#!/usr/bin/env node

const apiToken = process.env.CLOUDFLARE_API_TOKEN;
const zoneTag = process.env.CLOUDFLARE_ZONE_TAG;
const hostname = process.env.CLOUDFLARE_HOSTNAME || "linearvoid.tv";
const windowMinutes = Number.parseInt(process.env.CLOUDFLARE_CACHE_HIT_RATIO_WINDOW_MINUTES || "60", 10);
const endpoint = process.env.CLOUDFLARE_GRAPHQL_ENDPOINT || "https://api.cloudflare.com/client/v4/graphql";

if (!apiToken || !zoneTag) {
  console.error("Missing required environment variables: CLOUDFLARE_API_TOKEN, CLOUDFLARE_ZONE_TAG");
  process.exit(1);
}

const end = new Date();
const start = new Date(end.getTime() - windowMinutes * 60 * 1000);

const iso = (value) => value.toISOString();

const query = `
  query CacheHitRatio($zoneTag: string, $start: Time, $end: Time, $hostname: String) {
    viewer {
      zones(filter: { zoneTag: $zoneTag }) {
        requests: httpRequestsAdaptiveGroups(
          limit: 1000
          filter: {
            datetime_geq: $start
            datetime_lt: $end
            clientRequestHTTPHost: $hostname
            requestSource: "eyeball"
          }
        ) {
          count
          dimensions {
            cacheStatus
          }
        }
      }
    }
  }
`;

async function main() {
  const response = await fetch(endpoint, {
    method: "POST",
    headers: {
      Authorization: `Bearer ${apiToken}`,
      "Content-Type": "application/json",
      Accept: "application/json",
    },
    body: JSON.stringify({
      query,
      variables: {
        zoneTag,
        hostname,
        start: iso(start),
        end: iso(end),
      },
    }),
  });

  const payload = await response.json();
  if (!response.ok || payload.errors) {
    const message = payload.errors ? JSON.stringify(payload.errors) : `HTTP ${response.status}`;
    throw new Error(message);
  }

  const groups = payload?.data?.viewer?.zones?.[0]?.requests || [];
  let totalRequests = 0;
  let hitRequests = 0;

  for (const group of groups) {
    const count = Number(group?.count || 0);
    const status = String(group?.dimensions?.cacheStatus || "").toUpperCase();
    totalRequests += count;
    if (status === "HIT") {
      hitRequests += count;
    }
  }

  const ratio = totalRequests > 0 ? hitRequests / totalRequests : 0;

  console.log(
    `# HELP linearvoid_cache_hit_ratio Cloudflare cache hit ratio for the selected hostname and time window.`,
  );
  console.log(`# TYPE linearvoid_cache_hit_ratio gauge`);
  console.log(
    `linearvoid_cache_hit_ratio{zone="${zoneTag}",hostname="${hostname}",window_minutes="${windowMinutes}"} ${ratio.toFixed(6)}`,
  );
  console.log(`# HELP linearvoid_cache_hit_requests_total Cloudflare cache HIT requests counted in the time window.`);
  console.log(`# TYPE linearvoid_cache_hit_requests_total counter`);
  console.log(
    `linearvoid_cache_hit_requests_total{zone="${zoneTag}",hostname="${hostname}",window_minutes="${windowMinutes}"} ${hitRequests}`,
  );
  console.log(
    `# HELP linearvoid_cache_total_requests_total Cloudflare total eyeball requests counted in the time window.`,
  );
  console.log(`# TYPE linearvoid_cache_total_requests_total counter`);
  console.log(
    `linearvoid_cache_total_requests_total{zone="${zoneTag}",hostname="${hostname}",window_minutes="${windowMinutes}"} ${totalRequests}`,
  );
}

main().catch((error) => {
  console.error(error instanceof Error ? error.message : String(error));
  process.exit(1);
});