import { healthUtil, types as T } from "../deps.ts";

const API_BASE = "http://kamado-pool.embassy:8080";

interface HealthPayload {
  ok: boolean;
  ckpool: boolean;
  bitcoin: boolean;
  submit_gap: number;
  zmq_stale: boolean;
  last_error?: string;
}

async function fetchHealth(): Promise<HealthPayload | null> {
  try {
    const res = await fetch(`${API_BASE}/api/health`, {
      signal: AbortSignal.timeout(5_000),
    });
    return await res.json() as HealthPayload;
  } catch {
    return null;
  }
}

// Returns a "starting" result for the first 20 s after launch, then
// "failing" so a crashed service doesn't look like it's perpetually booting.
function apiUnreachable(duration: number, label: string): T.HealthProceduralResult {
  if (duration < 20_000) {
    return { status: "starting", message: `${label} is starting…` };
  }
  return { status: "failing", message: "Kamado API is unreachable — service may be down." };
}

export const health: T.ExpectedExports.health = {
  // Overall reachability: uses the SDK helper so StartOS marks the
  // service degraded (503) whenever ckpool or bitcoind is down.
  "web": async (effects, duration) => {
    return healthUtil.checkWebUrl(`${API_BASE}/api/health`)(effects, duration);
  },

  // Is the stratum server up and accepting miner connections?
  "ckpool": async (_effects, duration) => {
    const h = await fetchHealth();
    if (!h) return apiUnreachable(duration, "Stratum server");
    if (h.ckpool) return { status: "passing", message: "Stratum server is running." };
    const detail = h.last_error ? ` (${h.last_error})` : "";
    return { status: "failing", message: `Stratum server is not responding${detail}.` };
  },

  // Can we reach Bitcoin Core via RPC? (Required for block templates and
  // block submission — if this is down, mining produces no valid work.)
  "bitcoin": async (_effects, duration) => {
    const h = await fetchHealth();
    if (!h) return apiUnreachable(duration, "Bitcoin Core connection");
    if (h.bitcoin) return { status: "passing", message: "Connected to Bitcoin Core." };
    const detail = h.last_error ? ` (${h.last_error})` : "";
    return { status: "failing", message: `Bitcoin Core RPC is unreachable${detail}.` };
  },

  // Did every block submission get confirmed by bitcoind? A non-zero gap
  // means at least one "Possible block solve" never got a "Solved and
  // confirmed" response — the reward may have been lost or delayed.
  "submit-gap": async (_effects, duration) => {
    const h = await fetchHealth();
    if (!h) return apiUnreachable(duration, "Block submission check");
    const gap = h.submit_gap ?? 0;
    if (gap === 0) return { status: "passing", message: "All block submissions confirmed." };
    return {
      status: "failing",
      message:
        `${gap} block${gap === 1 ? "" : "s"} submitted to bitcoind but not confirmed — ` +
        `check Bitcoin Core logs for rejected or missing submissions.`,
    };
  },
};