export const name = "Amazon AWS";
export const url = "https://health.aws.amazon.com/health/status";

// Core services in both Pittsburgh-adjacent regions + global services.
// Expand this list if you discover specific services your vendors rely on.
const FEEDS = [
  { url: "https://status.aws.amazon.com/rss/ec2-us-east-1.rss", label: "EC2 (N. Virginia)" },
  { url: "https://status.aws.amazon.com/rss/ec2-us-east-2.rss", label: "EC2 (Ohio)" },
  { url: "https://status.aws.amazon.com/rss/s3-us-east-1.rss",  label: "S3 (N. Virginia)" },
  { url: "https://status.aws.amazon.com/rss/cloudfront.rss",    label: "CloudFront" },
  { url: "https://status.aws.amazon.com/rss/route53.rss",       label: "Route 53" },
];

const SEVERITY_ORDER = ["operational", "degraded", "outage"];

function worstStatus(a, b) {
  return SEVERITY_ORDER.indexOf(a) >= SEVERITY_ORDER.indexOf(b) ? a : b;
}

// Extract the text of the first <title> inside the first <item>.
// Returns null if there are no items (clean feed = all clear).
function parseFirstItemTitle(xml) {
  const itemMatch = xml.match(/<item[\s>][\s\S]*?<\/item>/i);
  if (!itemMatch) return null;
  const titleMatch = itemMatch[0].match(/<title>([\s\S]*?)<\/title>/i);
  return titleMatch ? titleMatch[1].trim() : null;
}

function titleToStatus(title) {
  if (!title) return "operational"; // no items = clean feed
  const t = title.toLowerCase();
  if (t.includes("operating normally") || t.includes("informational")) return "operational";
  if (t.includes("performance issues") || t.includes("degraded")) return "degraded";
  if (t.includes("service disruption") || t.includes("disruption")) return "outage";
  return "degraded"; // unknown incident title — assume degraded
}

async function checkFeed({ url, label }) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`${label}: HTTP ${res.status}`);
  const xml = await res.text();
  const title = parseFirstItemTitle(xml);
  const status = titleToStatus(title);
  return { label, status, title };
}

export async function checkStatus() {
  const results = await Promise.allSettled(FEEDS.map(checkFeed));

  let overall = "operational";
  const issues = [];

  for (const result of results) {
    if (result.status === "rejected") {
      overall = worstStatus(overall, "degraded");
      issues.push(`Check failed: ${result.reason?.message ?? "unknown error"}`);
      continue;
    }

    const { label, status, title } = result.value;
    overall = worstStatus(overall, status);

    if (status !== "operational") {
      issues.push(`${label}: ${title ?? "unknown issue"}`);
    }
  }

  const message =
    issues.length > 0 ? issues.join(" | ") : "All monitored services operating normally.";

  return {
    name,
    status: overall,
    message,
    lastUpdated: new Date().toISOString(),
  };
}