toISOString() };
    deps.logger?.info({ cl0ud: last.status }, "CL0UD probe done");
    return last;
  }

  let timer: NodeJS.Timeout | null = null;
  function start() {
    void probe().catch(() => {});
    if (deps.probeIntervalMs && deps.probeIntervalMs > 0) {
      timer = setInterval(() => void probe().catch(() => {}), deps.probeIntervalMs);
      timer.unref?.();
    }
  }

  function stop() {
    if (timer) clearInterval(timer);
  }

  return {
    probe,
    start,
    stop,
    get status(): Cl0udProbe {
      return last;
    },
  };
}